1974 chp10ONLa.fm Page 735 Tuesday, November 14,...

1974_chp10ONLa.fm Page 735 Tuesday, November 14, 2006 10:07 AM

C

H

A

P

T

E

R

S

U

P

P

L

E

M

E

N

T

10

This online supplement of Chapter 10 focuses on more advanced topics regarding Any Transport over MPLS (AToM). What if the attachment circuits (AC) on the two sides of the MPLS network have different encapsulation types? How do you interconnect multiple MPLS networks that are running the AToM service and provide a Layer 2 transport service end to end? How do you switch two pseudowire segments? To conclude, this chapter looks at what local switching entails on the provider edge (PE) routers of the MPLS network.

L2VPN Interworking

Up to this point in the book, the ACs on both sides have been the same encapsulation type, which is also referred to as like-to-like functionality.

L2VPN interworking

is an AToM feature that allows different encapsulation types at both sides of the AToM network. The interworking feature then “translates” one Layer 2 encapsulation to another.

The L2VPN interworking has two possible modes: IP and Ethernet. If the PE is configured for IP mode, you extract the IP packet from the received frame on the AC and label it before sending it into the MPLS network, effectively using AToM to transport pure (nonrouted) IP payload across the MPLS backbone. If the PE is configured for Ethernet mode, you extract the Ethernet frame from the received frame on the AC (all VLAN headers are removed) and label it before sending it into the MPLS network.

Table 10-1 lists the L2VPN interworking possibilities for both the IP and Ethernet modes in Cisco IOS.

Table 10-1

L2VPN Interworking Possibilities

Interworking Encapsulation IP Mode Ethernet Mode

Frame Relay to Ethernet/VLAN Yes Yes

Frame Relay to PPP Yes No

Frame Relay to ATM AAL5 Yes No

Ethernet/VLAN to ATM AAL5 Yes Yes

Ethernet to VLAN Yes Yes

Ethernet to PPP Yes No

Any Transport over MPLS


737

Chapter 10: Any Transport over MPLS

IP Interworking

The benefit of L2VPN interworking in IP mode is that you can provide AToM functionality, even if the encapsulation is different on both sides of the MPLS network. MPLS VPN can carry the IP traffic across the MPLS network, but MPLS VPN is a service that carries the IP protocol in a point-to-multipoint fashion, whereas AToM is strictly point-to-point. Furthermore, with MPLS VPN, the PE and CE router always interact at Layer 3; an IP routing protocol runs between the two routers. With AToM, however, an IP routing protocol never runs between the PE and CE router. With AToM, the routing protocol runs between the two CE routers across the pseudowire.

Figure 10-1 shows how the IP packet is transported across the AToM network. The ingress PE router PE1 strips off the Ethernet encapsulation, takes the IP packet, labels it with the tunnel and virtual circuit (VC) label, and switches the packets into the MPLS network. The egress PE router PE2 strips off the VC label, encapsulates the IP packet into PPP, and forwards the frame onto the correct interface to the CE router.

Figure 10-1

Example of IP Interworking: Ethernet to PPP

Example 10-1 shows you the configuration for the case of Ethernet to PPP interworking. IP interworking is simply configured by configuring

interworking IP

under the pseudowire-class.

NOTE

IP interworking is also known as routed interworking.

Example 10-1

Ethernet to PPP IP Interworking Example

PE1#

ppppsssseeeeuuuuddddoooowwwwiiiirrrreeee----ccccllllaaaassssssss oooonnnneeee

eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn mmmmppppllllssss

IP IP IP

Label 23 Label 23

Label 74 Label 88

Control Word

Control Word

Ethernet Header

Label 23

Control Word

PPP Header

IP IP

Ethernet

VCID 100

PE1-CE

Loopback 0 10.200.254.1/32 P P

FastEth 9/0/0

AttachmentCircuit (AC)

PE1 PE2 PE2-CE

PPP

VCID 100

Loopback 0 10.200.254.4/32

Serial 4/0/0

AttachmentCircuit (AC)


L2VPN Interworking

738

sssseeeeqqqquuuueeeennnncccciiiinnnngggg bbbbooootttthhhh

iiiinnnntttteeeerrrrwwwwoooorrrrkkkkiiiinnnngggg iiiipppp

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt9999////0000////0000

nnnnoooo iiiipppp aaaaddddddddrrrreeeessssssss

xxxxccccoooonnnnnnnneeeecccctttt 11110000....222200000000....222255554444....4444 111100000000 ppppwwww----ccccllllaaaassssssss oooonnnneeee

!!!!

PE2#



sssseeeeqqqquuuueeeennnncccciiiinnnngggg bbbbooootttthhhh


!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee SSSSeeeerrrriiiiaaaallll4444////0000////0000


eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn pppppppppppp


!!!!

PE1#

sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000

Local intf Local circuit Dest address VC ID Status

------------- -------------------- --------------- ---------- ----------

Fa9/0/0 Ethernet 10.200.254.4 100 UP

PE1#

sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000 ddddeeeettttaaaaiiiillll

Local interface: Fa9/0/0 up, line protocol up, Ethernet up

MPLS VC type is IP, interworking type is IP

Destination address: 10.200.254.4, VC ID: 100, VC status: up

Output interface: Et0/0/0, imposed label stack {74 23}

!output omitted for brevity

PE2#

sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000


------------- ----------------------- --------------- ---------- ----------

Se4/0/0 PPP 10.200.254.1 100 UP

PE2#


Local interface: Se4/0/0 up, line protocol up, PPP up



Preferred path: not configured

Default path: active

Tunnel label: 22, next hop point2point

Output interface: Se5/0, imposed label stack {22 24}


Example 10-1

Ethernet to PPP IP Interworking Example (Continued)


739


This particular example can lead to an interesting problem. On one side of the pseudowire, the AC is a point-to-point medium (PPP), whereas on the other side, it is a broadcast medium (Ethernet). This is a problem for some routing protocols, such as Open Shortest Path First (OSPF). Enhanced Interior Gateway Routing Protocol (EIGRP), however, does not have a problem. The EIGRP hello packets are broadcasted to the 224.0.0.10 multicast IP address. The two CE routers form an EIGRP neighborship across the pseudowire without special configuration.

OSPF is unique because it operates differently over point-to-point media than it does over broadcast media. If the default OSPF configuration is kept, OSPF does not function correctly across the pseudowire because it behaves in Broadcast mode over the Ethernet AC and in Point-to-Point mode over the PPP AC. To solve this problem, configure the Ethernet interface so that OSPF sees it as a point-to-point interface. You can do this with the command

ip ospf network point-to-point

on the Ethernet interface of the CE router. Example 10-2 shows the con-figuration needed on the CE routers to get OSPF working in the case of Ethernet to PPP IP interworking.

Example 10-2

Ethernet to PPP IP Interworking: OSPF

PE1-ce#

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt0000////1111

iiiipppp aaaaddddddddrrrreeeessssssss 11110000....111100000000....111100000000....1111 222255555555....222255555555....222255555555....0000

iiiipppp oooossssppppffff nnnneeeettttwwwwoooorrrrkkkk ppppooooiiiinnnntttt----ttttoooo----ppppooooiiiinnnntttt

!!!!

rrrroooouuuutttteeeerrrr oooossssppppffff 111100000000

lllloooogggg----aaaaddddjjjjaaaacccceeeennnnccccyyyy----cccchhhhaaaannnnggggeeeessss

nnnneeeettttwwwwoooorrrrkkkk 11110000....0000....0000....0000 0000....222255555555....222255555555....222255555555 aaaarrrreeeeaaaa 0000

!!!!

PE2-ce#

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee SSSSeeeerrrriiiiaaaallll0000////0000


eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn pppppppppppp

!!!!

rrrroooouuuutttteeeerrrr oooossssppppffff 111100000000

lllloooogggg----aaaaddddjjjjaaaacccceeeennnnccccyyyy----cccchhhhaaaannnnggggeeeessss

nnnneeeettttwwwwoooorrrrkkkk 11110000....0000....0000....0000 0000....222255555555....222255555555....222255555555 aaaarrrreeeeaaaa 0000

!!!!

PE1-ce#

sssshhhhoooowwww iiiipppp oooossssppppffff iiiinnnntttteeeerrrrffffaaaacccceeee ffffaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt 0000////1111

FastEthernet0/1 is up, line protocol is up

Internet Address 10.100.100.1/24, Area 0

Process ID 100, Router ID 10.1.1.1, Network Type POINT_TO_POINT, Cost: 1

Transmit Delay is 1 sec, State POINT_TO_POINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

oob-resync timeout 40


L2VPN Interworking

740

continues

Example 10-3 shows an AToM network with IP interworking between ATM AAL5 encapsulation on the PE router PE1 and Ethernet VLAN encapsulation on the PE router PE2. Notice that the MTU on the ATM interface has been changed to 1500 (the default is 4470); otherwise, the pseudowire VCID 1000 between the two PE routers would not function because of an MTU mismatch.

Hello due in 00:00:02

Index 2/2, flood queue length 0

Next 0x0(0)/0x0(0)

Last flood scan length is 1, maximum is 1

Last flood scan time is 0 msec, maximum is 0 msec

Neighbor Count is 1, Adjacent neighbor count is 1

Adjacent with neighbor 10.100.103.2

Suppress hello for 0 neighbor(s)

PE1-ce#

sssshhhhoooowwww iiiipppp oooossssppppffff nnnneeeeiiiigggghhhhbbbboooorrrr

Neighbor ID Pri State Dead Time Address Interface

10.100.103.2 0 FULL/ - 00:00:39 10.100.100.2 FastEthernet0/1

Example 10-3

Ethernet VLAN to ATM AAL5 IP Interworking

hhhhoooossssttttnnnnaaaammmmeeee PPPPEEEE1111----cccceeee

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee AAAATTTTMMMM2222////0000....1111 ppppooooiiiinnnntttt----ttttoooo----ppppooooiiiinnnntttt

mmmmttttuuuu 1111555500000000


nnnnoooo aaaattttmmmm eeeennnnaaaabbbblllleeee----iiiillllmmmmiiii----ttttrrrraaaapppp

ppppvvvvcccc 11110000////111100000000

eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn aaaaaaaallll5555ssssnnnnaaaapppp

!!!!

!!!!


!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt0000////1111


!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt0000////1111....111100000000

eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn ddddooootttt1111QQQQ 111100000000


!!!!

hhhhoooossssttttnnnnaaaammmmeeee PPPPEEEE1111

!!!!


Example 10-2

Ethernet to PPP IP Interworking: OSPF (Continued)


741




!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee AAAATTTTMMMM8888////0000////0000



ppppvvvvcccc 11110000////111100000000 llll2222ttttrrrraaaannnnssssppppoooorrrrtttt



!!!!


!!!!




!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt4444////1111////0000....111100000000



!!!!

PE1#


Local interface: AT8/0/0 up, line protocol up, ATM AAL5 10/100 up





Tunnel label: 23, next hop 10.200.200.2


!output trimmed for brevity

PE2#


Local interface: Fa4/1/0.100 up, line protocol up, Eth VLAN 100 up








PE1#

sssshhhhoooowwww aaaattttmmmm ppppvvvvcccc 11110000////111100000000

ATM8/0/0: VCD: 1, VPI: 10, VCI: 100

UBR, PeakRate: 149760

AAL5-LLC/SNAP, etype:0x0, Flags: 0x10000C20, VCmode: 0x0

Example 10-3

Ethernet VLAN to ATM AAL5 IP Interworking (Continued)

1974_chp10ONLa.fm 41 Tuesday, November 14, 2006 10:07 AM

L2VPN Interworking

742

continues

Ethernet Interworking

A second form of L2VPN interworking is Ethernet interworking, which is also referred to as bridged interworking. When the PE router receives Layer 2 frames, it extracts the Ethernet frame, labels it, and sends it across the MPLS network.

The advantage of using Ethernet interworking is that you can use integrated routing and bridging (IRB) or routed bridge encapsulation (RBE) on the CE router. One benefit of using RBE, for example, is that the Ethernet connectivity becomes alike when using an Interior Gateway Protocol (IGP) that would otherwise have problems dealing with a point-to-point interface on one CE and a multipoint interface on the other CE. Of course, just bridging the Ethernet frames is also a possibility. Another benefit of using Ethernet as the Interworking mode is that it supports the transport of multiple Layer 3 protocols across the pseudowire, whereas IP interworking does not.

An example in which Ethernet interworking for AToM is desirable is an enterprise network that has multiple sites interconnected through a service provider that provides the AToM service. For technical reasons or even pricing reasons, it might not be possible to have Ethernet encapsulation all the way up to the PE router. In those cases, Ethernet can be encapsulated into ATM, Frame Relay, and so on to bring it to the PE router.

Example 10-4 shows the configuration of the PE routers in an AToM network in which Ethernet interworking exists between VLAN and Ethernet. In other words, one PE has a VLAN toward the CE, whereas the other PE has a plain Ethernet link toward the CE. The two CE routers can communicate across the AToM network because of the Ethernet interworking that results in the VLAN (dot1q) header being stripped off from the Ethernet frame before sending the frame across the AToM network. For the frames in the opposite direction—from the Ethernet link to the VLAN link—the VLAN header is added before the frame is sent toward the CE router or switch. You configure Ethernet interworking by configuring

interworking ethernet

under the pseudowire-class.

OAM Cell Emulation: not configured

Interworking Method: IP

Remote Circuit Status = No Alarm, Alarm Type = None


Example 10-4

Ethernet to VLAN Interworking

PE1#



iiiinnnntttteeeerrrrwwwwoooorrrrkkkkiiiinnnngggg eeeetttthhhheeeerrrrnnnneeeetttt

!!!!


Example 10-3

Ethernet VLAN to ATM AAL5 IP Interworking (Continued)


743




!!!!

PE2#




!!!!




!!!!

PE1#


Local interface: Fa9/0/0 up, line protocol up, Ethernet up






Create time: 00:08:56, last status change time: 00:08:51

Signaling protocol: LDP, peer 10.200.254.4:0 up

MPLS VC labels: local 23, remote 19

Group ID: local 0, remote 0

MTU: local 1500, remote 1500

Remote interface description:

Sequencing: receive disabled, send disabled

VC statistics:

packet totals: receive 94, send 156

byte totals: receive 9174, send 19558

packet drops: receive 0, send 0

PE2#



MPLS VC type is Ethernet, interworking type is Ethernet












Example 10-4

Ethernet to VLAN Interworking (Continued)


L2VPN Interworking

744

continues

Example 10-5 shows the Ethernet interworking between ATM AAL5 and Ethernet VLAN. The configuration is similar to Example 10-3, except for the


on the PE routers and the configuration on the CE router with the ATM interface. That CE router PE1-ce is now using RBE. RBE allows a bridged segment to be terminated on a routed ATM point-to-point interface. You configure RBE with the command

atm route-bridged ip

on the ATM interface.

Sequencing: receive disabled, send disabled

Sequence number: receive 0, send 0

VC statistics:



packet drops: receive 0, seq error 0, send 0

Example 10-5

Ethernet VLAN to ATM AAL5 Ethernet Interworking with RBE on the CE


!!!!




aaaattttmmmm rrrroooouuuutttteeee----bbbbrrrriiiiddddggggeeeedddd iiiipppp

ppppvvvvcccc 11110000////111100000000


!!!!

hostname PE2-ce

!

interface FastEthernet0/1.100

encapsulation dot1Q 100

ip address 10.100.100.2 255.255.255.0

!

hostname PE1

!

pseudowire-class one

encapsulation mpls


!

!

interface ATM8/0/0

mtu 1500

no ip address

pvc 10/100 l2transport

encapsulation aal5snap

xconnect 10.200.254.4 1000 pw-class one

!

Example 10-4

Ethernet to VLAN Interworking (Continued)


745


Example 10-6 shows the Ethernet interworking between ATM AAL5 and Ethernet VLAN again. The only difference from the previous example is that the CE router PE1-ce is using IRB now. IRB allows for routing of a protocol between routed interfaces and bridge groups on one router. IRB creates a Bridge Group Virtual Interface (BVI), which enables the packets to be switched between the routed and bridged interfaces. The BVI interface is created so that the routed interfaces have one interface that represents the bridge group on that router.


!!!!




!!!!




!!!!

PE1#sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 1111000000000000 ddddeeeettttaaaaiiiillll

Local interface: AT8/0/0 up, line protocol up, ATM AAL5 10/100 up








PE2#sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 1111000000000000 ddddeeeettttaaaaiiiillll









Example 10-6 Ethernet VLAN to ATM AAL5 Ethernet Interworking with IRB on the CE


!!!!

bbbbrrrriiiiddddggggeeee iiiirrrrbbbb

!!!!

Example 10-5 Ethernet VLAN to ATM AAL5 Ethernet Interworking with RBE on the CE (Continued)


L2VPN Inter-Autonomous Networking 746

L2VPN Inter-Autonomous Networking

So far in this chapter, the MPLS network that has been supporting the AToM service has been one autonomous system (AS). If the MPLS network that provides AToM is split over two or more autonomous systems, the following must be true:

■ The loopback IP prefixes (/32 prefixes) of the PE routers must be known in the other autonomous system(s). These loopback IP prefixes are used by the xconnect commands.

■ The targeted Label Distribution Protocol (LDP) session must be set up between the PE routers.

■ A label switched path (LSP) must exist between the PE routers.



bbbbrrrriiiiddddggggeeee----ggggrrrroooouuuupppp 1111

ppppvvvvcccc 11110000////111100000000


!!!!

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee BBBBVVVVIIII1111



!!!!

bbbbrrrriiiiddddggggeeee 1111 pppprrrroooottttooooccccoooollll iiiieeeeeeeeeeee

bbbbrrrriiiiddddggggeeee 1111 rrrroooouuuutttteeee iiiipppp

!!!!


!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt0000////1111....111100000000



!!!!

Example 10-6 Ethernet VLAN to ATM AAL5 Ethernet Interworking with IRB on the CE (Continued)


747 Chapter 10: Any Transport over MPLS

If these requirements are met, AToM can work across different autonomous systems without a problem. Figure 10-2 shows the requirement for L2VPN Inter-Autonomous Networking. The link(s) between the autonomous system boundary routers (ASBRs) must carry labeled packets; otherwise, no end-to-end LSP exists between the PE routers. That also entails that a label distribution exists between the two ASBRs. This can be either an IGP with LDP, or it can be eBGP with label distribution for IPv4 prefixes.

Figure 10-2 L2VPN Inter-Autonomous Networking: Method 1

You can achieve Inter-Autonomous Networking of AToM networks in another way. You can connect two autonomous systems by connecting two PE routers, one from each autonomous system. These two border routers can share one subinterface or VC between them for each pseudowire they need to transport from one autonomous system to the other. Figure 10-3 shows this way of interconnecting the AToM service between two autonomous systems.

Targeted LDP Session

LSP

PECECE

LSP

Autonomous System 1 Autonomous System 2

Labeled Packets

PE ASBR ASBR


L2VPN Pseudowire Switching 748L2VPN Pseudowire Switching

Figure 10-3 L2VPN Inter-Autonomous Networking: Method 2

In this scenario, you do not need an end-to-end LSP between the PE routers or a targeted LDP session between the PE routers from different autonomous systems. The traffic between the ASBRs is not labeled traffic as in the previous scenario, but it is the native Layer 2 traffic. The disadvantage of this solution compared to the previous one is that you might need many interfaces between the ASBRs (for example, one interface for each High-Level Data Link Control [HDLC] link transported across autonomous systems) if you have several Layer 2 virtual private networks (VPNs) shared between the two autonomous systems. The previous solution, however, needed only one link between the ASBRs that could then carry all labeled packets for all shared pseudowires between the two autonomous systems. You can alleviate this disadvantage somewhat if only Ethernet VLANs are shared between the two AToM-enabled autonomous systems. In that case, one dot1q trunk between the two ASBRs can carry all the shared VLANs between the two autonomous systems.

L2VPN Pseudowire Switching

A third method for Inter-Autonomous AToM Networking is available. L2VPN Pseudowire Switching allows connection of two pseudowire segments. The two pseudowire segments are stitched together and form one pseudowire end to end. Although two pseudowire segments in one autonomous system can be stitched together by one LSR, the big advantage is the stitching of two


LSP

PECECE

LSP

Autonomous System 1

LSP

LSP

Autonomous System 2Layer 2 Frames

PE PE-ASBR PE-ASBR




pseudowire segments from different autonomous systems. Look at Figure 10-4, which shows two autonomous systems with one pseudowire segment. The two pseudowire segments are stitched together at the ASBR routers, by a third pseudowire segment. The three pseudowire segments together form one end-to-end pseudowire.

Figure 10-4 L2VPN Pseudowire Switching Between Two Autonomous Systems

The benefit of this method of Inter-Autonomous AToM Networking is that the PE addresses from one autonomous system do not need to be known on all routers in the other autonomous system. This is normally necessary for creating one pseudowire end to end. The ASBRs need configuration to stitch the two pseudowires together. They need to have the point-to-point Layer 2 virtual forwarding instance (VFI) configuration to make this work. Under the VFI configuration, the ASBRs have the PEs in the same autonomous system and the ASBRs of the other autonomous system configured as neighbors. The PE routers need only the normal AToM configuration. One LDP session exists between the two ASBRs as a result of the neighbor statement under the VFI toward the other ASBR. This creates a third pseudowire segment between the two ASBRs. The packets are then switched between two pseudowire segments on each ASBR. The AToM frames are label switched on the link between the ASBRs. The ASBRs must have a label binding for the loopback IP address of the other ASBR. Therefore, either an IGP with LDP is needed between the two ASBRs, or eBGP is needed for advertising IPv4 prefixes + label.



PE CE CE

HDLC

Loopback 0 10.100.1.1/32

Loopback 0 10.100.1.3/32

Loopback 0 10.100.2.1/32

Loopback 0 10.100.2.3/32

VCID 100 HDLC

VCID 100

Pseudowire Segment 1 Pseudowire Segment 3

Autonomous System 1

Pseudowire Segment 2

Autonomous System 2

PE ASBR1 ASBR2


Tunnel Label

VC Label

Control Word

Frame

VC Label

Control Word

Frame

Tunnel Label

VC Label

Control Word

Frame


L2VPN Pseudowire Switching 750

Example 10-7 shows the configuration needed on ASBR1 and how to verify the L2VPN Pseudowire Switching. In this example, eBGP for IPv4 is configured with the send-label keyword toward the other ASBR. BGP is advertising the ASBR loopback prefix to the other ASBR. The encapsulation of the AC at each end is HDLC.

Example 10-7 L2VPN Pseudowire Switching

!!!!

hhhhoooossssttttnnnnaaaammmmeeee AAAASSSSBBBBRRRR1111

!!!!



!!!!

llll2222 vvvvffffiiii llll2222vvvvppppnnnn----oooonnnneeee ppppooooiiiinnnntttt----ttttoooo----ppppooooiiiinnnntttt

nnnneeeeiiiigggghhhhbbbboooorrrr 11110000....111100000000....2222....1111 111100000000 ppppwwww----ccccllllaaaassssssss oooonnnneeee

nnnneeeeiiiigggghhhhbbbboooorrrr 11110000....111100000000....1111....1111 111100000000 ppppwwww----ccccllllaaaassssssss oooonnnneeee

!!!!

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee LLLLooooooooppppbbbbaaaacccckkkk0000


!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee SSSSeeeerrrriiiiaaaallll3333////0000

ddddeeeessssccccrrrriiiippppttttiiiioooonnnn iiiinnnntttteeeerrrrffffaaaacccceeee ttttoooo AAAASSSSBBBBRRRR2222


mmmmppppllllssss bbbbggggpppp ffffoooorrrrwwwwaaaarrrrddddiiiinnnngggg

!!!!

rrrroooouuuutttteeeerrrr bbbbggggpppp 1111

nnnneeeettttwwwwoooorrrrkkkk 11110000....111100000000....1111....3333 mmmmaaaasssskkkk 222255555555....222255555555....222255555555....222255555555

nnnneeeeiiiigggghhhhbbbboooorrrr 11110000....3333....1111....2222 rrrreeeemmmmooootttteeee----aaaassss 2222

nnnneeeeiiiigggghhhhbbbboooorrrr 11110000....3333....1111....2222 sssseeeennnndddd----llllaaaabbbbeeeellll

!!!!

ASBR1#sssshhhhoooowwww vvvvffffiiii llll2222vvvvppppnnnn----oooonnnneeee

VFI name: l2vpn-one, type: point-to-point

Neighbors connected via pseudowires:

Router ID Pseudowire ID

10.100.2.1 100

10.100.1.1 100

ASBR1#sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000


------------- -------------------------- --------------- ---------- ----------

MPLS PW 10.100.2.1:100 10.100.1.1 100 UP

MPLS PW 10.100.1.1:100 10.100.2.1 100 UP

ASBR1#sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000 ddddeeeettttaaaaiiiillll

Local interface: MPLS PW 10.100.2.1:100 up

L2VPN Pseudowire Switching

continues






Next hop: 10.1.2.1

Output interface: Et0/0, imposed label stack {40 72}







Sequencing: receive transparent, send transparent

Sequencing resync disabled

VC statistics:




Local interface: MPLS PW 10.100.1.1:100 up




Next hop: point2point

Output interface: Se3/0, imposed label stack {35}







Sequencing: receive transparent, send transparent

Sequencing resync disabled

VC statistics:




PE1#sssshhhhoooowwww mmmmppppllllssss llll2222ttttrrrraaaannnnssssppppoooorrrrtttt vvvvcccc 111100000000


------------- -------------------------- --------------- ---------- ----------

Se3/0 HDLC 10.100.1.3 100 UP

ASBR1#sssshhhhoooowwww xxxxccccoooonnnnnnnneeeecccctttt ppppeeeeeeeerrrr 11110000....111100000000....2222....1111 vvvvcccciiiidddd 111100000000 ddddeeeettttaaaaiiiillll

Legend: XC ST=Xconnect State, S1=Segment1 State, S2=Segment2 State

UP=Up, DN=Down, AD=Admin Down, IA=Inactive, NH=No Hardware

Example 10-7 L2VPN Pseudowire Switching (Continued)


Local Switching 752

Local Switching

Local switching is a feature whereby the PE router switches the Layer 2 frames without sending them across the MPLS network. The Layer 2 frames are never labeled, and as such, this feature has little to do with AToM. It is mentioned here because it might be useful when AToM is deployed. Imagine that a customer has two sites close to each other, but both sites need an independent connection to the AToM network. The two sites probably each have one connection to the same PE router of the service provider. If Layer 2 traffic needs to be switched between the two sites, it is not necessary to use the MPLS network; the PE router can switch the traffic locally. Figure 10-5 shows a PE router with local switching.

Figure 10-5 Local Switching on the PE Router

XC ST Segment 1 S1 Segment 2 S2

------+---------------------------------+--+---------------------------------+--

UP mpls 10.100.2.1:100 UP mpls 10.100.1.1:100 UP

Local VC label 73 Local VC label 46

Remote VC label 35 Remote VC label 72

pw-class: one pw-class: one

ASBR2#sssshhhhoooowwww xxxxccccoooonnnnnnnneeeecccctttt ppppeeeeeeeerrrr 11110000....111100000000....1111....3333 vvvvcccciiiidddd 111100000000 ddddeeeettttaaaaiiiillll

Legend: XC ST=Xconnect State, S1=Segment1 State, S2=Segment2 State

UP=Up, DN=Down, AD=Admin Down, IA=Inactive, NH=No Hardware

XC ST Segment 1 S1 Segment 2 S2

------+---------------------------------+--+---------------------------------+--

UP mpls 10.100.2.3:100 UP mpls 10.100.1.3:100 UP

Local VC label 32 Local VC label 35

Remote VC label 73 Remote VC label 73

pw-class: one pw-class: one

Example 10-7 L2VPN Pseudowire Switching (Continued)

PEPE

CE

CE

Local Switching

P

Frame Relay/ATM/Ethernet/VLAN

Frame Relay/ATM/Ethernet/VLAN



The encapsulations that local switching supports are ATM, Frame Relay, and Ethernet. In some cases, you can even have interworking for local switching, meaning that the encapsulation type is different for both links on the PE router. Cisco IOS supports the following interworking for local switching:

■ ATM to Ethernet

■ ATM to Frame Relay

You configure Local Switching by using the connect command in Cisco IOS. If the two interfaces have a different encapsulation type, the interworking can be IP or Ethernet. As seen in some previous examples of interworking, you might want to configure RBE or IRB on the CE routers when the Ethernet interworking is done.

ATM-to-ATM Local Switching

Example 10-8 shows a router configured for ATM-to-ATM Local Switching with encapsulation AAL5.

ATM-to-ATM local switching is also supported for AAL0 (Cell Relay) in VC mode.

ATM-to-Ethernet Local Switching

On a router, you can have Local Switching between ATM and Ethernet VLAN or Ethernet Port mode. This local interworking is supported in two modes: IP and Ethernet.

Example 10-8 ATM-to-ATM Local Switching

iiiinnnntttteeeerrrrffffaaaacccceeee aaaattttmmmm 1111////0000////0000


eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn aaaaaaaallll5555

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee aaaattttmmmm 2222////0000////0000


eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn aaaaaaaallll5555

!!!!

ccccoooonnnnnnnneeeecccctttt aaaattttmmmm----aaaattttmmmm aaaattttmmmm 1111////0000////0000 0000////111100000000 aaaattttmmmm 2222////0000////0000 0000////111100000000


Local Switching 754

ATM to Ethernet VLAN

Example 10-9 shows a router that is configured for local switching between an ATM PVC interface that is configured for AAL5SNAP encapsulation and an Ethernet VLAN. The connect command allows local switching between these two interfaces and specifies the interworking type as IP mode.

ATM to Ethernet

Example 10-10 shows a router that is configured for local switching between ATM and Ethernet. The connect command allows local switching between these two interfaces and specifies the interworking type as IP mode.

Example 10-9 ATM-to-Ethernet VLAN Local Switching

!

hostname PE2

!

interface ATM0/0/0

no ip address

pvc 10/100 l2transport

encapsulation aal5snap

!

!

interface FastEthernet4/1/0.100

encapsulation dot1Q 100

!

connect atm-eth ATM0/0/0 10/100 FastEthernet4/1/0.100 interworking ip

!

!

PE2#sssshhhhoooowwww ccccoooonnnnnnnneeeeccccttttiiiioooonnnn nnnnaaaammmmeeee aaaattttmmmm----eeeetttthhhh

Connection: 9 - atm-eth

Current State: UP

Segment 1: ATM0/0/0 AAL5 10/100 up

Segment 2: FastEthernet4/1/0.100 up

Interworking Type: ip

Example 10-10 ATM-to-Ethernet Local Switching

!!!!





!!!!

!!!!


continues



ATM-to-Frame Relay Local Switching

Example 10-11 shows a router that has two interfaces. One is configured for Frame Relay, and the other is an ATM interface that is configured for AAL5SNAP encapsulation. The connect command allows local switching between these two interfaces.


!!!!

ccccoooonnnnnnnneeeecccctttt aaaattttmmmm----eeeetttthhhh AAAATTTTMMMM0000////0000////0000 11110000////111100000000 FFFFaaaassssttttEEEEtttthhhheeeerrrrnnnneeeetttt4444////1111////0000 iiiinnnntttteeeerrrrwwwwoooorrrrkkkkiiiinnnngggg iiiipppp

!!!!

!!!!

PE2#sssshhhhoooowwww ccccoooonnnnnnnneeeeccccttttiiiioooonnnn nnnnaaaammmmeeee aaaattttmmmm----eeeetttthhhh

Connection: 10 - atm-eth

Current State: UP


Segment 2: FastEthernet4/1/0 up


Example 10-11 ATM-to-Frame Relay Local Switching

!!!!

iiiinnnntttteeeerrrrffffaaaacccceeee SSSSeeeerrrriiiiaaaallll0000////1111////0000


eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn ffffrrrraaaammmmeeee----rrrreeeellllaaaayyyy

ffffrrrraaaammmmeeee----rrrreeeellllaaaayyyy iiiinnnntttteeeerrrrffffaaaacccceeee----ddddllllcccciiii 333300000000 sssswwwwiiiittttcccchhhheeeedddd

!!!!





!!!!

!!!!

ccccoooonnnnnnnneeeecccctttt aaaattttmmmm----ffffrrrr AAAATTTTMMMM8888////0000////0000 11110000////111100000000 SSSSeeeerrrriiiiaaaallll0000////1111////0000 333300000000 iiiinnnntttteeeerrrrwwwwoooorrrrkkkkiiiinnnngggg iiiipppp

!!!!

!!!!

PE1#sssshhhhoooowwww ccccoooonnnnnnnneeeeccccttttiiiioooonnnn nnnnaaaammmmeeee aaaattttmmmm----ffffrrrr

Connection: 9 - atm-fr

Current State: UP


Segment 2: Serial0/1/0 300 up


Example 10-10 ATM-to-Ethernet Local Switching (Continued)


Local Switching 756

Frame Relay-to-Frame Relay Local Switching

Example 10-12 shows a PE router that has serial interfaces configured for Frame Relay. The connect command allows local switching between these two Frame Relay interfaces.

Example 10-12 Frame Relay-to-Frame Relay Local Switching

!

frame-relay switching

!

interface Serial0/1/0

no ip address

encapsulation frame-relay

frame-relay interface-dlci 300 switched

frame-relay intf-type dce

!

interface Serial0/1/1

no ip address

encapsulation frame-relay

frame-relay interface-dlci 400 switched

frame-relay intf-type dce

!

connect fr-fr Serial0/1/0 300 Serial0/1/1 400

!

!

PE1#sssshhhhoooowwww ccccoooonnnnnnnneeeeccccttttiiiioooonnnn nnnnaaaammmmeeee ffffrrrr----ffffrrrr

11 fr-fr Se0/1/0 300 Se0/1/1 400 UP


1974 chp10ONLa.fm Page 735 Tuesday, November 14,...

Documents

Transcript of 1974 chp10ONLa.fm Page 735 Tuesday, November 14,...