[c-nsp] Cisco memory requirements - Best practices

[David Coulson]

I'm trying to get together some metrics following the issues yesterday
with our 7500s. Right now we're just pulling <=/22 from two peers (about
66k routes) and we're running about 86Mb free of 256Mb.

>From a practical perspective, what is a reasonable amount of memory to
have available for things such as BGP soft resets, HSRP additions, and
so forth? We run both our 7507/RSP4 with dot1q, HSRP, BVIs and spanning
tree enabled on the bridge-groups. From what info I can find on the
router, these features don't seem to eat up much memory, however as we
made a significant number of config changes in the last 15 days (adding
bridges/BVIs, adding about 10 HSRP groups), the issue of memory
fragmentation is a major concern to me.

I guess options are:

1) Reduce size of BGP feeds to fit memory - Easy, and what we're doing
right now.
2) Offload some process-based features (HSRP, etc) onto 7206s and just
leave the 7500s as border routes doing BGP. This doesn't really solve
the problem that we potentially can't cram two full tables into the
RSP4s at some point, even with nothing else running. Plus I don't really
think these features really consume a whole lot of memory -
Fragmentation from changes is my concern here.
3) Use 7206s as border routers and use the 7500s for core - Seems messy,
plus we'd have to run NPE-G1s, which brings me to #4
4) Replace the RSP4s with RSP16s (RSP8 maxes at 256Mb, right?)
5) Pull a single full table into each of our 7507s and do limited iBGP
routes between the two. So, we'd pull 180k routes from each transit
peer, then share 66k (<=/22) between the two routers. This would solve
the problem with some of our downstreams who want full tables, but may
reduce the overall memory usage on the routers by avoiding two full 180k
tables. Backup the whole thing with default routes to transit peers and
a lower preference route to the other router.

Another question related to memory - How much RSP memory am I losing by
having various VIPs and PAs in the routers? If I pull anything that is
not active, is that going to save me anything worthwhile? If I get rid
of junk cards like FEIP, is it going to improve matters?

David