From: Jake Reynolds (JREYNOLDS@uscentral.org)
Date: Thu Feb 13 2003 - 19:06:27 GMT-3
Send us show ip bgp commands on R3, R4, R1, and R2.
Jake Reynolds
Systems Engineer - Information Systems
MCSE NT4 & W2K, CCNA, CCNP, A+
US Central Credit Union
9701 Renner Blvd.
Lenexa, KS 66219
Office- 913.227.6122
Cell- 816.305.6785
-----Original Message-----
From: Richard Young [mailto:cc_young@pacbell.net]
Sent: Wednesday, February 12, 2003 6:05 PM
To: miken
Cc: ccielab@groupstudy.com
Subject: Re: BGP Multihoming Two IBGP Routers to Two ISPs
Mike,
Thanks for the response. I have disables sync on both routers. The
routes do not show up in the BGP table. As far as the Synchronization
rule is concerned, the routes will be in the bgp table but not in the
routing table. In my case the routes do not get into the BGP table.
Thanks,
Rich
miken wrote:
> I suspect you have not disabled synchronization in router bgp on
> routers 1 and 2. The are iBGP peers and by default, will not
advertise
> routes to each other that are not synchronized with an IGP....in
other
> words aready in the routing table. You probably can see the routes
in
> "show ip bgp", but not in the routing table. Disable sync and that
> should solve your problem. URL and quotes from Cisco:
>
> http://www.cisco.com/warp/customer/459/bgp-toc.html#synch
>
> "Synchronization states: If your autonomous system is passing
traffic
> from another AS to a third AS, BGP should not advertise a route
before
> all routers in your AS have learned about the route via IGP. BGP
will
> wait until IGP has propagated the route within the AS and then will
> advertise it to external peers. This is called synchronization. "
>
> Thanks,
> Mike
>
> ----- Original Message -----
> From: "Richard Young" <cc_young@pacbell.net>
> To: <ccielab@groupstudy.com>
> Sent: Wednesday, February 12, 2003 11:26 AM
> Subject: BGP Multihoming Two IBGP Routers to Two ISPs
>
> > Hi,
> > I have a question about a lab I am working on. The Lab has 5
> > routers. R1 and R2 are directly connected ibgp neighbors in
AS1001.
> > R3 is connected as an EBGP neighbor to R1 in AS 300. R4 is an EBGP
> > neighbor to R2 in AS400. R5 is an EBGP neighbor ro both R3 and R4
in
> > AS 500
> >
> > R5 has one loopback 200.100.1.1 /24
> > R5 has one ethernet 200.100.2.0 /24
> >
> > After all neighbors are established, I see two bgp paths to both
> > networks of R5 on R1, but I only see one path to both networks of
R5
> > on R2. It is like R1 is getting both networks but not forwarding
> > them to R2.
> >
> > My goal is to use BGP communities to set local preference but
> > without seeing both paths on both routers with the command "show
ip
> > bgp" the route maps so not see the bgp paths and do not work.
> >
> > Is there some BGP rule similar to split horizon that prevents IBGP
> > neighbors from sending all routes to all other fully meshed IBGP
> > neighbors in the same AS?
> >
> > Thanks in advance.
> > Richard
> > .
.
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