10-03-2010 03:41 AM
Hi,
Is as-path prepending on an import map a tool that should be available?
I have found that on the IOS I'm testing that the prepending only applied if the same route-map is also setting local preference. Sounds like a bug to me but the bug toolkit is currently unavailable at time of posting.
The problem I wish to solve is to import overlapping routes with different route targets, with one route target's routes being preferred over another. Setting local preference would work, but I'd rather use as-path length as that is the metric we manipulate elsewhere.
If this a method that others have experience with?
Thanks,
Peter
10-03-2010 07:13 PM
Hi peter,
I have tried this scenario on two of platform (7600 and 10k) and I found i face similar problem,
without setting LP I do not see any path-prepending information in outputs.
but anyway let me try more on this , meanwhile if you can paste output of
sh ip bgp vpnv4 vrf CMPB 1.1.1.1/32
Regards
Mahesh
10-04-2010 01:38 AM
Hi Mahesh,
Thank you very much for recreating the issue on those platforms. Here's the output you requested:
GBLON-SQ41-LVG01#sh ip bgp vpnv4 vrf CMPB 1.1.1.1/32
BGP routing table entry for 1:2:1.1.1.1/32, version 6
Paths: (1 available, best #1, table CMPB)
Not advertised to any peer
Local, imported path from 1:1:1.1.1.1/32
0.0.0.0 (via CMPA) from 0.0.0.0 (10.196.111.3)
Origin IGP, metric 0, localpref 100, weight 32768, valid, external, best
Extended Community: RT:1:1
mpls labels in/out nolabel/nolabel(CMPB)
I opened a TAC case about this last night and they are investigating too, i'll post their findings once I know. I have also found that setting a community value also allows the prepending to apply - which obviously is a much less intrusive workaround...
In your experience is changing routing metrics on an import map not a tool that is often used? Or worse, is it not advisable/supported?
Thanks,
Peter
10-04-2010 01:59 AM
Hi peter,
I always seen that doing something via. import-map is not functioning as per our requirement.
Sometimes we need to clear routes frequently to see affect . But we can't blame untill we have some insight outputs.
Unfortunately there is no more debug options available for troubleshooting.
Inbetween is it possible to try this with any external route. i am not able to create such scenario here.
also please let me know tac reply. i am eager to know that
regards
mahesh
12-14-2011 02:12 PM
Hi all
I am in the same situation, do you have any info from the TAC?
thanks
regards
AC
12-15-2011 02:17 AM
Guys,
I believe the answer from TAC is:
15.0(1)M4.5
15.1(3.13)T
12.2(33)SRE3
12.2(33.2.20)SRE
15.1(1)S0.2
15.1(1.22)S
15.0(1.19)DPA12
15.1(3.8.3)PIB
15.2(0.0.12)PIL16
15.0(1)S2.3
15.1(2)T2.2
15.1(1)T2.4
15.1(3)T0.2
15.1(1)S1
15.0(1.19)DPB23
15.0(2.12)DPB1
15.0(1)SY
15.1(1)SG1.3
15.0(1)S3a
15.1(2)GC1
HTH,
Ivan.
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