"As far as I know, such drops shouldn't be caused by faulty hardware, but if the hardware is really faulty, you would need to involve TAC."
Ok, thanks.
"BTW, all the other interfaces, which have the low bandwidth rates you describe, are physically running at low bandwidth settings on the interface, e.g. 10 Mbps? If not, you can have short transient micros bursts which can cause drops. This can happen even when average bandwidth utilization is low. (NB: if these other ports average utilization is so low, if not already doing so, you could run the ports at 10 Mbps too.)
"
No. All ports on the switch connect to devices with 1Gb capable interfaces. They have been left to auto negotiate and have negotiated at 1000/full. The bandwidth described is more with regard to the actual data throughput of a call. Technically, the VCS devices are licence to handle 50 simultaneous call of up to 4Mbps so potentially could require a bandwidth of 200Mbps, although it is unlikely that we will see this amount of traffic.
"Also, even if you have physically low bandwidth ingress, with a high bandwidth egress, and even if the egress's bandwidth is more than the aggregate of all the ingress, you can still have drops caused by concurrent arrivals.
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In general, the ingress and the egress should be similar. Think of this as a stub network - one path in and out (via Gi0/23). The VCS act as a kind or proxy/router for video traffic, simply terminating inbound legs, and generating a next hop outbound leg. The traffic coming in to the VCS should be the same as the traffic go out.
There will of course be certain management traffic, but this will be relatively low volume, and of course the PathView traffic analyser can generate a burst of UDP packets to simulate voice traffic.
"Some other "gotchas" include, you mention you don't have QoS configured, but you're sure QoS is disabled too?
"
Yes.
switch#show mls qos
QoS is disabled
QoS ip packet dscp rewrite is enabled
I can't see a lot of point enabling QoS on this particular switch. Pretty much all of the traffic passing through it will be QoS tagged at the same level. Therefore it ALL prioritised.
Indeed running a test overnight with these multiple calls live and the PathView port shutdown, resulted in 0 Total Output Drops.Each leg did suffer a handful of dropped packets end-to-end, but I think I can live with 100 packets dropped in 10 million during a 12 hour period (and this, I suspect, will be somewhere else on the network).
"Lastly, Cisco has documented, at least for the 3750X, that uplink ports have the same buffer RAM resources as 24 copper edge ports. Assuming the earlier series are similar, there might be benefit to moving your uplink, now on g0/23, to an uplink port (if your 3650G has them).
"
Unfortunately, no can do. we are limited to the built in ports on the switch as we have no SFP modules installed.
Apologies about the formatting - this is yet another thing that has been broken in these new forums. I looks a lok better in the Reply window than it looks in this normal view.
