Ethernet

Tuan

GENERAL OF ETHERNETPart 1

Ethernet Version

Preamble SD DestinationAddress

Source Address Length Information Pad FCS

7 1 6 6 2 4

64 to 1518 bytesSynch Startframe

802.3 MAC Frame

Preamble SD DestinationAddress

Source Address Type Information Pad FCS

7 1 6 6 2 4

64 to 1518 bytesSynch Startframe

Ethernet II Frame

Length < 1518Type > 1536

46-1500

Ethernet Frame Format

• Preamble– 64 bits used for synchronisation

• Header– 48-bit globally unique destination address (DA)– 48-bit globally unique source address (SA)– 16-bit type field used for classification

• Body– 46-1500 bytes of data

• CRC– 32-bit CRC (Cyclic Redundancy Check) for error detection

Preamble Dest addr

Source addr Type Body CRC

8 6 6 2 46-1500 4 Bytes

Ethernet Frame Format (2)

• Start with 7 bytes of 1010101 to get timing synchronized (Layer 1)

• Then indicate the frame is starting (10101011) – last chance to sync!

• PDU headers (addresses + length type)

• Data (46-1500 bytes -- may contain some control info as well)

• Add bits if necessary to get to 46 bytes

• CRC-32 FCS

IP Packet Format

• 12 bytes of status fields e.g. version, length etc• 32-bit globally unique source address• 32-bit globally unique destination address• Optional fields of variable length• Body

Ver, len etc

Source addr

Dest addr Opt Body

12 4 4 Bytes0-65515

IP over Ethernet

• IP packets are encapsulated in Ethernet frames

Preamble Dest addr

Source addr Type Body CRC

Ver, len etc

Source addr

Dest addr Opt Body

VLAN Tag in an Ethernet Frame

IEEE 802.1Q VLAN Frame Tags

Dst Addr

Src Addr

802.1Q Tag

(in L/T field)

2 - bytes

Tag Ctrl Info

2-bytes

 

L/T 

 

Data 

Pad FCS

Tag: 0x8100 (always -- at least for Ethernet…)

Tag Ctrl Info: 1st 3 bits indicate priority (CoS), then a 1 bit Canonical Format Indicator (CFI) set to zero for Ethernet switches, remaining 12 bits indicate which VLAN the frame is from/for

Pause Frames

• Sent by full duplex DTE’s only• Requests that transmission to the

sending DTE be inhibited for a brief period

• Uses multicast address 01:80:C2:00:00:01

• Not forwarded by 802.1D capable bridges/switches

• Pause time is a 2 byte field specifying how many 512 bit times transmission should be inhibited

ETHERNET SWITCHINGPart 2

Concept of BW guarantee of VLAN-based Ethernet VPN (TLS)

MTU MTU

MACD

Metro CoreEthernet Network

End-to-end connection: 802.1q VLAN

At Ingress Point,Multi-Field Packet Classification(check L2/L3/L4 header)-> Rate-limiting/Guaranteeing-> 802.1p priority mapping

Priority queueing: 802.1pEthernet Switch of SP

Router of Customer

Ethernet Switch of Customer

End-to-end Connection: 802.1q VLAN

MTU MTU

MAC VLAN ID port B 7 a D 5 a

VLAN ID 7

VLAN ID 5

• One VLAN per customer• VLAN across MAN - Statically pre-configured, or - Automatically provisioned using GARP/GVRP

MAC VLAN ID port B 7 b D 5 b

ba

MAC VLAN ID port B 7 c D 5 d

c

d

MAC VLAN ID port D 5 f

MACD

MACB

MAC VLAN ID port B 7 e

e

f

MAC VLAN ID port D 5 i

MAC VLAN ID port B 7 g

g

i

MAC VLAN ID port D 5 j

j

Forwarding based-on {dst MAC addr. + VLAN ID}

Metro Ethernet Network

End-to-end Connection: 802.1q VLAN

MTU MTU

MAC VLAN ID port B 7 a D 5 a

VLAN ID 7

VLAN ID 5

• One VLAN per customer• VLAN across MAN - Statically pre-configured, or - Automatically provisioned using GARP/GVRP

MAC VLAN ID port B 7 b D 5 b

ba

MAC VLAN ID port B 7 c D 5 d

c

d

MAC VLAN ID port D 5 f

MACD

MACB

MAC VLAN ID port B 7 e

e

f

MAC VLAN ID port D 5 i

MAC VLAN ID port B 7 g

g

i

MAC VLAN ID port D 5 j

j

Forwarding based-on {dst MAC addr. + VLAN ID}

Metro Ethernet Network

AB

7 AB7 AB

7 AB

AB

CD5 CD

5 CD 5 CD 5 CD 5 CD

CD

Multi-Field Packet Classification at Ingress point

MTU MTUba

c

d

MACD

MACB

e

f

g

i

j

Metro CoreEthernet Network

At Ingress Point,Multi-Field Packet Classification(check L2/L3/L4 header)

- Rate-limiting/Guaranteeing (Customer-based/application based)- 802.1p priority mapping

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Ethernet(L2) IP (L3) TDP/UDP (L4)Pre dst

MACsrcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

802.1q/p tag

2B

Type0x8100

2B

Multi-Field packet Classification

Control packetsCustomer A + Voice flows

Customer B + FTP flowsCustomer A + E-mail flows

Multi-Field PacketClassification

Policy priorityqueues

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2BEthernet(L2) IP (L3) TDP/UDP (L4)

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

Packet Filter

Multi-Field packet Classification

MAC

IP0800

IPX8138

RARP8035

ARP0806

VLAN Tag1800

UDP17

TCP06

RSVP46

IGMP02

ICMP01

Telnet23

HTTP80

FTP20

SMTP25

DNS53

RTP5004

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2BEthernet(L2) IP (L3) TDP/UDP (L4)

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

Ingress Rate Limiting

MTU MTUba

c

d

MACD

e

f i

j

Metro CoreEthernet Network

Physical port speed 100Mbps

Up

5 Mbps

5 Mbps

Down

CustomerA

5 Mbps15 Mbps

CustomerB

15 Mbps

15 Mbps

CustomerC

MAN port

GbE

PRL (Port Rate Limiting)Customer port FE/GE port customer BW

QoS

Control packetsCustomer A + Voice flows

Customer B + FTP flowsCustomer A + Email flows

Multi-layer PacketClassification

Policy priorityqueues

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2BEthernet(L2) IP (L3) TDP/UDP (L4)

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

Packet Filter

Ingress Rate Limiting (cont’d)

ARL (Aggregate Rate Limiting) customer aggregate traffic rate customer aggregate traffic rate: VoIP aggregate traffic= 1Mbps)

Packet Filter

10Mbps

1Mbps

(PRLPRL)

((ARLARL))

Traffics fromCustomer A

(15Mbps) Voice aggregate traffic

Shaped Traffics fromATVN

(Total: 10MbpsVoIP: 1Mbps)

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2BEthernet(L2) IP (L3) TDP/UDP (L4)

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

Mapping to 802.1p

MTU MTUba

c

d

MACD

e

f i

j

Metro CoreEthernet Network

MTU MTUba

c

d

MACD

e

f i

j

Metro CoreEthernet Network

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Ethernet(L2) IP (L3) TDP/UDP (L4)Pre dst

MACsrcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

802.1p/q tag

2B

Type0x8100

2B

Policy

TPI0x8100 Priority CFI VLAN ID

16 b 3 b 1 b 12 b

Port srcMAC dstMAC TOS srcIP dstIP srcPort# dstPort# VLAN ID priority#1 mac_a mac_b 7 165.132/16 165.154/16 x y 7 1

802.1p/q header

Classification

At Ingress Point,

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Ethernet(L2) IP (L3) TDP/UDP (L4)Pre dst

MACsrcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

802.1p/q tag

2B

Type0x8100

2B

Policy

TPI0x8100 Priority CFI VLAN IDTPI0x8100 Priority CFI VLAN ID

16 b 3 b 1 b 12 b

Port srcMAC dstMAC TOS srcIP dstIP srcPort# dstPort# VLAN ID priority#1 mac_a mac_b 7 165.132/16 165.154/16 x y 7 1

802.1p/q header

Classification

At Ingress Point,

Priority queueing and scheduling

MTU MTUba

c

d

MACD

MACB

e

f

g

i

j

Metro CoreEthernet Network

Priority Field

Highest Priority

Lowest Priority

Priority Field(802.1p bits)

7 A B1

5 CD3

7 A B1

5 CD35 CD3

7 A B1

A B

CD7 A B1

5 CD3

802.1q tag (VLAN ID)802.1p tag (priority)

Concept of BW guarantee of VLAN-based Ethernet VPN (TLS)

MTU MTU

MACD

Metro CoreEthernet Network

End-to-end connection: 802.1q VLAN

At Ingress Point,Multi-Field Packet Classification(check L2/L3/L4 header)-> Rate-limiting/Guaranteeing-> 802.1p priority mapping

Priority queueing: 802.1pEthernet Switch of SP

Router of Customer

Ethernet Switch of Customer

7 A B1A B A B802.1p/q

L4 prioritization

VLAN ID 7

VLAN ID 5

A B

CD

Ethernet frame

MTU Last mile Metro core MTULast mile

802.1p/q Network

Lookup: {dst MAC addr. + VLAN ID}Queueing: check 802.1p tagOutput link scheduling: Priority scheduling based on 802.1p tag

7 A B1

5 CD2

A B

CD

7 A B1

5 CD2

7 A B1

5 CD2

7 A B1

5 CD2Classification:port , L2 MAC addr., IP addr., TOS/DSCP,PID, TCP/UDP Port numberPolicy/ACLRate-limiting802.1q VLAN tagging802.1p priority marking based-on TOS/DSCP, Port#

7 A B1

5 CD2

802.1q (VLAN ID)802.1p (priority)

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Ethernet(L2) IP (L3) TDP/UDP (L4)Pre dst

MACsrcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

8B 6B 6B 4B2B 1B 4B 4B1B 2B 2B

Pre dstMAC

srcMAC

Type0x0800 CRCdst

IPProtocol

IDsrc portnumber

UserdataTOS src

IPdst portnumber

802.1p/q tag

2B

Type0x8100

2B

Problem of VLAN-based TLS service

• VLAN space limitation: 4096 VLANs (VLAN ID=12bits)• MAC address limitation• No Bandwidth reservation in metro core (end-to-end)• No traffic engineering in metro core (STP Path)• Slow restoration time(STP, RSTP, EAPS)

VLAN space limitation ~ 4096

MTU MTU

LAN

Metro CoreEthernet Network802.1q network

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN LAN

LAN LAN

VLAN 1VLAN 1

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN 4096VLAN 4096

Supported MAC address limitation

MTU MTU

LAN

Metro CoreEthernet Network802.1q network

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN LAN

LAN LAN

Metro Core Ethernet Switches must learnMAC addresses of 1) Customer router, if CPE = L32) Individual machine, if CPE = L2

No Traffic Engineering

MTU MTU

LAN

Metro CoreEthernet Network802.1q network

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN LAN

LAN LAN

Not Traffic-Engineered Path(Path determined by STP)

VLAN 100’s PathVLAN 100’s Path

No end-to-end BW guarantee

MTU MTU

LAN

Metro CoreEthernet Network802.1q network

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN LAN

LAN LAN

VLAN 100’s PathVLAN 100’s Path

No BW reservation for VLAN’s connection in Metro CoreNo BW guarantee in Metro CoreOnly provide priority queueing (802.1p)

No End-to-end BW reservation

BW shared by 3 VLAN traffics: No BW guarantee in metro core trunk link

Priority queueing: 802.1p

200M

500M

500M

700M

500M

500M

1200M

VLAN AVLAN BVLAN C

Ingress rate limiting

MPLS in Metro Optical Ethernet Network

MTU MTU

LAN

Metro CoreEthernet Network

MPLS network

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN LAN

LAN LAN

VLAN 1VLAN 1

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN 3VLAN 3

MPLS LSP 100MPLS

LSP 100

VLAN 1VLAN 1

MPLS LSP 200MPLS

LSP 200

VLAN 3VLAN 3

VLAN 2VLAN 2VLAN 2VLAN 2

MPLS LER/LSR(MPLS over Ethernet)

Ethernet over MPLS: Martini draft

• Martini Internet draft:– Encapsulation Methods for Transport of Layer 2 Frames Over MPLS

(draft-martini-l2circuit-encap-mpls-01.txt ) – Transport of Layer 2 Frames Over MPLS

(draft-martini-l2circuit-trans-mpls-05.txt)• Layer 2 PDU (frame relay, ATM AAL5, Ethernet) MPLS Network (Encapsulation, Level

distribution)• No IP routing in Provider’s Network (LER/PE and LSR/P)• Service Provider provides L2 connectivity only• MPLS-based L2 circuit• Metro Ethernet Martini draft

Ethernet over MPLS (MPLS over Ethernet) network(Tunnel LSP, VC LSP, Encapsulation)

Tunnel LSP

MTU MTU

LAN

Metro Core

LAN

LAN

LAN

LAN

LAN LAN

T-LSP100

T-LSP100

T-LSP200

T-LSP200

tunnel LSP: LER(PE)- LER VLAN traffic Aggregation

T-LSP200

T-LSP200

LAN LAN

VC LSP

MTU MTU

LAN

Metro Core

LAN

LAN

LAN

LAN

LAN LAN

T-LSP100

T-LSP100

T-LSP200

T-LSP200

T-LSP200

T-LSP200

LAN LAN

Egress LER, R2Must know how to treat the received frame=> Define “VC label (VC LSP)”R2 can infer form the VC label the outgoing interface and perhaps the VLAN ID

VLAN1VLAN1

VC LSPVC LSP = per VLAN LSP

- Egress LER VLAN

Label.

VC LSP setup

MTU MTU

LANMetro Core

LAN

LAN

LAN

T-LSP200

T-LSP200

VLAN1VLAN1

Label mapping msg

VC label(VC label TLV) = 25

VLAN ID(FEC TLV) = 1

VLAN1VLAN1

configuration- VLAN 1, port 10- peer router: 10.0.0.1VC label = 25

Port VLAN VC lsp T-lsp 11 1 25 200

T-LSPVC-LSPVLAN

VC-LSPVLAN

10.0.0.1 20.0.0.1

Frame flow over MPLS Network

MTU MTU

LAN

Metro Core LAN

LAN

LAN

T-LSP200

T-LSP200

VLAN1VLAN1 VLAN1VLAN1VC-LSP

25VC-LSP

25

MACB

MACA

MTU Access Switch

MTU MTU

LANMetro Core

LAN

LAN

LAN

MAC VLAN ID outgoing port B 1 3

L3 PDU(IP packet)

DAB

SAA

E-type(0x0800)

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

VLAN tagging

3

MACB

MACA

Ethernet Type0x0800: IPv40x0806: arp0x8035: rarp0x8100: vlan

Ingress LER

MTU MTU

LANMetro Core

LAN

LAN

LAN

4

MACB

MACA

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

MAC VLAN ID outgoing port Tunnel Label VC label Label B 1 4 5 25

1) VLAN-to-LSP mapping (Label push) - Tunnel LSP: aggregation LSP - VC LSP: per-VLAN LSP2) CoS(Ext) field marking Classification (802.1p/MFPC)3) Outer MAC header (MACs of LSRs)

OuterEthernetHeader

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAb

SAa

E-type(0x8847)

Tunnellabel(5)

VClabel(25)

Original 802.1q frameLabel stack

a b

LSR

MTU MTU

LANMetro Core

LAN

LAN

LAN

3

MACB

MACA

C

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAd

SAc

E-type(0x8847)

Tunnellabel (30)

VClabel (25)

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAb

SAa

E-type(0x8847)

Tunnellabel (5)

VClabel (25)

1) Label Swapping: Tunnel Label2) Rewrite MAC header

Incoming port Tunnel Label outgoing port Tunnel Label 1 5 3 30

d

LSR (cont’d)

MTU MTU

LANMetro Core

LAN

LAN

LAN

3

MACB

MACA

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAf

SAe

E-type(0x8847)

VClabel (25)

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAd

SAc

E-type(0x8847)

Tunnellabel (30)

VClabel (25)

1) Pop Tunnel label2) Rewrite MAC header

Incoming port Tunnel Label outgoing port 1 5 3

e f

Egress LER

MTU MTU

LANMetro Core

LAN

LAN

LAN

4

MACB

MACA

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

DAf

SAe

E-type(0x8847)

VClabel (8)

1) Pop VC label2) Infer from VC label how to process

the original frame (output port)

Incoming port VC Label outgoing port 1 25 4

Original 802.1q frame

e f

Egress LER (cont’d)

MTU MTU

LANMetro Core

LANMAC

B

DAB

SAA

E-type(0x0800)

L3 PDU(IP packet)

802.1p/q(2/1)

DAB

SAA

E-type(0x8100)

E-type(0x0800)

L3 PDU(IP packet)

MAC VLAN ID outgoing port B 1 1

1

LANMAC

A

LAN

Good of MPLS

• VLAN space (VLAN ID Reuse)• Metro Core MAC• Traffic Engineering in Metro Core• Protection: MPLS Fast Reroute (<100msec)• MPLS QoS: LSP Ext/CoS• MPLS-based Layer 2 VPN• Scalability• Security

VLAN ID Reuse

MTU MTU

LANLER

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN

LAN

LAN LAN

VLAN 1VLAN 1

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN 3VLAN 3

MPLS LSP 200MPLS

LSP 200

VLAN 3VLAN 3

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN ID Reuse

VLAN 1VLAN 1

LER

VLAN 1VLAN 1

VLAN 1VLAN 1MPLS

LSP 100MPLS

LSP 100

MAC address learning

LocalMAC address

learning

MTU MTU

LANLER

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN

LAN

LAN LAN

VLAN 1VLAN 1

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN 3VLAN 3 VLAN 3VLAN 3

VLAN 2VLAN 2VLAN 2VLAN 2

VLAN 1VLAN 1

LER

VLAN 1VLAN 1

VLAN 1VLAN 1

MAC address

learning

802.1q MPLS

Traffic Engineering in Metro Core

MTU MTU

LANLER

LAN

LAN

LAN

LAN

MTU

LAN

LAN

MTU

LAN

LAN

LAN

LAN

LAN LAN

LER

Traffic-EngineeredPath

Traffic-EngineeredPath

Good of MPLS

MTU

LER/PELSR/P

LER/PELSR/P

VLAN space (VLAN ID Reuse)

Metro Core MAC address

VLANVLAN

VLAN

MPLS

• Traffic Engineering in Metro Core• MPLS restoration - pre-established standby LSP - Fast Reroute• MPLS QoS

LSP1

LSP2 LSP3

Thank You !