Configuration restrictions and guidelines
When you configure Frame Relay IPHC, follow these restrictions and guidelines:
To make IPHC take effect on a link, you must enable Frame Relay IPHC on both ends of the link.
You can configure Frame Relay IPHC on either an interface or a virtual circuit. The settings on an interface take effect on all virtual circuits of the interface. The settings on a virtual circuit take effect only on the virtual circuit. When the interface settings are different from the virtual circuit settings, the virtual circuit settings take effect.
When the encapsulation type is IETF, IPHC negotiation is triggered after you enable IPHC. IPHC takes effect only when IPHC negotiation succeeds. When the encapsulation type is nonstandard, IPHC takes effect without negotiation. In this case, the encapsulation type must be nonstandard on both ends of the link.
Compression does not stop after you disable IPHC on an interface or virtual circuit. To stop compression, you must also execute the shutdown/undo shutdown command sequence on the interface or virtual circuit.
You can set the maximum number of RTP/TCP header-compression connections only after you enable IPHC on an interface or virtual circuit. The configuration takes effect after you execute the shutdown/undo shutdown command sequence on the interface or virtual circuit. After you disable IPHC, the configuration is deleted.
The maximum number of RTP/TCP header-compression connections configured on an interface is inherited by all virtual circuits of the interface. If you set a different maximum number on a virtual circuit of the interface, the configuration on the virtual circuit takes effect.