BGP peering strategies for smaller routers

Eric Sabotta esabotta at
Tue May 3 02:35:30 UTC 2016


I just did this with a ASR1001.  I had to upgrade it to 8gb of ram (I got the real Cisco stuff for ~ $500).  Before the router would crash when loading the tables.

Right now, I have full tables from two providers:

router1#show ip bgp summary
BGP router identifier, local AS number 4505
BGP table version is 11150622, main routing table version 11150622
582461 network entries using 144450328 bytes of memory
911730 path entries using 109407600 bytes of memory
148924/93298 BGP path/bestpath attribute entries using 36933152 bytes of memory
132977 BGP AS-PATH entries using 6043938 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 296835018 total bytes of memory
BGP activity 962568/380103 prefixes, 5155645/4243915 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd     4         4505 2532914 1634867 11150622    0    0 3w0d       330377     4         4505  672950 1634865 11150622    0    0 3w0d            1  4         2828 1837130   48052 11150557    0    0 2w1d       581351

router1#show ip cef summary
IPv4 CEF is enabled for distributed and running
VRF Default
 582527 prefixes (582527/0 fwd/non-fwd)
 Table id 0x0
 Database epoch:        2 (582527 entries at this epoch)


-----Original Message-----
From: NANOG [mailto:nanog-bounces at] On Behalf Of Mike
Sent: Monday, May 2, 2016 3:07 PM
To: NANOG list <nanog at>
Subject: BGP peering strategies for smaller routers


     I have an ASR1000 router with 4gb of ram. The specs say I can get
'1 million routes' on it, but as far as I have been advised, a full table of internet routes numbers more than 530k by itself, so taking 2 full tables seems to be out of the question (?).

      I am looking to connect to a second ip transit provider and I'm looking for any advice or strategies that would allow me to take advantage and make good forwarding decisions while not breaking the bank on bgp memory consumption. I simply don't understand how this would likely play out and what memory consumption mitigation steps may be necessary here. Im open to ideas... a pair of route reflectors? 
selective bgp download? static route filter maps?

Thank you.


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