BGP Multihoming 2 providers full or partial?

William Herrin bill at
Sun May 31 14:23:58 UTC 2015

On Fri, May 29, 2015 at 4:36 AM, Maqbool Hashim <maqbool at> wrote:
> We are an enterprise that are eBGP multihoming to two ISPs. We wish to load balance in inbound and outbound traffic thereby using our capacity as efficiently as possible. My current feeling is that it would be crazy for us to take a full Internet routing table from either ISP. I have read this document from NANOG presentations:


Without a full table you are not protected from partitions. Partitions
are when a particular destination is reachable via one of your ISPs
but not via the other. Without receiving the route, you have no idea
which ISP can reach it.

Partitions happen fairly often but rarely last long (on the order of
minutes). The worst cases tend to be when two backbones get into a
peering dispute. Those have been known to last a week or more. See:
Cogent v. everybody else.

Think of it this way: a partial table is like an unsigned SSL
certificate. Better than static routes but not fully protected.

Bill Herrin

William Herrin ................ herrin at  bill at
Owner, Dirtside Systems ......... Web: <>

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