Best practice for BGP session/ full routes for customer

Mark Tinka mark.tinka at
Tue Jul 8 20:56:26 UTC 2014

On Monday, July 07, 2014 08:33:12 PM Anurag Bhatia wrote:
> In this scenario what is best practice for giving full
> table to downstream?

In our case, we have three types of edge routers; Juniper 
MX480 + Cisco ASR1006, and the Cisco ME3600X.

For the MX480 and ASR1006 have no problems supporting a full 
table. So customers peer natively.

The ME3600X is a small switch, that supports only up to 
24,000 IPv4 and 5,000 IPv6 FIB entries. However, Cisco have 
a feature called BGP Selective Download:

Using BGP-SD, we can send a full BGP table from our route 
reflectors to our ME3600X switches, without worrying about 
them entering the FIB, i.e., they are held only in memory. 
The beauty - you can advertise these routes to customers 
natively, without clunky eBGP Multi-Hop sessions running 

Of course, with BGP-SD, you still need a 0/0 + ::/0 route in 
the FIB for traffic to flow from your customers upstream, 
but that is fine as it's only two entries :-).

If your system supports a BGP-SD-type implementation, I'd 
recommend it, provided you have sufficient control plane 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: This is a digitally signed message part.
URL: <>

More information about the NANOG mailing list