BGP as-path assistance

[vaultnetworks]

BGP Gurus,

I've trying to setup a filter to local pref a particular AS # on my routers with your examples and have not had any success. After implementing them I did a soft and hard bgp config. Even did a hard shutdown on the session to see if that would solve the problem. Any assistance you can give would be much appreciated.

The platform is Cisco 7606 with Sup720-3BXL's

Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVIPSERVICESK9-M), Version 12.2(33)SRE2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Fri 06-Aug-10 02:50 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)SX5, RELEASE SOFTWARE (fc1)
BOOTLDR: Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVIPSERVICESK9-M), Version 12.2(33)SRE2, RELEASE SOFTWARE (fc1)

---------------------------------

router bgp 1234
no synchronization
bgp default local-preference 0
bgp log-neighbor-changes
bgp bestpath as-path multipath-relax
neighbor 1.1.1.1 remote-as 3356
neighbor 1.1.1.1 soft-reconfiguration inbound
neighbor 1.1.1.1 route-map Provider in

ip as-path access-list 1 permit _1111_

route-map Provider permit 10
set metric 1
!
route-map Provider permit 5
match as-path 1
set local-preference 200
!

[Peter Paluch]

Brian,

Can you please provide the ouput of the show ip bgp showing the paths through AS 1111 that are missing the local preference you have set?

Also please remove the soft-reconfiguration inbound command. All current BGP implementations support the Route Refresh feature and do not need to store a separate unfiltered database.

Best regards,

Peter

[vaultnetworks]

Peter,

Thanks for the advice. I removed the soft-reconfiguration inbound on each neighbor now. We are getting full routes from 2 upstream on this device so "show ip bgp is quite long. I've included a snippet of the AS # we're actually looking for and that pref has not been set.

Ibr3.mia#show ip bgp | inc 10429
*> 15.227.240.0/20  4.71.214.33              1             0 3356 12956 10429 7298 71 i
*  62.44.34.0/23    4.71.214.33              1             0 3356 12956 10429 41707 i
*  63.250.188.0/24  4.71.214.33              1             0 3356 12956 10429 11271 3300 i
*  63.250.189.0/24  4.71.214.33              1             0 3356 12956 10429 11271 3300 i
*  74.209.134.0/24  4.71.214.33              1             0 3356 12956 10429 15201 7162 18607 i
*m 141.113.160.0/22 4.71.214.33              1             0 3356 12956 10429 53070 i
*  141.113.164.0/22 4.71.214.33              1             0 3356 12956 10429 53070 i
*>                  67.17.198.5              1             0 3549 12956 10429 22876 i
*  148.188.162.0/23 4.71.214.33              1             0 3356 12956 10429 13878 15180 15180 15180 i
*m 161.148.0.0      4.71.214.33              1             0 3356 12956 10429 10954 i
*m 161.148.64.0/18  4.71.214.33              1             0 3356 12956 10429 10954 i
*  161.148.192.0/18 4.71.214.33              1             0 3356 12956 10429 10954 i
*m 177.8.160.0/20   4.71.214.33              1             0 3356 12956 10429 15201 7162 18479 28666 28666 28666 i
* i                 38.108.41.121            1      0      0 174 12956 10429 15201 7162 18479 28666 28666 28666 i
*>                  67.17.198.5              1             0 3549 12956 10429 15201 7162 18479 28666 28666 28666 i
*m 177.9.0.0/17     4.71.214.33              1             0 3356 12956 10429 27699 i

[cadet alain]

Hi Brian,

there is no AS 1111 in your output.

[vaultnetworks]

AS1111 was just to fill in as an example on my initial post. The actual AS I'm attempting to set local pref on is 10429.

[Peter Paluch]

Hello Brian,

Thank you for responding. I am a little confused now, however. You have been using an as-path matching the AS 1111 but there is no such AS in the routes you have quoted here. That alone would explain why the Local Preference is not set but is this observation correct?

Best regards,

Peter

[cadet alain]

Hi brian,

Can you do sh ip bgp 15.227.240.0 255.255.240.0

[vaultnetworks]

Ibr3.mia#sh ip bgp 15.227.240.0 255.255.240.0
BGP routing table entry for 15.227.240.0/20, version 17967116
Paths: (2 available, best #1, table default)
Multipath: eBGP
  Advertised to update-groups:
     2
  3356 12956 10429 7298 71, (aggregated by 71 16.96.179.55)
    4.71.214.33 from 4.71.214.33 (4.69.182.132)
      Origin IGP, metric 1, localpref 0, valid, external, best
  3549 7298 7298 7298 7298 7298 71, (aggregated by 71 16.96.179.54)
    67.17.198.5 from 67.17.198.5 (67.17.82.92)
      Origin IGP, metric 1, localpref 0, valid, external
      Community: 232592214 232621340 478289239

[cadet alain]

ok so now do a show ip bgp regexp _10429 and show route-map

[Peter Paluch]

Hello,

Even better:

show ip bgp regexp _10429_

Best regards,

Peter

[cadet alain]

Hi Peter,

So much for me 

Regards.

Alain.

[vaultnetworks]

Guys,

Thanks. In between posts I was fiddling around and managed to get it to work. Initially I have two route-maps setup as below. The metric was working just fine. I figured that the first route-map could be preventing it so I removed it and cleared bgp. It worked.

route-map Level_Announcement-In permit 5
set metric 1
!

route-map Level_Announcement-In permit 10
  match as-path 1
  set local-preference 500
!

So my question is now, what else needs to be added to the bgp session reads both of these configuration directives??

[cadet alain]

Hi,

So my question is now, what else needs to be added to the bgp session reads both of these configuration directives??

what do you mean by that? just apply the route-map inbound for each neighbour you want these routes to get a local pref of 500.

Then do a route refresh and verify if it's ok.

Regards.