[nsp] QoS not working

jlewis at lewis.org jlewis at lewis.org
Tue Mar 4 18:48:33 EST 2003

I'm trying to configure QoS to prioritize VOIP traffic on a few customer
DSL and frame T1's (delivered to us over ATM).  The customer I was working
with today is running a 1602 with 12.1(18).  My end is a 7206vxr with

I based my configs on info from 
but I'm not doing PPP over FR or ATM.

I've got a number of problems here.  On my end, IOS will let me put a 
'service-policy output cust-VOIP' in the pvc section of the customer's 
ATM3/0.45 interface, but the command doesn't show up in a show run...so 
I'm guessing that even though there was no error, it's not actually being 
accepted.  Can I do this or another type of prioritization without 
involving virtual templates?

On the customer end, I put the service-policy on the s1 interface (IP is
configured on s1.1, but the subinterface won't accept a service-policy).
It's accepted and seems to function.  At least the counters show
packets matching the priority queue, but when large files are uploaded
from a PC connected to the 1600's ethernet, VOIP quality noticably

Here's part of the config from the 1600.

class-map cust-voice
  match access-group 150
policy-map cust-VOIP
  class cust-voice
    priority 1158
  class class-default

access-list 150 permit ip host any is the IP of the VOIP device.  I started with lower priorities 
and ended up at 1158 (the max) with no improvement.

Only by using CAR on the 1600 (I was surprised it was supported) was I
able to guarantee bandwidth for the VOIP traffic by limiting everything
else.  That's not going to work for the customer's central site though,
where lots of people will be working from home and doing both VOIP and
file transfers and other traffic.

Is this a bug in LLQ, or am I not configuring it properly?  Ideally, I 
need some way of doing this that will scale to doing a bunch of customers 
on our 7206.
 Jon Lewis *jlewis at lewis.org*|  I route
 System Administrator        |  therefore you are
 Atlantic Net                |  
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