[nsp] BGP to IGP Redistribution

Stephen J. Wilcox steve at telecomplete.co.uk
Tue Aug 12 19:58:36 EDT 2003


erm you should see 10.1.1.0/27 not /24 

the /27s arent present on router A.. check the router thats sending out the rip, 
theres something wrong there...

Steve

On Tue, 12 Aug 2003, Hawthorne, Austin J [IT] wrote:

> Steve, 
> 
> The specific prefixes are exactly as depicted in the original post (the
> /27s).
> 
> 'sh ip eigrp top' does not show the routes as being learned locally (via
> redistribution) or remotely (via eigrp announcement).
> 
> 'sh ip eigrp neig' is as you would expect...RTR_A and RTR_B...passive
> interface every but the cross-over interface between RTR_A and RTR_B.
> 
> 'sh ip route 10.1.1.0':
> 
> RTR_A#sh ip route 10.1.1.0
> Routing entry for 10.1.1.0/24
>   Known via "bgp xxxxx", distance 200, metric 0, type locally generated
>   Redistributing via eigrp xxxxx, rip
>   Advertised by eigrp xxxxx metric 10000 750 255 1 1500
>                 rip metric 4
>   Routing Descriptor Blocks:
>   * directly connected, via Null0  <----aggregate-address
>       Route metric is 0, traffic share count is 1
>       AS Hops 0
> 
> RTR_B#sh ip route 10.1.1.0
> Routing entry for 10.1.1.0/24
>   Known via "bgp xxxxx", distance 200, metric 0, type locally generated
>   Redistributing via eigrp xxxxx, rip
>   Advertised by eigrp xxxxx metric 10000 750 255 1 1500
>                 rip metric 10
>   Routing Descriptor Blocks:
>   * directly connected, via Null0  <----aggregate-address
>       Route metric is 0, traffic share count is 1
>       AS Hops 0
> 
> Austin
> 
> > -----Original Message-----
> > From: Stephen J. Wilcox [mailto:steve at telecomplete.co.uk]
> > Sent: Tuesday, August 12, 2003 12:08 PM
> > To: Hawthorne, Austin J [IT]
> > Cc: cisco-nsp at puck.nether.net
> > Subject: RE: [nsp] BGP to IGP Redistribution
> > 
> > 
> > how far do the specifics get..
> > 
> > what do you have on rtrs a+b - 
> > sh ip eigrp top
> > sh ip eigrp neig
> > sh ip route 10.1.1.0
> > 
> > Steve
> > 
> > 
> > On Tue, 12 Aug 2003, Hawthorne, Austin J [IT] wrote:
> > 
> > > Sorry...
> > > 
> > > RIPv2, 
> > > 
> > > RIP_A into IGP, network statement brings into BGP_A, same for RTR_B.
> > > 
> > > Redistribute BGP_A into EIGRP_A, and same for RTR_B.
> > > 
> > > BGP_A and BGP_B are in same AS (no iBGP) and run eBGP to another AS.
> > > 
> > > No Auto-Summary on any of the protocols.
> > > 
> > > Expect RIP_A learned routes to appear in EIGRP_A and 
> > announced to RTR_B
> > > via EIGRP.
> > > 
> > > Thanks, 
> > > 
> > > Austin
> > > 
> > > > -----Original Message-----
> > > > From: Stephen J. Wilcox [mailto:steve at telecomplete.co.uk]
> > > > Sent: Tuesday, August 12, 2003 10:59 AM
> > > > To: Hawthorne, Austin J [IT]
> > > > Cc: cisco-nsp at puck.nether.net
> > > > Subject: Re: [nsp] BGP to IGP Redistribution
> > > > 
> > > > 
> > > > RIP v1 or v2?
> > > > 
> > > > What are you redistributing into which protocols - RIPA-BGPA, 
> > > > RIPA-EIGRPA, etc
> > > > 
> > > > Are BGPA and BGPB talking iBGP?
> > > > 
> > > > Which protocols are running auto-summary?
> > > > 
> > > > Steve
> > > > 
> > > > On Tue, 12 Aug 2003, Hawthorne, Austin J [IT] wrote:
> > > > 
> > > > > Hopefully someone can help with the following scenario:
> > > > > 
> > > > > BGP_A <---> RTR_A <---> EIGRP <---> RTR_B <---> BGP_B
> > > > > 
> > > > > BGP_A and BGP_B are learning about the following networks 
> > > > via RIP (via network statements, links not depicted):
> > > > > 
> > > > > BGP_A:  10.1.1.0/27
> > > > > BGP_B:  10.1.1.32/27, 10.1.1.64/27, 10.1.1.96/27
> > > > > 
> > > > > BGP_A and BGP_B are configured to announce aggregate of 
> > > > 10.1.1.0/24 (summary plus specifics).
> > > > > 
> > > > > EIGRP is configured to redistribute BGP.
> > > > > 
> > > > > Here's the problem:
> > > > > 
> > > > > I would assume that RTR_B would learn of RTR_A's prefixes 
> > > > via EIGRP (and vice versa)...this is not the case.  What I am 
> > > > seeing is that RTR_B learns the aggregate from RTR_A (but not 
> > > > vice versa, split horizon thing I think), yet no specifics 
> > > > are learned?
> > > > > 
> > > > > Can someone explain the behavior I am seeing?
> > > > > 
> > > > > Thanks, 
> > > > > 
> > > > > Austin
> > > > > 
> > > > > 
> > > > > 
> > > > > _______________________________________________
> > > > > cisco-nsp mailing list  cisco-nsp at puck.nether.net
> > > > > http://puck.nether.net/mailman/listinfo/cisco-nsp
> > > > > archive at http://puck.nether.net/pipermail/cisco-nsp/
> > > > > 
> > > > 
> > > 
> > 
> 
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