Cisco Systems CISCO1751 quick start RTP Header Compression, Configuring Multilink PPP Interleaving

Configuring Voice-over-IP

Configuring Multilink PPP Interleaving

To configure multilink PPP and interleaving on a dialer, ISDN PRI or ISDN BRI interface, or a virtual template, you must first configure multilink PPP and interleaving on the interface or template by entering the following commands in interface configuration mode:

Router(config-if)# encapsulation ppp

Router(config-if)# ppp multilink

Router(config-if)#ppp multilink interleave

Optionally, configure a maximum fragment delay:

Router(config-if)#ppp multilink fragment-delay milliseconds

You can also reserve a special queue for real-time packet flows to specified destination User Datagram Protocol (UDP) ports, allowing real-time traffic to have higher priority than other flows. You need the following command only if you have not configured RSVP:

Router(config-if)#ip rtp reserve lowest-UDP-port range-of-ports

For virtual templates only, apply the virtual template to the multilink bundle:

Router(config-if)#multilink virtual-template 1

To create a virtual template interface, enter the following interface virtual-templateglobal configuration command:

Router(config)# interface virtual-template 1

RTP Header Compression

RTP header compression on a PPP, HDLC, or similar serial interface compresses the packet header to reduce network overhead.

You should configure RTP header compression on a serial interface if you have either of the following:

•Links slower than 2 Mbps

•Need to save bandwidth

Note Do not use RTP header compression on links faster than 2 Mbps.

Configuring RTP Header Compression

Enable RTP header compression at both ends of the serial link by entering the following ip rtp header-compressioninterface configuration command:

Router(config-if)#ip rtp header-compression

Note When you enter the show running-configcommand, the format of the ip rtp header-compressioncommand will change to ip rtp header-compressioniphc-format.

Cisco 1751 Voice-over-IP Quick Start Guide

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