Motorola 110502USM001 - Vanguard 60 Router User Manual page 42

RTP/UDP/IP Header Compression
Motorola's
Implementation of
RTP/UDP/IP Header
Compression
Options for Header
Compression
2-26
Vanguard routers supports RTP/UDP/IP and/or UDP/IP header compression. As
shown in Figure 2-17, the Vanguard compresses the 40 byte header to between 2 to 4
bytes. If UDP checksum is being sent, the RTP/UDP/IP header is compressed from
40 bytes to 4 bytes. If no UDP checksum is being sent, header compression is 40
bytes to 2 bytes.
40 Bytes
IP UDP RTP
IP UDP RTP
2 to 4 Bytes
Figure 2-17. RTP/UDP/IP Header Compression
Motorola's Vanguard products support:
• header compression by traffic type - RTP/UDP/IP, UDP/IP, or both
• header compression on a link-by-link basis
• header compression of RTP/UDP/IP or UDP/IP packets carried over PPP or
Frame Relay WAN links
The Vanguard products can support header compression in four different
configurations. Header compression can be enabled to:
• Compress outgoing packets only; incoming compressed packets are not
recognized for decompression.
• Decompress the incoming compressed packets only; outgoing packets sent on
an interface are not compressed.
• Compress all the outgoing packets and decompress all the incoming
compressed packets on an interface.
In addition, header compression can be configured to autodetect the compression
state of incoming and outgoing packets. If an incoming packet received on a link is
compressed then the outgoing packets are also be compressed.
Packet Voice/Data
Packet Voice/Data
Vanguard Routing Model