QOS over MPLS

[moonraker169]

I have several offices on IPO 406 connected via thier LAN ports onto MPLS networks that supposedly have COS (Class of service) running. I'm experiencing voip degradation under busy times. Is there anyway I can confirm that the packets are being tagged by the IPO? Is there anything I need to enable or configure on the IPO to use QOS? Any help would be greatly appriciated.

 

[janni78]

Only setting in IPO is the DSCP value under System -> Gatekeeper. This is usually set to 46.
You should be able to see if your networking equipment gets packets tagged with this value.
Otherwise you coudl sniff the traffic with an app like ethereal to see if they are tagged.

 

[big70]

Be aware that COS is not the same as QOS.

The MPLS has COS and not Qos so there is no priority for the voice pakkets.

Class of Service (CoS) is a queuing discipline. An algorithm compares fields of packets or CoS tags to classify packets and to assign to queues of differing priority. Unlike Quality of Service (QoS) traffic management, CoS does not ensure network performance or guarantee priority in delivering packets.



Greets Peter

 

[moonraker169]

Though QOS differs from COS, would'nt COS use the QOS tags to clasify the traffic and give the VOIP traffic highest priority? How would I ensure VOIP quality over MPLS networks?

 

[big70]

http://www.cisco.com/en/US/tech/tk436/tk428/technologies_white_paper09186a00800a4455.shtml

Greets Peter