Subnet Size for BGP peers.

Paul Stewart pstewart at
Wed Jul 29 22:02:07 UTC 2009

/29's here for everyone.... great for troubleshooting and any future
additions typically required...;)

-----Original Message-----
From: Jim Wininger [mailto:jbotctc at] 
Sent: July 29, 2009 4:00 PM
To: nanog at
Subject: Subnet Size for BGP peers.

I have a question about the subnet size for BGP peers. Typically when we

turn up a new BGP customer we turn them up on a /29 or a /30. That seems

be the "norm".

We connect to many of our BGP peers with ethernet. It would be a simple

matter to allocate a /24 for connectivity to the customer on a shared

This would help save on some address space.

My question is, is this in general good or bad idea? Have others been

this path and found that it was a bad idea? I can see some of the
pothols on

this path (BGP session hijacking, incorrectly configured customer

etc). These issues could be at least partially mitigated. Are there

issues when doing something like this or is it a practical idea?


Jim Wininger

Jim Wininger
jbotctc at



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