QoS on Cisco 861 Voice Packet Support

[felipe.sevillano]

I configure my Cisco Router 861 for VPN Site-to-Site with ASA 5510, but when i uses all bandwith on my remote office i have troubles with my voice ip telephone (SIP), somebody knows how to fix this trouble with QoS?, i review that´s Cisco Router 861 only support Class-Based WFQ (CBWFQ).

Thanks,

Felipe Sevillano

[Steven Holl]

Can you draw out the topology end-to-end for this call?  That will help potentially with the specifics of what you'll need to do.

The short answer is you need to shape the interface to the speed of your upload bandwidth, and apply a priority queue inside the shaper:

class-map match-any rtp
  match ip rtp  16384 16383
 class-map match-any voice-control
  match dscp cs3 af31
  match protocol mgcp
  match protocol h323
  match protocol sip
  match protocol skinny

policy-map voice-qos
 class rtp
  priority 
  set dscp ef
class voice-control
  bandwidth 
  set dscp 
class class-default
  fair-queue
  random-detect dscp-based
  set dscp 0


policy-map shaper
class class-default
  shape average 3000000
  service-policy voice-qos

interface 
  service-policy output shaper

Estimate either .25K of signaling traffic per phone/gateway across the link, or 8K (whichever number is *greater*).  You can find out how much bandwidth you will need for RTP traffic with the voice-call bandwidth calculator found here:

http://tools.cisco.com/Support/VBC/do/CodecCalc1.do

The ASA doesn't support shaping, so you have to police the link instead.

[felipe.sevillano]

Hi Steven, Thanks for your answer, the topology is that i think to configure:

Voice Device ATA Cisco(SIP Protocol/G.711)++VPN(Router Cisco 861)--------To-------VPN(Cisco ASA 5510 Plus Security Firewall)----------++Voice Device ATA Cisco(SIP Protocol/G.711).

The config is pass data and voice trafic for the VPN and created a QoS police for voice.

Attachment the topology on image.

Thanks My friend for your answer.

Felipe Sevillano.

[Steven Holl]

I assume the WAN connection is between the 861 and the ASA, so:

Configure a traffic shaper on the 861 to the upload speed, and nest the QoS policy inside of that.

Configure QoS on the ASA, and police the ASA's outbound speed on that link to the upload speed of that side's circuit.

Leverage my previous post for what the QoS policies should look like.

[felipe.sevillano]

That´s Correct, The WAN connection is between the 861 and the ASA, i go to test the configuration that you post here

Thanks again,

Felipe Sevillano