From: ccie2be (ccie2be@nyc.rr.com)
Date: Mon Apr 14 2003 - 18:35:00 GMT-3
Off hand, I'm not sure about the rules regarding use of a IGP within a RR
cluster, but I know that the concept behind confeds is to provide a work
around to having a full mesh ibgp within the AS and that it is used for the
most part by ISPs. True, there's a lot of config to do if you're a large
ISP with hundreds of routers, but using confed's does reduce that amount of
work quite abit. Imagine having 800 fully meshed routers. What happens
when you need to add just one more. YOu'd have to change the config of all
800 routers just to add that next additional router. Wow, I wouldn't want
to have to do that. With confed, that becomes unnecessary.
Jim
----- Original Message -----
From: "OhioHondo" <ohiohondo@columbus.rr.com>
To: "ccie2be" <ccie2be@nyc.rr.com>; "Group Study" <ccielab@groupstudy.com>;
"OhioHondo" <ohiohondo@columbus.rr.com>
Sent: Monday, April 14, 2003 4:20 PM
Subject: RE: BGP Confederation and Synchronization
> That would work and I've seen examples used in that way. I haven't seen
> anything that explicitly says it has to be done that way. If what you're
> saying is true:
>
> 1) It is a definite difference between when to use router reflectors and
> when to use confederations. What your saying is that Route Refectors have
to
> be used if all of the BGP routers in the AS are in the same IGP domain.
>
> 2) If your using OSPF and you have to divvy up your IGP into 2 or 3 or 4
> OSPF domains to accommodate a confederation, that's a lot of work!!!
>
>
>
> -----Original Message-----
> From: ccie2be [mailto:ccie2be@nyc.rr.com]
> Sent: Monday, April 14, 2003 3:54 PM
> To: Group Study; OhioHondo
> Subject: Re: BGP Confederation and Synchronization
>
>
> Hi,
>
> The way I understand it, each sub -AS s/b a different IGP domain, so you
> shouldn't have OSPF or any other IGP advertising routes outside the
sub-As -
> that's the job of BGP. So, it looks like in your case, where you have R3
> and R2 in the same OSPF domain, you have a config which wouldn't work.
Jim
> ----- Original Message -----
> From: "OhioHondo" <ohiohondo@columbus.rr.com>
> To: <ccielab@groupstudy.com>
> Sent: Monday, April 14, 2003 10:26 AM
> Subject: BGP Confederation and Synchronization
>
>
> > Hello
> >
> > I have a question for someone with a grasp on BGP Confederations and how
> > synchronization affects it. My scenario
> >
> > AS301/R7 --- AS501/sub-AS65001/R3 --- AS501/sub-AS65002/R1 --- AS101/R9
> > |
> > |
> > AS501/subAS65001/R2
> >
> > Routers R1, R2 and R3 are in a single OSPF domain. The BGP router-id's
and
> > OSPF router-ids are the same on all routers.
> >
> > My problem --- an advertisement comes in from AS101/R9, let say
> 49.0.0.0/8.
> > That advertisement is propagated via OSPF to router R2 with R1's OSPF
> > router-id.
> >
> > When that advertisement crosses the sub-AS border between R1 and R3, the
> BGP
> > router-id is changed to that of R3, therefor when the iBGP route gets to
> R2,
> > the BGP router-id is from R3 while the OSPF router-id is from R1. The
> result
> > is no sync. Any advice????
This archive was generated by hypermail 2.1.4 : Thu May 01 2003 - 13:35:52 GMT-3