[c-nsp] re-advertising eBGP learned prefixes

[Andrey Koklin]

Hi,

On 10/21/2011 13:30, Gert Doering wrote:

> On Fri, Oct 21, 2011 at 01:25:11PM +0400, Andrey Koklin wrote:
>> Gert, I've tried "soft out" without results, and full bgp neighbor restart after.
>> Seems, nothing changed...
>>
>> Would it be useful to try some other IOS version, perhaps?
>>
>> spring#sh ver
>> System image file is "flash:c3845-adventerprisek9-mz.124-25c.bin"
>
> 12.4(25*) should be fine.  So we're overlooking something.
>
> You mentioned that exporting of the /27 works if you remove all the
> output filters?  In that case, something in the prefix-list would be
> the only thing left as "suspicious" - but it looks all fine to me
> ("le 28" definitely does match /27...).
>
> Maybe - just for testing - add the /27 to the prefix-list, as a
>
>   "permit 10.36.72.32/27"
>
> just to see what happens.

Additional permit didn't work either.
Finally, I've got some results, but still don't understand the problem's source.

If I remove all the output filters, needed nets ain't advertised either, but I get
many similar /27, /28 external nets, which are advertised.

The only difference I see is in their incoming paths
(with output filters removed):

spring#sh ip bgp 10.36.72.32
BGP routing table entry for 10.36.72.32/27, version 602983
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Flag: 0x820
  Not advertised to any peer
  20485 30835, (received & used)
    10.36.2.22 (metric 3072) from 213.129.126.1 (10.36.1.1)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Originator: 10.36.1.4, Cluster list: 10.36.1.1

While this one works fine:

spring#sh ip bgp 10.20.69.16                                  
BGP routing table entry for 10.20.69.16/28, version 592359
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to update-groups:
     1        
  21017 44237 30835, (received & used)
    10.36.2.22 (metric 3072) from 213.129.126.1 (10.36.1.1)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Originator: 10.36.1.4, Cluster list: 10.36.1.1

I've changed now the incoming prefixes weight on other router for testing,
to choose alternate channel. After this, the needed prefixes started advertising,
even with output filters applied:

spring#sh ip bgp 10.36.72.32                                  
BGP routing table entry for 10.36.72.32/27, version 603507
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to update-groups:
     1        
  21017 44237 30835, (received & used)
    10.36.2.22 (metric 3072) from 213.129.126.1 (10.36.1.1)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Originator: 10.36.1.4, Cluster list: 10.36.1.1

It's good already, but I need the other channel too for redundancy.

Do you have an idea with fresh eye, how this could be fixed?

Thanks,
Andrey