Internet Edge Router replacement - IPv6 route table size considerations

Blake Hudson blake at
Thu Mar 10 15:01:22 CST 2011

> My concern is trying to find a router (within our budget) that has room for growth in the IPv6 routing space.  When compared to the live table sizes that the CIDR report and routeviews show, some can't handle current routing tables, let alone years of growth.  BGP tweaks may keep us going but I can't see how 16k or fewer IPv6 routes on a router is going to be viable a few years from now.
> Thank you,
> Chris Enger

Does anyone think that the IP6 routes will grow like IP4 routes have?
With most organizations being granted IP6 /32's - e.g. something larger
than they could ever use -  wouldn't you expect the number of routes to
be much much fewer than with today's IP4 setup where even small
organizations often have multiple routes, and big organizations may have

When sizing routers, shouldn't we be looking at the number of expected
ISPs (AS's) active on the Internet, within the anticipated lifetime of
the router? If so, then the question becomes how many is that - 16k
seems very shortsighted, 128k maybe overkill (at least, for now). We're
currently at 37k AS's ( So 64k IP6
routes would probably be the minimum that I would accept on a new single
homed router. If I expected to act as a carrier, or participate in equal
cost BGP routing on a multi-homed router, I'd need more.

As IP6 adoption grows, and networks start to de-aggregate, 128K IP6
routes sound like a better number for the second or third revision of
"IP6 ready" gear that would be purchased in 5+ years.


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