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Re: Cisco PPP DS-3 limitations - 42.9Mbpbs?

  • From: Jon Mansey
  • Date: Wed Feb 20 15:41:04 2002

OMG! Arent we missing the point here? What about never running links above 60% or so to allow for bursts against the 5 min average, and <shudder> upgrading or adding capacity when we get too little headroom.

And here we are, nickel and diming over a few MBps near to 45M on a DS3...

Or has the world changed so much that saturated pipes are The Way Things Are TM now.


On Wednesday, February 20, 2002, at 09:37 AM, Alex Rubenstein wrote:


  30 second input rate 13039000 bits/sec, 8055 packets/sec
  30 second output rate 45531000 bits/sec, 10021 packets/sec

Thats a pa-2t3+ on a flexwan in a 6509.

On Wed, 20 Feb 2002, Stephen J. Wilcox wrote:

Hmm, reasonable explanation..

presumably this can be improved (a little) with increased interface
buffers.. ? and possibly non fifo queuing eg custom queuing in favour of
TCP rathen than UDP/ICMP etc which wont have the backoffs



On Wed, 20 Feb 2002, Randy Bush wrote:

we run HDLC on DS3 and we max at about 40.something too
if you're using five min (or three min) samples, and you're seeing 70%,
peaks are likely much higher and some users' packets are being dropped.
by 80%, enough packets are being dropped that users are likely to see
the effects of exponential backoff.  things do not improve above 80%.


Stephen J. Wilcox
IP Services Manager, Opal Telecom
Tel: 0161 222 2000
Fax: 0161 222 2008

-- Alex Rubenstein, AR97, K2AHR, [email protected], latency, Al Reuben --
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