mod4_ eda system overview

Volume 10 Module 04EDA System Overview

INDEXVolume 10 Module 04

EDA System Overview

Section Contents Page No.

1.0 Introduction To Ethernet DSL Access 48

1.1 ADSL Standards 48

1.1 Main Features 49

2.0 Ethernet DSL Architecture 49

2.1 Aggregation Node 50

2.2 Ethernet Controller 51

2.3 IP DSLAM 54

3.0 Line And Loop Test 57

3.1 Single Ended Line Test 58

3.2 Loop Diagnostics 58

4.0 Link Aggregation And Redundancy 58

4.1 Link Aggregation 59

4.2 Link Redundancy 60

5.0 Telephony Over IP Scenario 60

6.0 Baseband Telephony Scenarios 61

6.1 Baseband POTS/ISDN 61

6.2 Baseband POTS Using MDF Filter 62

6.3 Pre-Cabled Solutions 63

7.0 Ethernet Conversion 66

7.1 Ethernet To E1 Conversion 66

CETTM, MTNL, Mumbai G430D10 45


7.2 Ethernet To ATM Conversion 67

8.0 Network Example 67

9.0 Exercise 68

10.0 Solution To Exercise 69

Notes



Volume 10 Module 04

EDA System Overview

This chapter is designed to provide the student with an architectural overview of

the EDA system, and a description of how the EDA system supports data, video,

and telephony services. The chapter also describes how EDA supports link

aggregation and redundancy.

Objectives

Upon completion of this chapter the student will be able to:

Describe the EDA network including EDA management proxy

Describe the main features of the EDA solution

Describe EDA data, video, and telephony scenarios



1.0 INTRODUCTION TO ETHERNET DSL ACCESS

Ethernet DSL Access (EDA) is the 3rd generation DSL system from Ericsson.

The system sets a new standard for implementation of digital access systems in

a fast, flexible, and future proof way. With the EDA solution, the main

transmission technology is shifted from ATM to switched Ethernet. Compared to

ATM, the Ethernet technology is superior in important areas like scalability,

simplicity, and equipment cost.

EDA deploys integrated high-speed always-on triple play services (data, video,

and voice) and it supports more advanced services such as multicasting.

1.1 ADSL standard

EDA 2.1 supports the following ADSL transmission modes:

ADSL: ITU-T G.992.1 Annex A (POTS) and Annex B (ISDN)

ADSL: ITU-T G.992.2 Splitterless ADSL

ADSL2: ITU-T G.992.3 Annex A (POTS) and Annex B (ISDN)

ADSL2: ITU-T G.992.3 Annex M (Symmetrical services)

ADSL2: ITU-T G.992.3 Annex L (Reach Extended)

ADSL2+: ITU-T G.992.5 Annex A (POTS) and Annex B (ISDN)

ADSL2+: ITU-T G.992.5 Annex M (Symmetrical services)

While the ADSL2 standards specify a downstream frequency band up to 1.1

MHz, ADSL2+ specifies a downstream frequency up to 2.2 MHz. The result is a

significant increase in data rates on shorter phone lines. ADSL2+ increases

downstream data rates up to 25 Mbps.CETTM, MTNL, Mumbai G430D10 48


1.2 Main features

EDA offers the following features:

Cost-effective ADSL deployment

288 ADSL, ADSL2 or ADSL2+ lines in one single chassis

99.999% service availability uptime

Full range of data, video and voice services supported

Supports baseband POTS, baseband ISDN and telephony over IP

Wide range of access methods supported

Multicast support (IGMP snooping)

IGMP white list

Single ended line test (SELT); built-in algorithm, measuring line quality before

activating ADSL

Loop diagnostics (LD) test: advanced testing of both IP DSLAM and CPE

ILMI support for remote CPE configuration

Advanced security mechanisms

ETSI compliant outdoor solution

Comprehensive quality of service features

Local craft tool for on-site installation, testing and provisioning

2.0 ETHERNET DSL ARCHITECTURE

The Ethernet DSL Access solution deploys an access network with switched

Ethernet. The following paragraphs describe in detail the components of the

EDA solution with emphasis on the cornerstone of the system – the IP DSLAM.



Figure 4-1 Ethernet DSL architecture.

The figure above shows a network with the 12-line IP DSLAM EDN312 and the

288-line IP DSLAM EDN288, which comprises 24 EDN312 and one Ethernet

controller. The IP DSLAM EDN312 has a built-in filter and a splitter, which

enables baseband telephony solutions by separating voice and data traffic. The

IP DSLAMs and the aggregation nodes are managed by the public Ethernet

manager (PEM) via SNMP.

2.1 AGGREGATION NODE

An aggregation node provides layer-2 Ethernet switching with built-in power over

Ethernet (PoE). Furthermore, the node may automatically load software into the

IP DSLAMs.



An access domain contains the EDA network elements and it is based on

switched Ethernet technology creating a network around a number of

aggregation nodes. Ethernet switching facilitates a significant increase in

bandwidth by enabling simultaneous switching of data packets between ports,

and segmenting the network into different broadcast domains. Furthermore, an

Ethernet switch may be able to perform more advanced functions regarding the

traffic, such as prioritizing and traffic separation.

A LAN is defined as a single broadcast domain. Therefore, when a user

broadcast information on the LAN, every user on the LAN receives the

broadcast. The virtual LAN (VLAN) standard describes how a LAN can be

logically segmented into different layer-2 broadcast domains. In EDA, VLANs are

used to separate services, such as data, video, and voice, into different service

VLANs. To prevent unauthorized access to the service, end-users are solely

connected to the service VLANs to which they have subscribed.

The IP DSLAMs are connected towards the aggregation nodes using 100 Mbps

Ethernet connections. The aggregation nodes have optical or electrical 1 Gbps

Ethernet uplink ports.

The number of aggregation nodes in an access domain depends on parameters

such as the number of subscribers, the amount of traffic and redundancy

requirements, the number of switch ports, and service level agreements with

subscribers.

2.2 Ethernet controller

Another type of aggregation node is the Ethernet controller ECN320 with 24 fast

Ethernet downlink ports and two electrical/optical Gigabit Ethernet uplink ports.



The ECN320 feeds the IP DSLAMs with - 48 V using existing wires in the

standard Ethernet cables according to the power over Ethernet (PoE) standard

IEEE802.3af.

One large IP DSLAM

EDA management proxy (EMP) is a built-in application in the Ethernet controller

ECN320. EMP removes dependency of PEM during start-up and restart, and

reduces the number of IP addresses needed in the management network as it

defines the ECN320 and its connected network elements as one logical node. In

this way there is only one management interface and one IP address. An

aggregation node comprising an ECN320 and embedded network elements is

named Ethernet access node (EAN).

Figure 4-2 Aggregation node with ECN320

The EAN above shows a number of network elements connected to an ECN320.

The ECN can manage up to 2016 lines. This number of lines can be reached, if



all the ECN320 downlink ports are used to aggregate ESN108 switches, and if

each ESN108 aggregates 7 12-port EDN312 IP DSLAMs.

If the EDN312s are connected directly to the downlink ports of ECN320, 288

ADSL lines will be available. If the connection between the management system

and the ECN320 is lost, end-user traffic will continue. Once the link to the

management system recovers, the ECN320 identifies itself to themmanagement

system and receives the latest software and configuration data.

Inventory

The EMP inventory function ensures that all embedded nodes are automatically

registered by the ports to which they are connected, and not by their MAC

addresses. This means that implementation, expansion and replacement of

nodes are very user-friendly.

It also means that the embedded nodes are automatically loaded with application

software and a configuration file from the ECN320 and not from the management

system, thus reducing management traffic in the network.

The EAN only requires access to the PEM management system for software

upgrade, synchronization, and for SNMP commands.

EMP entities

The EMP in the ECN320 contains the following servers:

DHCP server for assigning local IP addresses to the embedded nodes

FTP server for file transfer from the PEM management server into the EMP

TFTP server for download of software into the embedded network elements

SNTP server for time synchronization



Figure 4-3 EMP entities.

Application software and configuration files for the network elements are stored

in the ECN320. The EMP is also the primary alarm receiver for the network

Elements

Local craft tools

The ECN320 contains an extensive number of functionalities for configuration,

test, and service provisioning of EANs.

Characteristics

Main characteristics of an aggregation node with EMP:

Auto-registration of network elements

Network element software and configuration files are automatically loaded

from the ECN320

One IP address per aggregation node

Built-in local craft tool functionalities

2.3 IP DSLAM



The IP DSLAM is a complete DSLAM in a box, terminating 10 or 12 subscriber

lines. The IP DSLAM converts and aggregates all incoming ADSL subscriber

lines into one or two 100 Mbps Ethernet connections.

Figure 4-4 IP DSLAM protocol stack.

As opposed to a traditional DSLAM system, the ATM layer in the ADSL protocol

stack is terminated directly in the IP DSLAM. To ensure a secure network, the IP

DSLAM is equipped with a filter to control the traffic to and from end-users.

Logical interfaces

Each subscriber may use up to 8 ATM permanent virtual circuits (PVCs) on the

local loop. The maximum number of active PVCs in an IP DSLAM is limited to

36. Each PVC is individually configured with a service specification (UBR, CBR,

VBR-rt or VBR-nrt) and a maximum bandwidth.



Figure 4-5 IP DSLAM logical interfaces.

The IP DSLAM distributes the traffic from the PVCs into different virtual local

area networks (VLANs). Each PVC is usually mapped into a single VLAN, but it

is possible to map several PVCs into the same VLAN. The figure above shows 8

PVCs mapped into 8 VLANs.

Application software and a configuration file are loaded into the flash memory

from a file server located in the ECN320 or the PEM domain server. The

configuration file in the IP DSLAM configures ports, filters, services and other

parameters.

IP DSLAM restart

When an IP DSLAM restarts, the boot software broadcasts a DHCP request. The

DHCP server responds with an IP address for the IP DSLAM, the IP address of

the domain file server and the names of and path to the application software and

configuration files.

The application software file name, which is stored in flash, iscompared with the

file name received from the DHCP server. If the file names are identical, the

application software will be fetched from the flash memory. If the file names are

different, the IP DSLAM will download the application software from the domain

file server and store it in the flash.

The configuration file, which was also specified in the DHCP response, is

downloaded from the domain file server and saved in flash.



Figure 4-6 IP DSLAM restart.

Remote storage

If an IP DSLAM restarts during an ongoing CPE session, it is essential that

configuration data is not lost. Remote storage ensures that configuration that

should survive a restart is stored.

Figure 4-8 Remote storage.

The IP DSLAM uses the domain file server as a remote storage device. The IP

DSLAM will dynamically save data concerning ongoing CPE sessions.



Each time a change occurs in the dynamic IP address table in the IP DSLAM,

the IP address table is saved to the domain file server. The tables contain the

MAC address, IP address and IP address lease time of the user equipment.

Furthermore, traffic information counters are contained.

If the IP DSLAM receives a restart command from PEM, it will always save CPE

data via remote storage before executing the restart.

3.0 LINE AND LOOP TEST

EDA offers two methods for line testing: single ended line test (SELT) and loop

diagnostics (LD).

3.1 SINGLE ENDED LINE TEST

SELT uses advanced frequency and time domain analysis to estimate both the

length of the local loop and possible ADSL service that can be carried through

the local loop. Main figures will be shown in PEM and all detailed data can be

exported for further processes.

SELT can only be performed with no CPE modem connected.

3.2 LOOP DIAGNOSTICS

Loop diagnostics is an ADSL2 feature, (ITU G.992.3), that uses both the IP

DSLAM and the customer premises equipment (CPE) to estimate the line

quality. Main figures will be shown in PEM and all detailed data can be exported

for further processing.

Loop diagnostics requires a CPE modem to be connected that supports loop

diagnostics.



4.0 LINK AGGREGATION AND REDUNDANCY

Aggregation in EDA is about ensuring end-users bandwidth. Load sharing and

redundancy are some benefits coming from using link aggregation. EDN312x

link aggregation allows double bandwidth to a node. ECN320 link aggregation

allows double bandwidth to an EAN.

ECN320 link redundancy ensures end-user traffic will continue when an ECN320

is down. Redundancy of an ENC320 is achieved by using the rapid spanning

tree protocol (RSTP). The RSTP can be used to detect and disable network

loops, and to provide backup links between switches, bridges or routers.

The EDN312x versions have two uplink ports, which facilitate power supply

redundancy, and either link aggregation or link redundancy as shown below.

Figure 4-7 Link aggregation and redundancy.

4.1 LINK AGGREGATION

Downlink ports



Link aggregation between the ECN320 and the EDN312x is always done using

the dynamic link aggregation control protocol (LACP). There is no difference

between the two uplink ports of the EDN312x. It does not matter which port is

connected to which aggregation switch port.

The EDN312x draws power from one of the links. If the link that currently

supplies the EDN312x is disconnected, or the power fails, the EDN312x will

restart and draw power from the other link. The link aggregation enables link

bandwidth up to 200 Mbps for a single EDN312x. The link that is first up will be

used for all uplink traffic. The downlink traffic will be distributed by the ECN320

between the two downlinks. Any of the ECN320 ports 1 - 24 can be used for

aggregation, but only 6 trunks can be created simultaneously due to switch

limitations.

Uplink ports

ECN320 port 25 and 26 can be configured to use dynamic or static link

aggregation toward a second level aggregation switch. LACP is used for

dynamic link aggregation.

4.2 LINK REDUNDANCY

When link redundancy is deployed, one ECN320 is configured as active and one

ECN320 is configured as standby. During normal operation, all data and

management traffic goes through the active ECN320. When the active ECN320,

the uplink connection, or the link between the ECN320 and the EDN312x fails,

the EDN312x will go over to unmanaged state, and all end-user traffic will be

directed through the standby ECN320.

5.0 TELEPHONY OVER IP SCENARIO



Figure 4-8 Telephony over IP.

Telephony over IP provides a number of independent phone lines on a single

local loop, emulated on the ADSL link in order to provide derived telephony

services. Telephony over IP may consequently be used to supply additional lines

to customers, either alone or in combination with baseband POTS. In the latter

case, up to three lines per subscriber can be supported, one as baseband POTS

and two as telephony over IP, when the Ericsson HM250dp integrated access

device (IAD) is used. Implementation of telephony over IP gives full advantage of

the EDA system.

6.0 BASEBAND TELEPHONY SCENARIOS

There are three scenarios for implementation of baseband POTS or baseband

ISDN. The first uses a 12-line IP DSLAM with integrated filter/splitter. The

second and third scenarios use a 10-line IP DSLAM in connection with external

filters/splitters.

The filters and the splitter are designed according to ETSI specifications.

6.1 BASEBAND POTS/ISDN



Figure 4-9 Baseband POTS/ISDN with EDN312.

In this solution, the 12-line IP DSLAM EDN312 is mounted in a pre-cabled

subrack and wired to the broadband MDF in the central office. This solution can

be used with any exchange system. The IP DSLAM contains the necessary

filters and a splitter and separates the ADSL signal and the baseband

POTS/ISDN signal. The ECN320 is contained in the lower part of the subrack.

6.2 BASEBAND POTS USING EXTERNAL FILTER

In this solution, the 10-line IP DSLAM EDN110 and the external filter are

mounted in a pre-cabled subrack. The external filter contains low-pass filters

designed to protect the local exchange line circuitry from the ADSL signal.



Figure 4-10 Baseband POTS with EDN110.

The 10-line POTS filter is designed for a 10-position KRONE LSA-plus connector

and it is mounted between the IP DSLAM and the local exchange.

6.3 PRE-CABLED SOLUTIONS

The following pre-cabled solutions are available:

Micro pre-cabled subrack, covers 24/36 subscribers

Small pre-cabled subrack, covers up to 80/96 subscribers

Medium pre-cabled subrack, covers up to 240/288 subscribers

Large-size cabinet solution, covers up to 720/1152 subscribers

The cabinet solutions are delivered with pre-cabled KRONE connectors. The

Ethernet cables are mounted and ready for installation. The only connections

needed are power (- 48 V), aggregation link and subscriber line interface cabling.

Micro pre-cabled subrack



Figure 4-11 Micro pre-cabled subrack.

The micro pre-cabled subrack can be equipped with three EDN312s and an

ESN108 Ethernet aggregation switch and provides 36 lines. The ESN108

supports power over Ethernet (PoE) on downlink ports and has optical uplink.

Optionally, an FE-E1 converter for electrical Ethernet uplink via four E1 PCMs

can replace one of the EDN312s. This option supports 24 lines as shown in the

figure above. The 2 HU 19” subrack can be integrated into existing cabinets.

Small pre-cabled subrack

The subrack is pre-cabled with internal LAN cabling and is delivered with the

ESN108 Ethernet aggregation switch supporting power over Ethernet (PoE). All

that remains to be done is to plug in the IP DSLAMs and to connect - 48 V,

Ethernet uplink and subscriber lines. The 5 HU 19” subrack can be mounted into

an existing cabinet.

Figure 4-12 Small pre-cabled subrack.

The unique scalability means, that this subrack covers the range between 10 to

80 subscribers using up to 8 EDN110 and 8 filters. It can also cover the range of



12 to 96 subscribers using EDN312. The figure shows the small pre-cabled

subrack mounted with 8 EDN312 and the 8-port Ethernet switch ESN108.

Medium pre-cabled subrack

Figure 4-13 Medium pre-cabled subrack with extension.

The 11 HU 19” medium subrack for 288 subscribers houses 24 EDN312 and an

ECN320. This node is called EDN288. A 15 HU 19” version for the EDN110 and

filters is also available and it supports 240 subscribers. If redundancy is required,

the medium cabinet is equipped with an extra ECN320 as shown above.

Large cabinet

This cabinet solution consists of an Ericsson BYB501 cabinet with dimensions

HxWxD 2200 x 600 x 400 mm (46 HU). It houses up to 72 EDN110 and 3

ESN310 or 4 EDN288, and it supports up to 720 or 1152 subscriber.

Outdoor cabinet



Figure 4-14 Outdoor cabinet.

The outdoor cabinet has the dimensions HxWxD 800 x 650 x 425 mm and

scales from 12 to 96 ADSL subscribers. It is equipped with EDN312 and an

ESN108 aggregation switch. Network connectivity is provided by a 100 Base-FX

optical uplink. The outdoor cabinet can also be equipped with the FE-E1

converter.

7.0 ETHERNET CONVERSION

7.1 ETHERNET TO E1 CONVERSION

The fast Ethernet (FE) to E1 converter is a small, managed converter developed

for EDA rollout where no Ethernet uplink is available. A cost-effective solution to

this problem is to transport Ethernet traffic via vacant E1 lines using the FE-E1

converter.



Figure 4-15 Ethernet to E1 conversion.

The FE-E1 converter is intended for installation at small sites with few

subscribers. The 2-port power distribution unit typically feeds the FE-E1

converter at the remote site where - 48 V is available. At the central site, any

switch capable of Ethernet power feeding can be used for aggregation of the FE-

E1 converter.

7.2 ETHERNET TO ATM CONVERSION

The Ethernet to ATM gateways EXN401 and EXN410 are both developed to

facilitate re-use of existing ATM core networks. The gateways support the

migration of broadband access networks from traditional ATM over SDH/SONET

to cost-efficient Ethernet, while preserving the quality of service and service

availability. Ethernet frames are encapsulated (RFC2684 bridged mode) onto

ATM AAL5 PVCs and transmitted via STM-1/OC-3 ports.



Figure 4-16 Ethernet to ATM conversion.

Priority queues are used to guarantee the quality of service (QoS) needed for

delay-sensitive applications like voice, video conference or video broadcast.

VLAN can be used to separate traffic types and services, and to improve

security. A mapping between VLAN priority and ATM service class can be

defined to maintain the priority in both directions.

8.0 NETWORK EXAMPLE

The network example below displays two different types of sites. At the remote

site, there are a small number of subscribers and an IP DSLAM terminates them.

The uplink is converted from Ethernet to PCM by the FE-E1 converter. Power is

supplied to both the IP DSLAM and the FE-E1 converter from an 8-port Ethernet

switch. A large number of subscribers are connected at the central site. An EAN

terminates the subscriber lines. The Ethernet uplink is aggregated into the

broadband network via Gigabit Ethernet. The FE-E1 converter at the central site

terminates the PCM based uplink from the remote site and forwards the frames

to the broadband network via the Ethernet switch.



Figure 4-17 Network example.

9.0 EXERCISE

1 What is the advantage of using Ethernet as the transmission technology in the

EDA solution?

2 How is baseband telephony implemented in the EDA solution?

3 What is the function of EMP and what is the advantage of using it?

4 How does an IP DSLAM get its IP address, and how does it fetch application

software and configuration data?

5 What is the purpose of remote storage?

10.0 SOLUTION TO EXERCISE

1 The Ethernet technology is superior in important areas like scalability,

simplicity, and equipment cost. Ethernet switches provide the capability to

increase the aggregated LAN bandwidth dramatically. Furthermore, an Ethernet

switch may be able to perform more advanced functions regarding the traffic,

such as prioritizing and traffic separation.

2 If baseband telephony is implemented, filters must be used for separating the

baseband signal from the ADSL signal. Two scenarios are possible:

- Using the 12-line IP DSLAM EDN312 with built-in filters

- Using the 10-line IP DSLAM EDN110 with MDF filters



3 The function of EMP is to maintain the connected network elements by loading

application software and configuration files into them.

Some advantages of using EMP:

- Automatic registration of network elements

- Only one IP address for maintenance

- EMP can work without connection to PEM

4 Figure 1-7 describes how an IP address, application software and

configuration data are fetched.

5 Remote storage ensures that an ongoing CPE session can be reestablished

without loss of configuration data if an IP DSLAM restarts.

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