[c-nsp] Changing from iBGP to eBGP - Again

[Mark Tohill]

Oliver,

Our current setup look something like:
           

PoP No.1                                 PoP No.2        
                         WAN
   |----------------------------------------|

   |                                        |
PriRouter ---LAN----- SecRouter            PriRouter ---LAN--- SecRouter
   |         [HSRP]       |                  |          [HSRP]    |
   |                      |                  |                    |
  ibgp                   ibgp               ibgp                 ibgp
   |                      |                  |                    |
   |                      |                  |                    |
ProviderRtr1---LAN----ProviderRtr2
ProviderRtr1---LAN----ProviderRtr2
                |                                         |
                |                                         |
           ProviderRtrX                               ProviderRtrX    
                |                                         |
                | ----------------------------------------|
                                   WAN
                                
     Provider                                             Provider
     Pop No.1                                             Pop No.2


I hope that makes sense!

Following points:
We announce chunk of our class B from each of our PoP's (non-contiguous)

Neighbor relationships between us and provider are all iBGP

We are not implementing route-reflectors, communities, confederations
etc.,
just have multiple neighbor statements, alot of repetition. Probably
about        six ibgp neighbors per router.

Synchronization not running

Will I post configs....?  :)

Thanks
Mark



                             





-----Original Message-----
From: Oliver Boehmer (oboehmer) [mailto:oboehmer at cisco.com] 
Sent: 06 July 2005 16:50
To: Mark Tohill; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] Changing from iBGP to eBGP - Again

Mark,

it would be best if you pasted your current BGP config and topology so
we know what you are doing today. I assume you have an iBGP peer to your
upstream, and do route-reflector-client to your iBGP peers in order to
reflect the upstream routes to them and vice versa.
Changing this to an eBGP config should be easy, you wouldn't need
RR-client configuration anymore, and you want to investigate
next-hop-self on your iBGP peers (possibly not a requirement as you had
to advertise the upstream's next-hop into your IGP previously).

Or do you also need to change your ASN, so you'd need to touch all
routers? This is a larger migration task than just change one neighbor..

please clarify..

	oli


Mark Tohill <> wrote on Wednesday, July 06, 2005 5:37 PM:

> I realize this is probably against rules of list but I'm reposting
> this during what seems a busy time.
> 
> 
> 
> Any help appreciated.
> 
> 
> 
> Thanks,
> 
> Mark
> 
> ________________________________
> 
> From: Mark Tohill
> Sent: 05 July 2005 11:32
> To: cisco-nsp at puck.nether.net
> Subject: Changing from iBGP to eBGP
> 
> 
> 
> Hi,
> 
> 
> 
> We're hoping to change our setup with our sole up-stream provider
> (peered with them across 2 x  PoPs) from iBGP to eBGP. We hope this
> will give us more flexibility and control in the future
> 
> 
> 
> -          we accept the full routing table.
> 
> -          advertise non-contiguous (!!!) portions our our address
> space from each of our PoP's.
> 
> -          already secured our own ASN from RIPE.
> 
> -          have out-of-date route objects in RIPE which we are hoping
> to amend. (or our provider, they maintain them)
> 
> -          hope to request this change fairly soon.
> 
> 
> 
> 
> 
> Has anyone out there hands-on experience of same/similar?
> 
> 
> 
> Apart from neighbor configuration (remote-as etc...), are there any
> other major config changes?
> 
> 
> 
> Are there any potential pitfalls?
> 
> 
> 
> Thanks,
> 
> Mark
> 
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