FRF.20
FRF.20 compresses the IP header (including the RTP/TCP header) of packets transmitted over frame relay. For example, you can use it to compress voice packets (RTP packets) to save bandwidth, decrease load, and improve transmission efficiency on a frame relay network.
FRF.20 classifies packets into control packets and data packets. Control packets are sent between FRF.20-enabled interfaces to negotiate status information. The interfaces cannot exchange FRF.20 data packets before the negotiation succeeds. If FRF.20 fails to negotiate the state after ten control packets are sent, the interfaces stop negotiation and their compression settings do not take effect.
FRF.20 compresses only RTP packets and TCP ACK packets.