From: Narbik Kocharians (narbikk@gmail.com)
Date: Wed Jul 02 2008 - 18:15:15 ART
Without going through and referencing *some old RFCs* and/or "*long winded
explanation*" as some will call it, there are basically two approaches in
solving the full mesh IBGP peering within an AS:
- Route-reflectors
- Confederation
I think you need to tackle this from the perspective of the following items,
here are some of the reasons you would select one over the other:
*Merging new ASes:*
This is definitely one of the benefits of confederation because a brand new
AS can be merged into the confederation as a sub-as of the existing
confederation, whereas that concept is missing from RR.
*Experience:*
You will probably find that there are more people that have experience
configuring and maintaining route-reflectors versus confederation and as a
result of that there must be more efforts on training.
*Scalability:*
Confederation has more scalability built in versus route-reflectors, I know
that we can configure hierarchical route-reflection, but remember that you
can have that within each sub-as, meaning that in confederation, within each
sub-as you can have route-reflectors and/or even go as far as having
hierarchical RRs .
Scalability is also apparent when you look at the IGP that must run within a
single AS and how it can reach its maximum capacity with growth and become
unmanageable or having huge number of routes in the routing table of each
router, whereas, in confederation, each sub-confed can have its own IGP or
it's own version of IGP and as a result of that lesser routes in the routing
table and etc.
*Migration:*
Well it must be easier to migrate to route-reflectors versus confederation,
when you think about the sub-ases and how some of the attributes work just
the way they are advertised and some don't, such as: next-hop, local-pref
and MED.
But you must also remember that when it comes to policy control,
confederations have a better policy control than route-reflectors.
On Wed, Jul 2, 2008 at 1:19 PM, Sharifi, Reza <Reza.Sharifi@gdit.com> wrote:
> Mike,
>
> Take a look at this brief document.
> It explains the differences and maybe helpful to you
>
> https://www.juniper.net/customers/csc/documentation/techdocs/downloads/p
> df/350010.pdf
>
> Reza
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> M_A_Jones@DellTeam.com
> Sent: Wednesday, July 02, 2008 3:57 PM
> To: ccielab@groupstudy.com
> Subject: BGP CONFED VS ROUTE RELFLECTIES!
>
> Can somone clarify-When to use BGP Confederations over Route Reflectors
> (or
> vice versa)...I have been unable to get a complete answer ???
>
> Experts help me out !
>
>
> Michael Jones
> Network Engineer
> Global Network Operations
> Dell Inc. | J&M Consultants
> W. 512.723.3268 | C. 512.966.6908
>
>
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-- Narbik Kocharians CCSI#30832, CCIE# 12410 (R&S, SP, Security) www.Net-Workbooks.com Sr. Technical Instructor
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