pull-ups on route annoucements to deter route flap

Mon Apr 24 13:58:54 UTC 1995

Randy Bush wrote:
> To move along an other tangent...  What is the general wisdom on putting
> pull-ups on route annoucements to deter route flap?

I don't know about the general wisdom, but Internet Africa (not a North
American operator) uses pull-ups for all routes that belong to
single-homed customers.  We figure that there's no reason for BGP speakers
around the world to hear the flap when one of our single-homed customers
drops a route. 

> Hence, you won't get the !H until you get to our border.
> Los pobre packitos will travel all the way and then get whacked.  Seems
> to subvert one interpretation one could read into the intent of BGP.

I don't have stats, but I don't worry about the added load.  TCP backs off
pretty quickly when it figures out that the packets aren't getting
through.  Poorly-behaved UDP applications are another story, of course,
but we hope there's not too much of that. 

--apb (Alan Barrett)