Frame Relay Compression

Stacker vs Predictor
1. Stacker is more CPU intensive.
2. Predictor is more Memory intensive.

Frame relay compression schemes:
1. Data payload compression.
1.1 Cisco proprietary packet-by-packet payload compression. It uses Stacker compression
For a multiple interface use:
frame-relay map ip 10.1.1.1 100 payload-compress packet-by-packet
For P2P interface:
frame-relay payload-compress packet-by-packet.

1.2 FRF.9 uses Stacker. It has better compression ratio than packet by packet.
You should use IETF encapsulation for the pvc that uses FRF.9. Actually when you enable the rfr9 stac keyword, IETF encapsulation is automatically enabled.
For a multiple interface use:
frame-relay map ip 10.1.1.1 100 payload-compress FRF9 stac
For P2P interface:
frame-relay payload-compress FRF9 stac.



2. Packet header compression
2.1 TCP/IP. See RFC 1144
It is important to note that TCP/IP header compression is hop-by-hop compression scheme. The TCP/IP header must be replaced at each node. So it adds latency and CPU load.
And TCP/IP compression requires Cisco proprietary encapsulation.
For physical interface:
frame-relay ip tcp head-compression [passive]
For DLCI
frame-relay map ip 10.1.1.1 100 tcp header-compression [active|passive]
You can also disable it by:
frame-relay map ip 10.1.1.1 100 nocompress

2.2 RTP. See RFC 1889
It is also hop-by-hop compression. And only support Cisco encapsulation
frame-relay ip rtp header-compression [passive]
frame-relay map ip 10.1.1.1 100 rtp header-compression.
frame-relay map ip 10.1.1.1 100 compress (Enabel both tcp and rtp compression).