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Beginner

Point to Point L2VPN in IOS XR

Hi,

Im working out p2p L2vpn between ASR9K and IOS platforms (7600). PE-CE connectivity is using vlan encapsulation at both ends. Default PW type negotiated is ethernet (VC type 5) and VC comes up. But CE to CE communication is not happening. I changed the interworking mode to IP at both ends and it started working.

What is the difference between these PW types. Has anyone come across the same problem? I believe it should work with Ethernet type itself.

Below are the output details before and after changing PW types.

Default PW-type:

Group ASR-G2, XC A-G2, state is up; Interworking none

  AC: GigabitEthernet0/0/0/1.607, state is up

    Type VLAN; Num Ranges: 1

    VLAN ranges: [607, 607]

    MTU 1546; XC ID 0x840004; interworking none

    Statistics:

      packets: received 1045, sent 25782

      bytes: received 123094, sent 1706886

      drops: illegal VLAN 0, illegal length 0

  PW: neighbor 10.20.0.3, PW ID 107, state is up ( established )

    PW class not set, XC ID 0xc0000004

    Encapsulation MPLS, protocol LDP

    Source address 124.7.227.20

    PW type Ethernet, control word disabled, interworking none

    PW backup disable delay 0 sec

    Sequencing not set

    PW Status TLV in use

      MPLS         Local                          Remote

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

      Label        16022                          45285

      Group ID     0x4000100                      0x0

      Interface    GigabitEthernet0/0/0/1.607     unknown

      MTU          1546                           1546

      Control word disabled                       disabled

     PW type      Ethernet                       Ethernet

      VCCV CV type 0x2                            0x2

                   (LSP ping verification)        (LSP ping verification)

      VCCV CC type 0x6                            0x2

                   (router alert label)           (router alert label)

                   (TTL expiry)

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

    Incoming Status (PW Status TLV):

      Status code: 0x0 (Up) in Notification message

    Outgoing Status (PW Status TLV):

      Status code: 0x0 (Up) in Notification message

    MIB cpwVcIndex: 3221225476

    Create time: 19/06/2013 16:23:08 (00:02:30 ago)

    Last time status changed: 19/06/2013 16:25:28 (00:00:10 ago

Interworking IPv4:

Group ASR-G2, XC A-G2, state is up; Interworking IPv4

  AC: GigabitEthernet0/0/0/1.607, state is up

    Type VLAN; Num Ranges: 1

    VLAN ranges: [607, 607]

    MTU 1546; XC ID 0x840004; interworking IPv4

    Statistics:

      packets: received 1045, sent 25780

      bytes: received 123094, sent 1706750

      drops: illegal VLAN 0, illegal length 0

  PW: neighbor 10.20.0.3, PW ID 107, state is up ( established )

    PW class not set, XC ID 0xc0000004

    Encapsulation MPLS, protocol LDP

    Source address 124.7.227.20

    PW type IP, control word disabled, interworking IPv4

    PW backup disable delay 0 sec

    Sequencing not set

    PW Status TLV in use

      MPLS         Local                          Remote

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

      Label        16022                          45280

      Group ID     0x4000100                      0x0

     Interface    GigabitEthernet0/0/0/1.607     unknown

      MTU          1546                           1546

      Control word disabled                       disabled

      PW type      IP                             IP

      VCCV CV type 0x2                            0x2

                   (LSP ping verification)        (LSP ping verification)

      VCCV CC type 0x6                            0x2

                   (router alert label)           (router alert label)

                   (TTL expiry)

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

    Incoming Status (PW Status TLV):

      Status code: 0x0 (Up) in Notification message

    Outgoing Status (PW Status TLV):

      Status code: 0x0 (Up) in Notification message

    MIB cpwVcIndex: 3221225476

    Create time: 19/06/2013 14:16:02 (02:04:47 ago)

    Last time status changed: 19/06/2013 15:18:07 (01:02:41 ago)

    Statistics:

      packets: received 25780, sent 1045

      bytes: received 1706750, sent 123094

Appreciate your help!

Regards,

Darshak

1 ACCEPTED SOLUTION

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sorry. necro posting. cisco page loading slow today.

View solution in original post

9 REPLIES 9
Highlighted
Beginner

Hi,

I recommend you to create PW Classes:

7600 Series
Router(config)#
pseudowire-class TEST

Router(config-pw-class)#encapsulation mpls

Router(config-pw-class)#interworking ?

  ethernet  Ethernet interworking

  ip        IP interworking

  vlan      VLAN interworking

Router(config-pw-class)#internetworking ethernet

And call above in the interface

Router(config-if)# xconnect   pw-class TEST

ASR9k Series 

RP/0/RSP0/CPU0:router# configure

RP/0/RSP0/CPU0:router(config)# l2vpn

RP/0/RSP0/CPU0:router(config-l2vpn)# pw-class TEST

RP/0/RSP0/CPU0:router(config-l2vpn-pwc)# encapsulation mpls

RP/0/RSP0/CPU0:router(config-l2vpn-pwc-encap-mpls)# transport-mode ethernet

RP/0/RSP0/CPU0:router(config-l2vpn-pwc-encap-mpls)# exit

RP/0/RSP0/CPU0:router(config-l2vpn-pwc-encap)# exit

RP/0/RSP0/CPU0:router(config-l2vpn-pwc)# exit

RP/0/RSP0/CPU0:router(config-l2vpn)# xconnect group TESTGROUP

RP/0/RSP0/CPU0:router(config-l2vpn-xc)# p2p TESTP2P

RP/0/RSP0/CPU0:router(config-l2vpn-xc-p2p)# neighbor pw-id

RP/0/RSP0/CPU0:router(config-l2vpn-xc-p2p-pw)# pw-class TEST

RP/0/RSP0/CPU0:router(config-l2vpn-xc-p2p-pw)# exit

RP/0/RSP0/CPU0:router(config-l2vpn-xc-p2p)# interface TenGigE0/0/0/0.40 //Example

Recommended:

L2VPN on ASR9k

http://www.cisco.com/en/US/docs/routers/asr9000/software/asr9k_r4.1/lxvpn/command/reference/b_lxvpn_cr41asr9k_chapter_010.html#wp3681643325

Regards.

Please don't forget to rate helpful posts.

Highlighted

Hello Samil,

Thanks for the response.

As I mentioned earlier, VC stays up in all the cases. I tried VCtype 5 (Ethernet) and VCtype4 (Ethernet Vlan). I beleive it should be VC type 4, since im using vlan encapsulation on both attachmet circuits. But there is no communication between CE's.

It starts working after configuring Interworking IP on both ends, which removes the layer2 header while sending the payload across the pseudowire.

Regards,

Darshak

Highlighted

Hello everyone,

I got this solved. I applied " rewrite ingress tag pop..." command on the AC interface. Below is the working configuration.

XR Config:

interface GigabitEthernet0/0/0/1.900609 l2transport

encapsulation dot1q 900 second-dot1q 609

rewrite ingress tag pop 2 symmetric

mtu 1522

l2vpn

pw-class MPLS

  encapsulation mpls

   transport-mode vlan 

xconnect group ASR-J2

  p2p ASR-J2

   interface GigabitEthernet0/0/0/1.900609

   neighbor 10.10.10.255 pw-id 109

    pw-class MPLS

IOS Config:

interface G0/1.609

xconnect 124.7.227.20 109 encapsulation mpls

What I observed is the difference in the L2 header size calculation. Without the "rewrite" command, XR is calculating L2 header size as 14 bytes without taking the double tag (extra 8 bytes) in consideration. So to get the payload size as 1500 bytes, i applied 1514 bytes on the interface. This matched with the remote end device MTU 1500. But there is no communication between CE.

After applying "rewrite ingress tag pop2 symmetric" command, it does consider the extra bytes as well. I had to set the MTU as 1522 to get the payload size as 1500. Now the CE is able to commmunicate with each other. I tested with IOS and JUNOS on the remote end, the behavior remains the same.

"rewrite ingress tag pop2 symmetric" removes the vlan tags (both outer and inner) while sending the packet across MPLS pseudowire and add both tags back while sending to Attachment circuit.

So here are my questions ,

  1. why XR is not considering vlan tags for L2 header size calculation
  2. How does this behavior change when "rewrite.." command is applied

Appreciate your response.

Regards,

Darshak

Highlighted
Cisco Employee

because IOS pops the tage by default and XR does not.

on XR interface.. you have 2 dot1Q tags so with rewrite POP 2 symmetric

encapsulation dot1q 900 second-dot1q 609

rewrite ingress tag pop 2 symmetric

you are removing tags when sending to Core and adding them back when going towards AC side

Reagrds, Satish.
Highlighted

Thanks Satish,

"because IOS pops the tage by default and XR does not. "

So the Packets are carried through the MPLS pseudowire with native ethernet header (14 bytes SA + DA + Ethertype). Vlan Tags will be stripped out.

Regards,

Darshak

Highlighted

Thats correct...the core wont have any dot1q tags

Reagrds, Satish.
Highlighted

Hello ALL,

 

 

by any chance does any one have this configuration working between Junos and Cisco 7600 with the double tag

Highlighted
Beginner

Sorry replied on wrong place.
Highlighted

sorry. necro posting. cisco page loading slow today.

View solution in original post

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