Wide-Area Networking Configuration Guide: Frame Relay, Cisco IOS Release 15S
Frame Relay IP RTP Priority
Frame Relay IP RTP Priority
Last Updated: November 26, 2012
This feature module describes the Frame Relay IP RTP Priority feature.
Finding Feature Information
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The Frame Relay IP RTP Priority feature provides a strict priority queueing scheme on a Frame Relay permanent virtual circuit (PVC) for delay-sensitive data such as voice. Voice traffic can be identified by its Real-Time Transport Protocol (RTP) port numbers and classified into a priority queue configured by the frame-relay ip rtp prioritycommand. The result of using this feature is that voice is serviced as strict priority in preference to other nonvoice traffic.
This feature extends the functionality offered by the ip rtp priority command by supporting Frame Relay PVCs. This feature allows you to specify a range of User Datagram Protocol (UDP) ports whose voice traffic is guaranteed strict priority service over any other queues or classes using the same output interface. Strict priority means that if packets exist in the priority queue, they are dequeued and sent first--that is, before packets in other queues are dequeued.
The strict priority queueing scheme allows delay-sensitive data such as voice to be dequeued and sent first--that is, before packets in other queues are dequeued. Delay-sensitive data is given preferential treatment over other traffic. This process is performed on a per-PVC basis, rather than at the interface level.
Related Features and Technologies
The Frame Relay IP RTP Priority feature is related to the following features:
This feature runs on the platforms listed. However, it is most useful on voice supported platforms, such as the Cisco 2600 series, Cisco 3600 series, Cisco 7200 series, and Cisco 7500 Route Switch Processor (RSP) series.
Supported Standards and MIBs and RFCs
Frame Relay traffic shaping (FRTS) and Frame Relay Fragmentation (FRF.12) must be configured before the Frame Relay IP RTP Priority feature is used.
Configuring Frame Relay IP RTP Priority
To reserve a strict priority queue on a Frame Relay PVC for a set of RTP packet flows belonging to a range of UDP destination ports, use the following command in map-class configuration mode.
Verifying Frame Relay IP RTP Priority
To verify the Frame Relay IP RTP Priority feature, use one of the following commands in EXEC mode:
Monitoring and Maintaining Frame Relay IP RTP Priority
To tune your RTP bandwidth or decrease RTP traffic if the priority queue is experiencing drops, use the following command in EXEC mode:
Frame Relay IP RTP Priority Configuration Example
The following example first configures the Frame Relay map class called voip and then applies the map class to PVC 100 to provide strict priority service to matching RTP packets:
map-class frame-relay voip frame-relay cir 256000 frame-relay bc 2560 frame-relay be 600 frame-relay mincir 256000 no frame-relay adaptive-shaping frame-relay fair-queue frame-relay fragment 250 frame-relay ip rtp priority 16384 16380 210 interface Serial5/0 ip address 10.10.10.10 255.0.0.0 no ip directed-broadcast encapsulation frame-relay no ip mroute-cache load-interval 30 clockrate 1007616 frame-relay traffic-shaping frame-relay interface-dlci 100 class voip frame-relay ip rtp header-compression frame-relay intf-type dce
In this example, RTP packets on PVC 100 with UDP ports in the range 16384 to 32764 will be matched and given strict priority service.
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