[c-nsp] full routing table / provider-class chassis

Chris Adams cmadams at hiwaay.net
Thu Jun 11 12:13:05 EDT 2009

Once upon a time, Gert Doering <gert at greenie.muc.de> said:
> As far as I understand, Juniper handles this a bit different, with no
> separate tables for "inside BGP" stuff, so things might look different
> there.

Juniper JUNOS keeps all routes (static, OSPF, BGP, etc.) in the "route
table" in the routing engine (where the protocols run), and exports the
best routes to the "forwarding table" in the forwarding engine (where
the packets are forwarded).  The forwarding table in a router with full
Internet BGP routes currently has ~282K routes, while the route table
has ~282K times however many full-route peers you have (plus internal
routes in both cases).

The route table has all the routes (from all sources and peers) known to
the router, but routing engine RAM is (relatively) cheap since the RE is
basically just a PC running FreeBSD.  I'm not sure off the top of my
head how much additional RAM is used per full-route peer.

Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

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