On Mon, 6 Mar 2006, Gerald Krause wrote: > On Monday 06 March 2006 16:48, Gunther Stammwitz wrote: > > What do the others say: does aggregation help and does the cam > > usually fill up in an isp enviorment? > > I do not use aggregation yet but this might be also interesting: I > see a lot of /32 CAM entries for destinations that are reachable > through a supernet which the router learned via OSPF from two neighbors > via two Ethernet links (= 4 equal paths): > > > (System: NI4GMR/B2P08000) > > #sh ip route 212.79.18.100 > Total number of IP routes: 180834 > Destination NetMask Gateway Port Cost Type > 212.79.0.0 255.255.192.0 212.79.49.135 1/4 20 O > 212.79.0.0 255.255.192.0 *212.79.49.131 1/4 20 O > 212.79.0.0 255.255.192.0 212.79.48.3 1/3 20 O > 212.79.0.0 255.255.192.0 212.79.48.5 1/3 20 O > #sh cam ip 1/1 | inc 212.79.0.0 > (nothing) > > but: > > #sh cam ip 1/1 | inc 212.79.18 > 1 8374 212.79.18.198/32 00e0.1e7e.4101 37 1 ether 1/4 > 1 8642 212.79.18.53/32 0050.0b3b.5400 120 1 ether 1/4 > 1 9142 212.79.18.94/32 00e0.1e7e.4101 30 1 ether 1/4 > 1 10131 212.79.18.44/32 0050.0b3b.5470 52 1 ether 1/3 > 1 10601 212.79.18.68/32 00e0.1e7e.4101 7 1 ether 1/4 > 1 11572 212.79.18.100/32 00e0.1e7e.4102 125 1 ether 1/3 >
i dont see this behaviour on both routers with and without aggregation enabled, i checked against routes learned in ospf with 2 or 3 next hops of the same cost however i do observe /32s being added where the route is to discard (by having a static 0.0.0.0/0 to null0) - this may explain why my CAM is getting so full > Reading the 'Changing CAM Partitions' document on the Foundry website > does not really enlighten me - especially "Example 2" looks weird for > me. In my opinion the /32's would make sense for directly connected > systems or host routes only.... or have I missed something? yeah i have no idea why they would need to use /32s when simply adding the /30 and not applying aggregation would be better Steve
