nanog mailing list archives

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


From: Randy Bush <randy () psg com>
Date: Sat, 28 Jan 2012 11:02:14 +0900

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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