nanog mailing list archives
Re: Peering best practices advice needed.
From: Graham Blake <grahamb () ssimicro com>
Date: Wed, 08 Dec 2004 11:45:23 -0700
Hi there,If I understand your predicament correctly, our company has a similar situation. We have two locations from which we need to advertise routes from our AS, but our internal link between these two locations is a very high cost satellite link. This means we can not afford to advertise our whole IP allocation equally from both locations.
We have a /19 allocated, and we advertise both the /19 from each location, and the more specific /20 particular to each location. To circumvent the loop detection, we use the hidden Cisco command, neighbour x.x.x.x allow-as in. This allows each location to accept the remote's advertised /20 to be inserted into the routing table. Should connectivity ever be lost across the public networks in between, there is a higher cost static route over the satellite link.
Perhaps in a more complex and more meshed AS, this loop dodging would be a bad thing(tm). In our simple two location, semi-discontiguous network layout, it has been a problem-free solution. Hope this helps in some way.
Regards, Graham Blake SSI Micro Network Services At 10:03 AM 08/12/2004, Rolo Tomassi wrote:
Hi all, Please forgive the simplistic nature of the query..Basically my company is multi-homed with 2 different providers in the UK, and advertising a /18. Now some colleaguges in another part of the world want to break that /18 into two /19's and advertise one /19 and we advertise the other. This is fine, however we are NOT running IBGP in the core, therefore the UK customers in the /19 will not be able to reach the other /19 as there would be a loop detected through EBGP.Now someone mentioned that we could use AS-LOOP-IN feature which will overcome this problem and allow us to route to each other via EBGP. I really think this is a bad idea but until we get an internal link - I dont see a way forward. So... anyone doing this currently in their network or have any "best practices" way round this. I want our company to be good Netizens but still be able to pass traffic between the 2 /19's.Any help would be greatly appreciated. Rolo ! _________________________________________________________________Stay in touch with absent friends - get MSN Messenger http://www.msn.co.uk/messenger
Current thread:
- Peering best practices advice needed. Rolo Tomassi (Dec 08)
- Re: Peering best practices advice needed. Richard Irving (Dec 08)
- Re: Peering best practices advice needed. Patrick W Gilmore (Dec 08)
- Message not available
- Re: Peering best practices advice needed. Richard Irving (Dec 08)
- Re: Peering best practices advice needed. Rolo Tomassi (Dec 09)
- Re: Peering best practices advice needed. Richard Irving (Dec 08)
- Re: Peering best practices advice needed. Graham Blake (Dec 08)
- RE: Peering best practices advice needed. Ejay Hire (Dec 08)
- Re: Peering best practices advice needed. David Gethings (Dec 09)
- Re: Peering best practices advice needed. Iljitsch van Beijnum (Dec 09)