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MPLS L2vpn Interwroking - Traffic Forwadring issue

Hi,

Can any one support me to find out what can i do to let this l2vpn work as expected .

let me share with you my topolgy and configuration .

[R14-CE]-pos1/0<---------PPP--------->pos2/0[PE-R13]<----->[P]<----->[P]<------->[PE-R15]s3/1<---------FR--------->s0/1[CE-R18]

Nodes and used interfaces as shown , for L2vpn interworking between PPP and FR.

Configuration :

==========

R14#

=====

interface POS1/0

mtu 1500

ip address 2.2.2.1 255.255.255.0

encapsulation ppp

R13:

====

pseudowire-class INTER-PPP-FR

encapsulation mpls

interworking ip

interface POS2/0

mtu 1504

no ip address

encapsulation ppp

xconnect 15.15.15.15 1315 pw-class INTER-PPP-FR

R15:

===

pseudowire-class Inter

encapsulation mpls

interworking ip

interface Serial3/1

mtu 1504

no ip address

encapsulation frame-relay

load-interval 30

serial restart-delay 0

frame-relay intf-type dce

connect FR-2-FR Serial3/1 101 l2transport

xconnect 13.13.13.13 1315 pw-class Inter

R18:

===

interface Serial0/1

ip address 2.2.2.2 255.255.255.0

encapsulation frame-relay

serial restart-delay 0

The above topology has been deployed using GNS3 with 7200 routers with IOS

Version 12.2(33)SRE9

Tests:

====

1- Ping failed , no arp resolution successed

2-Resulting of my troubleshooting , ATOM is UP as below log shown .

R13-PE1#sh mpls l2transport vc 1315 detail

Local interface: PO2/0 up, line protocol up, PPP up

  Interworking type is IP

  Destination address: 15.15.15.15, VC ID: 1315, VC status: up

    Output interface: Fa1/0, imposed label stack {19 16}

    Preferred path: not configured 

    Default path: active

    Next hop: 10.13.3.3

  Create time: 00:48:50, last status change time: 00:48:48

  Signaling protocol: LDP, peer 15.15.15.15:0 up

    Targeted Hello: 13.13.13.13(LDP Id) -> 15.15.15.15, LDP is UP

    Status TLV support (local/remote)   : enabled/supported

      LDP route watch                   : enabled

      Label/status state machine        : established, LruRru

      Last local dataplane   status rcvd: No fault

      Last local SSS circuit status rcvd: No fault

      Last local SSS circuit status sent: No fault

      Last local  LDP TLV    status sent: No fault

      Last remote LDP TLV    status rcvd: No fault

      Last remote LDP ADJ    status rcvd: No fault

    MPLS VC labels: local 24, remote 16

    Group ID: local 0, remote 0

    MTU: local 1504, remote 1504

    Remote interface description:

  Sequencing: receive disabled, send disabled

  Control Word: On (configured: autosense)

  VC statistics:

    transit packet totals: receive 0, send 20

    transit byte totals:   receive 0, send 2520

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

so i tried debug mpls packets in the core to check label traffic through core network , i found that R14-CE1 send ICMP packet to the connected edge R13 then it forwarded normally through the core untill reached CE2 then , the reply on this packet towards the originator from CE2 forwarded from connected Edge towards core network with one label [ PW Label ] only , no AC Label. so traffic get dropped when reached the orginator CE's connected Edge.

Can any support what can i do or if there are any missing configurations ???

Thank you

Mohamed

Everyone's tags (1)
5 REPLIES
Cisco Employee

MPLS L2vpn Interwroking - Traffic Forwadring issue

Hi Mohamed,

Can you please provide show mpls forwarding-table output from both R13 & R15 PE router for this l2vpn entry

Regards,

Sandip

MPLS L2vpn Interwroking - Traffic Forwadring issue

R13-PE1#sh mpls forwarding-table

Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop   

Label      Label      or Tunnel Id     Switched      interface             

16         No Label   l2ckt(1315)      0             PO2/0      point2point

17         Pop Label  3.3.3.3/32       0             Fa1/0      10.13.3.3  

18         16         4.4.4.4/32       0             Fa1/0      10.13.3.3  

19         19         15.15.15.15/32   0             Fa1/0      10.13.3.3  

20         Pop Label  10.3.4.0/24      0             Fa1/0      10.13.3.3  

21         Pop Label  10.3.6.0/24      0             Fa1/0      10.13.3.3  

22         17         10.15.4.0/24     0             Fa1/0      10.13.3.3  

23         20         10.15.6.0/24     0             Fa1/0      10.13.3.3  

R15-PE2#sh mpls  forwarding-table

Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop   

Label      Label      or Tunnel Id     Switched      interface             

16         No Label   l2ckt(1315)      0             Se3/1      point2point

17         Pop Label  4.4.4.4/32       0             Fa1/0      10.15.4.4  

18         17         3.3.3.3/32       0             Fa1/0      10.15.4.4  

19         21         13.13.13.13/32   0             Fa1/0      10.15.4.4  

20         Pop Label  10.3.4.0/24      0             Fa1/0      10.15.4.4  

21         19         10.3.6.0/24      0             Fa1/0      10.15.4.4  

22         20         10.13.3.0/24     0             Fa1/0      10.15.4.4  

MPLS L2vpn Interwroking - Traffic Forwadring issue

Hi Sandip ,

do you see no any configuration missing ? and please check above your requested output

Cisco Employee

MPLS L2vpn Interwroking - Traffic Forwadring issue

Hi Mohamed,

Configuration looks ok to me, can you try configuring frame-relay switches, and source interface in psedowire-class, like configured in this document

http://www.cisco.com/en/US/docs/ios-xml/ios/wan_lserv/configuration/15-mt/mp-l2vpn-intrntwkg.html#GUID-1C26085B-A100-4A8A-A7DB-22919A87E559

Look at

Example: Frame Relay to PPP over AToM (Routed)

Also look at Frame Relay Interworking Restrictions in the same document, make sure u followed guidlines given in this document for Frame relay interworking.

If this still not work, can you try with real hardware, sometime we have issue in GNS with labeling.

If this still not work, can you please provide debug output for both frame-relay and ppp connection ?

If u configure both side ppp and both side frame-relay does it work ? I just want to make sure, there is no issue with labling in between.

Regards,

Sandip

MPLS L2vpn Interwroking - Traffic Forwadring issue

Hi Sandip ,

i tried your suggestions and here's the result :

1-  Also look at Frame Relay Interworking Restrictions in the same   document, make sure u followed guidlines given in this document for   Frame relay interworking. --> Followed no missing points.

2- If this still not work, can you try with real hardware, sometime we have issue in GNS with labeling. --> Unfortunately , not avaialble the right moment , but i will try it soon.

3-If this still not work, can you please provide debug output for both frame-relay and ppp connection ? --> Here's for ppp , unfortunately FR Debug doesn't show any output !!

*Nov 30 12:34:27.639: PO2/0 LCP: O ECHOREQ [Open] id 5 len 12 magic 0x061AD0EA

*Nov 30 12:34:27.667: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:27.675: PO2/0 LCP: I ECHOREQ [Open] id 5 len 12 magic 0x071AD5BB

*Nov 30 12:34:27.675: PO2/0 LCP: O ECHOREP [Open] id 5 len 12 magic 0x061AD0EA

*Nov 30 12:34:27.683: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:27.683: PO2/0 LCP: I ECHOREP [Open] id 5 len 12 magic 0x071AD5BB

*Nov 30 12:34:27.683: PO2/0 LCP: Received id 5, sent id 5, line up

R13-PE1#

*Nov 30 12:34:37.655: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:37.663: PO2/0 LCP: O ECHOREQ [Open] id 6 len 12 magic 0x061AD0EA

*Nov 30 12:34:37.667: PO2/0 LCP: I ECHOREQ [Open] id 6 len 12 magic 0x071AD5BB

*Nov 30 12:34:37.667: PO2/0 LCP: O ECHOREP [Open] id 6 len 12 magic 0x061AD0EA

*Nov 30 12:34:37.695: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:37.703: PO2/0 LCP: I ECHOREP [Open] id 6 len 12 magic 0x071AD5BB

*Nov 30 12:34:37.703: PO2/0 LCP: Received id 6, sent id 6, line up

R13-PE1#

*Nov 30 12:34:47.671: PO2/0 LCP: O ECHOREQ [Open] id 7 len 12 magic 0x061AD0EA

*Nov 30 12:34:47.699: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:47.707: PO2/0 LCP: I ECHOREP [Open] id 7 len 12 magic 0x071AD5BB

*Nov 30 12:34:47.707: PO2/0 LCP: Received id 7, sent id 7, line up

*Nov 30 12:34:47.711: PO2/0 PPP: I pkt type 0xC021, datagramsize 16 link[ppp]

*Nov 30 12:34:47.711: PO2/0 LCP: I ECHOREQ [Open] id 7 len 12 magic 0x071AD5BB

*Nov 30 12:34:47.711: PO2/0 LCP: O ECHOREP [Open] id 7 len 12 magic 0x061AD0EA

4-If  u configure both side ppp and both side frame-relay does it work ? --> Yes , [ PPP-PPP] , [FR-FR],[PPP-Ether] all of these setp up are working , but [ PPP-FR] [Ether-FR] not working , like an issue with Frame relay configuration or progress which is the common in this failure scenarios.

5-I  just want to make sure, there is no issue with labling in between. -->  simply [ traffic travels from PE13 to PE 15 with 2 labels ] and the  reply from PE15 towards PE13 i found it with one label only . so i don't  know what's reason ??

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