[c-nsp] Understanding TCAM/route limitations in the GSR..

[Doug Clements]

We actually had to upgrade the DRAM in our Engine 2 cards recently just
because of this. We take about 5 full BGP feeds plus the normal internal
stuff, and the cards just couldn't hold the TCAM. We went from 128Mb to
256Mb, and now we're sitting pretty:

ca-la2-core-c12016#show ip cef res
Hardware resource allocation status summary
Green (Normal), Yellow (Caution) Red (Alarm)
Slot HW Resource Name        Util     Alert
0    E2_Rx_PLU                23        G
0    E2_Rx_TLU                24        G
10   E2_Rx_PLU                23        G
10   E2_Rx_TLU                24        G


Our GRP-Bs with 512Mb of ram on the same box run with about 100Mb free.

I would consider this setup would be the mininum "useful" setup that doesn't
require fancy filter games to keep TCAM/table size down.

We also have no numbers for anything more fancy than Engine 2.

--Doug

On 10/29/07, John van Oppen <john at vanoppen.com> wrote:
>
> I needed an answer to this question too and from what I can tell the
> answer is as follows:
>
> The GRP-B is just a route processor, so the only limitation is ram and
> CPU speed...   assuming convergence times are not an issue, once it runs
> out of ram, you have a problem...    As of today, I am running about 170
> MB free on my GRP-B with the most bgp peers (2 full routes + 80 peers +
> 5 customers + 8 internal routers).
>
> Engine0 linecards are not TCAM limited as they run in software, so when
> the card runs out of ram, that is the limit of its TCAM.   We have 256
> MB of ram on all our engine0 cards, they run with about 100 MB of free
> ram as of today.
>
> Engine2 cards (three port gigE) for example have already run out of TCAM
> if they are running ACLs or MPLS.   With a straight IPv4 table and no
> ACLs ours seem to run right at 30% utilization (show ip cef resource).
> The newer cards have larger TCAMs.
>
>
> If I missed anything, please add it...  Then newer cards will have to be
> commented-on by others as we don't have any data as our network is
> mostly the older cards.
>
>
>
> John van Oppen
> Spectrum Networks LLC
> 206.973.8302 (Direct)
> 206.973.8300 (main office)
>
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Drew Weaver
> Sent: Monday, October 29, 2007 9:40 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Understanding TCAM/route limitations in the GSR..
>
>         Hi, I know I've been quite the pest as of late ;-) I have been
> recently scouring the net and Cisco's site seeking information on TCAM
> (or route memory) limitations on the GRP-B (or the GSR) in general. Do
> they suffer from the same limitations (worse, or better?) with TCAM
> exhaustion from routes that the 7600/6500 series does? Does anyone know
> what the "shelf-life" of a GRP-B would be? I haven't really been able to
> find any hard data on it.
>
> Thanks,
> -Drew
>
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