[ppml] Legacy /24s

Jonathan Barker jonathan at qx.net
Sun Sep 2 12:17:55 EDT 2007

>> You've nicely bounded the problem of upgrading Sup2+MSFC boxes to
>> Sup720 boxes.  (I'm guessing, because I've seen you talking about
>> the problem on the nanog mailing list and all the numbers fit.)
> That includes most of the Sup720 boxes too; they're bounded at 260k.
> In the 6500/7600 product line, only the Sup720-3BXL and RSP720-3CXL
> accommodate more than 260k routes. And as you point out there are no
> in-place upgrades for the remaining 7200 and 7500 routers.
We upgraded to the 7613, 3BXL a few years ago from a 7513, RSP8. It was 
one of the best upgrades we ever made for our network. The 7513's 
backplane is nowhere near as capable as the 7613, and quite a few of the 
backplane performance bottlenecks we saw before evaporated with the new 
hardware. Similarly the problem of DoS attacks evaporated for us, as 
we've been fortunate enough to not see one over 180,000 pps, and at that 
it just increased the router's CPU a couple percent.

Despite the fact we have 2, 4000 watt power supplies, the chassis and 
cards only use 1537.62 Watts, with the requisite air conditioning 
requirements - so it's actually about the same as our old 7513 on power 
and cooling load. I just hope they come up with something better than 
the RSP720-3CXL for our next upgrade cycle. It really doesn't offer much 
more than we already have with the 3BXL, and we've had it for nearly 2 
and a half years.

If you are lucky enough to have a 7200VXR chassis - there is a NPE-G2 
available (we just ordered a couple to serve as agg  / VPN routers.) I 
know the G-2 comes default with 1 Gig RAM, and can be upgraded to 2 
Gigs. Surely that router will be able to take more than 256k routes - 
and the upgrade for the VXR chassis is only 15k or so.... I can't find 
the statistic on Cisco's site - but having the capability of more ram 
than the 3BXL, I don't see why it would choke with the increased routes. 
The only thing the Cisco docs state is that the NPE-G2 "Supports more 
routes, and routing tables"

Of course... I have to say I don't like running BGP on 7200s. With the 
way Cisco prioritizes the BGP scan process, it spikes the single CPU 
each time it runs, and it 'can' in some configurations with large route 
tables, cause a little lag for a second or two every minute. With the 
distributed processing on the 7600 series, that's not an issue.


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