Kevin Loch wrote:
Unfortunately, Cisco's partners are useless. They propose 6509s without
the DFCs, which we know will fall over.
Well that depends...
The DFC's only do next-hop (tcam) lookups and netflow. All packets are
switched on the centralized PFC. Each line card has two 20Gbit/s
Łukasz has already addressed this; suffice to say he's right, and the
above is not correct. A TCAM lookup *is* the forwarding operation, and
the DFC has all information required locally to switch the packet (via
the fabric) to the output linecard, and does so.
Netflow is subsampled on this platform. I have been able to get
I don't know what you mean by "subsampled", but my experience of netflow
on this platform does not match this description.
Because we are within the netflow TCAM limits, I get 100% accurate
netflow. There's no sampling in hardware - the hardware is in fact not
*capable* of such - and we see all packets in our flow table.
pretty good estimates of traffic flow (checked against SNMP counters)
but I would not use that for any kind of accounting. The
Again, this depends on your traffic pattern. We use it for accounting
and it is essentially totally reliable, given our traffic patterns.
It's popular to bash netflow on the 6500s, but I personally think that's
unfair. It's very effective for the (large numbers of) sites who are
within the design limits of the platform. I can understand it's
frustrating to be outside those limits though.
SNMP counters are fairly noisy due to the several second update
intervals. SNMP counters on vlans are even worse and loop
over after a few gbit/s even though the coutners themselves
are 64bit. You may find using smaller switches (like 3560)
for most customer ports and using 10Gig uplinks is better
than using copper ports on the 6500/7600.
I think that would depend on the architecture one was trying to build.
By terminating the link on a 6748-TX, you get:
* sensible power redundancy
* sensible control-plane redundancy
* better performance / lower contention
* fewer devices to manage
I would avoid the sup720, the rsp720 has 2x the ram and more
Obviously it's worth emphasising that the RSP720 is 7600-only, and from
posts on this list it's still not in general availability I think?
than 2x the cpu power. cpu on the sup720 is by far it's biggest
limitation.
That's certainly true; 600Mhz is pretty derisory these days.
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