Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

QoS and VoIP

Here is a config of a frame relay link over which Voice and data will traffic.



policy-map Voice

class premium

priority 48

class silver

bandwidth percent 5

class gold

bandwidth percent 5

class class-default



interface Serial0/0.1 point-to-point

bandwidth 256

ip address

frame-relay class PVoice

frame-relay interface-dlci xx

frame-relay ip rtp header-compression

frame-relay ip rtp compression-connections 3


map-class frame-relay PVoice

frame-relay fragment 320

frame-relay cir 256000

frame-relay bc 1000

frame-relay be 0

frame-relay mincir 256000

service-policy output Voice

My understanding is this -

That the priority class will always be serviced first and will have at least 48Kbs of bw available but not more that 48Kbs.

That the Silver and Gold classes will always have a minimum of 5% of the total link bw available to them but they may use as much bw as is available.

What I am not clear on is:

1. If the line is in congestion by traffic from all classes, will Silver and Gold get their 5%? Can they grow beyond their 5% and if so, at what other class's expense - the default class?

2. How much bw may the default class use in this case of congestion? Will it attempt to use all bw- how is it limited from using the 48Kbs of priority bw and 5% + 5% of assigned bw with no policing to restrict it?

3. Are the Silver and Gold classes, since they have assigned bandwith (5%), serviced after the premium (priority) queue but before the default class?

New Member

Re: QoS and VoIP

I have been told by my Cisco Rep:

1. Yes and Yes

2. All bandwidth until congestion and then the priority and bandwidth percent values take precedence - and the bandwidth percent classes may continue to grow at the default classes expense - no policing required.

3. Bandwidth percent classes are service after priority classes and before the default class

CreatePlease login to create content