User's Manual

Chapter 3 - Operation and Administration Using the CLI NPU Configuration
4Motion 333 System Manual
3.3.11.16 Configuring PHS Rules
Packet Header Suppression (PHS) is a mechanism that conserves air-interface
bandwidth by removing parts of the packet header that remain constant along the
traffic session. PHS operates by allowing the MS and ASN-GW to associate PHS
rules to each service flow.
When PHS is enabled, a repetitive portion of the payload headers of higher layers
is suppressed in the MAC SDU by the sending entity and restored by the receiving
entity. At the uplink, the sending entity is the MS and the receiving entity is the
NPU. At the downlink, the sending entity is the NPU, and the receiving entity is
the MS. If PHS is enabled at the MAC connection, each MAC SDU is prefixed with
a PHSI, which references the Payload Header Suppression Field (PHSF).
For instance, the ASN-GW will associate a PHS rule to each provisioned service
flow intended for VoIP traffic that will suppress the IP address field from the IP
header and other unvarying fields (e.g. protocol version) from the IP and RTP
headers. The PHS rules are provisioned on a per-service profile name basis. (For
details, refer Section 3.3.11.15.4.)
PHS rules define:
 Header fields that need to be suppressed
 Static values that can be configured for the suppressed header fields
Syntax
Description
Parameter Description Presence Default
Value
Possible
Values
[<rulename>] Denotes the name of the
classification rule that you
want to delete. Specify this
parameter only if you want to
delete a specific classification
rule, otherwise all configured
classification rules are
deleted.
Optional N/A String
Command
Modes
Global configuration mode