From: Dan.Thorson@seagate.com
Date: Wed May 25 2005 - 18:29:52 GMT-3
You said:
> I think the most point with regards to the transmit queue is that it's a
> hardware queue and is independent of any software shaping queues you
might
> configure.
I very much disagree. Some Cisco hardware platforms will automatically
adjust TxRing based on ATM PVC sizes (when CBWFQ is applied), i.e. the
7507/PA-A3, but others won't, i.e. 7206/PA-A3. Without modifying the
TxRing when needed (i.e. if the platform is leaving a T1 interface with a
default value of TxRing=128) then you will DEFINITELY have voice quality
issues. We have seen dramatic VoIP quality improvements after adjusting
TxRing down (due to lower jitter and serialization delay).
Note also that if you're sending voice across a GRE tunnel you'll have
similar issues. Using a TxRing size on the GRE tunnel is acceptable, and
works good. [ I think you can use the qos-preclassify, too, and only have
to apply the TxRing changes to the physical interface, but I may be
wrong.... can't recall ]
danT
===================================================
Dan Thorson - Seagate Technology - CCIE 10754
desk +1 (952) 402-8293 fax +1 (952) 402-1007
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