From: Nigel Taylor (nigel_taylor@xxxxxxxxxxx)
Date: Sun Jun 16 2002 - 09:50:18 GMT-3
Nick,
I almost read this the way I think you did.. I don't believe that
the 150.150.150.0/24 network on RTA
was ever a part of any IGP since Hunt mentioned that it is injected into BGP
with the use of the "network" command.
Since this is the case and only RTB, C, D, and E are running the IGP I don't
see how the OSPF/BGP route ID could
be an issue.
http://www.ietf.org/rfc/rfc1403.txt
The problem here is that although OSPF is being redistributed into BGP on
RTB and not vice-versa, the 150.150.150.0/24
network is never a part of the IGP, hence RTC's and RTE's inability to
become synchronized. Another option just thinking
about it maybe be to have both RTB and RTD propagate the route to their iBGP
peers with the "next-hop-self" bgp command
and using the "update-source" command to establish the TCP peering
connection.
.
Anyone care to comment... :->
HTH
Nigel
----- Original Message -----
From: "Nick Shah" <nshah@connect.com.au>
To: "Hunt Lee" <ciscoforme3@yahoo.com.au>; <ccielab@groupstudy.com>
Sent: Sunday, June 16, 2002 7:54 AM
Subject: Re: BGP w/ no synchronization
> Dude,
>
> Here's a hint...
>
> http://www.cisco.com/warp/customer/459/25.shtml
>
> OSPF/BGP router - id :) (Check out my post a couple of weeks ago)
>
> rgds
> Nick
> ----- Original Message -----
> From: Hunt Lee <ciscoforme3@yahoo.com.au>
> To: <ccielab@groupstudy.com>
> Sent: Sunday, June 16, 2002 9:05 PM
> Subject: BGP w/ no synchronization
>
>
> > Okay folks, starting off some late nite studying and just noticed
> something
> > weird. Got a Confederation setup like:
> >
> > 150.150.150.0/24---RTA ---RTB ---RTD---RTF
> > | |
> > RTC RTE
> >
> > RTA, B, C, D, & E are in a Confederation called AS 1, in which:-
> >
> > RTA is sub-AS 65530
> > RTB & RTC are both in sub-AS 65531
> > RTD & RTE are both in sub-AS 65532
> >
> > RTF is in AS 2
> >
> > RTB, C, D & E are running OSPF as IGP. And OSPF is being redistributed
> into
> > BGP at RTB.
> >
> > The network 150.150.150.0/24 is being advertised into BGP by BGP
"network"
> > command on RTA.
> >
> > Ok, here is the thing. The 150.150.150.0/24 network is being seen by
RTA,
> RTB,
> > RTD, & RTF. I could ping 150.150.150.1 from these four routers.
However,
> it
> > can't be seen by RTC & RTE (shown as follows). But when I put "no
> > synchronization" on the middle four routers (RTB, RTC, RTD, & RTE), then
> > everything becomes fine again... I thought since I used IGP (OSPF),
and
> if
> > the router can see the EBGP Next-Hop (193.16.0.2) in their routing
table,
> then
> > the synch. rule shouldn't apply anymore.
> >
> > Am I missing something here?
> >
> > RouterC#sh ip bgp
> > BGP table version is 4, local router ID is 172.16.0.2
> > 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
> > * i150.150.150.0/24 193.16.0.2 0 100 0 (65530) i
> > <-----193.16.0.2 is the Serial int of RTA
> >
> > *>i172.16.0.0/30 172.16.0.1 0 100 0 ?
> > * i172.16.0.12/30 172.16.0.18 30 100 0 ?
> > *>i172.16.0.16/30 172.16.0.1 0 100 0 ?
> > *>i193.16.0.0/30 172.16.0.1 0 100 0 ?
> > * i193.16.0.8/30 172.16.0.18 0 100 0 (65532) i
> > RouterC#sh ip route
> > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
> default
> > U - per-user static route, o - ODR
> >
> > Gateway of last resort is not set
> >
> > 172.16.0.0/30 is subnetted, 3 subnets
> > O 172.16.0.16 [110/128] via 172.16.0.1, 01:35:04, Serial1
> > O 172.16.0.12 [110/192] via 172.16.0.1, 01:35:04, Serial1
> > C 172.16.0.0 is directly connected, Serial1
> > 193.16.0.0/30 is subnetted, 1 subnets
> > O 193.16.0.0 [110/74] via 172.16.0.1, 01:35:04, Serial1
> > RouterC#
> > RouterC#ping 193.16.0.2
> >
> > Type escape sequence to abort.
> > Sending 5, 100-byte ICMP Echos to 193.16.0.2, timeout is 2 seconds:
> > !!!!!
> > Success rate is 100 percent (5/5), round-trip min/avg/max = 28/32/36 ms
> > RouterC#
> >
> >
> > Thanks all!
> >
> > Hunt
> >
> > http://www.sold.com.au - SOLD.com.au
> > - Find yourself a bargain!
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