ABF applicability to MPLS-TE

[Tiziano Tofoni]

Hi all,

in IOS you can drive traffic into an MPLS-TE tunnel using, beside stating routing, autoroute announce and forwarding adjacency, PBR (Policy Based Routing).

I'm wondering whether you can do the same in IOS XR using ABF (Access-list Based Forwarding). 

For instance, suppose you have on an IOS XR router an "inteface tunnel-te 100" configured and up, and you want to steer traffic entering interface Gi0/0/0/0 with source IP address in 20.1.1.0/24 net and destination IP address in 30.1.1.0/24 net into "tunne-te 100". Can I use the following configuration ?

ipv4 access-list TEST-ABF

  10 permit ipv4 20.1.1.0/24 30.1.1.0/24 nexthop1 tunnel-te 100

  20 permit ipv4 any any

!

interface Gi0/0/0/0

  ipv4 access-group TEST-ABF ingress

Unfortunately I do not the possibility to test. I did some research on Cisco docs and it seems that you can only use IPv4 addresses as Next-Hop. Is it correct ?

Thanks a lot in advance to anybody who can give me an answer.

[Vinit Jain]

Hello,

regarding the above configuration, i can test it and let you know if the configuration is valid or not.

to your last point, yes, the next-hop address can only be set as IPv4 for TE tunnels

[Vinit Jain · Accepted solution]

just checked the above configuration and it doesn't seems to be valid:

RP/0/RSP0/CPU0:ASR9010-A(config)#ipv4 access-list test
RP/0/RSP0/CPU0:ASR9010-A(config-ipv4-acl)#per ipv4 20.1.1.0/24 30.1.1.0/24 nexthop1 ?
  ipv4   Enter nexthop1 ipv4 address
  track  Enter specific TRACK Name for this nexthop
  vrf    Enter specific VRF Name for this nexthop
  <cr>   
RP/0/RSP0/CPU0:ASR9010-A(config-ipv4-acl)#per ipv4 20.1.1.0/24 30.1.1.0/24 nexthop1 ipv4 ?
  A.B.C.D  Enter nexthop1 IPv4 address
RP/0/RSP0/CPU0:ASR9010-A(config-ipv4-acl)#per ipv4 20.1.1.0/24 30.1.1.0/24 nexthop1 track ?
  WORD  Enter Track Name
RP/0/RSP0/CPU0:ASR9010-A(config-ipv4-acl)#per ipv4 20.1.1.0/24 30.1.1.0/24 nexthop1 track test ?
  ipv4  Enter nexthop1 ipv4 address
  vrf   Enter specific VRF Name for this nexthop
  <cr>  

from what i understand, ABF is IP only. The stuff that you are trying to achieve is similar to PBTS

http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r4-3/mpls/configuration/guide/b_mpls_cg43xasr9k/b_mpls_cg43asr9k_chapter_0100.html#con_1325561

Hope this helps.

Vinit

[Tiziano Tofoni]

Hi Vinit,

I gave a look to the doc on PBTS.

I found out PBTS is the equivalent of IOS Class Based Tunnel Selection and not of PBR. So, I guess that IOS XR does not have an equivalent of PBR to steer traffic with certain characteristic inside an MPLS-TE tunnel.

Anyway, thank you very much.

Tiziano

[Tiziano Tofoni]

Thanks a lot for your help Vinit, wonderful. I think PBTS is exactly what I was looking for. I will read the document ASAP but at a first look it seems definitely good.

Thanks a lot again.

Tiziano