data communication basics - honor cup · 2017. 5. 26. · physical layer, but they have no...

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved

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Ethernet Technology

Rev 1.0


Objectives

Ethernet Development

Physical Layer

MAC Address and Ethernet Header

Layer 2 Switch Working Principles

VLAN


Ethernet Origin

Doctor Robert Metcalfe is considered as the father of Ethernet.

The operating rate of the laboratory system that he developed is

2.94 Mbit/s.

Page3

Bob Metcalfe的以太网早期草图 Robert M. Metcalfe Ph.D

Early Ethernet drafted by Bob Metcalfe

http://wwwhost.ots.utexas.edu/ethernet/metcalfe-drawing.html

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page4

10GE Ethernet

Ethernet Evolution

IEEE802.3 Ethernet standard

IEEE802.3u 100BASE-T Fast Ethernet standard

IEEE802.3z/ab 1000Mb/s Ethernet standard

IEEE802.3ae 10GE Ethernet standard

1970s 1980s 1990s

Ethernet

Developed 10M Ethernet

LAN Switch

100M FE

1992 1996

Developing GE Ethernet

2002


Objectives


Physical Layer



VLAN


Ethernet Cable Standards

The following standards at the physical layer of

Ethernet have been widely applied:

● 10BASE-2/10BASE-5/10BASE-T/10BASE-F

● 100BASE-T4/100BASE-TX/100BASE-FX

● 1000BASE-SX/1000BASE-LX/1000BASE-CX/1000BASE-TX

In the preceding standards, 10, 100, and 1000 indicate

the operating rate, BASE indicates that signals are

transmitted in baseband mode, and the numbers after

BASE indicate the maximum transmission distance or

the type of transmission media.

Page6


Ethernet Cable Standards—10M

Ethernet

Name Cable Maximum

Transmission

Distance

Diagram

10BASE-5 Thick coaxial

cable 500m

10BASE-2 Thin coaxial

cable 200m

10BASE-T Twisted pair

cable 100m

10BASE-F Optical fiber 2000m

Page7



Ethernet The 100M Ethernet is also called Fast Ethernet (FE). Compared with the

10M Ethernet, the 100M Ethernet has a higher transmission rate at the

physical layer, but they have no difference at the data link layer.

Page8

Name Cable Maximum Transmission

Distance

100Base-T4 Four category 3 (Cat 3)

twisted pairs

100 m

100Base-TX Two category 5 (Cat 5)

twisted pairs

100 m

100Base-FX Single-mode or multi-

mode optical fiber

2000 m



Ethernet The 1000M Ethernet is an extension of the IEEE802.3 Ethernet. Based on

the Ethernet protocols, the transmission rate of the FE is increased by

10 times and reaches 1000 Mbit/s.

Page9

Name Cable Maximum

Transmission Distance

1000Base-LX Single-mode or multi-mode

optical fiber

316 m

1000Base-SX Multi-mode optical fiber 316 m

1000Base-CX Balanced shielded twisted

pair

25 m

1000Base-TX Cat 5 twisted pair 100 m


GE Cable Standard

IEEE 802.3ae defines the GE cable standard. Only optical fibers in full

duplex mode are supported.

The GE is being deployed and will be widely applied.

Page10

Name Cable Maximum

Transmission

Distance

10GBase-SR/SW Multi-mode optical fiber 300 m

10GBase-LR/LW Multi-mode optical fiber 10 km

10GBase-ER/EW Single-mode optical fiber 40 km

10GBase-CX Copper coaxial cable 15 m

10GBase-T Cat 5 twisted pair 100 m


CSMA/CD

CS: carrier sense

MA: multiple access

CD: conflict detection

Page11

IN IN

t1 t1

Listening Listening Listening

10BASE - 5/10BASE - 2 collision


Duplex Mode of the Ethernet

Based on the transmission mode, the physical layer of the

Ethernet supports half and full duplex modes.

Page12

Hub

Half Duplex Data direction at t1

Data direction at t2 Hub

Full Duplex Data direction at all times


Auto-Negotiation

The auto-negotiation function allows interfaces on both ends of a

link to select the same operating parameters by exchanging

information. Information to be negotiated includes parameters

such as the duplex mode, operating rate, and flow control. If the

negotiation succeeds, the two interfaces work in the same

duplex mode and at the same operating rate.

● 1000 Mbit/s full duplex

● 1000 Mbit/s half duplex





Page13


Working Mode of a Hub

Page14

Application

Layer

Presentation

Layer

Session Layer

Transport

Layer

Network Layer

Data Link

Layer

Physical Layer Physical

Layer

Physical

Layer

Hub

Application

Layer

Presentation

Layer

Session Layer

Transport

Layer

Network Layer

Data Link

Layer

Physical Layer


Working Procedure of a Hub

Page15

1 2 3 4 5

In

Out Out Out Out

All hubs work in half duplex mode.


Objectives


Physical Layer



VLAN


MAC Address

Unicast

Broadcast (All bits equal “1”: 0xFFFFFFFFFFFF)

Multicast (8th bit equal “1”):

00E0FC 012345

Vender Code Serial Number

24 bits 24 bits

00000001 10111011 00111010 10111010 10111110 10101000


DMAC SMAC Length/Type DATA/PAD FCS

The Frame Structure of Ethernet

>1500

Yes No Type Length

Ethernet 802.3 Ethernet II


Format of Ethernet Frames

DMAC SMAC Type Data CRC

6 bytes 6 bytes 2 bytes 46~1500 bytes 4 bytes

Ethernet II

DMAC SMAC Length Data CRC

6 bytes 6 bytes 2 bytes 38~1492 bytes 4 bytes

LLC

DSAP SSAP Control

1 bytes 1 bytes 1 bytes

SNAP

Org code Type

3 bytes 2 bytes

Ethernet 802.3


Objectives


Physical Layer



VLAN


Principle of L2 Switch

Learning

Flooding

Forwarding

Aging


Principle of L2 Switch Receive Frame

Source MAC

in Table?

Save MAC/Port Null Age

Dest. MAC

unicast?

Dest. MAC

in table?

Forward frame from

corresponding port

Flood frame from all

port except received

no yes

yes no

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 24

PC C

Learning, Flooding, Forwarding

LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

LSW2

MAC Port

3 3 6

Destination

Source

B A


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

LSW2

MAC Port

3 3 6

Destination

Source

B A


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3 6

Destination

Source

B A


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

B A

6

B A

Destination

Source


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

B A

A 3 A 5

6

B A

Destination

Source


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

A 3 A 5

6

Destination

Source

A B


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

A 3 A 5

6

Destination

Source

B 9

A B


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

A 3 A 5

6

A B

Destination

Source

B 9


PC C


LSW1

LSW3

PC A

PC B 1

2

5 9

MAC Port MAC Port

A 1

LSW2

MAC Port

3 3

A 3 A 5

6

A B

Destination

Source

B 2 B 9


Objectives


Physical Layer



VLAN


Broadcast Storm

broadcast ……


Divide Broadcast Domain by Router

broadcast ……


Divide Broadcast Domain by VLAN

Engineering Department

Financial DepartmentMarketing Department

Broadcast domain1

VLAN 10

Broadcast

domain2

VLAN 20

Broadcast domain3

VLAN 30


Advantages of VLAN

Compared to the traditional LAN technology, the

vlan has the following advantages:

● Improve the bandwidth utilization rate

● Enhance the communication security

● Strengthen the network robustness.


Port Based VLAN

VLAN Table

Port 1

Port 2

Port 3

Port 4

Host A Host B Host C Host D

LAN

Switch

Port VLAN

Port 1 VLAN5

Port 2 VLAN10

Port 3 VLAN5

Port 4 VLAN10


MAC Based VLAN

VLAN

Table

Host A Host B Host C Host D MAC A MAC B MAC C MAC D

MAC VLAN

MAC A VLAN5

MAC B VLAN10

MAC C VLAN5

MAC D VLAN10

LAN

Switch


Protocol Based VLAN

VLAN Table

Host A Host B Host C Host D

IPX Protocol IP Protocol IPX Protocol IP Protocol

Protocol VLAN

IPX Protocol VLAN5

IP Protocol VLAN10

…… ……

LAN

Switch


Subnet Based VLAN

VLAN

Table

Host A Host B Host C Host D 1.1.1.5 1.1.2.88 1.1.1.8 1.1.2.99

IP VLAN

IP 1.1.1.0/24 VLAN5

IP 1.1.2.0/24 VLAN10

…… ……

LAN

Switch


Format of 802.1Q Frame

DA SA Type Data CRC

Standard Ethernet Frame

DA SA Type Data CRC tag

TPID Priority CFI VLAN ID

TCI

Ethernet Frame with IEEE802.IQ Flag


Link Type

Access Link

Trunk Link or Hybrid Link


Frame Changes in Network

Communication

VLAN 2 VLAN 3

VLAN 3 VLAN 2

Ethernet frame with tag

Ethernet frame with tag

Ethernet

frame

without tag


Trunk and VLAN

Broadcast

Trunk Link

VLAN 4

VLAN 2 VLAN 4 VLAN 3 VLAN 2 VLAN 4 VLAN 5 VLAN 5 VLAN 2

VLAN 5


Receiving Principles of VLANs

(Access Port)

Page 50

Access Port

Receive Frame

Carry

VLAN

tag?

Accept frame, add tag

= PV ID

Accept frame Discard frame

-

+

+

-

Frame VLANID =

PV ID


Receiving Principles of VLANs

(Trunk Port)

Page 51

Trunk/Hybrid Port

Receive Frame

Carry

VLAN

tag?

Accept frame Discard frame

-

+

+

-

Frame VLANID

allowed?

Add tag = PV ID


Receiving Principles of VLANs (QinQ

Port)

Page 52

QinQ Port

Receive Frame

Accept frame

Add tag = PV ID


Sending Principles of VLANs

(Access, QinQ & Trunk)

Page 53

Search out port

using DMAC and

VLANID

Remove tag,

Send frame Send frame

+ - Frame VLANID =

PV ID

Access/

QinQ Port

Trunk Port

Remove tag,

Send frame

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data communication basics - honor cup · 2017. 5. 26. · physical layer, but they have no...

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