modulation coding in a radio link and data transfer...

i

FACULTY OF ENGINEERING AND SUSTAINABLE DEVELOPMENT .

MODULATION CODING IN A RADIO LINK AND DATA

TRANSFER APPLICATION USING L2 VPN ETHERNET

OVER MPLS IN A LARGE NETWORK

MSc Thesis

Doğan VARLI

September 2015

Master’s Thesis in Electronics

Master’s Program in Electronics/Telecommunications

Examiner: Dr. JOSẺ CHILO

Supervisor: Dr.Recep BENZER

ii

HÖGSKOLAN I GÄVLE FACULTY OF ENGINEERING AND

SUSTAINABLE DEVELOPMENT

MODULATION CODING IN A RADIO LINK AND DATA

TRANSFER APPLICATION USING L2 VPN ETHERNET

OVER MPLS IN A LARGE NETWORK

Doğan VARLI

September 2015

Master’s Thesis in Electronics

This thesis work has been submitted to Högskolan I Gävle Electronics/Telecommunications department in order to fulfill the requirement

of completing 30 ECTS credit for the degree of MSc in Telecommunications

Gävle/SWEDEN

Doğan VARLI MODULATION CODING IN A RADIO LINK AND DATA TRANSFER APPLICATION USING L2 VPN ETHERNET OVER MPLS IN A LARGE NETWORK

iv

Preface

I would like to express the deepest appreciation to Milens Construction Communication Inc.

which is serving in area of Telecommunication and construction in Turkey, for their permission to use Path Loss

Programming for my designs and also I am grateful to two engineers, Ekrem AKGUN and Tolga COLAK, who

work in the same company for their expert guidance and assuming an active role during my thesis work. Grateful

thanks are expressed to Turkish Telecommunication Inc. for they gave an opportunity to use backbone router in

my work, and to Dr. Recep BENZER who is my adviser for sharing his experience throughout my thesis plan

and process, and to Prof. Edvard NORDLANDER, Prof. Gurvunder VIRK, Dr. Jose CHILO who are my

lecturers in Gavle University for their helping and assisting throughout my Master’s education, and to Prof.

Caner OZDEMIR, Assoc. Prof. Ali YILDIZ and Assoc. Prof. Huseyin CANBOLAT who are my honorable

lecturers from Mersin University for they gave an opportunity to study Master’s in Sweden, also Fatih SAKIZ

who is my colleague friend sharing his experience for my thesis work, and last I would like to thank to my

family and friends and my wife who have most important role during my thesis research.


v

Abstract

In this thesis work, the locations where we are unable to reach via fiber are considered for wireless transmission

links. In the practical part of this thesis different modulation techniques and antenna sizes were analyzed in

order to provide the most efficient way of data transmission. The data between this wireless links was transfered

using MPLS L2 VPN solution.

According to improving technology and increasing internet usage, the communication speed, which is between

users and providers, becomes more inevitable for transmitting data without any delays. More than one users

might use same connection line for transmitting their packets and it is able to be caused an online traffic and

some delays and data loss could occur. In this circumstance, high rate internet demands would lead extra costs

for Internet Service Providers (ISPs) and users.

In the introduction part, a brief description for the history of communications and basic equipments for Radio

Link and Fiber Optic cable are done.

In the theory part, detailed information was provided about modulation techniques and multiplexing techniques

followed by general information about computer networks and comprehensive information about OSI layers.

In the process and result parts, program outputs for Path Loss design which was used for R/L was mentioned in a

detailed way. After that, Ethernet Over MPLS L2 VPN was highlighted and a simulation from point-to-point

"Ethernet Over MPLS L2 VPN” was conducted in GNS3 software. Furthermore, the simulation for point-to-

multipoint case was then applied in a laboratory environment in order to achieve the desired result.

In the result part, different R/L simulation results are compared to determine the optimized modulation technique

and antenna sizes which could then be merged with simulation results from the previous part.

Keywords: Radio Link, Path loss, GNS3, VPN, QAM, MPLS (Multi-Protocol Label Switching),

Routing, Ethernet, L2 Switch, ISP (Internet Service Provider)


vi

Table of Contents

Preface ................................................................................................................................................... iv

Abstract .................................................................................................................................................. v

1.INTRODUCTION ............................................................................................................................ 14

1.1 BASIC EQUIPMENTS OF COMMUNICATION SYSTEMS ............................................ 14

1.2 FIBER OPTIC COMMUNICATION ..................................................................................... 15

1.3 PROPOSE OF THESIS ............................................................................................................ 16

1.4 METHOD USED ....................................................................................................................... 16

2. THEORY .......................................................................................................................................... 17

2.1 MODULATION......................................................................................................................... 17

2.1.1 ANALOG MODULATION ............................................................................................... 18

2.1.2 QUADRATURE AMPLITUDE MODULATION (QAM) ............................................. 18

2.2. MULTIPLEXING .................................................................................................................... 24

2.2.1. TIME DIVISION MULTIPLEXING .............................................................................. 24

2.2.2. FREQUENCY DIVISION MULTIPLEXING ............................................................... 25

2.2.3. WAVELENGTH DIVISION MULTIPLEXING ........................................................... 27

2.3. CLASSIFICATION OF COMPUTER NETWORKS .......................................................... 27

2.3.1. LOCAL AREA NETWORK ............................................................................................ 27

2.3.2. METROPOLITAN AREA NETWORK ......................................................................... 28

2.3.3. WIDE AREA NETWORK ............................................................................................... 28

2.4. ISO-OSI REFERANCE MODEL ........................................................................................... 29

2.4.1 PHYSICAL LAYER .......................................................................................................... 29

2.4.2 DATA LINK LAYER ........................................................................................................ 30

2.4.3 NETWORK LAYER .......................................................................................................... 30

2.4.4 TRANSPORT LAYER ...................................................................................................... 30

2.4.5 SESSION LAYER .............................................................................................................. 30

2.4.6 PRESENTATION LAYER ............................................................................................... 31

2.4.7 APPLICATION LAYER ................................................................................................... 31

2.5 ROUTING PROTOCOL .......................................................................................................... 31


vii

2.5.1. STATIC ROUTING PROTOCOL ................................................................................. 31

2.5.2. DYNAMIC ROUTING PROTOCOL ............................................................................. 32

2.5.2.1 OPEN SHORTEST PATH FIRST (OSPF) ............................................................... 33

2.5.2.2 EIGRP .......................................................................................................................... 34

2.6 VIRTUAL PRIVATE NETWORK (VPN) ............................................................................. 35

2.7 MULTI PROTOCOL LABEL SWITCHING (MPLS) ......................................................... 35

2.7.1 MPLS ARCHITECTURE AND BASIC COMPONENTS ............................................. 36

2.7.1.1 MPLS LABEL ............................................................................................................. 36

2.7.1.2 LABEL CHANGES ..................................................................................................... 37

2.7.1.3 LABEL SWITCHING ROUTER (LSR) ................................................................... 38

2.7.1.4 LABEL SWITCHED PATHS (LSPs) ........................................................................ 38

2.7.1.4.1 HOP BY HOP ROUTING ................................................................................... 38

2.7.1.4.2 EXPLICIT ROUTING ......................................................................................... 39

2.7.1.5 FORWARDING EQUIVALENCE CLASSES (FEC) ............................................. 39

2.7.2. LABEL DISTRBUTION PROTOCOL (LDP) ............................................................... 39

3 PROCESS AND RESULTS ........................................................................................................ 41

3.1. RADIO LINK DESIGN BY USING PATHLOSS PROGRAM ........................................... 41

3.1.1.1 DESIGN SIMULATION -1 ........................................................................................ 46



3.1.1.4 DESIGN SIMULATION -4 ....................................................................................... 55

3.1.1.5 DESIGN SIMULATION -5 ....................................................................................... 58

3.2 L2 VPN ETHERNET OVER MPLS ....................................................................................... 62

3.2.1. POINT TO POINT L2 VPN ETHERNET OVER MPLS IN GNS3 ............................. 62

3.2.1 MULTIPOINT L2 VPN ETHERNET OVER MPLS IN LABORATORY ................. 65

3.2.1.1 MULTIPOINT ETHERNET OVER MPLS L2 VPN WITHOUT L2 SWITCH .. 65

4 DISCUSSION ................................................................................................................................... 73

5 CONCLUSIONS ............................................................................................................................... 74

References ............................................................................................................................................ 76


viii

Appendix A ........................................................................................................................................ A-1

Appendix B ......................................................................................................................................... B-1

Appendix C ........................................................................................................................................ C-1

Appendix D ........................................................................................................................................ D-1


ix

List of Figures & Tables

Figures

Figure 1.1 The equipment used in a communication system 14

Figure 1.2 The basic equipment of a radio communication system 14

Figure 1.3 The basic equipment of optical communication system 15

Figure 2.1 The scheme of modulation techniques 17

Figure 2.2 Modulation Method for Digital Data 18

Figure 2.3 QAM Modulator Architecture 20

Figure 2.4 QPSK, 4-QAM (Gray coded) 21

Figure 2.5 16-QAM (Gray coded) 21

Figure 2.6 64-QAM (Gray coded) 22

Figure 2.7 256-QAM 23

Figure 2.8 TDM Multiplexing 24

Figure 2.9 TDM Block Diagram 25

Figure 2.10 TDM formation with Two PAM signal 25

Figure 2.11 FDM Multiplexing 26

Figure 2.12 FDM Block Diagram 26

Figure 2.13 160 λ has the capacity to example WDM transmission 27

Figure 2.14 OSI Reference Model 29

Figure 2.15 Dynamic Routing Protocol Examples 32

Figure 2.16 Dynamic Routing Protocol structure 33

Figure 2.17 Formation of MPLS 36

Figure 2.18 MPLS Label Format 37

Figure 2.19 Formation of LSR 38

Figure 3.1 Link Definitions in Path Loss 43

Figure 3.2 Generating Path Profile and terrain data for Site 1 43

Figure 3.3 Generating Path Profile and terrain data for Site 2 44

Figure 3.4 Clutter Backdrop and terrain data 44

Figure 3.5 Terrain data 45

Figure 3.6 Antenna Heights 45

Figure 3.7 Transmission Analysis 1 47

Figure 3.8 Transmission Analysis for Antenna 1.8m 47

Figure 3.9 Transmission Analysis 2, Pathloss Calculation with 1.2m Antenna 50

Figure 3.10 Transmission Analysis 2 for Antenna 1.2m 50

Figure 3.11 Transmission Analysis 3, Pathloss Calculation with 0.6m Antenna and 64 QAM modulation

53

Figure 3.12 Transmission Analysis 3 for Antenna 0.6m an 64 QAM modulation 53

Figure 3.13 Transmission Analysis 4 Pathloss Calculation with 0.6m Antenna and 16QAM modulation

55


x

Figure 3.14 Transmission Analysis 4 for Antenna 0.6m and 16 QAM modulation 56

Figure 3.15 Transmission Analysis 5, Pathloss Calculation with 0.6m Antenna and 4QAM modulation

58

Figure 3.16 Transmission Analysis 5 for Antenna 0.6m and 4 QAM modulation 59

Figure 3.17 Point To Point Ethernet Over MPLS L2 VPN 63

Figure 3.18 CDP Neighbourship between R2 and R4 63

Figure 3.19 EIGRP Neighbourship between R2 and R4 64

Figure 3.20 Ethernet Over MPLS L2 VPN application 65

Figure 3.21 Cisco ASR9010 Picture And Cards 66

Figure 3.22 L2 Switch 67

Figure 3.23 Generated Pseudowires Tunnel between Sites 67

Figure 3.24 Site 2-PC-2 to Site 1-PC-1 Reaction time 68




Figure 3.28 Ethernet Over MPLS L2 VPN application Link Failure Site 2 to Site 3 70

Figure 3.29 Site 2-PC-2 to Site 1-PC-1 Link Failure 70




Figure A-1 Radio and Antenna Model A1

A1

1

Figure A-2 Transmission Analysis for rain loss A1

Figure A-3 Transmission Analysis for path profile data A2

Figure A-4 Radio Specification for 256QAM A2




xi

Tables

Table 2.1 Bandwidth efficiency limit of the modulation types 23

Table 3.1 Design 1 Result 48





Table 3.6 R/L Total Result 61

Table 3.7 Distance Between Sites 66


xii

Abbreviations

AM : Amplitude Modulation

ATM : Asynchronous Transfer Mode

BGP : Border Gateway Protocol

CoS : Class of Service

CDP : Cisco Discovery Protocol

DHCP : Dynamic Host Configuration Protocol

DWDM : Dense Wavelength Division Multiplexing

EIGRP : Enhanced Interior Gateway Routing Protocol

FDDI : Fiber Distributed Data Interface

FDM : Frequency Division Multiplexing

FEC : Forwarding Equivalence

FM : Frequency Modulation

FR : Frame Relay

FTP : File Transfer Protocol

HDLC : High Level Data Link Control

HTTP : Hyper Text Transfer Protocol

IEEE : Institute of Electrical and Electronics Engineers

IETF : Internet Engineering Task Force

IGRP : Interior Gateway Routing Protocol

IP : Internet Protocol

ISDN : Integrated Services Digital Network

ISO : International Organization for Standardization

ITU : International Telecommunication Union

ITU-T : ITU Telecommunication Standardization Sector

LAN : Local Area Network

LDP : Label Distribution Protocol

LER : Label Edge Router

LIB : Label Information Base

LLDP : Link Layer Discovery Protocol

LSP : Label Switching Path

LSR : Label Switching Router

MAC : Medium Access Control

MAN : Metropolitan Area Network

MPLS : Multi-Protocol Label Switching

NFS : National Science Foundation

NFS : Network File System

OSI : Open System Interconnection


xiii

OSPF : Open Shortest Path First

PAM : Pulse Amplitude Modulation

PM : Phase Modulation

PVC : Private Virtual Circuits

QAM : Quadrature Amplitude Modulation

QoS : Quality of Service

QPSK : Quadrature Phase Shift Keying

R/L : Radio Link

RIB : Routing Information Base

RIP : Routing Information Protocol

RSVP : Resource Reservation Protocol

SDH : Synchronous Digital Hierarchy

SMDS : Switched Multimegabit Data Service

SMTP : Simple Mail Transfer Protocol

SNMP : Simple Network Management Protocol

SSB : Single Side Band

TCP : Transmission Control Protocol

TDM : Time Division Multiplexing

TFTP : Trivial File Transfer Protocol

TTL : Time To Live

VPN : Virtual Private Network

WAN : Wide Area Network

WDM : Wavelength Division Multiplexing

EIRP : Effective Isotropic Radiated Power


14

1.INTRODUCTION

In the introduction part, simulations used in this project and general logics of communication systems and fiber

communications are briefly discussed. Furthermore, the modulation techniques used in Radio Link simulation

design and functions of MPLS mechanism are mentioned.

1.1 BASIC EQUIPMENTS OF COMMUNICATION SYSTEMS

It is necessary that, to form an information, electronic signals firstly must be converted to electrical format in

non-optical system. This process takes place by means of a converter, which converts the audio or data to

electrical signals and the level of this signal are powered by the help of the equipped amplifiers and transmitted

via a transmission line from one point to another. After this process, considering the losses in the level of this

signal, the signal is strengthened again and the received signals are converted into voice or data signals via a

converter. In Figure 1.1 some basic equipments are shown for an example of communication system. [1]

Figure 1.1 The equipment used in a communication system [1]

The radio link systems are used for transportation of information from one point to another without using a

cable. As shown in Figure 1.2 a receiver and a transmitter is necessary to transfer the information in radio link

systems. In both figures, electronic noise disrupts the signal which are the unwanted effects for the process and

they are needed to be minimized during the system design.

Figure 1.2 The basic equipment of a radio communication system [1]

Schemas introduced in Figure 1.1 and Figure 1.2 are only valid for one way communication systems and they are

only equipped with basic communication and basic radio link.


15

1.2 FIBER OPTIC COMMUNICATION

Copper cables does not meet demand for high speed, due to this, there is an increase in the use of fiber optic

systems and communication tools and they become a medium of equipments that provides higher quality service.

By using light as the information carrier in such systems, high capacity and low losses for information

transportation, fiber optic communication expands through the world and constitutes a main element for the

communication infrastructure.

There is an increase by means of usage of fiber optic cable and amount of transferred data. The increase in the

internet usage and data usage, and for the effective and fast transportation of audio and image traffic through

optic data way a device named SDH (Synchronous Digital Hierarchy) was developed which uses TDM

multiplexing technology. It provides data transportation in different speeds without changing the existing fiber

infrastructure it was planned to increase the capacity of sending data and using wavelength Division

Multiplexing WDM (wavelength Division Multiplexing) method Tbit/s speeds have been achieved.

Figure 1.3 The basic equipment of optical communication system [3]

Fiber optic communication systems also consist of transmitter, communication channel and receiver. Figure 1.3

is an example of optic communication system. It consist of transmitting circuit, driver circuit and light source

and its objective is to transmit the electrical signal to the light signal and transfer it to the fiber optic cable. For

the light source, LED and semi-conductor lasers are used.

Optic communication channel is used for the transport the signal without any disruption. Atmosphere is used as a

communication medium and this called "Free Space Optic". By using fiber optic cable as a medium of optic

communication channel, a huge amount of information can be transferred to the long distances and losses are

minimized in fiber optic cables.

Optic receivers do the reverse action of transmitters and transforms the light signal to the electrical signal.

Optical receivers consist of photodetector, electrical fortifier and signal shaper. [3]


16

1.3 PROPOSE OF THESIS

In this thesis work, wireless transmission links were considered for the locations which were unreachable via

fiber. By this way the user sites were connected to MPLS backbone. In the practical part of this thesis different

modulation techniques and antenna sizes were analyzed in order to provide the most efficient way of data

transmission. The data between these wireless links was transfered using MPLS L2 VPN solution.

The aim of the thesis is to provide the highest throughput between R/L locations using available modulation

techniques. In order to do this, a simulation named PathLoss was used where one can take different parameters

into consideration, such as modulation tehnique and antenna size and than can model a formula. So the idea is to

find the best correlation of the parameters for the objective of providing the best service to the computers in R/L

designed locations and other locations as if they were on the same network using Ethernet over MPLS L2 VPN

application. In addition, the costs can be minimized using this solution. In this case, an emerging technology

which is called Multi-Protocol Label Switching (MPLS) is used for minimization of the costs. This protocol has

a labelling technology which enables routers to forward the incoming packets by using tunneling mechanism.

1.4 METHOD USED

Path loss test tool and modulation techniques for 256 QAM, 64 QAM, 16 QAM and 4 QAM have been used in

order to perform simultaneous simulations so that best correlation of stated variables are characterized for the

project. The variables are then simulated with various antenna sizes for the best throughput of 155 Mbit/s data

transfer.

In GNS3 tool, simulations were done for point-to-point scenarios in order to achieve the results for MPLS L2

VPN connectivity. This simulation was then applied for point-to-multipoint topology in a lab environment. The

latter was done using 5 edge routers located separately in Turkey and the measurement (ping delay, jitter and

packet loss) was taken in each of them.


17

2. THEORY

In this part, modulation techniques, Quadrature Amplitude Modulation types which is especially used in R/L

design in thesis, multiplexing techniques, classification of computer networks, routing protocols and MPLS

labelling protocols were described.

2.1 MODULATION

Modulation is the event that low frequency signal (information) is superimposed to a high frequency signal

carrier to send long distance in order to transmit information signal to a more suitable transformation shape. [5]

Modulation type is chosen by considering existing noise, transmitter power and bandwidth. The feature of the

carrier signal can be changed according to the modulation signal. This signal is called as modulated signal. In

Figure 2-1, modulation techniques are given under two title and in Figure 2-2 the modulation techniques for

digital data are given.

Figure 2.1 The scheme of modulation techniques


18

Figure 2.2 Modulation Method for Digital Data

In this part modulation multiplexing techniques are given and a brief description about amplitude modulation

and phase modulation from Analog modulation techniques. Furthermore, a comprehensive description is given

about QAM modulation used in R/L design.

2.1.1 ANALOG MODULATION

It can be inferred that two reasons are important for the modulation of analog data over analog signals. Firstly, it

is possible that the needed data may be different for transmission. Without modulation, it is not possible to

transmit baseband signals in wireless transmissions. The other reason is that frequency division multiplexing can

be applicable in analog modulation so that, by modulating them, data can be transferred by different uses over

different bands.

2.1.2 QUADRATURE AMPLITUDE MODULATION (QAM)

Basically, in Quadrature Amplitude Modulation technique, QPSK (4QAM), 16QAM, 64QAM and 256QAM

techniques were used to introduce R/L simulation activities and here the main principles of these techniques are

described and QAM architecture was explained.

Compared to the some low efficient modulation shapes, QAM is able to provide, high data ratio with a mid-level

application complexity and high spectrum efficiency. Linear modulation forms provides, high bandwidth and

power efficiency thus, it can be used frequently in wireless communication. In mobile and cellular systems m-

QAM modulation as a two dimensional modulation type, provides the necessary high speed service. [6,8]

MODULATION METHODS FOR DIGITAL DATA

TRELLIS CODED MODULATION

PHASE SHIFT KEYING (PSK)

QUADRATURE AMPLITUDE

MODULATION (QAM)

CONTINUOUS PHASE MODULATION

GAUSSIAN MINUMUM SHIFT KEYING (GMSK)

MINIMUM SHIFT KEYING (MSK)

CONTINUOUS PHASE FREQUENCY SHIFT

KEYING (CPFSK)

FREQUENCY MODULATION

FREQUENCY SHIFT KEYING (FSK)

PHASE MODULATION

PHASE SHIFT KEYING (PSK)

DIFFERENTIAL PHASE SHIFT KEYING (DPSK)

OFFSET PHASE SHIFT KEYING (OPSK)

AMPLITUDE MODULATION

PULSE AMPLITUDE MODULATION (PAM)

QUADRATURE AMPLITUDE

MODULATION (QAM)


19

As shown in Figure 2-3; and are calculated by simultaneously applied both information

flow {an} and k-bit signal over on two upright carriers. And this achieved modulation is called Quadrature

Amplitude Modulation and the signal is expressed as follows [8]

(2.4)

Here, and = tan−1

QAM modulation signal wave form is a combination of

amplitude and phase modulations.

The signal wave forms of QAM Modulation, was shown as a linear combination of the wave type which are

and . When put into the formulas (2.5) and (2.6) the complex baseband signal can be derived as in

mentioned in Figure 2-3. [8]

Eg the energy of signal impact

(2.6)

(2.5)


20

Figure 2.3 QAM Modulator Architecture [9]

M-QAM describes the bit number for each star (point) within the QAM star diagram. In the context of this

thesis, a simulation for QAM techniques for Nbps = 2, 4, 6, 8 and M= 4, 16, 64, 256 was conducted. For M, the

formula in 2.7 is applicable which describes Nbps as a symbol

The formula applies in 2.7 for M which is the alphabet number of QAM modulation and represents the number

of bits transmitted per symbol. In Table 2.1 the speeds for QAM modulation types are shown

: Symbol of the number of bits

Number of QAM modulation alphabet

In order to minimize the errors resulted during code solving in QAM modulation and minimizing the frequency

bandwidth, Gray coding is using for this process. In gray coding, in each time only one change of a bit is

permitted for modulation levels. In Figure 2-4, which can be seen in the modulation of QAM-QPSK that each

star includes a value of 2 bit for a total of 4, there is a jump from 00 value to 01 or 10 not 11.

Star diagrams of modifications are shown in Figure 2-5 which each star includes a value of 4 bits whit a total of

16 QAM, in Figure 2-6 which each star includes a value of 6 bits whit a total of 64QAM, in Figure 2-7 which

each star includes a value of 8 bits whit a total of 256QAM.

(2.7)


21

Figure 2.4 QPSK, 4-QAM (Gray coded)

Figure 2.5 16-QAM (Gray coded)


22

Figure 2.6 64-QAM (Gray coded)


23

Figure 2.7 256 QAM

Modulatıon Format Theoretıcal Bandwıdth Efficiency

limits

MSK 1 bit/second/Hz

BPSK 1 bit/second/Hz

QPSK 2 bit/second/Hz

8PSK 3 bit/second/Hz

16QAM 4 bit/second/Hz




Table 2.1 Bandwidth efficiency limit of the modulation types


24

2.2. MULTIPLEXING

It became an important necessity to increase the capacity of transmission lines from the beginning of the

communication. The aim of the multiplexing is transferring multiple voice or image data simultaneously. It is not

efficient to transfer only a voice or image data information in an electrical or optical transmission line because it

is not only a costly procedure but also it is a waste of high capacities for only one user.by multiplexing, multiple

data can be transmitted simultaneously or one by one. Some techniques can be used in order to share this

transmission line to users. These are: Time Division Multiplexing (TDM) and Frequency division multiplexing

(FDM). [5]

2.2.1. TIME DIVISION MULTIPLEXING

In TDM, a time period is determined for every user thus, transmission time can be shared for all users. TDM is a

multiplexing type which transfer two or more information in a communication channel to the sub channels

simultaneously. This means that, it divides the space into particular time periods and uses different time period

for each numerical sign. The time situation of TDM was shown in Figure 2-8.

Figure 2.8 TDM Multiplexing

In Time Division Multiplexing, the whole bandwidth was engaged to each channel with a regular time periods.

In order to avoid an overlap during the multiplexing of signs with TDM in time level, it is necessary that, the

sampling frequency of signs should be an integer of each other. Each receiver should know the arrival time of

the sign thus, a synchronization between receiver and transmitter is necessary. [5]

In figure 2-9, a block diagram of TDM multiplexing has shown [7]. signs come from channels are switched by a

selector and transmitted to the transmission environment in appropriate times. The signal sent from the receiver

through the transmission line is transmitted to the right channel in right time.


25

Figure 2.9 TDM Block Diagram

The Time Division Multiplexing can be used by pulse amplitude modulation (PAM). N number of signals are

modulated in right periods and can be sent from one channel. In Figure 2-10, a TDM signal structured by two

signals can be seen. X1(t) and X2(t) signals represent the samples from different time periods. . [11]

Figure 2.10 TDM formation with Two PAM signal

2.2.2. FREQUENCY DIVISION MULTIPLEXING

In FDM, each user is assigned only with right transmitter to the determined frequency period. In Figure 2-11, it

uses different frequency for each signal transmission by sharing communication resources’ frequency bandwidth.

[5]


26

Figure 2.11 FDM Multiplexing

An information signal is transmitted from point to point by using a communication line. This communication

line can be a line just like in a phone communication line or in space just like for the communication of radio or

television. The bandwidth of the signal which is meant to be sent is generally represents a small area of the

transmission line’s bandwidth. Due to this, it is a waste to send just a signal through a transmission line.

Furthermore, it is not possible to send multiple signals which cover same frequency bandwidth through a single

transmission line. It is hard to separate these signals by receiver. So, this problem can be solve in this way: the

frequency circles of the signals that covers the same frequency bandwidth need to be switched the same

frequency bandwidth. Thus, the signals that does not cover the same frequency bandwidth is going to be derived

[1].

In figure 2.12, a FDM multiplexing diagram was shown.[7] When looking to the spectrum of the signal, it can be

seen that there are frequency number as much as number of message sent. Signals are filtered and according to

the signal type, a demodulation is applied and the message obtained by receiver.

Figure 2.12 FDM Block Diagram


27

2.2.3. WAVELENGTH DIVISION MULTIPLEXING

Wavelength division multiplexing (WDM) is a method of signal multiplexing at different wavelength over fiber.

During processing, virtual fibers which have different carrying signal capacities are generated. It might be

considered that WDM system is a set of parallel optical transmission channels which uses the different

wavelength of each lights but shares same transmission line. WDM network consists of different optical channel

paths. In other word, each the lights of channel are composed different color. A simple example WDM structure

is shown in Figure 2.13. WDM systems, that are designed to supply the demand of higher bandwidth level in

terabits, increase the capacity of existing network without any needs for rewiring. WDM can operate only two

channels that are either the two wavelength of 1310 and 1550 nm or 850 and 1310 from a pair of fiber.[12]

In dense wavelength multiplexing divide (DWDM), the wavelengths are closer each other than the wavelength

of WDM. In the DWDM technology, the wavelength range in between 1530 and 1560 nm are used and it is

possible to transmit the number of 8,16,32,80 and 160 traffic channels in narrower channel between 10nm-01nm

ranges.

Figure 2.13 160 λ has the capacity to example WDM transmission

2.3. CLASSIFICATION OF COMPUTER NETWORKS

2.3.1. LOCAL AREA NETWORK

Local Area Network (LAN) is a network that is created to connect the computers which are distributed up to 7

km area in a particular location. Initially LAN was consisted a small system that a server connected with a small

number terminals via coaxial cable. But today, LAN has become highly productive network that supports higher

speed demand and also it supports audio and video-conferencing as well as data transmitting. Home network,

office network, and a university network could be given an example for local area network. It could be created as

a large network that contains hundred computers, fax-modems, CD-ROM drivers, printers and other connected

equipment as well as it could be a small network that consists two computers. One of the major advantages of

the local area network is that allows users to use available resources such as hardware, software, printer, etc.

which are connected in same LAN. And this sharing is providing to be achieved the saving source. [13]

LAN can be classified according to these three criteria; communications type of LAN, connection type of LAN

and transmission environment of LAN.


28

2.3.2. METROPOLITAN AREA NETWORK

The network which structure consists connected computers around 5-100 km area is called Metropolitan Area

Network (MAN). It could be applied in wider range than local area network. For example the network which is

establishing between cities. MAN is a mod-scale network system. Audio and data communication can be

performed in MAN. Its network scale is between WAN and LAN’s size. MAN connections usually perform the

sharing of local resources on the network with high speeds. MAN protocols are defined by as IEEE, ITU-T

standards protocols. ATM (Asynchronous Transfer Mode), DQDB(Distributed Queue Dual Bus), FDDI(Fiber

Distributed Data Interface), Gigabit Ethernet, 10 Giga Ethernet, WiMAX and SMDS (Switched Multimegabit

Data Service) can be listed as example of protocol and technology by using MAN connectivity.[1]

2.3.3. WIDE AREA NETWORK

Wide Area Network (WAN) is composed by connecting the computers with each other in an area which is larger

than 100 km. This network is used with both MAN and LAN clusters.

WANs are a structure that is connecting together all local area networks in different locations of country.

Internet which is used actively in todays is a good example for wide area network. It supports that the users of

institutions who are located in different areas can transfer their data to other users, agencies etc. According to

this feature this network design is more efficient to reduce cost and delays (i.e. time saving). The main feature of

WAN connection is that it has long communication line and according to this feature to keep the transmission

between long distances it is necessary to rent a telecomm operator. The bandwidth of communication is limited

so a fee is paid based on using bandwidth. Thus, the important points for WAN connection are bandwidth, cost,

connection quality and service quality.

In order to provide secure communication in WAN system, a communication tunnel which is called Virtual

Private Network (VPN) is open over on Public Switching Data Network (PSDN). With this manner the users are

protected and provided using high speed communication line. SONET, Frame Relay (FR), X.25, ATM, and PPP

can be listed the most important equipment in WAN system. LAYER-2 protocols that are defined by many

organizations are used in WAN for data link layer. These are; IETF for PPP, ITU-T for ATM, ISO and SONET

for X.25. ATM, ds(DSL,IDSL,ADSL,HDSLDSL,VDSL), ISDN,PPP( Point to Point Protocol over ATM or

Ethernet: PPPoA, PPPoE) can be sorted as basic protocols of WAN.[1]


29

2.4. ISO-OSI REFERANCE MODEL

Every computer manufacturer in the early years of the network was developing its own standards. Therefore,

only the same manufacturer's devices could communicate with each other. This situation implies that who want

to establish a network of institution needs to buy from a single device manufacturers. Due to the lack of inability

to communicate with a different devices. Manufacturer from other institutions were needed to create an

international standards. OSI (Open System Interconnection) model was developed by the ISO (International

Organization for Standardization) in the late 1970s to put an end to this complication. With OSI model

regardless of the type of the model, all equipments are able to communicate with each other. According to the

OSI reference number: data communication is occurred in 7 layer. These are shown in Figure 2-14.[13]

Figure 2-14 OSI Reference Model

2.4.1 PHYSICAL LAYER

Physical layer is the layer that data sets are turned to the digital bits. This layer is responsible with the physical

transportation of data which is mostly interested with shape, connector type, network cables, and hubs. It

describes the transportation and transformation of data which are shaped as 1 and 0 type into electric, light and

radio signals. There is no protocol for this layer. [13]


30

2.4.2 DATA LINK LAYER

This layer is responsible with control of the transportation and flow of data from one point to another. It forms

the 2nd layer by attaching error control bits to data sets which are derived from link layer. In data layer, the

transportation type of data in physical environment and addressing are described. By means of physical

addressing is MAC (Media Access Control) addresses. This layer have the function of addressing, error

identification, arbitration, and identification of the encapsulated data.

For addressing issue examples MAC, Unicast, Broadcast and Multicast addresses can be given. In data link

layer, Frame Relay, ATM, HDLC protocols can be used. Furthermore, repeaters, switches, hubs and bridges are

work in Layer 2 Datalink layer. [13]

2.4.3 NETWORK LAYER

Network layer is a layer which provides the movements of data sets between local or wide networks. It allows

data packets to be routed through the network to reach its destination addresses. Addressing can be done by

dynamic or static. The dynamic addressing is done by DHCP protocol with servers, the static addressing is done

manually. In this layer, the best way to send data to the target can be done by router devices. Routing activities

can be done by using routing protocols such as RIP, IGRP, OSFP and EIGRP.

2.4.4 TRANSPORT LAYER

The transport layer is the layer for two units which provides end to end connection and provides network service

for these units. It provides a safety transportation of the data from the source to the target computer. The delivery

situation of the data can be checked by appropriate protocols. It provides communication between OSI’s first

three lower layer and upper layer. The most important role of this layer is Security and Flow Control. The aim of

the flow control is to control the data in order to send to the correct address and to ensure that if the data is not

delivered correctly, the flow control is responsible to send data again.

2.4.5 SESSION LAYER

The session layer controls the sessions and presentations if they are open between the two connected computers.

This means that, it facilitates the installation, management and termination of the session between the connected

points. The user’s access is provided in this layer. Thinking briefly, it controls the presentations such as

Facebook, MSN and Skype if they are open in the other network.


31

2.4.6 PRESENTATION LAYER

It can be described as a high level communication interface between user programs and network. It is also used

for the identification of a common format for the computer that data are planned to send. In another word, it

describes the file extension’s identity. It resolves the problem of disconformity occurred from the usage of

different protocols used by devices. For example: MPEG, GIF, TXT, ASCII, JPEG, AVI etc.

2.4.7 APPLICATION LAYER

It is the layer in which the network operating system, providing service to the users, and application programs

exist. All the programs, used by the users, are declared in this layer. This layer presents some tools to the

programs to use the network we can give everything we see in our monitor as an example. It’s the closest layer

to the user, does not serve anything to the other layers. FTP, TFTP, HTTP, TELNET, SNMP, and SMTP

protocols are applications used in this layer as an example. Reaching the internet, sharing the documents,

emailing and database management and such operations are done in this layer. [13]

2.5 ROUTING PROTOCOL

Router devices using appropriate router protocols build a database. Database is built, by using IP address

information, subnet mask, the data of neighboring routers. The alteration of this data are organized in RIB charts

and all the needed calculations are done. Routing process is done by choosing the most appropriate path. Chosen

or chosen to be used paths should have been introduced to the neighbor routers in the network. In this way, the

router knows the ways going to the different routers too. The handshake between the routers is named routing

update. If the routers are under the control of one management team, and all the describing, management rule

detections are only done by this team, this means routing domain is constituted. Each different router orbit is

used as a different autonomous system. [14]

Each router, according to the method, forms a RIB chart referring to the updates coming from the other router.

By this chart, the best way to target is defined. Routing protocol, to use the ways and find the new ways, uses

two main protocols named Dynamic Routing Protocol and Static Routing Protocol.

2.5.1. STATIC ROUTING PROTOCOL

In this protocol, network manager determines the route from the source to the target. There is no need for any

protocol to calculate or transact. Routing protocols are calculated or determined by network administrator in

advance. By adding, route data to data package which routers are going to be used are identified. During the

static routing, next hop data is identified by network administrator. Thus, during transferring data to a different

network the data is sent to the next router.

Static routing protocol is used for the applications which have small capacity and not using larger applications.


32

2.5.2. DYNAMIC ROUTING PROTOCOL

By large applications in network, more operations were being done via these networks. Static routing protocol

was poor for large inclusive applications and for making the operations faster, comes the dynamic routing

protocol. Dynamic routing protocol as a structure, uses routing protocol messages, thus given info to the leaders

about networks gives way to periodic updates, and the best ways to these updates. By this means, routing charts

are updated and the updated charts are transferred to other routers. In line with this process, the most appropriate

way for the data from the source to the target is chosen.

For all these routing process to be done, all the routers in the network should use the same routing protocols. [15]

Figure 2.15 Dynamic Routing Protocol Examples

In dynamic routing protocol, for each packet the route can be determined according to separate calculations. To

form the routing information, routing calculations are used. As it can be seen at the figure 2.15, using static

routing protocol in a large and complicated network, can lead a lot of problems. In dynamic routing protocol

structure, while sending data packages the most appropriate way can be chosen according to that very moment.

The package between the routers can be transferred in different ways according to the situation of the network.

The router, choosing the dynamic ways and learning the ways, treats the data according to various rules. Thanks

to dynamic routing protocol, the network runs fast and correct in a network containing a lot of routers and

binding. In the structure of static routing protocol, for each router to be added, it should be applied for each and

separate routes. At the figure 2.16, dynamic routing protocol structure can be seen it’s divided mainly into two,

internal network protocols and external network protocols.


33

Since we are going to handle with EIGRP from distance vector protocols and OSPF, form link state protocols,

below we are going to handle with all these protocols separately.

Figure 2.16 Dynamic Routing Protocol structure

2.5.2.1 OPEN SHORTEST PATH FIRST (OSPF)

OSPF is in the group of link-state routing protocols and is built on the structure of interior gateway protocol. In

short, IGP does routing only in autonomous systems. It cannot be used between autonomous systems. Thus, the

changing of the routing charts can be faster. In the link-state routing protocol, for choosing the best path Dijkstra

Algorithm (the shortest path calculation algorithm) is used. Routers, because of the characteristics of Dijkstra

Algorithm, has all the topological routing protocol data of the network which they depend on link-state. Thanks

to the multicast characteristic feature sends the updates which are in their own routing charts to the routes which

are indicated in advance.

In OSPF, routers running with line status protocols have information about all network and they can be aware of

any changes that occur in the network. Thus, all subnets can be grouped under a tree and according to the

Shortest Path First algorithm, the shortest path can be decided for the destination. In networks which use these

protocols, information is just sent about the change when changes occur and with this way unnecessary protocol

traffic is avoided.

By using OSPF, the information that is unavailable in network becomes known by all routers which applied the

protocol and the packets that are transmitting to the unreachable network does not allow any data flow. Due to

this optimization all disadvantages which are occurred by static routing are resolved. [4]

With OSPF, each router is able to gather information and get all information from that topology and have each

router’s topology table. Routers locate the shortest path for the destination network based on these tables.


34

Depending on the situation, the network administrator can take into account the hop number for the shortest path

or can create a more effective topology by considering factors such as delay in switching path, intensity of usage

and bandwidth. Routers in OSPF can exchange information with each other. On the other hand, OSPF is not able

to know how many steps needed for reaching a network but is able to know when and in which speed it can

reach to the network. In addition to this, OSPF have four different network ranks: Backbone area, Stub area,

Totally stubby area and Not-so-stubby area [4]

Likewise, router can be ranked as below:

• ABR - Area Border Router

• ASBR – Autonomous System Boundary Router

• IR – Internal Router

• BR – Backbone Router

• DR – Designated Router

• BDR – Backup Designated Router [18]

2.5.2.2 EIGRP

Enhanced Interior Gateway Routing Protocol is a protocol developed by Cisco. EIGRP protocol can only be

used in Cisco devices. It cannot be used in different router brands. EIGRP can be classified under Hybrid

Routing protocols. This means that, in appropriate cases, Link-State can be active or Distance-Vector can be

active.

Protocols such as RIP and IGRP are able to update topology updates and all network information as well as other

new updates to routers. However, EIGRP protocol works totally in the opposite way and only share new

topology differences with other routers.

EIGRP protocol works with the help of TCP protocol. In this case, the aim is to gather information for both

positive or negative situation differences are fulfilled or not. For this case, routers send Hello and ACK messages

to each other. Furthermore, they provide this message delivery activity with TCP protocol. [15]


35

2.6 VIRTUAL PRIVATE NETWORK (VPN)

Virtual Private Networks provide secure connection over communication networks by using encapsulation. Main

purpose of the VPN is to establish secure virtual communication channels between two end points over leased

connections from service providers. For virtual connection, end points should have both physical connections

established between and also end point communication devices supporting VPN features. With this, from a

single physical connection, many virtual VPN tunnels can be defined. These logically separated VPN

connections provide independent communication channels between end points.[16]

2.7 MULTI PROTOCOL LABEL SWITCHING (MPLS)

Multi-Protocol Label Switching (MPLS) is getting stems from Toshiba’s cell switch routing, Ipsilon’s IP

switching, IBM’s Aggregate Route-Based IP Switching, (ARIS) and Cisco’s Label Switching. MPLS technology

has been started to be developed by an IETF task force in 1997. It adds label switching mechanism to existing IP

backbone functionality. With this approach, normally datagram based IP networks obtain virtual leased line

based data networks’ characteristics and qualities. [16]

Many companies worked for solution to have Layer 2 switching speed in Layer 3, to get rid of difficulties in

controlling, managing the network and providing better scalability for IP over ATM applications, to have QoS

support for multimedia applications and to have multi Layer 2 protocol support. These studies show a necessity

to have some kind of common ground and integration between ATM based cell switching and IP routing based

internet. MPLS solves many of the problems associated with somewhat synthetically establishing connection

based circuits for IP protocol over ATM network.[2]

Due to rapid internet growth in recent years, internet technologies also face rapid changes. Increasing internet

subscriber quantity encouraged worldwide access to internet infrastructure, better service quality, more

bandwidth and allows for internet service versatility. For this reason, internet service providers and

Telecommunication companies are forced to adopt their existing infrastructure for continuous technological

advances and to cope up with increasing subscriber demand.

Telecommunication companies utilized IP over ATM approach in 1990s which was the best technology for this

time period. MPLS technology employs label swapping for reaching target node instead of node to node IP

routing (label swapping and forwarding). MPLS can be considered as an enhancement to existing IP

infrastructure. New applications include traffic engineering, IP VPN, integration with IP routing and Layer 2 or

optical switching. This provides for high performance IP backbone architecture. [2]

As this technology minimizes the packet routing processes and tasks, both packet processing speed and

scalability increases. As MPLS distinguishes routing process from forwarding, it does not change the forwarding

path and allows for in each node router gets routing decision but uses dedicated and pre-formed label paths.

MPLS technology integrates IP’s datagram structure and ATM’s cell header label mechanisms. MPLS takes


36

advantage of both IP routers’ routing protocol support and ATM switches’ cell header (label) switching. Basic

structure is shown in Figure 2.17.

Figure 2.17 Formation of MPLS

MPLS has short, fixed length labels that identify IP packet headers which allow for easier packet forwarding. IP

packets are wrapped inside additional MPLS headers and then forwarded. This makes forwarding easier as it

avoids hop by hop routing and uses label switching instead. MPLS frames can be transported over any Layer 2

infrastructure like ATM, Frame Relay, PPP or Ethernet etc. In frame based MPLS labels are inserted between

Layer 2 and Layer 3 headers. This labelling process is called inserting Shim Header. MPLS enables forwarding

of IP packets through a predefined label path over the network. This predefined path is called as Label Switched

Path (LSP). LSPs are uni directional and similar to ATM PVC (Private Virtual Circuit). Label Switch Router

(LSR) defines the path where packet will be forwarded and each LSR which this LSP traverses makes

forwarding decision according to these labels and forwards this MPLS frame to next LSR node.

2.7.1 MPLS ARCHITECTURE AND BASIC COMPONENTS

Main components of MPLS architecture are as follows; MPLS Label, Label Switching, Label Switched Path

(LSP), Label Switching Router (LSR) and Forwarding Equivalence Class (FEC). MPLS network is composed of

LSRs that are located in the center of the network and surrounding Edge-LSRs (Label Edge Router – LER).

2.7.1.1 MPLS LABEL

MPLS label defines the path which the packet has to follow. It is a short, fixed length identifier that is used for

packet forwarding. These labels can be stacked and include other information like Time to Live (TTL). In case

ATM infrastructure is used in a network, MPLS frame in encapsulated and transported inside the ATM cell.

Regardless of the type, adding labels and other necessary information to packets is called “MPLS

Encapsulation”. If MPLS label values and other relevant information cannot be transported, special MPLS

headers that is added to packets are used. General MPLS label format is shown in Figure 2-18.[16]


37

Figure 2-18 MPLS Label Format

MPLS header which is located between Layer 2 header and IP header is composed of 4 octets (32 bits). 3 bits

inside this header is used for Class of Service (CoS). This service class information is for traffic precedence for

special applications and defines QoS levels in the MPLS network. 8 bits TTL value is used for mimicking IP

TTL which is inside the IP header. Each IP packet has a Time to Live (TTL) value that prevents packets from

entering into an infinite forwarding loop. TTL field value reduced by one for each forwarding action and when it

reaches to zero, this packet is discarded. There is also a 1 bit field which shows the stacking status and indicates

whether encapsulated label is the last one in the stack or not. Remaining 20 bits of the header has the real MPLS

label value.[2]

2.7.1.2 LABEL CHANGES

Label switching logic should be provided to the nodes before MPLS packets arrive to the nodes, this is realized

by signaling and label distribution. Each packet should be classified in the edge of the MPLS network in order to

associate them with an MPLS label, this is performed by Label Edge Router (LER). LER searches its routing

table for a match, adds corresponding label to this packet as ingress router that is in charge of this classification,

and sends the MPLS frame to next LSR via defined Label Switches Path (LSR).

Central Label Switch Routers (LSR) simply perform label switching by looking at MPLS labels, without further

investigating network layer header information. When MPLS labelled path reaches to LSR, LSR makes a packet

lookup in the forwarding table by using packet’s label information and ingress port number. In case it finds a

match, it changes the label and port information according to the defined egress MPLS label and egress output

port. This packet then is sent through this outbound interface for the next hop switching. When packet reaches to

egress LER node, packet lookup procedure again searches for next MPLS label for outbound port but as there is

no further MPLS label remains, packet is transported by using plain IP longest match approach without using

further MPLS labels. Label switching is realized with higher speed compared with traditional hop by hop

routing.[17]


38

Arguably the most prominent benefit of label switching is the ability to associate any user traffic type with a

Forwarding Equivalence Class (FEC) and then forwarding this classified traffic through a LSP path. This

functionality helps ISPs to make an exact and deterministic flow control over their networks, better and

controllable utilization of the network resources and more predictable overall network behavior.[2]

2.7.1.3 LABEL SWITCHING ROUTER (LSR)

LSR is the high speed switching and routing device in a MPLS network which participates in formation of Label

Switched Paths (LSP). It fulfills the functions of forwarding packets from source to destination and populating

the routing-label table. LSRs are placed in the core of the network and makes label switching according to

available forwarding table information. They can be routers or switches. They combine the Layer 2 performance

and traffic management qualities with Layer 3 routing support and flexibility. Figure 2-19 shows LSR function.

Figure 2-19 Formation of LSR

2.7.1.4 LABEL SWITCHED PATHS (LSPs)

Within MPLS network before any data communication starts, LSPs are formed between two endpoints where

packet transport intended to take place. LSP labels are distributed via signaling and FEC associations are

realized. All traffic has to go through LSPs in MPLS. LSPs are formed by two methods, Explicit Route or Node

by Node routing. [18]

2.7.1.4.1 HOP BY HOP ROUTING

In hop by hop routing, each LSR looks its topology database and then decides which interface to use. Afterwards

it sends label request to neighboring node. This procedure continues until egress LER is reached. As procedure is

initiated from sender node to receiving node step by step, this method is based on hop by hop processing. LER is

the edge device of the MPLS network.


39

2.7.1.4.2 EXPLICIT ROUTING

Explicit routing is based on having defined LSR address list in the sender node explicitly, which includes all the

intermediate nodes that interconnect sender node to the receiver node. This list is arranged in a way to have the

ip addresses of the equipments that participate in this LSP. Explicit routing is realized with two methods, strict

and loose explicit routing. In strict method, only LSRs defined by sending LER is used. Additionally it is

required to follow the sequence defined in LER. In loose routing mode, it is allowed to use additional LSRs

other than the defined ones when it becomes necessary. Each LSR cannot select next hop independently. In the

first sending LSR, the node list is defined. By this way resources in the network can be reserved for data

transport with sufficient QoS guarantees.

2.7.1.5 FORWARDING EQUIVALENCE CLASSES (FEC)

FEC represents the group of packets which will receive the same treatment while being transported. Can be

defined as a packet group which has the same source and destination address. For the packets that are grouped in

this way, routing to destination node is performed in the same manner. Grouping of the packets which are

destined for the same end point allows to assign them a single label and allows a common routing for them.

Thus, according to traffic type different prioritization and service qualities can be provided. For each LSP a FEC

definition is done. Each FEC defines one or more FEC element group and each FEC element defines the group

of packets that correspond to LSP.

2.7.2. LABEL DISTRBUTION PROTOCOL (LDP)

LDP is the protocol which is responsible for the distribution of labels. It is set of procedures that an LSR informs

the other LSRs about its label/FEC assignments. LSR routers that communicates their label/FEC assignments to

each other are called “label distribution pairs”. These LSR routers have “label distribution neighborhood”. The

important point is that while two LSR routers can be label distribution pairs for some label/FEC assignments,

they may not be label distribution pairs for other label/FEC assignments. Additionally LDP protocol includes the

procedures for label distribution pairs to learn MPLS capabilities of each other.

MPLS architecture does not oblige to use single type of label distribution protocol (LDP). RSVP and BGP

protocols are extended in a way to make it possible to exchange labels and make label distribution.

Required information in order to give packet forwarding decision is obtained from routing protocols like OSPF

and BGP. This routing information divides the forwarding plane into pieces and each piece becomes associated

with previously defined FECs. The group of packets which follow the same path or belonging to the same FEC

are called as flow and forwarded in the same way.


40

Each FEC is assigned with short, fixed length and locally significant identifiers/labels. This label is either

located inside the data link layer header or network layer header. In case there is no available field for label value

to be inserted, a special header is inserted into the packet.

The information obtained from routing protocols are used for distribution and assignment of labels between

MPLS pairs. In general, one MPLS node takes the label assignments for a flow from the next MPLS node which

is the LSR router. This MPLS node then assigns label for coming packets and distributes this information to the

former MPLS nodes. This process is repeated through whole MPLS network until there is a matching egress

label for each ingress label. Corresponding consecutive path is called Label Switched Path (LSP). LDP protocol

is used for this label distribution process. MPLS nodes form LDP neighborhood sessions for exchanging labels.

LDP supports two types of label distribution. These are called independent and regular. In independent label

distribution, when a node senses a flow it can distribute the label which it assigns for this flow at any time. In

regular type of distribution, the egress node of a flow distributes the label information instead. This means that

for a node to be able to distribute its ingress label to others, it should be either the receiving node of this flow or

it should have an egress label for this flow. Regular label distribution protocol guarantees more controlled label –

flow association and lowers the possibility of unlabeled packets to be forwarded to the following neighbor

nodes. Label assignment in MPLS is done by the next downlink nodes in the flow direction. There are two types

in label assignment like label distribution, these are downlink flow and on request downlink flow methods. In

downlink flow method label assignments is realized by next hop in the flow direction and this labels are

distributed to neighbor nodes. For the on request downlink flow method, a node in the uplink of the flow

direction can specifically request for a label assignment from a node in the downlink of the flow direction. [19]

41

3 PROCESS AND RESULTS

This part of the thesis is realized in two sections. First section is devoted to microwave radio link design in order

to provide communication between two locations and based on modelling of different radio link solutions with

different modulation techniques, different antenna dimensions etc. by using PathLoss program software. Results

are evaluated against annual transmission loss rate and optimal radio link solution is decided. Second section

focusses on L2 Ethernet VPN over MPLS lab simulation by using GNS3 program software for point to point and

point to multipoint MPLS applications.

3.1. RADIO LINK DESIGN BY USING PATHLOSS PROGRAM

PathLoss program software requires exact geographical coordinates of two radio link end points and by using

SRTM (Shuttle Radar Topography Mission) Digital Elevation Model information of the Earth ( high-resolution

digital topographic database of Earth), calculates LoS (Line of Sight) status and link budget by taking into

account free space loss, rain loss, refraction, diffraction, reflection,aperture-medium coupling loss,

and absorption.

Path loss (or path attenuation) as a definition is the reduction in power density (attenuation) of an

electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design

of the link budget of a telecommunication system. Other than free space loss and rain loss etc., path loss /

attenuation is also influenced by terrain contours, environment (urban or rural, vegetation and foliage),

propagation medium (dry or moist air), the distance between the transmitter and the receiver, and the height and

location of antennas.

Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free

space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called

penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction

losses when part of the radio wave front is obstructed by an opaque obstacle, and losses caused by other

phenomena.

The signal radiated by a transmitter may also travel along many and different paths to a receiver simultaneously;

this effect is called multipath. Multipath waves combine at the receiver antenna, resulting in a received signal

that may vary widely, depending on the distribution of the intensity and relative propagation time of the waves

and bandwidth of the transmitted signal. The total power of interfering waves in a Rayleigh fading scenario vary

quickly as a function of space (which is known as small scale fading). Small-scale fading refers to the rapid

changes in radio signal amplitude in a short period of time or travel distance.

https://en.wikipedia.org/wiki/Refraction

https://en.wikipedia.org/wiki/Diffraction

https://en.wikipedia.org/wiki/Reflection_(physics)

https://en.wikipedia.org/wiki/Aperture_(antenna)

https://en.wikipedia.org/wiki/Transmission_medium

https://en.wikipedia.org/wiki/Coupling_loss

https://en.wikipedia.org/wiki/Absorption_(optics)

42

In the study of wireless communications, path loss can be represented by the path loss exponent, whose value is

normally in the range of 2 to 4 (where 2 is for propagation in free space, 4 is for relatively lossy environments

and for the case of full specular reflection from the earth surface—the so-called Flat Earth model). In some

environments, such as buildings, stadiums and other indoor environments, the path loss exponent can reach

values in the range of 4 to 6. On the other hand, a tunnel may act as a waveguide, resulting in a path loss

exponent less than 2.

Path loss is usually expressed in dB. In its simplest form, the path loss can be calculated using the formula [20]

Where L is the path loss in decibels, n is the path loss exponent, d is the distance between the transmitter and the

receiver, usually measured in meters, and C is a constant which accounts for system losses.

Radio and antenna engineers use the following simplified formula (also known as the Friis transmission

equation) for the path loss between two isotropic antennas in free space:

Path loss in dB: [20]

Where L is the path loss in decibels, lambda is the wavelength and d is the transmitter-receiver distance in the

same units as the wavelength.

3.1.1. PATH LOSS RADIO LINK DEFINITIONS FOR SAMPLE LINK

Firstly geographical coordinate information for two sites where more than 100Mbps transmission capacity

required is entered into PathLoss software tool, as Site 1 and Site 2 by using their Longitude and Latitude values.

SRTM database which PathLoss software is getting terrain data, yields the height information as 1178.3m for

Site 1 and 1027m for Site 2. Tower height is considered as 30m which is the common practice in microwave

radio link applications.

43

Figure 3-1 Link Definitions in Path Loss

Figure 3-2 Generating Path Profile and terrain data for Site 1

44

Figure 3-3 Generating Path Profile and terrain data for Site 2

Figure 3-4 Clutter Backdrop and terrain data

Figure 3-4 demonstrates the longitude and latitude information and a high resolution geographical map of this

sample radio link. It provides some understanding for terrain height and general (LoS) Line of Sight status for

the link but we cannot be sure about LoS availability from this screen only.

45

PathLoss tool has another screen (Figure 3-5) for analyzing exact LoS status where the height profile between

Site 1 and Site 2 can be graphically and tabular seen.

Figure 3-5 Terrain data

Figure 3-6 Antenna Heights

Figure 3-6 shows the exact LoS status for the selected antenna heights of Site 1 and Site 2. Antenna height

parameter is editable and depending on tower defined maximum height, can be adjusted to have optimal LoS. In

this study, antenna height for Site 1 is taken as 22.9m and for Site 2 as 14.2m.

46

Next sections use this antenna height assumption and by changing modulation and antenna types, the overall

radio link availability values with different transmission capacities are evaluated for five different radio link

designs.

3.1.1.1 DESIGN SIMULATION -1

Various design simulations are studied for achieving the highest radio link capacity while still

satisfying the high transmission availability values. All radio link models are based on a commercial microwave

equipment manufacturer’s (DragonWave Inc.) Harmony Radio product family which has a wide range of

microwave radios that start from 3.5Ghz to 42Ghz and variable spectrum which can be adjusted between 3.5 to

56Mhz channel bandwidth.

For all radio link calculations, PathLoss IP radio model of 8Ghz Dragonwave Harmony Radio is used and

antenna is selected from Andrew Corporation (VHLP series, frequency range 7125 Mhz – 8500Mhz) with

various diameters but with single polarization in order to be able to decide on optimal design.

For the Simulation -1, Harmony Radio with 256QAM modulation and 56 MHz channel bandwidth is considered

together with 1.8m antenna. Harmony Radio can provide a transmit power of TX = 17 dBm for this mode, and

antenna gain is 40.8 dBm for 1.8m antenna. This results in an EIRP (Equivalent Isotropically Radiated Power)

value of 57.8 dBm for both end points in Site 1 and Site 2. If we consider additional antenna gain of 40.8dBm

on the receiving site as well, total gain budget of 98,6 dBm becomes available both for Site 1 and Site 2. At this

modulation level Harmony Radio has a receiver sensitivity of 65dBm so, if we consider the free space loss of

138,33dBm (for a distance of 24,54km) and Atmospheric absorption loss of 0,26dBm and Field margin of

1dBm, we end up with receive signal of -40.99dBm (which is safely in line with -65dBm receiver sensitivity).

This allows for quite sufficient thermal fade margin of 24dB, which in turn provides a good overall transmission

link availability (Annual rain + multipath availability : %99,99990).

Figure 3-7 and Figure 3-8 show consecutively the transmission analysis screen with calculated attenuation

values, selected antenna model and radio model with gain values and the antenna pattern for 1.8m 8 GHz single

polarized antenna. Figure A-1 provides detailed information for Radio and Antenna model used in this

simulation and related threshold and gain values to achieve a BER ratio of 10-6.

Figure A-2 shows the rain loss related PathLoss tool values for the selected geographical area, ITU-T Region K

is automatically selected by using ITU algorithm Rec. ITU-R P.530-8/13 for 8 GHz frequency. Used rain rate

data source is ITU-R P.837-5 database.

Figure A-3 has the other path profile data and fading factor for this radio link. Some parameters like “inland path

classification”, “Use over water modifications” and “Over water classification” are selected according to

geographical data and map info for this specific link. Multipath fading method - Rec. ITU-R P.530-7/ 8 is

applied for this link analysis.

47

Figure 3-7 Transmission Analysis 1

Figure 3-8 Transmission Analysis for Antenna 1.8m

Figure A-4 shows the Radio Specification for 256QAM modulation level, PathLoss program uses the specified

values of TX_POWER and RX_THRESHOLD values specific for this microwave radio.

Table 3-1 Design 1 Result summarizes the radio link result and annual availability values for 1.8m antenna, 56

MHz spectrum bandwidth and 256 QAM modulation for the whole year and shows the effect of rain and

multipath related extra losses.

48

Site 1 Site 2

True azimuth (°) 32.58 212.68

Vertical angle (°) -0.46 0.29

Elevation (m) 1178.30 1026.99

Tower height (m) 30.00 30.00

Antenna model VHLP6-7W (TR) VHLP6-7W (TR)

Antenna file name vhlp6-7w vhlp6-7w

Antenna gain (dBi) 40.80 40.80

Antenna height (m) 22.93 14.22

Frequency (MHz) 8000.00

Polarization Vertical

Path length (km) 24.54

Free space loss (dB) 138.33

Atmospheric absorption loss (dB) 0.26

Field margin (dB) 1.00

Net path loss (dB) 57.99 57.99

Radio model 08HR56HET348v01 08HR56HET348v01

Radio file name 08hr56het348v01 08hr56het348v01

TX power (dBm) 17.00 17.00

Emission designator 56M0D7WET 56M0D7WET

EIRP (dBm) 57.80 57.80

RX threshold criteria 1E-6 BER 1E-6 BER

RX threshold level (dBm) -65.00 -65.00

Receive signal (dBm) -40.99 -40.99

Thermal fade margin (dB) 24.01 24.01

Dispersive fade margin (dB) 37.27 37.27

Dispersive fade occurrence factor 1.00

Effective fade margin (dB) 23.81 23.81

Geoclimatic factor 1.768E-006

Path inclination (mr) 6.52

Fade occurrence factor (Po) 6.731E-004

Worst month multipath availability (%) 99.99972 99.99972

Worst month multipath unavailability (sec) 7.35 7.35

Annual multipath availability (%) 99.99995 99.99995

Annual multipath unavailability (sec) 16.04 16.04

Annual 2 way multipath availability (%) 99.99990

Annual 2 way multipath unavailability (sec) 32.08


0.01% rain rate (mm/hr) 26.71

Flat fade margin - rain (dB) 24.01

Rain attenuation (dB) 24.01

Annual rain availability (%) 100.00000

Annual rain unavailability (min) 0.01

Annual rain + multipath availability (%) 99.99990

Annual rain + multipath unavailability (min) 0.54

Table 3-1 Design 1 Result

49

Site 1 to Site 2 radio link design with the specified modulation and antenna type results in an overall link

availability value of %99,99990 (including annual rain and multipath related effects) which means 0,54 minutes

of interruption of traffic for one year. With 56 MHz spectrum bandwidth and 256QAM modulation level, a high

traffic capacity of 348Mbps is achievable between Site 1 and Site 2 with very limited interruption annually.






on the receiving site as well, total gain budget of 138,33 dBm becomes available both for Site 1 and Site 2. At

this modulation level Harmony Radio has a receiver sensitivity of 65dBm so, if we consider the free space loss

of 138,33dBm (for a distance of 24,54km) and Atmospheric absorption loss of 0,26dBm and Field margin of

1dBm, we end up with receive signal of -47.99dBm (which is safely in line with -65dBm receiver sensitivity).

This allows for quite sufficient thermal fade margin of 17dB, which in turn provides a good overall transmission




polarized antenna.

50

Figure 3-9 Transmission Analysis 2, Pathloss Calculation with 1.2m Antenna

Figure 3-10 Transmission Analysis 2 for Antenna 1.2m



multipath related extra losses

51

Site 1 Site 2

True azimuth (°) 32.58 212.68


Elevation (m) 1178.30 1026.99


Antenna model VHLPX4-7W (TR) VHLPX4-7W (TR)

Antenna file name vhlpx4-7w vhlpx4-7w












TX power (dBm) 17.00 17.00


EIRP (dBm) 54.30 54.30


























52


availability value of %99,99947 (including annual rain and multipath related effects) which means 2,40 minutes











1dBm, we end up with receive signal of -59.39 (which is safely in line with -65dBm receiver sensitivity). This

allows for quite sufficient thermal fade margin of 11.61dB, which in turn provides a good overall transmission




polarized antenna.

53

Figure 3-11 Transmission Analysis 3, Pathloss Calculation with 0.6m Antenna and 64 QAM modulation

Figure 3-12 Transmission Analysis 3 for Antenna 0.6m a 64 QAM modulation



multipath related extra losses

54

Site 1 Site 2

True azimuth (°) 32.58 212.68


Elevation (m) 1178.30 1026.99


Antenna model DW-T555A07.06

(TR)

DW-T555A07.06

(TR)

Antenna file name thp_06_071_s_wb thp_06_071_s_wb












TX power (dBm) 19.00 19.00


EIRP (dBm) 49.60 49.60


























55


availability value of %99,99804 (including annual rain and multipath related effects) which means 10.30 minutes
















polarized antenna.


56

Figure 3-14 Transmission Analysis 4 for Antenna 0.6m and 16 QAM modulation


values of TX_POWER and RX_THRESHOLD values specific for this microwave radio.



multipath related extra losses.

57

Site 1 Site 2

True azimuth (°) 32.58 212.68


Elevation (m) 1178.30 1026.99


Antenna model DW-T555A07.06 (TR) DW-T555A07.06 (TR)













TX power (dBm) 21.00 21.00


EIRP (dBm) 51.60 51.60
























Annual rain + multipath unavailability

(min) 1.18


58



of interruption of traffic for one year. With 56 MHz spectrum bandwidth and 16QAM modulation level, traffic

capacity of 160Mbps is achievable between Site 1 and Site 2 with very limited interruption annually.













values, selected antenna model and radio model with gain values and the antenna pattern for 0.6m 8 Ghz single

polarized antenna.


59

Figure 3-16 Transmission Analysis 5 for Antenna 0.6m and 4 QAM modulation


values of TX_POWER and RX_TRESHOLD values specific for this microwave radio.


MHz spectrum bandwidth and 4 QAM modulation for the whole year and shows the effect of rain and multipath

related extra loss

60

Site 1 Site 2

True azimuth (°) 32.58 212.68


Elevation (m) 1178.30 1026.99


Antenna model DW-T555A07.06

(TR) DW-T555A07.06 (TR)











Radio model 08HR56HET080v

01 08HR56HET080v01


TX power (dBm) 23.00 23.00


EIRP (dBm) 53.60 53.60


























61



of interruption of traffic for one year. With 56 MHz spectrum bandwidth and 4QAM modulation level, traffic

capacity of 80Mbps is achievable between Site 1 and Site 2 with very limited interruption annually.

Table 3-6 summarizes the various radio link design results studied with different modulation and antenna

schemes and provides overall annual availability value, related free space loss, rain loss and multipath fading

effects. As the purpose of the traffic calculation is to provide 155Mbps traffic capacity, the minimal antenna

dimension and acceptable interruption rate are considered for optimal design.

Radio Link Design Study -4 with 16 QAM modulation and with 0.6m Antenna is considered as the suitable one

with annual interruption time of 1,18 minutes. The obvious reason for this selection is its ability to transport

155Mbps traffic smoothly and at the same time allowing to use considerably small diameter antenna of 0,6m.

Small diameter antennas is very favorable to use when possible because of its small aperture for wind and tower

that results in considerably less tower leasing costs. Some studies show that using smaller antennas can provide

up to %75 savings in tower leasing costs over a five years period which is sometimes equal to the cost of radio

link equipment itself.

Another design consideration for achieving better radio link availability and less transmission path interruption is

to use automatic Adaptive Modulation feature of selected radio link equipment to fight against adverse weather

conditions. Adaptive Modulation can lower modulation level from 16QAM in our study to 4QAM level and this

allows even much smaller interruption time (0,18 minute) but with a bit smaller capacity (80Mbps) for this short

adverse weather conditions period.

1.Design 2.Design 3.Design 4.Design 5.Design

Frequency

Band

Channel

Band The Values Obtained

256QAM

Antenna

Height

1.8m

256QAM

Antenna

Height

1.2m

64QAM

Antenna

Height

0.6m

16QAM

Antenna

Height

0.6m

4QAM

Antenna

Height

0.6m

7125-8500

MHz 56 MHz

Annual rain + multipath

availability (%) 99.9999 99.99947 99.99804 99.99978 99.99997

Annual rain + multipath

unavailability (min) 0.54 2.8 10.3 1.18 0.18

Tx and Rx Data Rate (Mhz) 348 348 254 160 80

EIRP (dBm) 57.8 54.3 49.6 51.6 53.6

Table 3-6 R/L Total Result

62

3.2 L2 VPN ETHERNET OVER MPLS

Service Providers are adopting their ATM and Frame Relay infrastructure to Metro Ethernet technology. For this

reason standard methods are needed which can enable migration from Frame Relay and ATM architecture to

IP/MPLS architecture.

It is not required for Service Provider to know about user’s IP address structure, network topology, routing

information and the protocols used. This allows better security for users. Layer 2 VPN connections emulate

LAN behavior over IP/MPLS network. Thus Ethernet devices can communicate as if they are connected to the

same LAN segment. L2VPN feature enables service providers to define L2 services between geographically

distant end points. Service provider uses access network in order to connect a user to the backbone. This access

network can be a mixture of Layer 2 technologies like Ethernet and/or Frame Relay.

The connection between the user and service provider is called as attachment circuit (AC). Traffic coming from

the user transported to service provider backbone through this connection. This traffic is then tunneled inside the

service provider backbone inside pseudo wires. Traffic leaves the service provider network at the other end and

reaches to user’s network. This way two end point of a user where located in different geographies can

communicate as if they are connected to the same switch.

In order to keep separation of user traffic, two vpns can be defined as VLAN mode and Port mode. Relevant IP

block traffic belonging to different VPNs can be forwarded without interaction on the same switch by using

VLAN mode.

As obtaining Leased Line is more costly than L2 Ethernet services and Ethernet provides the same level of

convenience and security, L2 Ethernet is preferred. L2 VPN Ethernet over MPLS service application is realized

in GNS3 with Cisco 7200 routers as point to point. Two distant PCs which located in separate locations are

connected as if they are the members of the same local area network. This application is performed in laboratory

environment with Cisco ASR9010 router as point to multipoint connections.

3.2.1. POINT TO POINT L2 VPN ETHERNET OVER MPLS IN GNS3

GNS3 Software is used for simulating real router IOS of the field routers. With GNS3 software point to point

Ethernet over MPLS (EoMPLS) L2 VPN application is realized. User side R2 router is connected to Service

Provider’s R1 router. R1 and R3 router interconnection is for mimicking service provider network as shown in

Figure 3-17. R3 router is then connected to user network in the other end. R2 user router has IP address of

11.11.11.1, but R1 router’s (f 0/1) port has no IP address as it is defined as L2 interface. The IP addresses

defined for R1 (f 0/0) port and R3 (f 0/0) port communication are 13.13.13.1/24 (R1) and 13.13.13.3/24 (R3).

The router configuration information is available in Appendix-B.

63

Figure 3-17 Point To Point Ethernet Over MPLS L2 VPN

Ethernet over MPLS (EoMPLS) provides a tunneling mechanism for Ethernet traffic over MPLS backbone and

allows Ethernet frames to be encapsulated inside MPLS packets.

As R2 and R4 routers are virtually connected to each other via EoMPLS, CDP/LLDP and dynamic routing

protocols (EIGRP) are opened, results are shown in Figure 3-18 and Figure 3-19.

.

Figure 3-18 CDP Neighbourship between R2 and R4

64

Figure 3-19 EIGRP Neighbourship between R2 and R4

From the dynamic routing protocol point of view of user routers, IP backbone of service provider seems as

transparent. Due to this reason it is possible for user to run the protocols that it wishes between its locations.

GNS3 simulation confirmed that Point To Point Ethernet Over MPLS L2 VPN setup is working properly and

provides the expected behavior that two user routers work as if they are connected to the same local LAN switch.

It is also observed that even service provider’s backbone network does not support user’s EIGRP protocol or any

other protocol, user has the chance to use its own protocols for its network. Next phase is realized in laboratory

environment by using Point To Multipoint Ethernet Over MPLS L2 VPN service over a MPLS backbone

composed of Cisco ASR 9010 routers that are interconnected via DWDM and SDH nodes.

65

3.2.1 MULTIPOINT L2 VPN ETHERNET OVER MPLS IN LABORATORY

3.2.1.1 MULTIPOINT ETHERNET OVER MPLS L2 VPN WITHOUT L2 SWITCH

This part explains the Point to Multipoint Ethernet over MPLS L2 VPN service work realized in a real network

that is interconnected with different transmission media like DWDM and SDH in laboratory environment as

depicted in Figure 3-20. PCs which are located in different places are interconnected with this p2mp MPLS VPN

service by connecting to the backbone routers and making necessary configurations. These configurations are

detailed in Appendix-C.

Figure 3-20 Ethernet Over MPLS L2 VPN application

There are 5 PCs located in 5 different places. Firstly, all PCs are configured in a way that to have the IP

addresses from the same IP block. Suitable ports on backbone routers are selected and configured accordingly

and connected to these PCs. In this first application, the connections between backbone router and PCs are

realized via 40x1 GE ports of CISCO ASR9010 backbone routers.

The distances between each site are given in Table 3-7. Site 1 – Site 2 and Site 1 – Site 5 transmission

connection is realized through 40x1 GE port Ethernet card of ASR 9010 Backbone Router and provides 1Gbps

transmission capacity over Ethernet over SDH transport environment. As distance is quite long for Site 2 - Site

3, Site 3 - Site 4 and Site 4 -Site 5; transmission is provided by 4x10 GE port Ethernet card of ASR 9010

Backbone Routers, these 10GE ports go through a DWDM network once traffic becomes colored by the use of

DWDM transponders of DWDM nodes.

66

SITE A SITE B DISTANCE

1. SITE 1 SITE 2 2 KM





Table 3-7 Distance Between Sites

Planning of transmission lines are performed according to the services that the service provider considers to offer

its customers and available network topology/span, and whether it should go through over SDH or over DWDM

is decided accordingly. One of the important parameters in giving this decision is the efficient use of the existing

infrastructure while providing requested user traffic capacities. As an example, adding extra cards to an existing

DWDM line is far more expensive than adding card or capacity to SDH path. The Cisco ASR 9010 40x1 GE and

4x10 GE line cards are shown in Figure 3-21 and used L2 Switch is shown in Figure 3-22.

Figure 3-21 Cisco ASR9010 Picture and Cards

67

Figure 3-22 L2 Switch

After completing transmission connections and PC to router connections, router configurations are entered to

enable router to router communication. This is started with Site 1 location router and MPLS and required

configurations are realized. Afterwards Site-2, Site-3, Site-4 and Site 5 routers are configured, tunnels are

defined according to Appendix-C and below configuration commands. Figure 3-23 depicts the generated pseudo

wire tunnels between sites.

Sample Site 1 tunnel configuration

l2vpn

bridge group STOCKHOLM

bridge-domain GAVLE

interface GigabitEthernet0/0/0/6

!

vfi L2VPN_TEST

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!

Figure 3-23 Generated Pseudowires Tunnel between Sites

68

The response times are observed from the PC that is located in Site 2 to all other PCs after defining pseudowire

tunnels. Site 2 to Site 1, Site 2 to Site 3, Site 2 to Site 4 and Site 2 to Site 5 response times are shown in Figure

3-24, 3-25, 3-26 and 3-27 accordingly.

Figure 3-24 Site 2-PC-2 to Site 1-PC-1 Reaction time


69



While PC-2 in Site 2 continues to send packets to all other PCs in the other site locations, the 10Gbps DWDM

link between Site 2 and Site 3 is cut. New connection setup is given in Figure 3-28. This caused a temporary loss

of PC communication but it is regained again by using Site 2 – Site 5 SDH 1 Gbps connection. As this cut

affected both the link capacity (link capacity is reduced from 10Gbps to 1Gbps) and transmission distance,

longer response times are observed for some sites. New Site 2 to Site 1, Site 2 to Site 3, Site 2 to Site 4 and Site

2 to Site 5 response times are shown in Figure 3-29, 3-30, 3-31 and 3-32 accordingly.

70

Figure 3-28 Ethernet Over MPLS L2 VPN Application Link Failure Site 2 to Site 3

Figure 3-29 Site 2-PC-2 to Site 1-PC-1 Link Failure

71



72


It is seen that when Site 2 – Site 3 interconnection is lost, the communication between the PCs that are located in

Site 3, Site 4 and Site 5 becomes temporarily interrupted and within a very short time, the predefined path

between Site 2 – Site 5 takes the responsibility and actively continues to tunnel MPLS packets. Site 2 – Site 1 PC

connection is not interrupted because Site 2 – Site 1 MPLS tunnel traverses through another SDH channel. This

work is realized with port mode. After L2 switches are connected to ASR 9010 routers, ASR 9010s are

configured as VLAN mode and L2 switch configurations are performed. These are shown in Appendix-D.

As result L2 Ethernet over MPLS application is realized in 5 distinct locations and user PCs are observed to be

properly working as if they are connected to the same local area network with a secure, cost efficient solution.

Both for customer and Service Provider, information security (as sharing of IP address information and routing

details are not required) is achieved. Additionally, customers can continue to use of protocol of its choice

regardless of the service provider.

Future Work: MPLS technology allows for opening tunnels automatically on the Service Provider routers with

the use of configurable “BGP auto discovery” feature that can provide full mesh pseudowire connections. This

feature lessens the possibility of configuration related problems due to adding more routers to the network and

provides better scalability as it removes the need for manual and error-prone service work for pseudowire tunnel

configurations.

73

4 DISCUSSION

STRENGTHS:

PathLoss radio link planning software is well known and widely used tool in GSM, 3G, point to point and point

to multipoint radio link calculations. In addition to standard distinct radio link planning, interference effects

caused by using other close frequency bands, or effect of cross polar interference can be considered and be taken

into account when required for more realistic radio link planning results. Close approximation for rain related

fading and multipath fading effects provides realistic result information for achieving required link availability

targets.

WEAKNESS:

Especially for the microwave radio links with a long distance over sea, PathLoss tool calculation results for hot

season with strong evaporation conditions may not fully reflect the real world link availability achievement

values.

74

5 CONCLUSIONS

As the purpose of the traffic calculation is to provide 155Mbps traffic capacity, the minimal antenna dimension

and acceptable interruption rate are considered for optimal design. Radio Link Design Study -4 with 16 QAM

modulation and with 0.6m Antenna is considered as the suitable one with annual interruption time of 1,18

minutes. The obvious reason for this selection is its ability to transport 155Mbps traffic smoothly and at the same

time allowing to use considerably small diameter antenna of 0,6m. Small diameter antennas is very favorable to

use when possible because of its small aperture for wind and tower that results in considerably less tower leasing

costs. Some studies show that using smaller antennas can provide up to %75 savings in tower leasing costs over

a five years period which is sometimes equal to the cost of radio link equipment itself.

Another design consideration for achieving better radio link availability and less transmission path interruption is

to use automatic Adaptive Modulation feature of selected radio link equipment to fight against adverse weather

conditions. Adaptive Modulation can lower modulation level from 16QAM in our study to 4QAM level and this

allows even much smaller interruption time (0,18 minute) but with a bit smaller capacity (80Mbps) for this short

adverse weather conditions period.

As radio link design part is concluded by deciding on which frequency and spectrum bandwidth to use, the

optimal modulation scheme and antenna size, we can continue with next step where MPLS modelling has been

studied and results are as follows.

As L2 point to point service based leased line costs are quite expensive, L2 VPN based approach is considered in

order to provide the same service with smaller cost base line. With L2 VPN approach, Service Providers do not

require customer’s IP address structure, network topology, routing information and the protocols to be

transported before defining a connection between customer sites and this makes it unnecessary for customer to

share its confidential network information with Service Provider which means better security for some

customers. L2 VPN based connections provide LAN behavior over IP/MPLS network (emulation of Local Area

Network over a geographically spread WAN). With this service type, distinct geography Ethernet customer end

points communicate with each other as if they are part of the same single Local Area Network.

Within the scope of this thesis study, for MPLS application, firstly Point to Point L2 VPN Ethernet over MPLS

is simulated on GNS3 software and then in the lab environment, Point to Multipoint Ethernet over MPLS L2

VPN is realized for 5 distinct location connections and PC client connection between these five locations is

provided with a cost effective and secure manner. Both for customer and Service Provider, information security

(as sharing of IP address information and routing details are not required) is achieved.

As a result, for the customer locations which require data connections but lack fiber optical cable infrastructure,

designed radio link connection is considered for enabling a cost effective transport for communication between

all customer sites. Together with cost effective Ethernet over MPLS L2 VPN approach, providing radio link

connection for non-fiber customer sites, help us in achieving an overall secure, isolated and cost effective

solution.

75

Future Work

Different Radio Link simulation designs can be considered for obtaining lower annual interruption time and

better link availability by using different modulation techniques, different antenna sizes and even different radio

models depending on customer site connection requirements like needed bandwidth and geographical customer

site information.

Even not simulated/considered in this thesis work, used MPLS technology allows for opening tunnels

automatically on the Service Provider routers with the use of configurable “BGP auto discovery” feature that can

provide full mesh pseudowire connections. This feature lessens the possibility of configuration related problems

due to adding more routers to the network and provides better scalability as it removes the need for manual and

error-prone service work for pseudowire tunnel configurations.

76

References

[1] C. Taşkın, “Ağ Teknolojileri ve Telekomünikasyon,” , p:336, CA Istanbul, 2012.

[2] L. Fuentelsaz, J. P. Maicas and Y.Polo, “The Evolution of Mobile Communications in Europe:

The Transition from the Second to the Third Generation,” Telecommunications Policy Vol:32,

Issue 6, July 2008, 436-449, Elsevier.

[3] G.P. Agrawal, “Fiber-Optic Communication Systems”, p:561, John Wiley&Sons, New York.

1997.

[4] G.Held, “Understanding Data Communications,” Indianapolis: Sams Publishing, p:874, ISBN:

978-0-417-6 2745-6, 1996.

[5] S. Ertürk, “Sayısal Haberleşme”, Birsen Yayınevi, p: 197, İstanbul, 2005.

[6] J.G. Proakis, “Digital Communications,” 5th ed. , p:319, Mc Graw-Hill, New York, 1995.

[7] H.P. HSU, “Schaum’s Outlines: Analog and Digital Communication,” 2nd ed. Mc Graw-Hill,

p:320, ISBN: 0-07-030644-3, New York, 2003.

[8] M.K. Simon and M.S. Alouini, “Digital Communication over Fading Channels” , 2nd ed.,

Wiley, p:936, ISBN:978-0-471-64953-3, New Jersey, 2005.

[9] P.Bergholm, “Tietoliikenteen radiolaitteet Modeemit I. Page 7. Available,” 2011.

https://noppa.aalto.fi/noppa/kurssi/s-26.3301/materiaali/S-

26_3301_luentomateriaali_15.3.2011.pdf , March 2011.

[10] G.L. Stüber, “Principles of Mobile Communication”, 2nd ed., Kluwer Academic Publishers,

Massachusetts, 248-299. 2001.

[11] A.H. Kayran, “Analog Haberleşme”, Birsen Yayınevi, İstanbul, 103:111-123. 2002.

[12] S.V.Kartalopoulos, “DWDM: Networks, Devices, and Technology,” John Wiley & Sons, New

York, p:68, 2003.

[13] D.Wetteroth, “OSI Reference Model for Telecommunications,” McGraw-Hill, p:396, New

York, 2002.

[14] R.Çölkesen and B.Örencik, “Bilgisayar Haberleşmesi ve Ağ Teknolojileri,” Papatya Yayınları,

p:480, ISBN: 978-975-6797-00-6, İstanbul, 2012.

[15] H.Koray Tutkun., "Telekomünikasyon Sistemleri Sistem Uzmanı El Kitabı", Seçkin Yayıncılık,

p:291, ISBN: 978-975-0224-84-3, Ankara, 2013.

[16] H.G.Perros., “Connection-Oriented Networks : SONET/SDH, ATM, MPLS and Optical

Networks,” John Wiley&Sons, p:356, ISBN:978-0-470-02163-7, Hoboken NJ, 2005.

[17] E. Rosen, A. Viswanathan and R.Callon, “Multiprotocol Label Switching Architecture,” RFC

3031, p:61, 2001.

[18] S.B.J. Yoo, “Optimal Label Switching, MPLS, MPLSmS and GMPLS,” Optical Network

Magazine, 17-31. 2003.

https://noppa.aalto.fi/noppa/kurssi/s-26.3301/materiaali/S-26_3301_luentomateriaali_15.3.2011.pdf

https://noppa.aalto.fi/noppa/kurssi/s-26.3301/materiaali/S-26_3301_luentomateriaali_15.3.2011.pdf

77

[19] IEC, “Multiprotocol Label Switching (MPLS),” International Engineering Concertium Web

ProForum Tutorials. www.iec.org. 2015.

[20] H. T. Friis "A note on a simple transmission formula", Proc. IRE, vol. 34, 254-256. 1946.

http://www.iec.org/

A1

Appendix A

Figure A-1 Radio and Antenna Model

Figure A-2 Transmission Analysis for rain loss

A2

Figure A-3 Transmission Analysis for path profile data

Figure A-4 Radio Specification for 256QAM

A3



B1

Appendix B

POINT TO POINT L2 VPN ETHERNET OVER MPLS IN GNS3 ROUTER CODE

Cisco Router IOS Configuration

We used the Cisco 7200 Series router IOS version 15.1 as GNS3 router IOS. To implement point-to-point L2

VPN Ethernet over MPLS, firstly OSPF neighbourship was established between the directly attached routers.

Then, MPLS was configured on each router and Label Distribution Protocol was used to exchange labels

between the neighbours. Finally, the pseudowire (L2VPN tunnel) was created between the end-points where no

ip addresses were configured on the interfaces attached to PCs.

R1 CODE:

! Last configuration change at 15:57:33 UTC Wed Jun 17 2015

!

version 15.1

service timestamps debug datetime msec

service timestamps log datetime msec

!

hostname R1

!

boot-start-marker

boot-end-marker

!

no aaa new-model

no ip icmp rate-limit unreachable

!

no ip domain lookup

ip cef

no ipv6 cef

!

multilink bundle-name authenticated

!

ip tcp synwait-time 5

ip ssh version 1

pseudowire-class test

encapsulation mpls

!

interface Loopback0

ip address 1.1.1.1 255.255.255.255

!

interface FastEthernet0/0

description to_R3

ip address 13.13.13.1 255.255.255.0

speed auto

duplex auto

mpls ip

no keepalive

!


description PC2

no ip address

speed auto

duplex auto

B2

xconnect 3.3.3.3 10 encapsulation mpls pw-class test

!

router ospf 1

redistribute connected subnets

network 13.13.13.0 0.0.0.255 area 0

mpls ldp sync

!

ip forward-protocol nd

!

no ip http server

no ip http secure-server

!

control-plane

!

line con 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line aux 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line vty 0 4

login

!

end

R2 CODE:

!


!

version 15.1



!

hostname R2

!

boot-start-marker

boot-end-marker

!

no aaa new-model


!

no ip domain lookup

ip cef

no ipv6 cef

!


!


ip ssh version 1

!


ip address 11.11.11.1 255.255.255.0

speed auto

duplex auto

!

B3


no ip address

shutdown

speed auto

duplex auto

!

router eigrp 100

network 11.11.11.0 0.0.0.255

!


!

no ip http server


!

control-plane

!

line con 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line aux 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line vty 0 4

login

!

end

R3 CODE:


!

version 15.1



!

hostname R3

!

boot-start-marker

boot-end-marker

!

no aaa new-model


!

no ip domain lookup

ip cef

no ipv6 cef

!


!


ip ssh version 1

pseudowire-class test

encapsulation mpls

!

interface Loopback0

B4

ip address 3.3.3.3 255.255.255.255

!


description to_R1

ip address 13.13.13.3 255.255.255.0

speed auto

duplex auto

mpls ip

!


description PC4

no ip address

speed auto

duplex auto

xconnect 1.1.1.1 10 encapsulation mpls pw-class test

!

router ospf 1

redistribute connected subnets

network 13.13.13.0 0.0.0.255 area 0

mpls ldp sync

!


!

no ip http server


!

control-plane

!

line con 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line aux 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line vty 0 4

login

!

end

R4 CODE:


!

version 15.1



!

hostname R4

!

boot-start-marker

boot-end-marker

!

enable password cisco

!

B5

no aaa new-model


!

no ip domain lookup

ip cef

no ipv6 cef

!


!


ip ssh version 1

!


ip address 11.11.11.2 255.255.255.0

speed auto

duplex auto

!


no ip address

shutdown

speed auto

duplex auto

!

router eigrp 100

network 11.11.11.0 0.0.0.255

!


!

no ip http server


!

control-plane

!

line con 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line aux 0

exec-timeout 0 0

privilege level 15

logging synchronous

stopbits 1

line vty 0 4

password cisco

login

!

end

C1

Appendix C

MULTIPOINT L2 VPN ETHERNET OVER MPLS CODE WITHOUT L2 SWITCH

Cisco Router IOS XR Configuration

We used Cisco ASR 9010 routers on production with IOS XR version 4.0.3. To implement multipoint L2 VPN

Ethernet over MPLS, firstly OSPF neighbourship was established between the directly attached routers. Then,

MPLS was configured on each router and Label Distribution Protocol was used to exchange labels between the

neighbours. Finally, the pseudowire (L2VPN tunnel) was created between the end-points where no ip addresses

were configured on the interfaces attached to PCs. A separate L2VPN tunnel is established from each site to the

remaining four sites. The PCs were directly connected to Cisco ASR 9010 router ports without using L2

switches.

SITE 1 CONFIGURATION

RP/0/RSP0/CPU0:Site_1#sh run

Thu May 7 23:42:18.469 UTC

Building configuration...

!! IOS XR Configuration 4.0.3

!! Last configuration change at Thu May 7 23:12:35 2015 by admin

!

hostname Site_1

logging disable

telnet vrf default ipv4 server max-servers 15

domain name Net_1

cdp

line console

exec-timeout 0 0

length 40

!

line default

exec-timeout 0 0

session-timeout 0

!

vty-pool default 0 15

interface Loopback0

ipv4 address 1.1.1.1 255.255.255.255

!

interface MgmtEth0/RSP0/CPU0/0

shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


C2

shutdown

!


description to_L2switch

ipv4 address 1.1.9.1 255.255.255.252

!


description to_Site_2_over_SDH

speed 100

!

interface GigabitEthernet0/0/0/3.800

ipv4 address 1.13.255.2 255.255.255.252

encapsulation dot1q 800

!


shutdown

!


shutdown

!


description PC_1

speed 100

l2transport

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

C3

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

C4

!


shutdown

!

interface TenGigE0/1/0/0

shutdown

!


shutdown

!


shutdown

!


shutdown

!

router ospf 10

mpls ldp sync

redistribute connected

area 0


network point-to-point

!

l2vpn


bridge-domain GAVLE


!

vfi L2VPN_TEST

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!

mpls ldp

nsr

igp sync delay 30


!

end

RP/0/RSP0/CPU0:Site_1#show mpls ldp neighbor

Thu May 7 23:42:39.222 UTC

Peer LDP Identifier: 1.123.255.255:0

TCP connection: 1.123.255.255:20406 - 1.1.1.1:646

Graceful Restart: No

Session Holdtime: 180 sec

State: Oper; Msgs sent/rcvd: 1352/1346; Downstream-Unsolicited

Up time: 01:22:42

LDP Discovery Sources:

Targeted Hello (1.1.1.1 -> 1.123.255.255, active)

Addresses bound to this peer:

1.123.9.1 1.123.255.255 60.5.10.66 60.5.14.54


TCP connection: 1.13.255.255:63774 - 1.1.1.1:646

C5




Up time: 01:22:39



GigabitEthernet0/0/0/3.800


1.13.9.1 1.13.255.1 1.13.255.255 60.5.13.1 192.168.200.5


TCP connection: 1.14.255.255:59431 - 1.1.1.1:646




Up time: 01:22:33




1.14.9.1 1.14.255.255 60.5.13.2 60.5.14.53


TCP connection: 1.10.255.255:57417 - 1.1.1.1:646




Up time: 01:22:27




1.10.9.1 1.10.255.255 60.5.10.65 192.168.200.6



Thu May 7 18:31:45.376 UTC




!

hostname Site_2

logging disable


cdp

line console

exec-timeout 0 0

length 0

!

line default

exec-timeout 0 0

session-timeout 30

!

interface Loopback0

ipv4 address 1.13.255.255 255.255.255.255

!


shutdown

!


shutdown

C6

!


shutdown

!



ipv4 address 1.13.9.1 255.255.255.252

!



!


ipv4 address 192.168.200.5 255.255.255.252


!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!



!


ipv4 address 1.13.255.1 255.255.255.252


!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


description PC_2

speed 100

l2transport

!


shutdown

!

C7


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C8


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


description to_Site_3_over_DWDM

cdp

ipv4 address 60.5.13.1 255.255.255.252

transceiver permit pid all

!


shutdown

!


shutdown

!


shutdown

!

controller dwdm0/1/0/0

admin-state out-of-service

!



!



!



!

router ospf 10

mpls ldp sync

auto-cost reference-bandwidth 10000


redistribute static

area 0



!



!



!

l2vpn


bridge-domain GAVLE

C9


!

vfi L2VPN_TEST

neighbor 1.1.1.1 pw-id 1000

!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!

mpls ldp

nsr

igp sync delay 30


!


!


!

end


Thu May 7 19:25:35.181 UTC


TCP connection: 1.123.255.255:63275 - 1.13.255.255:646




Up time: 1d02h




1.123.9.1 1.123.255.255 60.5.10.66 60.5.14.54


TCP connection: 1.14.255.255:54999 - 1.13.255.255:646




Up time: 1d02h


TenGigE0/1/0/0



1.14.9.1 1.14.255.255 60.5.13.2 60.5.14.53


TCP connection: 1.10.255.255:646 - 1.13.255.255:29999




Up time: 03:58:23





1.10.9.1 1.10.255.255 60.5.10.65 192.168.200.6

C10


TCP connection: 1.1.1.1:646 - 1.13.255.255:63774




Up time: 02:20:55





1.1.1.1 1.1.9.1 1.13.255.2

RP/0/RSP0/CPU0:Site_2#



Thu May 7 23:34:09.948 UTC




!

hostname Site_3

logging disable


cdp

line console

exec-timeout 0 0

length 0

!

vty-pool default 0 10

interface Loopback0

ipv4 address 1.14.255.255 255.255.255.255

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

C11

!


description PC_3

l2transport

!


shutdown

!


shutdown

!


shutdown

!



ipv4 address 1.14.9.1 255.255.255.252

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C12


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!



cdp

ipv4 address 60.5.13.2 255.255.255.252


!



cdp

ipv4 address 60.5.14.53 255.255.255.252


!

C13


shutdown

!



!



!



!



!

router ospf 10

mpls ldp sync



redistribute static

area 0



!



!

l2vpn


bridge-domain GAVLE


!

vfi L2VPN_TEST


!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!

mpls ldp

nsr

igp sync delay 30


!


!

end


Thu May 7 23:34:33.782 UTC


TCP connection: 1.123.255.255:56160 - 1.14.255.255:646




Up time: 1d01h


C14

TenGigE0/1/0/2



1.123.9.1 1.123.255.255 60.5.14.54 60.5.10.66


TCP connection: 1.13.255.255:646 - 1.14.255.255:54999




Up time: 1d01h


TenGigE0/1/0/1



1.13.9.1 1.13.255.1 1.13.255.255 60.5.13.1

192.168.200.5


TCP connection: 1.10.255.255:646 - 1.14.255.255:52491




Up time: 03:08:01




1.10.9.1 1.10.255.255 60.5.10.65 192.168.200.6


TCP connection: 1.1.1.1:646 - 1.14.255.255:59431




Up time: 01:29:31




1.1.1.1 1.1.9.1 1.13.255.2




Thu May 7 23:24:20.829 UTC




!

hostname Site_4

logging disable


cdp

line console

exec-timeout 0 0

length 0

!

interface Loopback1

ipv4 address 1.123.255.255 255.255.255.255

C15

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!



ipv4 address 1.123.9.1 255.255.255.252

!


shutdown

!


description PC_4

l2transport

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C16


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C17


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!



cdp

ipv4 address 60.5.10.66 255.255.255.252


!


shutdown

!



cdp

ipv4 address 60.5.14.54 255.255.255.252


!


shutdown

!



!



!



!



!

router ospf 10

mpls ldp sync



area 0



!



!

l2vpn


bridge-domain GAVLE


C18

!

vfi L2VPN_TEST


!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

mpls ldp

nsr

igp sync delay 30


!


!

end


Thu May 7 23:24:49.539 UTC


TCP connection: 1.14.255.255:646 - 1.123.255.255:56160




Up time: 1d01h


TenGigE0/1/0/2



1.14.9.1 1.14.255.255 60.5.13.2 60.5.14.53


TCP connection: 1.13.255.255:646 - 1.123.255.255:63275




Up time: 1d01h




1.13.9.1 1.13.255.1 1.13.255.255 60.5.13.1 192.168.200.5


TCP connection: 1.10.255.255:646 - 1.123.255.255:46287




Up time: 03:04:02


TenGigE0/1/0/0



1.10.9.1 1.10.255.255 60.5.10.65 192.168.200.6


TCP connection: 1.1.1.1:646 - 1.123.255.255:20406


C19



Up time: 01:24:34




1.1.1.1 1.1.9.1 1.13.255.2




Thu May 7 15:18:56.681 UTC




!

hostname Site_5

logging disable


cdp

line console

exec-timeout 0 0

length 0

!

interface Loopback0

ipv4 address 1.10.255.255 255.255.255.255

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C20


shutdown

!


shutdown

!


shutdown

!


description PC_5

l2transport

!



ipv4 address 192.168.200.6 255.255.255.252

!



ipv4 address 1.10.9.1 255.255.255.252

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!

C21


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!


shutdown

!



cdp

ipv4 address 60.5.10.65 255.255.255.252


!


shutdown

!

C22


shutdown

!



!



!



!



!

router ospf 10

mpls ldp sync



area 0



!



!

l2vpn


bridge-domain GAVLE


!

vfi L2VPN_TEST


!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!

mpls ldp

nsr

igp sync delay 30


!


!

end

RP/0/RSP0/CPU0:Site_5#sh mpls ldp neighbor

Thu May 7 16:17:14.915 UTC


TCP connection: 1.123.255.255:46287 - 1.10.255.255:646




Up time: 04:03:23


TenGigE0/1/0/1

C23



1.123.9.1 1.123.255.255 60.5.10.66 60.5.14.54


TCP connection: 1.14.255.255:52491 - 1.10.255.255:646




Up time: 04:02:16




1.14.9.1 1.14.255.255 60.5.13.2 60.5.14.53


TCP connection: 1.13.255.255:29999 - 1.10.255.255:646




Up time: 04:01:19



GigabitEthernet0/0/0/9


1.13.9.1 1.13.255.1 1.13.255.255 60.5.13.1 192.168.200.5


TCP connection: 1.1.1.1:646 - 1.10.255.255:57417




Up time: 02:23:39




1.1.1.1 1.1.9.1 1.13.255.2


D1

Appendix D

THE FOLLOWING L2 SUB-INTERFACE IS CREATED FOR VLAN-MODE

Cisco Router IOS XR Configuration

We used Cisco ASR 9010 routers on production with IOS XR version 4.0.3. To implement multipoint L2 VPN

Ethernet over MPLS, firstly OSPF neighbourship was established between the directly attached routers. Then,

MPLS was configured on each router and Label Distribution Protocol was used to exchange labels between the

neighbours. Finally, the pseudowire (L2VPN tunnel) was created between the end-points. A separate L2VPN

tunnel is established from each site to the remaining four sites. The PCs were connected to L2 switches, the L2

switches were connected to Cisco ASR 9010 router ports which were configured as L2 interfaces which were

assigned to a VLAN.




ipv4 address 1.1.9.1 255.255.255.252

!

The following L2 sub-interface is created for VLAN-MODE.

interface GigabitEthernet0/0/0/2.501 l2transport

encapsulation dot1q 501 exact

rewrite ingress tag pop 1 symmetric

!

L2 switch port 4 (where the PC is connected) is untagged on VLAN 501. Cisco ASR 9010 is connected to L2

switch port 25. VLAN 501 is sent tagged from switch to ASR.

l2vpn


bridge-domain GAVLE

interface GigabitEthernet0/0/0/6 (when in Port-Mode, PC is connected to this port)

!

interface GigabitEthernet0/0/0/2.501 (when in VLAN-Mode, PC is connected to L2 switch port 4)

!

vfi L2VPN_TEST

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

SITE 1 SWITCH 1 CONFIGURATION

L2switch_Site_1# sh run

!

hostname L2switch_Site_1

!

syslog output info local volatile

syslog output info local non-volatile

!

D2

bridge

vlan create 501

!

vlan add default 1-3,5-43 untagged

vlan add br501 25 tagged

vlan add br501 4 untagged

!

vlan pvid 1-3,5-43 1

vlan pvid 4 501

!

port description 4 PC_1

port description 25 ASR_9010_Site_1

!

interface lo

no shutdown

!

interface default

no shutdown

description Mgmt

ip address 1.1.9.2/30

!

ip route 0.0.0.0/0 1.1.9.1

!

end




ipv4 address 1.13.9.1 255.255.255.252

!





!



l2vpn


bridge-domain GAVLE


!


!

vfi L2VPN_TEST


!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

SITE 2 SWITCH 2CONFIGURATION


!

D3


!



!

bridge

vlan create 502

!




!


vlan pvid 4 502

!



!

interface lo

no shutdown

!

interface default

no shutdown

description Mgmt


!

ip route 0.0.0.0/0 1.13.9.1

!

end




ipv4 address 1.14.9.1 255.255.255.252

!





!



l2vpn


bridge-domain GAVLE


!


!

vfi L2VPN_TEST


!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

D4

!



!


!



!

bridge

vlan create 503

!




!


vlan pvid 4 503

!



!

interface lo

no shutdown

!

interface default

no shutdown

description Mgmt


!

ip route 0.0.0.0/0 1.14.9.1

!

end




ipv4 address 1.123.9.1 255.255.255.252

!





!



l2vpn


bridge-domain GAVLE


!


!

vfi L2VPN_TEST


D5

!

neighbor 1.10.255.255 pw-id 1000

!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!



!


!



!

bridge

vlan create 504

!




!


vlan pvid 4 504

!



!

interface lo

no shutdown

!

interface default

no shutdown

description Mgmt

ip address 1.123.9.2/30

!

ip route 0.0.0.0/0 1.123.9.1

!

end




ipv4 address 1.10.9.1 255.255.255.252

!





!



l2vpn


bridge-domain GAVLE

D6


!


!

vfi L2VPN_TEST


!

neighbor 1.13.255.255 pw-id 1000

!

neighbor 1.14.255.255 pw-id 1000

!

neighbor 1.123.255.255 pw-id 1000

!



!


!



!

bridge

vlan create 505

!




!


vlan pvid 4 505

!



!

interface lo

no shutdown

!

interface default

no shutdown

description Mgmt


!

ip route 0.0.0.0/0 1.10.9.1

!

end

modulation coding in a radio link and data transfer...

Documents