GroupStudy.com GroupStudy.com - A virtual community of network engineers
 Home  BookStore  StudyNotes  Links  Archives  StudyRooms  HelpWanted  Discounts  Login
Re: LLQ/CBWFQ w/ FRTS vs. posted 09/15/2004
[Chronological Index] [Thread Index] [Top] [Date Prev][Date Next] [Thread Prev][Thread Next]


I understand that "ip rtp priority" only matches a certain range of UDP ports and that LLQ/CBWFQ is more flexible.
 
My question is, what happens when both are configured at the same time?  I think this is a pertinent question since it is stated that the two can be configured together.
 
My interpretation is this:
Traffic is evaluated agains the "ip rtp priority" first.  If it matches, it goes into the priortiy queue and is forwarded.  If it does not, it is then passed to the normal queueing mechanism which in this case would be LLQ/CBWFQ.  It the traffic happens to match the class for the priority queue it is placed into the priority queue and forwarded.  If not it is evaluated against the the remaining classes that have been configured for CBWFQ.
 
Can anyone set me straight if this is incorrect?
 
Thanks,
 
Fly

gladston@xxxxxxxxxx wrote:
This seems to be related to the question:

========
quoted
With RTP prioritization and PQ/WFQ, traffic that matches a specified User Datagram Protocol (UDP)/RTP port range is considered high priority and allocated to the PQ. With Low Latency Queueing for Frame Relay, you set up classes of traffic according to protocol, interface, or access lists, and then define policy maps to establish how the classes are handled in the priority queue and weighted fair queues.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_guide09186a0080080122.html#wp1033474
========

I understand it is saying that, while RTP Priorization just allow you to match a UDP range, LLQ is more flexible. It is your decision to use one or another, though. LLQ allows you to match using RTP Priorization or other facilities.

r6(config)#class-map Voice
r6(config-cmap)#match ip rtp ?
<2000-65535> Lower bound of UDP destination port

You can use both. For example, use "match ip rtp..." to match a UDP range and "match access-group name Control-1720" to match control traffic. All these under the same class, so you match voice and control packets, which will go to the priority queue.

Makes sense?

_______________________________________________________________________
Please help support GroupStudy by purchasing your study materials from:
http://shop.groupstudy.com

Subscription information may be found at: 
http://www.groupstudy.com/list/CCIELab.html

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com