We currently run (2) 7206-VXR w/NPE-G1 as our edge routers and (2) Catalyst 3750G's as our core L3 switches. Our entire network only pushes 50-100 Mbps at the moment. We want to go with a 100% hardware based platform for IPv4 and IPv6 and give ourselves plenty of growth room, while not overspending on capacity. We will soon double our bandwidth utilization to 200-300 Mbps. Our upstreams consist of (2) 1 Gbps Ethernet hand-offs and we're currently taking full BGP routes. This could expand to (4) 1 Gbps uplinks in the future as needs dictate.
I'm concerned with 1 Gbps connections between our edge/core and have therefore been considering a collapsed core model in order to avoid this. The Catalyst 6506's sound ideal due to being all hardware based, supporting BFD, NSF/SSO redundancy, etc. The Sup720 is more than sufficient for us on an L2 basis. My only concern is their BGP capability (RAM and TCAM capacity for IPv4 and IPv6).
Questions
1) Can the SUP 720-3BXL's handle 2 full routes with IPv6 growth sufficiently and without us having to worry about running out of RAM and TCAM capacity? I realize the 7220-3BXL's have 1GB or RAM just like our NPE-G1's. The NPE-G1's seem to be fine with 2 full BGP tables:
border1>show mem
Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)
Processor 67621140 865987916 493838592 372149324 370634320 312339788
I/O C000000 67108864 3751420 63357444 63326624 63332732
Transient 7B000000 16777216 348252 16428964 11575076 16428928
border1>show ip bgp summ
...
BGP using 146906170 total bytes of memory
What about TCAM utilizaiton here?
2) If the answer to the above is "no", can we just filter incoming BGP routes to adjacent + default in order to free up memory/TCAM? Or, filter anything less than /24 and use default routes? Maybe we run either of the two aforementioned for the next few years, and then upgrade to Sup 2T later, as RAM/TCAM utilization increase?
The reason I'm leaning to the above is:
1) Elimination of potential bottleneck between edge/core, while not having to spend $$ on 10G
2) Ability to upgrade to 10GB as needed
3) Ability to upgrade SUP's as needed
Like I said, by no means so I want to under purchase here. But, if the SUP720-3BXL's can suit our current and future needs, then I'm inclined to go this route. We know that even a 3560 can handle our L2 and L3 switching/routing capacity easily. I don't want to have to spend another $20-40k simply to support BGP if there is a more economical and/or practical way to achieve our goals.
I could also go with (2) ASR 1002's for our edge and then stacked 3750-X's for our core, with a total of 4-8 Gbps links between them. Getting rid of the edge <-> core links sounds appealing however.
