From: Peter van Oene (pvo@xxxxxxxxxxxx)
Date: Tue Jun 04 2002 - 14:43:49 GMT-3
This is correct. Moreover, it is normal for IBGP routers to be separated
by more than one link. Loopback reachability is one of the key function
the IGP provides in a BGP network.
At 12:06 PM 6/4/2002 -0500, Treptow, Georg wrote:
>I believe the the ttl for IBGP is automatically set to 255 as not every IGP
>router must speak iBGP. The key is to advertise the loopback address within
>the IGP so the BGP router knows how to get to it. Someone correct me if I am
>wrong....
>
>Georg
>
>-----Original Message-----
>From: Edward Monk [mailto:emonk@att.net]
>Sent: Tuesday, June 04, 2002 10:16 AM
>To: 'Paglia, John (USPC.PCT.Hopewell)'; 'Logan, Harold'; 'Annu Roopa';
>ccielab@groupstudy.com
>Subject: RE: BGP Update-Source issue
>
>
>I tested and the update-source loopback command had to be used in all
>cases where you point to a loopback address. Regardless of whether you
>have an eBGP or an iBGP peer relationship. eBGP multihop is added to get
>around the TTL=1 issue of BGP when working with an eBGP peer.
>
>So the story is:
>
>Add neighbor x.x.x.x eBGP-multihop 2<-- or higher if you want to eBGP
>peers when going to a loopback.
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Paglia, John (USPC.PCT.Hopewell)
>Sent: Monday, June 03, 2002 2:33 PM
>To: 'Logan, Harold'; Annu Roopa; emonk@att.net; ccielab@groupstudy.com
>Subject: RE: BGP Update-Source issue
>
>I believe you are correct. You have to use the loop in the neighbor
>statement for update-source loop 0 to be effective.
>
>And you need to use EBGP-Multihop when peering ebgp peers via loopback
>addresses.
>
>Pags
>
> > -----Original Message-----
> > From: Logan, Harold [SMTP:loganh@mccfl.edu]
> > Sent: Tuesday, May 28, 2002 5:25 PM
> > To: Annu Roopa; JPaglia@NA2.US.ML.com; emonk@att.net;
> > ccielab@groupstudy.com
> > Subject: RE: BGP Update-Source issue
> >
> > To get a BGP session to work using a loopback as the update source,
>I've
> > had to use the remote router's loopback IP in the neighbor command.
>That
> > is, if you use update-source Lo0 on a router, then that router's BGP
>peer
> > needs to use the IP address of the Lo0 interface in its neighbor
>command.
> > Anyone else run into that?
> >
> > Hal
> >
> > > -----Original Message-----
> > > From: Annu Roopa [mailto:annu_roopa@yahoo.com]
> > > Sent: Tuesday, May 28, 2002 5:16 PM
> > > To: JPaglia@NA2.US.ML.com; Logan, Harold; emonk@att.net;
> > > ccielab@groupstudy.com
> > > Subject: RE:BGP Update-Source issue
> > >
> > >
> > > Group,
> > >
> > > This is my understanding.Whenever u create a EBGP peer
> > > u generally do it with the neighbors peer address
> > > which is the next hop serial link IP address. Now
> > > since the peer relationship is being formed using ur
> > > Loopback address u use "update-source" .U will use the
> > > same command irespective of what interface u
> > > use..other than serial IP.
> > >
> > > Whenever u dont form a peer/neighbor relationship
> > > using point-point link (with TTL=1)... it could be any
> > > other IP address on the neighbor u need to use the
> > > "ebgp-multihop". This works only with EBGP as i know.
> > >
> > > Thus u may both being used togethter most of the
> > > times.
> > > HTH.
> > >
> > > Annu
> > >
> > >
> > > >From: "Paglia, John (USPC.PCT.Hopewell)"
> > > <JPaglia@NA2.US.ML.com>
> > > >Reply-To: "Paglia, John (USPC.PCT.Hopewell)"
> > > <JPaglia@NA2.US.ML.com>
> > > >To: "'Logan, Harold'" <loganh@mccfl.edu>, "Edward
> > > Monk" <emonk@att.net>, ccielab@groupstudy.com
> > > >Subject: RE: BGP Update-Source issue
> > > >Date: Tue, 28 May 2002 16:28:56 -0400
> > > >
> > > >Isn't Update Source used only when configuring within
> > > a single AS? What I
> > > >understood from my reading (although I may have been
> > > whacked from lack of
> > > >sleep at the time) is that Update Source will have no
> > > effect when
> > > >configuring with reference to a router in another AS.
> > > I do know that
> > > >ebgp-multihop is necessary when pointint ot a
> > > loopback from another AS.
> > > >
> > > >Am I way off on this one?
> > > >
> > > > > -----Original Message-----
> > > > > From: Logan, Harold [SMTP:loganh@mccfl.edu]
> > > > > Sent: Tuesday, May 28, 2002 12:50 PM
> > > > > To: Edward Monk; ccielab@groupstudy.com
> > > > > Subject: RE: BGP Update-Source issue
> > > > >
> > > > > When you set that up, what's the output of your
> > > show ip bgp neighbors?
> > > > > Remember, bgp networks won't show up in your
> > > routing tables unless you
> > > > > redistribute into bgp or use the network command.
> > > If you've done that
> > > > > already there are several other possibilities,
> > > would you mind posting the
> > > > > configs?
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Edward Monk [mailto:emonk@att.net]
> > > > > > Sent: Tuesday, May 28, 2002 12:16 PM
> > > > > > To: ccielab@groupstudy.com
> > > > > > Subject: BGP Update-Source issue
> > > > > >
> > > > > >
> > > > > > I am trying to use loopbacks as the
> > > update-source with BGP and cannot
> > > > > > get the following to work. I have rebooted
> > > etc....
> > > > > >
> > > > > >
> > > > > >
> > > > > > Both routers can ping the others loopback
> > > address. Anyone
> > > > > > have any idea
> > > > > > what is wrong?
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > R8:
> > > > > >
> > > > > >
> > > > > >
> > > > > > router bgp 500
> > > > > >
> > > > > > bgp log-neighbor-changes
> > > > > >
> > > > > > neighbor 10.10.10.7 remote-as 400
> > > > > >
> > > > > > neighbor 10.10.10.7 update-source Loopback0
> > > > > >
> > > > > >
> > > > > >
> > > > > > R7:
> > > > > >
> > > > > >
> > > > > >
> > > > > > router bgp 400
> > > > > >
> > > > > > bgp log-neighbor-changes
> > > > > >
> > > > > > neighbor 10.10.10.8 remote-as 500
> > > > > >
> > > > > > neighbor 10.10.10.8 update-source Loopback0
> > >
> > >
> > > =====
> > > Thanks in advance for ur time and replies.
> > > Annu.
> > >
This archive was generated by hypermail 2.1.4 : Tue Jul 02 2002 - 08:12:23 GMT-3