From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Fri Apr 26 2002 - 22:01:29 GMT-3
For a start, think about this...
* Route Reflector clients and server behave like *one single AS* so most of
the rules of IBGP apply (minus the full mesh) There are a few bells and
whistles to it, you could manipulate the routes only in certain ways (as you
would do in an IBGP network). You would generally run a single IGP within a
route-reflector cluster. Also behavior of next hop is different in RR's and
in confeds.
* Confederations behave as separate AS's and have a few (actually many)
rules that can be applied to EBGP (you could use MED as between EBGP peers).
You *can* run different IGP's in different confed AS's etc.
Most of the times, the inherent design would let out the secret. You must
see what attributes you will need to manipulate, and then decide, what are
the constraints. (To confuse you more, both of them can do most of the
things in the same way :)
RR's are simpler to implement, while CONFEDS offer more finer control (as in
EBGP-like policies), I think CONFEDS require some minimum IOS version, so
you can run them only if all the routers support it, while in case of RR's
only the RR should have IOS support (RRclients can be set up like normal
clients)
hth
Nick
-----Original Message-----
From: kym blair <kymblair@hotmail.com>
To: ccielab@groupstudy.com <ccielab@groupstudy.com>
Date: Saturday, 27 April 2002 10:19
Subject: BGP Route-Reflector vs. Confederations
>I know the mechanics of how to set up both route-reflectors and
>confederations, but I'm not sure when to use one or the other, and where to
>place the route-reflector or various confederations.
>
>How would you solve the following example:
>
>AS2-----AS1--------------AS1-----AS2
>
>.........R1----R3---R4---R5.........
>
>All four BGP routers are in AS1. All four (plus R2) are known via your
>IGPs. R1 and R5 are both connected to different routers in AS2 (outside
>your control). You'll want to manipulate weight, local preference,
>community settings, etc via R1 and R5.
>
>Would you set up a route-reflector with 3 clients, or would you set up
>confederations? Where would you put the route-reflector(s) or how would
you
>set up confederations for best results? Also, very important: which
>router(s) would you use to redistribute between BGP and IGP?
>
>I've read Halabi, Doyle Vol 2, and Parkhurst and understand the mechanics,
>but am not good at deciding where to put things. What section of these
>books (or others) should I reread to get a better understanding of bgp
>network design?
>
>Thanks, Kym
>
>
>
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