Configuring Compressed Real-Time Transport Protocol
Compressed Real-Time Transport Protocol (CRTP) is typically used for compressing voice and video packets. The topics below discuss the overview of CRTP and its configuration details.
Understanding Compressed Real-Time Transport Protocol
Compressed Real-Time Transport Protocol (CRTP) is typically used for compressing voice and video packets. You can configure CRTP with LFI on a link services interface.
CRTP can be configured as a compression device on a T1 or E1 interface with PPP encapsulation, using the link services interface.
F-max period—Maximum number of compressed packets allowed between transmission of full headers. It has a range from 1 to 65,535.
Maximum and Minimum—UDP port values from 1 to 65,536 reserve these ports for RTP compression. CRTP is applied to network traffic on ports within this range. This feature is applicable only to voice services interfaces.
Example: Configuring the Compressed Real-Time Transport Protocol
This example shows how to configure CRTP to improve packet transmission, especially for time-sensitive voice packets.
Before you begin, you should have two Juniper Networks devices configured with at least two serial interfaces that communicate over serial links.
In this example, you create a T1 interface called t1-1/0/0 and set the type of encapsulation to PPP. You set the link services intelligent queuing interface to lsq-0/0/0.0. You then create an interface called lsq-0/0/0 and set the logical unit 0. Finally, you set the F-max period to 2500, the minimum UDP port value to 2000, and the maximum UDP port value to 64009.
CLI Quick Configuration
To quickly configure this example, copy the following command, paste it into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the command into the CLI at the  hierarchy level, and then enter commit from configuration mode.
The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode.
To configure CRTP on a device:
- Create the T1 interface.user@host# edit interfaces t1-1/0/0
- Set the type of encapsulation.[edit interfaces t1-1/0/0]user@host# set encapsulation ppp
- Add the link services intelligent queuing interface to
the physical interface.[edit interfaces t1-1/0/0]user@host# edit unit 0user@host# set compression-device lsq-0/0/0.0
- Create an interface and set the logical unit.[edit interfaces]user@host# edit lsq-0/0/0 unit 0
- Configure the link services intelligent queuing interface.[edit interfaces lsq-0/0/0 unit 0]user@host# set compression rtp f-max-period 2500 port minimum 2000 maximum 64009
From configuration mode, confirm your configuration by entering the show interfaces command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.
If you are done configuring the device, enter commit from configuration mode.
Confirm that the configuration is working properly.
Verifying the CRTP Configuration
Verify the CRTP configuration.
From operational mode, enter the show interfaces command.