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

[Martin T]

Thanks for all the information! So in case the utilization of tBGTask
process is less than 90%, all the other IP traffic should suffer as
well? For some odd reason I didn't observe this. Based on my
tests(hping and custom-made script utilizing bash UDP and TCP
sockets), only the RTT of ICMP traffic increased while RTT for example
for UDP or TCP traffic did not change at the time when CPU utilization
of tBGTask was <90%.


thanks,
Martin

On 9/1/14, Mikael Abrahamsson <swmike at swm.pp.se> wrote:
> On Tue, 26 Aug 2014, Shankar wrote:
>
>> ICMP traffic is always software forwarded in EWare....so the RTT is
>> higher when compared to other traffic that is hardware forwarded....
>
> Well, that is not strictly true. If you have newer ASICs in your hardware
> (manufactured after 2005 or so depending on platform), you can do "disable
> icmp access-list" (if I remember correctly) and ICMP will be hardware
> forwarded, but downside is that ICMP becomes "invisible" to access-lists.
>
> Otherwise all traffic is punted to CPU for forwarding and will experience
> increased latency depending on current CPU load, and also will max out at
> approximately 10 megabit/s or so.
>
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
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