BGP aggregation - as-set

Hi

I'm having problem with the lab from iewb 4.1 vol 1. Whenever I add as-set to aggregate-address command on R5, the aggregate route no longer gets advertised to R5's neighbors (R1, R2 and R3 are spokes connected to R5 hub by means of FR)

router bgp 1
 no synchronization
 bgp log-neighbor-changes
 network 150.1.1.0 mask 255.255.255.0
 neighbor 155.1.0.5 remote-as 5
 neighbor 155.1.0.5 soft-reconfiguration inbound
 no auto-summary

router bgp 5
 no synchronization
 bgp log-neighbor-changes
 network 150.1.5.0 mask 255.255.255.0
 aggregate-address 150.1.0.0 255.255.248.0
 neighbor 155.1.0.1 remote-as 1
 neighbor 155.1.0.2 remote-as 2
 neighbor 155.1.0.3 remote-as 3
 no auto-summary

The aggregate is advertised to R1:

Rack1R1#sh ip bgp
     Metric LocPrf Weight Path
*> 150.1.0.0/21     155.1.0.5                0             0 5 i
*> 150.1.1.0/24     0.0.0.0                  0         32768 i
*> 150.1.2.0/24     155.1.0.2                              0 5 2 i
*> 150.1.3.0/24     155.1.0.3                              0 5 3 i
*> 150.1.5.0/24     155.1.0.5                0             0 5 i

Then, I add the as-set keyword:

Rack1R5#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Rack1R5(config)#router bgp 5
Rack1R5(config-router)#aggregate-address 150.1.0.0 255.255.248.0 as-set

and the aggregate route is gone from R1:

Rack1R1#sh ip bgp
   Network          Next Hop            Metric LocPrf Weight Path
*> 150.1.1.0/24     0.0.0.0                  0         32768 i
*> 150.1.2.0/24     155.1.0.2                              0 5 2 i
*> 150.1.3.0/24     155.1.0.3                              0 5 3 i
*> 150.1.5.0/24     155.1.0.5                0             0 5 i

What's more, I have noticed that it is advertised by R5 to R1 but not received by R1:

Rack1R1#sh ip bgp neigh 155.1.0.5 received-routes
   Network          Next Hop            Metric LocPrf Weight Path
*> 150.1.2.0/24     155.1.0.2                              0 5 2 i
*> 150.1.3.0/24     155.1.0.3                              0 5 3 i
*> 150.1.5.0/24     155.1.0.5                0             0 5 i

Total number of prefixes 3
Rack1R1#

Any help much appreciated, I'm stuck with this one.

Thanks in advance.

Sebastian

Comments

  • Ok, I've figured it out -- the next labs actually gives the solution which is adding "allowas-in" to R1's config. I don't see why the solution doesn't include this command and still you can see aggregate route on R1..

  • jonbovjonbov ✭✭

    Hi, I did the same mistake by not reading and fully understanding the task.

    1: do NOT create a loopback with 150.1.3.3/21 on R3

    2: R3 only should learn the summary 150.1.0.0/21 from R5

    3: there is no requirement that R1 or R2 should should learn summary 150.1.0.0/21 from R5

    jonbov

     

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