BGP next-hop self benefits

Ken Chase math at sizone.org
Fri Dec 1 15:30:56 CST 2017


On an IX, without next-hop-self peer A leaking peer B's routes they receive to
C will have C send direct to B on the IX (assuming flat layer 3 addressing,
and not multiple little /30s or /96s everywhere or something - do any
exchanges do that?)

This may seem more efficient than sending C's traffic to A to get to B (pumping up
the IX's usage graphs) but B may not have peering agreements with C.

Setting next-hop-self avoids this. An 'advantage' in some views. Not related to
n-h-s in an igp specifically, but an interesting (mis)use case.

/kc


On Fri, Dec 01, 2017 at 03:06:34PM +0000, craig washington said:
  >Hello everyone,
  >
  >
  >Question, what are the true benefits to using the next-hop self feature, doesn't matter what vendor.
  >
  >Most information I see is just to make sure you have reach-ability for external routes via IBGP, but what if all your IBGP knows the eBGP links?
  >
  >Is there a added benefit to using next hop self in this situation?
  >
  >
  >Any feedback is much appreciated, either for the question specifically or whatever else you got ????, L3VPN's or underlying technology that has to have that.
  >
  >
  >Thanks
  >
  >

-- 
Ken Chase - math at sizone.org Guelph Canada


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