From: "Ben
Date: Sun Dec 07 2003 - 05:43:55 GMT-3
Howard,
Please correct me if you find otherwise, but I believe the Local
Preference is preserved as it crosses all the sub ASs within the
confederation.
"Each AS by itself will have iBGP fully meshed and has connections to
other AS's inside the confederation. Even though these ASs will have
EBGP peers to ASs within the confederation, they exchange routing as if
they were using iBGP; next hop, metric and local preference information
are preserved."
http://www.cisco.com/en/US/tech/tk365/tk80/technologies_tech_note09186a00800c95bb.shtml#bgpconfed
Regards,
Ben
--- "Howard C. Berkowitz" <hcb@gettcomm.com> wrote: > At 10:29 PM
-0500 12/4/03, Bob Sinclair wrote:
> >CCIE2B,
> >
> >Doyle V2 is the only reference I can find that explicitly says that
> you only
> >have to include sub-AS's with with you actually peer (page 289).
> If a
> >particular router does not peer with a router in another sub-AS,
> then it
> >does not need to list that sub-AS in the confederation peer
> statement. This
> >makes sense given Halabi's explanation of this command:
> >
> >quote from page 421>
> >
> >RTG uses the router command bgp confederation peers 65060 to
> preserve all
> >the attributes, such as local preference and next hop when
> traversing the
> >EBGP session to AS 65060
> >
> >end quote.
>
> I'm a little confused by that quote. next_hop is a mandatory
> attribute, but local preference shouldn't go outside the sub-AS.
> Even between sub-AS, you should be using MED or other preference
> setting mechanisms such as communities with route maps.
>
> >
> >In other words, the command qualifies a peer statement. If there is
> no peer
> >statement to a given sub-AS, then there is no need to qualify it.
> >
> >Hope that helps,
> >
> >-Bob Sinclair
> > CCIE #10427, CISSP, MCSE
> > bsinclair@netmasterclass.net
> >
> >
> >----- Original Message -----
> >From: "ccie2be" <ccie2be@nyc.rr.com>
> >To: "kasturi cisco" <kasturi_cisco@hotmail.com>;
> <ccielab@groupstudy.com>
> >Sent: Wednesday, December 03, 2003 8:50 AM
> >Subject: Re: The bgp confederation peers as-number [... as-number]
> command
> >
> >
> >> Hi Kasturi,
> >>
> >> Thanks for your response. I think, however, you didn't quite
> understand
> >what
> >> I was asking.
> >>
> >> What you said is correct but doesn't address the question I had.
> My
> >question
> >> was which sub AS's should be specified with this command. There
> are 2
> >> possible choices: List all sub AS's in the confed or list just
> those sub
> >AS's
> >> to which the router is peering.
> >> ----- Original Message -----
> >> From: kasturi cisco
> >> To: ccie2be@nyc.rr.com ; ccielab@groupstudy.com
> >> Sent: Wednesday, December 03, 2003 8:08 AM
> >> Subject: RE: The bgp confederation peers as-number [...
> as-number]
> >command
> >>
> >>
> >> Hi,
> >>
> >> The way i have used it and seen it being used is follows:
> >>
> >> If there is a Confed with multiple Sub-As then the confed peers
> is for
> >> routers which have another Sub As peer. Routers within
> confed-sub-As
> >and/or
> >> routers with no peering to another sub AS need not use the
> command.
> >>
> > > As always correct me if needed.
>
>
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