From: Justin Menga (Justin.Menga@xxxxxxxxxxxxxxxxxx)
Date: Sun Oct 29 2000 - 17:01:15 GMT-3
I would first check that the 10.1.1.0/24 route is in the route table in each
configuration.
Basically, BGP won't advertise a route unless the route is in the IP route
table. Also, check the next hop address is reachable (I'm sure it is from
your diagram).
Regards,
Justin Menga MCSE+I CCNP CCSE ASE
WAN Specialist
Computerland New Zealand
PO Box 3631, Auckland
DDI: (+64) 9 360 4864 Mobile: (+64) 25 349 599
mailto: justin.menga@computerland.co.nz
-----Original Message-----
From: Jack Heney [mailto:jheneyccie@hotmail.com]
Sent: Sunday, 29 October 2000 6:01 a.m.
To: Vito.Trimlett@callisma.com
Cc: ccielab@groupstudy.com
Subject: Re: BGP/OSPF problem
Rtr A:
interface fastethernet 0/0
ip address 10.2.1.254 255.255.255.0
router bgp 2
neighbor 10.2.1.253 remote-as 1
RtrB:
interface fastethernet 0/0
ip address 10.2.1.253 255.255.255.0
interface serial 0/0
ip address 10.10.1.1 255.255.255.0
encapsulation frame-relay
ip ospf interface point-to-multipoint
router ospf 1
network 10.10.1.0 0.0.0.255 area 0
router bgp 1
neighbor 10.2.1.254 remote-as 2
neighbor 10.10.1.2 remote-as 1
neighbor 10.1.1.254 remote-as 1
RtrC:
interface serial 0/0
ip address 10.10.1.2 255.255.255.0
encapsulation frame-relay
ip ospf interface point-to-multipoint
interface fastethernet 0/0
ip address 10.1.1.253 255.255.255.0
router ospf 1
network 10.10.1.0 0.0.0.255 area 0
network 10.1.1.0 0.0.0.255 area 0
router bgp 1
neighbor 10.10.1.1 remote-as 1
neighbor 10.1.1.254 remote-as 1
network 10.1.1.0 mask 255.255.255.0
RtrD:
interface fastethernet 0/0
ip address 10.1.1.254 255.255.255.0
ip ospf priority 2
router ospf 1
network 10.1.1.0 0.0.0.255 area 0
router bgp 1
neighbor 10.1.1.253 remote-as 1
neighbor 10.10.1.1 remote-as 1
The above configuration led to RtrB NOT advertising 10.1.1.0 to RtrA via
BGP....When I removed the priority command and made RtrC the DR, RtrB
advertised the network to A.
>From: "Vito Trimlett" <Vito.Trimlett@callisma.com>
>To: <jheneyccie@hotmail.com>
>Subject: Re: BGP/OSPF problem
>Date: Sat, 28 Oct 2000 11:13:06 -0400
>
>Could you send the configs?
>----- Original Message -----
>From: Vito Trimlett <Vito.Trimlett@callisma.com>
>To: Jack Heney <jheneyccie@hotmail.com>
>Sent: Saturday, October 28, 2000 11:11 AM
>Subject: Re: BGP/OSPF problem
>
>
> > I know its soun
> > ----- Original Message -----
> > From: Jack Heney <jheneyccie@hotmail.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Saturday, October 28, 2000 9:47 AM
> > Subject: BGP/OSPF problem
> >
> >
> > > Intersting behavior...wondering if anyone can explain?
> > >
> > > RtrA---------RtrB-----------RtrC------------RtrD
> > > BGP2 BGP1 BGP1 10.1.1.0 BGP1
> > >
> > > A has neighbor relationship with B only; B,C,D have full-mesh of
>neighbor
> > > relationships
> > > B,C,D are running OSPF (area 0)
> > > C has a "network 10.1.1.0 mask 255.255.255.0" statement under BGP1
> > >
> > > Now, here's the strange part....I left synchronization on on RtrB to
>see
> > if
> > > I could get it to advertise 10.1.1.0 to A via BGP. I figured that B
>would
> > > learn about 10.1.1.0 through OSPF and BGP, so leaving synchronization
>on
> > > shouldn't be a problemm. At first, B wouldn't advertise 10.1.1.0 to
>A.
>I
> > > did a little investigating and found that D was the designated router
>on
> > the
> > > 10.1.1.0 network. For some reason, I decided to try changing the DR
>to
>C.
> > > After making this change, B started advertising 10.1.1.0 to A. I
>couldn't
> > > believe that this was the actual source of my problem, so I changed
>the
>DR
> > > back to D, and B stopped advertisiing the network to A again. I have
> > since
> > > replicated this experiment and the behavior continues to be the same.
>I
> > am
> > > using 12.07t....Can anyone explain why changing which router on the
>data
> > > link is the designated router would affect BGP synchronization with
>OSPF?
> > > I'm stumped.
> > > Thanks,
> > > Jack
> > >
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