From: Nathan Chessin (nchessin@cisco.com)
Date: Fri Nov 08 2002 - 15:15:01 GMT-3
I diagree with the statement. I am not wondering why they aren't installed,
I am wondering why they aren't marked as valid. Just because there are
already valid paths in the IGP doesn't mean BGP should be valid and best.
That is what I was trying to figure out. Why isn't the BGP route
synchronizing?
Well, turns out the it was the BGP - OSPF router id issue. For *iBGP*, if a
route is learned via OSPF, the OSPF router-id that the route was learned
from has to match the iBGP peer BGP router-id for it to be marked as valid.
You can image what a pain this would be if you have all your virtual links
set up with router-ids in OSPF and then you have to change them to match the
iBGP peer of a particular router. Or I guess you could change the BGP
router-id, but still, could get ugly.
Nate
> -----Original Message-----
> From: ying c [mailto:bf5tgh1@yahoo.com]
> Sent: Friday, November 08, 2002 6:00 AM
> To: Conrad Bullock; 'Nathan Chessin'; ccielab@groupstudy.com
> Subject: RE: OSPF and BGP
>
>
> I agree with your statement. There's one more problem
> need to be fixed before BGP routes can be considered -
> none of the routes in his BGP table were marked as
> best path.
>
> Chang
> --- Conrad Bullock <cjbullock@xtra.co.nz> wrote:
> > Unless I'm missing the point, this looks like normal
> > behaviour.
> >
> > iBGP has an administrative distance of 200.
> >
> > As the iBGP routes that you're talking about from
> > iBGP are already in
> > the routing table with an AD of less than 200, the
> > iBGP routes are not
> > installed.
> >
> > Conrad
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com] On Behalf Of
> > Nathan Chessin
> > Sent: Friday, 8 November 2002 9:10 p.m.
> > To: ccielab@groupstudy.com
> > Subject: OSPF and BGP
> >
> > Hi All,
> >
> > My routing and BGP tables look like the below.
> > Question is, why isn't
> > the
> > BGP route being installed as valid. I have routes
> > to next-hop and also
> > the
> > networks in the bgp table.
> >
> > I read that If the matching route is learned from an
> > OSPF neighbor, its
> > OSPF
> > router ID must match the BGP router ID of the iBGP
> > neighbor.
> > I tried changing those and still no luck.
> >
> > Any ideas
> >
> > (AS 2) (AS 2)
> > R3 ----iBGP---- R5
> >
> >
> >
> > R5 output below...
> >
> > Gateway of last resort is not set
> >
> > 34.0.0.0/24 is subnetted, 1 subnets
> > O IA 34.1.1.0 [110/112] via 35.1.1.3, 00:00:22,
> > Serial2/0
> > 1.0.0.0/16 is subnetted, 1 subnets
> > O E2 1.1.0.0 [110/50] via 35.1.1.3, 00:00:22,
> > Serial2/0
> > 35.0.0.0/24 is subnetted, 1 subnets
> > C 35.1.1.0 is directly connected, Serial2/0
> > O IA 2.0.0.0/8 [110/113] via 35.1.1.3, 00:00:22,
> > Serial2/0
> > 100.0.0.0/24 is subnetted, 1 subnets
> > O E1 100.100.100.0 [110/132] via 35.1.1.3,
> > 00:00:22, Serial2/0
> > 3.0.0.0/32 is subnetted, 1 subnets
> > O 3.3.3.3 [110/49] via 35.1.1.3, 00:00:23,
> > Serial2/0
> > 12.0.0.0/24 is subnetted, 1 subnets
> > O 12.1.1.0 [110/112] via 35.1.1.3, 00:00:23,
> > Serial2/0
> > R5#sib
> > BGP table version is 1, local router ID is
> > 33.33.33.33
> > Status codes: s suppressed, d damped, h history, *
> > valid, > best, i -
> > internal
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric
> > LocPrf Weight Path
> > * i1.1.0.0/16 12.1.1.1 23
> > 100 0 1 ?
> > * i100.100.100.0/24 12.1.1.1 23
> > 100 0 1 ?
> >
> >
> > Nate
>
>
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This archive was generated by hypermail 2.1.4 : Tue Dec 03 2002 - 07:22:55 GMT-3