What should I tell my Cisco programmer to setup QoS for BCM Ip Phones?

[spmcevoy]

Our company has an existing Cisco WAN infrastructe, and we have a BCM in our primary office and ip2004 phones in three satelitte locaions, all linked by an IP WAN.

I would like to tell my Cisco consultant to setup QoS on the routers, but he ask "what protocol" do the Nortel phones use. I guess with Cisco IP phones you just enable QoS, but he's worried that Nortels are the same.

Thoughts? Recommendations?

 

[gwebster]

Go to

http://www.nortel.com/ip2004

then "Technical Documentation" and download the document entitled "Communication Server 1000 IP Phone Inter-Working with Cisco L2 Switches".

 

[DBrewsky]

The Nortel IP phones use Differentiated Services Code Point (DSCP) with a default value of 40 (0x28). This value I believe is in the GOLD level of service and that number is 46 (0x2e). The next level being Premium is reserved for video QOS.


--DB

 

[gm85]

A class needs to be established for Signalling Packets. Nortel IP Phones use DSCP CS5. I've never been able to determine how much per phone is required, but I've found that for 4 IP phones, a bandwidth class of at least 40kbps seems fine.

For voice, a class needs to be established for DSCP EF (Expedited Forwarding). This requires a Priority class and the bandwidth required depends on the protocol used. For instance, G.711 requires AT LEAST 64kbps priority bandwidth per phone.

 

[gm85]

A class needs to be established for Signalling Packets. Nortel IP Phones use DSCP CS5. I've never been able to determine how much per phone is required, but I've found that for 4 IP phones, a bandwidth class of at least 40kbps seems fine.

For voice, a class needs to be established for DSCP EF (Expedited Forwarding). This requires a Priority class and the bandwidth required depends on the protocol used. For instance, G.711 requires AT LEAST 64kbps priority bandwidth per phone.

This is a very basic example of a policy class we've allocated for a 1meg link. We've increased the bandwidth classes slghtly to accomodate a couple phones using the link.

class-map match-any Nortel-Signaling-1
match dscp cs5
class-map match-any Nortel-Voice-1
match dscp ef
!
!
policy-map QoS-Policy-1
class Nortel-Voice-1
priority percent 16
class Nortel-Signaling-1
bandwidth percent 4
class class-default
fair-queue
random-detect

 

[gm85]

Didn't mean for that to be posted twice, I think the tek-tip servers are acting up tonight. That took a very long time to post.

 

[spmcevoy]

Thanks all, I will pass this great info along to my Cisco guy and see if I can finally get my QoS working just right.


I will probably follow you example for the bandwidth allocations. I am using the G.711-uLaw with a medium jitter buffer. Do you think thats a good idea?