Enabling IP header compression
IP header compression (IPHC) compresses packet headers to speed up packet transmission. IPHC is often used for voice communications over low-speed links.
IPHC provides the following compression features:
RTP header compression—Compresses the IP header, UDP header, and RTP header of an RTP packet, which have a total length of 40 bytes.
TCP header compression—Compresses the IP header and TCP header of a TCP packet, which have a total length of 40 bytes.
To use IPHC, you must enable it on both sides of a PPP link.
Enabling or disabling IPHC on a VT interface does not immediately take effect. You must execute the shutdown and undo shutdown commands on the interface or the bound physical interface to apply the new setting.
After you enable IPHC, you can configure the maximum number of connections for RTP or TCP header compression. The configuration takes effect after you execute the shutdown and undo shutdown command on the interface. The configuration is removed after IPHC is disabled.
To configure IPHC:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Enable IP header compression. | ppp compression iphc enable [ nonstandard ] | By default, IP header compression is disabled. The nonstandard option must be specified when the device communicates with a non-HPE device. When the nonstandard keyword is specified, only RTP header compression is supported and TCP header compression is not supported. |
4. Set the maximum number of connections for which an interface can perform RTP header compression. | ppp compression iphc rtp-connections number | The default setting is 16. |
5. Set the maximum number of connections for which an interface can perform TCP header compression. | ppp compression iphc tcp-connections number | The default setting is 16. |