[c-nsp] VOIP QoS problem

[Brant I. Stevens]

What does the output of "show policy-map interface" provide?


On 8/27/06 4:44 PM, "Scott Granados" <sgranados at jeteye.com> wrote:

> This may be totally unimportant, but shouldn't the bandwidth setting be
> 1536?  ESF, B8zs with 8K framing?
> 
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Eric Kagan
> Sent: Sunday, August 27, 2006 1:35 PM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] VOIP QoS problem
> 
> We have several customers that utilize service with a 3rd party VOIP
> provider.  We have applied a very simple QoS policy (below) to several
> customers interfaces on our Cisco 7206VXR's as well as the CPE.  One
> customer in particular is complaining of frequent problems.  We could not
> find anything real obvious of why they are having issues.  Traffic on the
> norm is about 200-300k on a full T1 which should not even warrant needing
> the QoS in place.  From what I understand and have read on the Qos config
> below - it will only get applied as the circuit starts to get congested. We
> put some real time traffic monitors on the customers interface and saw a few
> real short spikes almost maxing out the circuit.  Is it possible for the
> circuit to experience a really quick burst of traffic that doesn't allow the
> QoS policy to "kick-in" quick enough so the customer experiences some drops
> ?  Anyone have any ideas on how to best troubleshoot or determine this
> problem ?  Should we consider reserving a fixed amount of bandwidth vs the
> config below.  Could the output drops be contributing to this problem ?  Any
> pointers would be appreciated.
>  
> Thanks
> Eric
>  
>  
> class-map match-any VOIP
>   match protocol rtp
>   match protocol sip
> !
> policy-map voice
>   class VOIP
>    priority percent 65
>    set ip precedence 5
> 
> interface Serialx/x/x
>  bandwidth 1544
>  ip address x.x.x
>  ip flow ingress
>  ip nbar protocol-discovery
>  service-policy output voice
>  encapsulation ppp
>  no clns route-cache
> 
>  
> show int Sx/x/x
> Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 5222
> Queueing strategy: weighted fair
> Output queue: 0/1000/64/5222 (size/max total/threshold/drops)
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