[c-nsp] Sizing peering router / FIB

Sami Joseph sami.joseph at gmail.com
Wed Mar 14 07:07:36 EST 2007


Hello,

We are planning to get a new router as internet gateway, it should have one
OC12 PoS and GigE.

I am trying to compare between different vendors.

We will peer with one provider and carry the Full table at the first stage
and maybe later we will add another link and add another copy of the full
table, but that wont be in the near future.

One router i am looking at supports up to 200K FIB entries, so i would like
to clear somethings first.

Please correct me if i am wrong on the below:

The BGP table of the internet is almost 211K prefixes, if these routes are
installed in the RIB (global table/without changing Admin. distance) then i
need the same number of prefixes as FIB entries?

Assuming another transit peer is established and another copy of the routing
table will be downloaded into the RIB, there will be comparisons and after
decision is made, some more will be installed and FIB will increase?

I will peer with some customers of mine over this router and maybe give them
the routing table, does that affect FIB in any way?

Am i missing other significant number of FIB entries i should add to my
consideration (if hte above is correct)?

If the above is not clear, i want to calculate the amount of FIB
entries/Memory i need?

Private messages are always welcomed.

Thanks,
Sam


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