05-03-2011 07:34 AM - edited 03-04-2019 12:15 PM
Hi,
One of our clients have plans to use VOIP. Since we only manage their 1841 routers I've been issued the following parameters-
DIFFSERV/TOS PARAMETERS RTCP Reporting Enabled? y
Call Control PHB Value: 46 RTCP MONITOR SERVER PARAMETERS
Audio PHB Value: 46 Use Default Server Parameters? y
Video PHB Value: 26
802.1P/Q PARAMETERS
Call Control 802.1p Priority: 6
Audio 802.1p Priority: 6
Video 802.1p Priority: 5
Since I'm new relatively new to Qos, could you shed some light on how best to turn this into meaningful config fit for an 1841 router? Will Auto Qos lessen & simplify this type of configuration?
Much appreciated.
05-03-2011 07:46 AM
Hi,
AutoQoS will indeed simplify things but to get it working you need to issue correct bandwidth command on WAN interfaces.
Who gave you these params? PHB of 46 is EF is for voice bearer not for voice control and the same goes for CoS( 802.1p priority) and furthermore it is highly discouraged to use CoS 6 and 7.
Regards.
Alain.
05-04-2011 04:02 AM
Thanks for your response Alan.
I've recommended they adopt the preferred IP precedence 5 marking & look at validating the call control parameters.
If I turn on "auto qos voip trust" on my MPLS interface I guess this will then load the neccessary config on the 1841 by copying the Qos settings from the LAN.
My bandwidth commands I'm going to look at deploying are:-
policy-map EGRESS_MARKING
class VOICE_TRAFFIC
bandwidth percent 50
Seems I've covered everything now or am I missing any of the other parameters?
05-04-2011 04:23 AM
It is recommended that voice traffic to be assigned to the low latency queue.
Therefore you should use the command priority percent 50 rather than bandwidth percent 50 in the class VOICE_TRAFFIC.
Please rememeber to rate all posts that are helpful.
05-04-2011 01:31 PM
Thanks Sean.
I've now amended accordingly.
LLQ is better suited for my voice traffic thanks to the strict priority queues. Thanks for pointing this out.
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