06-05-2014 09:42 AM
Hi All,
I have a basic requirement about splitting traffic path when the flow are going to different destination, it seems a PBR solution as usual as IOS router environment as before, due to our routing setup restriction under our network. And I checked some related document about PBR on ASR 9K, but I couldn't find exact command as " set next hope IP x.x.x.x" under policy map, so my question is: does the ASR 9K can do same thing as IOS based router ? or is there some converter setup about PBR for this requirement on 9K ?
or other idea or solution we could choose ?
please share your idea if you could, thanks so much in advance !
Eric
06-05-2014 10:20 AM
Hello, replacement of PBR in IOS-XR is called ABF,
here I leave a link where he talks about the ABF
https://supportforums.cisco.com/document/145271/abf-acl-based-forwarding-asr9k
is, more easy to configured and flexible to the PBR of IOS.
06-05-2014 12:39 PM
thanks very much for your information, fcacerescabrera!
I am seeking for how to write down this ACL syntax as match specific destination IP to first next hope IP , then send rest of traffic to other next hop IP, as we don't have and couldn't have default route 0.0.0.0/0 in routing table, could you please know how to make it out ?
thanks,
Eric
06-07-2014 01:27 PM
Here is a config example on ABF. It is basically an ACL entry with a nexthop directive.
If the nexthop is not available, it is skipped. If you like redundant nexthops, then you can use EOT (enhanced object tracking), this is done via IPSLA. IPSLA requires the MGBL pie.
ABF is a regular ACL that is applied with the ipv4 access-group directive, inbound on the interface.
CFG
IPSLA config for tracker:
ipsla
operation 61
type icmp echo
source address x.x.x.(x-1)
destination address x.x.x.x !!(nexthop to track)
timeout 1000
frequency 1
!
!
Start that probe:
schedule operation 1
start-time now
life forever
!
!
Configure a tracker on an object (the ipsla probe).
we call it tracker 161 and it is looking at probe 61 (the previously defined IPSLA)
track 161
type rtr 61 reachability
delay up 5
delay down 30
!
Access-list for ABF config:
ipv4 access-list abf
10 permit 0.0.0.0 255.255.255.0 any nexthop track 161 x.x.x.x y.y.y.y
this says that any traffic with 0.0.0.x should follow x.x.x.x and is tracked by tracker 161, which uses a probe from ipsla on that next hop and if that probe fails we use y.y.y.y
When ABF fails over from one nexthop to another it will do that until that other nexthop becomes unavailable.
regards
xander
06-20-2014 12:07 PM
thanks xander as well !
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