Traffic Redirection

[kijush.maharjan]

I am currently using NCS5500 for core routing. I want to redirect some type of traffic to a directly connected IP. How can i achieve it?

I tried using access-list but it is not working. 

[Giuseppe Larosa]

Hello kijush,

you should use policy based routing PBR on your device.

NCS 5500 runs IOS XR.

I don't see any equivalent of PBR in NCS Routing configuration guide

https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5500/routing/66x/b-routing-cg-ncs5500-66x.html

There is a routing policy chapter in NCR6000 Routing guide, but it is the equivalent of route-maps for route filtering applications

https://www.cisco.com/c/en/us/td/docs/routers/ncs6000/software/ncs6k-r6-4/routing/configuration/guide/b-routing-cg-ncs6000-64x/b-routing-cg-ncs6000-64x_chapter_01011.html

Hope to help

Giuseppe

[kijush.maharjan]

Hi Giuseppe,

Thank you for your reply. 

But I doubt using RPL can match any type of traffic like say dns, http etc.

I didn't find anything related to matching any traffic in the provided document and didn't find it anywhere except ACL. 

Please point me to the correct document if you have any beside the provided one.

[Giuseppe Larosa]

Hello kijush,

look at the ePBR feature that is supported on ASR 9000.

https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r5-3/addr-serv/configuration/guide/b-ipaddr-cg53asr9k/b-ipaddr-cg53asr9k_chapter_01110.html

This should be what you need if it is supported on your platform.

ePBR uses a modified version of policy-map instead of route-maps.

/* Configure an ePBR policy map with the class map */
Router(config)# policy-map type pbr INBOUND-POLICY
Router(config-pmap)# class type traffic INBOUND-CLASS
Router(config-pmap-c)# redirect nexthop 192.168.10.1
Router(config-pmap-c)# exit
Router(config-pmap)# class type traffic class-default
Router(config-pmap-c)# transmit
Router(config-pmap-c)# commit
Mon Nov  6 17:25:33.858 IST
Router(config-pmap)# end-policy-map 

Please note that a class class-default for all traffic that is to be normally destination based routed is present in the example.

In cisco IOS PBR this is not needed.

Hope to help

Giuseppe

[kijush.maharjan]

Hi Giuseppe,

Unfortunately, NCS doesnt support the way it does in ASR. Need to find out how it is carried out in NCS. This ePBR seems the ultimate solution but tricky in setting it up in NCS.

Thank you for your effort. :)

[Giuseppe Larosa]

Hello kijush,

I was afraid the NCS could not support it like the ASR 9000 does.

I hope you can find a way to implement this PBR.

Your question is interesting, because I realized I had never done PBR in IOS XR.

Hope to help

Giuseppe