pontification bloat (was 10GE TOR port buffers (was Re: 10G switch recommendaton))

Randy Bush randy at psg.com
Fri Jan 27 20:02:14 CST 2012


>> when a line card is designed to buffer the b*d of a trans-pac 40g, the
>> oddities on an intra-pop link have been observed to spike to multiple
>> seconds.
> Please turn that buffer down.

not my router.  research probes seeing fun anomalies around the global
network.

> cribbing from a previous ob where I rolled it out network wide:
> 
> policy-map atm-queueing-out
>   class class-default
>    fair-queue
>    random-detect
>    random-detect precedence 0   10    40    10
>    random-detect precedence 1   13    40    10
>    random-detect precedence 2   16    40    10
>    random-detect precedence 3   19    40    10
>    random-detect precedence 4   22    40    10
>    random-detect precedence 5   25    40    10
>    random-detect precedence 6   28    40    10
>    random-detect precedence 7   31    40    10
> 
> int atm1/0.1
>  pvc 1/105
>   vbr-nrt 6000 5000 600
>   tx-ring-limit 4
>   service-policy output atm-queueing-out
> 
> Those packet thresholds were computed as the best balance for
> 6-20MMbps PVC's on an ATM interface.

while i hope few folk other than telephants still have atm <g>, thanks
for posting running code.

one problem is that we do not have good tools to look at a link and
suggest parms.  how did you derive those?

randy



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