[c-nsp] Dumb question

Brault, Ryan RYAN.BRAULT at illinois.gov
Wed Aug 3 12:06:33 EDT 2011


No synchronization on RTR2?  Not sure if that is part of the obvious and irrelevant...

Ryan Brault
Illinois Century Network
Illinois Department of Central Management Services
815-936-4647

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Ziv Leyes
Sent: Wednesday, August 03, 2011 10:44 AM
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Dumb question

OK, this is what I have configured (omitting the obvious and irrelevant):

RTR1#
router bgp 100
 neighbor RTR2 remote-as 100
 neighbor x.x.x.x peer-group RTR2 
 neighbor RTR2 send-community
 neighbor RTR2 route-map RTR2-OUT out
!
route-map RTR2-OUT permit 10
 match ip address prefix-list COMMUNITY-1
 set community 100:1
!
route-map RTR2-OUT permit 20
 match ip address prefix-list COMMUNITY-2
 set community 100:2 
! 
ip prefix-list COMMUNITY-1 seq 5 permit 1.1.1.0/24
ip prefix-list COMMUNITY-2 seq 5 permit 2.2.2.0/24

RTR2#
router bgp 100
 neighbor RTR1 remote-as 100
 neighbor y.y.y.y peer-group RTR1
 neighbor RTR1 route-map RTR1-IN in 
 neighbor ISP1 remote-as 11111
 neighbor z.z.z.z peer-group ISP1
 neighbor ISP1 send-community
 neighbor ISP1 route-map ISP1-OUT out
(similar settings for ISP2, with opposite prepending settings)
  
ip bgp-community new-format
ip community-list standard COMMUNITY-1 permit 100:1
ip community-list standard COMMUNITY-2 permit 100:2
!
route-map RTR1-IN permit 10
 match community 100:1
!
route-map RTR1-IN permit 20
 match community 100:2
!
route-map ISP1-OUT permit 10
 match community COMMUNITY-1
!
route-map ISP1-OUT permit 20
 match community COMMUNITY-2
 set as-path prepend 100 100 100 100
!
route-map ISP2-OUT permit 10
 match community COMMUNITY-2
!
route-map ISP2-OUT permit 20
 match community COMMUNITY-1
 set as-path prepend 100 100 100 100
!

Now, checking what I see, I get the following:

RTR1# sh ip bgp neighbor x.x.x.x advertised
   Network          Next Hop            Metric LocPrf Weight Path
*> 1.1.1.0/24   0.0.0.0                  0         32768 i
*> 2.2.2.0/24   0.0.0.0                  0         32768 i

RTR2# sh ip bgp neighbor y.y.y.y received-routes
   Network          Next Hop            Metric LocPrf Weight Path
* i1.1.1.0/24   207.226.45.254           0    100      0 i
* i2.2.2.0/24   207.226.45.254           0    100      0 i

RTR2# sh ip bgp 1.1.1.0
BGP routing table entry for 1.1.1.0/24, version 7234660
Paths: (1 available, no best path)
  Not advertised to any peer
  Local, (Received from a RR-client), (received-only)
    y.y.y.y (metric 100) from y.y.y.y (y.y.y.x)
      Origin IGP, metric 0, localpref 100, valid, internal
      Community: 100:1

Same result for 2.2.2.0/24, as you can see, community is seen correctly, now, if seen, then it must be matched and set to go out to ISPs, theoretically, however:

RTR2# sh ip bgp neighbor z.z.z.z advertised

Total number of prefixes 0

BUMMER!!!!

What I do find very strange is the following:
route-map RTR1-IN, permit, sequence 10
  Match clauses:
    community (community-list filter): 100:1 
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes
route-map RTR1-IN, permit, sequence 20
  Match clauses:
    community (community-list filter): 100:2 
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes
route-map ISP1-OUT, permit, sequence 10
  Match clauses:
    community (community-list filter): COMMUNITY-1 
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes
route-map ISP1-OUT, permit, sequence 20
  Match clauses:
    community (community-list filter): COMMUNITY-2 
  Set clauses:
    as-path prepend 100 100 100 100
  Policy routing matches: 0 packets, 0 bytes

See? all the counters are zero!

I tried resetting all the sessions in and out, soft, hard, harder, nothing!
I'm sure I'm missing something here!
Please help
Ziv



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