commonly accepted prefix length filters?

Mailman List Mirror (Read Only)
1

our bgp tables are starting (?) to get out of hand.

we are thinking maybe we should start nuking some routes in order to reduce
the size of the tables.

is there a list of commonly accepted aggregating prefix filters?

2

I'm seeing 103000 routes..

I imagine the limit on what you discard has to be that of the smallest
block of addresses that the registries will allocate, as if you filter
anything smaller you will start to lose genuine networks. Not sure what
that limit is, /24 ?

Steve

3

Some people use filters such as the example provided

ip prefix-list bad-nets-in description input prefix-list for BGP sessions
ip prefix-list bad-nets-in seq 1 deny 0.0.0.0/1 ge 21
ip prefix-list bad-nets-in seq 2 deny 0.0.0.0/8 le 32
ip prefix-list bad-nets-in seq 3 deny 10.0.0.0/8 le 32
ip prefix-list bad-nets-in seq 4 deny 127.0.0.0/8 le 32
ip prefix-list bad-nets-in seq 5 deny 128.0.0.0/2 ge 21
ip prefix-list bad-nets-in seq 6 deny 128.0.0.0/16 le 32
ip prefix-list bad-nets-in seq 7 deny 169.254.0.0/16 le 32
ip prefix-list bad-nets-in seq 8 deny 172.16.0.0/12 le 32
ip prefix-list bad-nets-in seq 9 deny 191.255.0.0/16 le 32
ip prefix-list bad-nets-in seq 10 deny 192.0.0.0/3 ge 25
ip prefix-list bad-nets-in seq 11 deny 192.0.0.0/24 le 32
ip prefix-list bad-nets-in seq 12 deny 192.0.2.0/24 le 32
ip prefix-list bad-nets-in seq 13 deny 192.168.0.0/16 le 32
ip prefix-list bad-nets-in seq 14 deny 198.32.175.0/24 le 32
ip prefix-list bad-nets-in seq 15 deny 198.32.176.0/24 le 32
ip prefix-list bad-nets-in seq 16 deny 198.32.177.0/24 le 32
ip prefix-list bad-nets-in seq 17 deny 223.255.255.0/24 le 32
ip prefix-list bad-nets-in seq 18 permit 0.0.0.0/0 ge 1