[e-nsp] Extreme Networks Summit1iTx L3 switch delays ICMP traffic routed through the switch or addressed to the switch

[Martin T]

I see, thanks! However, any suggestions how to see exactly which
traffic causes CPU utilization of tNetTask process to increase? It
looks like that in my case it's not the ICMP traffic which actually
loads the tNetTask process.



regards,
Martin

On 8/26/14, Shankar <shankarp5 at gmail.com> wrote:
> ICMP traffic is always software forwarded in EWare....so the RTT is higher
> when compared to other traffic that is hardware forwarded....
>
> Regards,
> Shankar
> On 25 Aug 2014 20:56, "Martin T" <m4rtntns at gmail.com> wrote:
>
>> Hi,
>>
>> I have a legacy Extreme Networks Summit1iTx L3 switch(running EW
>> 7.8.4.1), which delays ICMP traffic routed through the switch and ICMP
>> traffic addressed to the switch while traffic switched through the
>> switch is not affected. For an odd reason, only ICMP traffic seems to
>> be affected and not for example TCP or UDP traffic. There is a clear
>> correlation between high RTT and low CPU utilization(less than 90%) of
>> tBGTask process. It is always the tNetTask process, which CPU usage
>> increased and thus forced tBGTask process utilization below 90%.
>> According to ExtremeWare 7.0 software manual, tNetTask(network stack
>> task) process is responsible for handling all the software-based
>> processing of packets including:
>>
>> 1) Packets that cannot be handled by the switch's ASIC because the
>> forwarding tables do not have entries built in.
>> 2) Packets destined to the CPU for one of the router interfaces.
>> 3) Packets that must be examined or snooped by the CPUPackets detected
>> for copying to the CPU.
>>
>> Has anyone seen such behavior before? Why does low CPU utilization of
>> tBGTask process affect only ICMP traffic? Any suggestions how to see
>> exactly which traffic causes CPU utilization of tNetTask process to
>> increase?
>>
>>
>>
>> thanks,
>> Martin
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>