4108 Packet Drops

[Ralf Reinartz]

Hello,
We've a 4108 GL full of Git SX.
None of the Ports are use above 50% of Bandwith. So the Backplane connection of 2GB is not overloaded. In additional there are 2 high loaded Trunks (2GB 50%).
on some Ports (none of the Trunks) We've dropped Packets.
Firmware ist up to date.
I've replaced some of these Transceivers. No change.
I wonder that not all Ports have this Problem. It this the same application with same load.

Normally I would say that this is not really a Problem. The drops are around 1 per 1000 packets. But I guess, there is a perfomance problem in this applikation and so i have to be sure it is not caused by this switch.

any suggestions?

So long

Ralf

[Gonzo Granello · Accepted solution]

Ralf,

the internal design of the switch is the problem. Some of the ports are connected to the same link to the backplane, hence can be on the limit even if you only run 50% on each. I dont have the internal wiring of the modules handy right now, but i will find it if you need those. As example, port 1 uses connection 1 port 2 connection 2 port 3 connection 1 port 4 connection 1 port 5 connection 2 and port six connection 1 - that would mean they are indeed not evenly spread as you might expect. That is where your problem might is. The manual used to have the internal wiring but i'm not sure if it still does. As far as trunking goes, that is where things get really messed up, you almost want to use both backplane interconnects but as far as I remember the overhead in getting this working right is killing performance. One packet out of 1000 should not slow your app down, however that is indeed a poor way to measure that since you need to know what the latency for the data is (how long from a to b). Not sure if procurve publishes those numbers. (if not you know why...)

Hope that helps and points are apprechiated.

GG