Peering best practices advice needed.

Wed Dec 8 19:47:18 UTC 2004

acennami at neupath.com wrote:
> That is what he is doing, however if he is advertising the two /19's, 
 >from two disconnected sites with the same ASN,
 > they will not be able to reach each other as BGP will
 >interpret this as a path loop.

   Yup.  I would presume, as they aren't connected, nor running
iBGP, they would be running different ASN's.

   Anything else hurts.

> On Wed, Dec 08, 2004 at 12:56:13PM -0500, Richard Irving wrote:
> 
>>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.
>>
>>   Pardon my simplistic solution, try dropping the /18, and -only-
>>advertise the corresponding /19 from each region.
>>
>>
>>>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.
>>
>>  See above. K.I.S.S. (No offense intended ;)
>>
>>
>>>Any help would be greatly appreciated.
>>>
>>>Rolo !
>>>
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