From: Curtis Phillips (cphillips@xxxxxxxxxx)
Date: Sun Jun 16 2002 - 11:28:08 GMT-3
I think Nigel is right. 150.150.150.0 never was in the IGP. Since that is
so, then there can never be synchronization.
Also, notice RTC and RTE are the only routers sharing a sub-as and thus
relying on IBGP within the sub-as. All routers connected via EBGP will of
course
have no sync problems.
I do not think next-hop will resolve any of these issues however. It does
not address the lack of the 150 route in the routing able.
Curtis
----- Original Message -----
From: "Nigel Taylor" <nigel_taylor@hotmail.com>
To: <ccielab@groupstudy.com>
Sent: Sunday, June 16, 2002 8:50 AM
Subject: Re: BGP w/ no synchronization
> 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!
This archive was generated by hypermail 2.1.4 : Tue Jul 02 2002 - 08:12:34 GMT-3