[c-nsp] Cat 6500 and counters

[Jay Ford]

On Wed, 27 Apr 2005, Gert Doering wrote:
> we'll be getting our first 6500/7600 "real soon now", and I'm wondering
> whether to go for a Sup2/MSFC2 or for a Sup720*
>
> This box will be running as peering router, and it will also have backhaul
> lines to customers.  For the first job, it will need to handle a full BGP
> table, for the second job it needs to do uRPF and it needs to have working
> interface counters (for billing), and netflow (for billing and IDS).
>
> Soooo...
>
>  - if I understand this right, uRPF on the Sup2/MSFC2 will reduce the number
>    of possible forwarding table entries to 128k, and otherwise, you'll get
>    256k entries?
>
>  - Sup 720 does 256k entries, with or without uRPF
>
>  - Sup 720-3BXL does 1m entries
>
> ... seems to imply that we want a Sup 720-3BXL.

I have 2 boxes with 720-base sups, soon to be cranked up to 720-3b just to
stay a little ahead, not because the 720-base is out of gas yet.

I take 2 full BGP feeds plus some other partials.  So far so good.

I don't do uRPF, so I can't comment on that.

> What about the interface counters?  Will the boxes count packets and
> bytes on the hardware interface (FastEthernet X/Y) and on the SVIs
> (Vlan XYZ) properly?  Or is it limited like the 3750G that will only
> count packets sent or received from the router CPU, but no packets
> forwarded in hardware (at least on the SVIs)?   What about subinterfaces
> on OSM GE ports (in case I want some)?

The counters on physical interfaces & vlan interfaces seem to work.  The
counters on sub-ints don't work.  It's reportedly only for OSMs and/or MPLS,
which annoyed me greatly.  I have to endure the mess of switchport & vlan
ints just to get working counters, when I just wanted sub-ints for a tagged
link.  Argh!

> Corrolary question: how do people handle the case "customer wants 3
> ethernet ports in the same VLAN, and layer 3 routing out of it" with the
> 6500s?  Will the combination of "switchport" and "SVI" behave properly
> for all counting purposes (as it does on the Cat5k and C5RSM)?

I do that in several boxes & it seems to work correctly.

> What about netflow?  Does it work on the Sup2/MSFC2 and/or the Sup720?
> I saw one post claiming "v5 only", so IPv6 netflow isn't there?

Netflow v5 seems to work.  I don't try to do netflow for IPv6 yet.

________________________________________________________________________
Jay Ford, Network Engineering Group, Information Technology Services
University of Iowa, Iowa City, IA 52242
email: jay-ford at uiowa.edu, phone: 319-335-5555, fax: 319-335-2951