topic Port congestion drops, microbursts or something else in ExtremeSwitching (EXOS/Switch Engine)

Port congestion drops, microbursts or something else

Mick_Mocha — Mon, 07 Aug 2017 18:10:00 GMT

Hi

BD X8 chassis, BDXA-10G48X module, sw 15.5.2.9

A port operating as 10G is displaying about 2500-4000 pps constant drop rate with "show port congestion" command.
At the same time "show port util" is displaying 13% peak TX BW.

The cause for such a high drop rate with only 13% peak BW is not immediately obvious.
Do you think microbursts might cause this?

"conf ports XX shared-packet-buffer 100" did not make any difference.
As reported by "sh port XX buffer" there is either 8MB or 2MB max shared buffer (depending on configuration).

If this is a microburst issue the solution would be a 2x10GE LAG.
But if this a SW bug the LAG is useless.

The traffic loading this link is (mostly) multicast.

Thanks

RE: Port congestion drops, microbursts or something else

Steven_Lin — Wed, 09 Aug 2017 05:23:00 GMT

Hi Mick,
Did you try to replace the cable,fiber or SFP to ger rid of the physical issue? And you could identify the microburst congestion with Wireshark by youself from below link.

RE: Port congestion drops, microbursts or something else

Steven_Lin — Wed, 09 Aug 2017 05:25:00 GMT

Sorry forgot the link
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-identifying-microburst-congestion-w...

RE: Port congestion drops, microbursts or something else

Bin — Tue, 06 Mar 2018 11:58:00 GMT

Hi,

Kindly add "Port congestion" on hub for your reference
https://community.extremenetworks.com/extreme/topics/port-congestion

Best regards,
Bin

RE: Port congestion drops, microbursts or something else

davidj_cogliane — Tue, 23 Apr 2019 02:31:00 GMT

Could micro bursts also affect just the CPU?

I was investigating a very random video issue and the only thing I have found so far is congestion on the CPU.

Slot-1 WWPS-X670-Core.1 # debug hal show congestion
Congestion information for slot 1 type X670G2-48x-4q since last query
CPU congestion present: 399432073

Congestion information for slot 2 type X670G2-48x-4q since last query
CPU congestion present: 719827618

Slot-1 WWPS-X670-Core.2 # debug hal show congestion
Congestion information for slot 1 type X670G2-48x-4q since last query
No switch fabric or CPU congestion present

Congestion information for slot 2 type X670G2-48x-4q since last query
No switch fabric or CPU congestion present

TOP looks good and there are no issues other than this very random video issue.

Thanks,