Configuring Ppp Link Efficiency Mechanisms; Configuring Iphc; Configuring Stac Lzs Compression - HPE FlexNetwork MSR Series Comware 5 Layer 2 - Wan Access Configuration Manual

Step
Enter interface view.
2.
Configure the MP endpoint
3.
descriptor.

Configuring PPP link efficiency mechanisms

Four mechanisms are available for improving transmission efficiency on PPP links:
•
IP Header Compression (IPHC)
•
Stac Lempel-Ziv Standard (Stac LZS) compression on PPP packets
•
V. Jacobson Compressing TCP/IP Headers (VJ TCP/IP header compression)
•
Link Fragmentation and Interleaving (LFI).

Configuring IPHC

IPHC is a host-to-host protocol used to carry real-time multimedia services such as voice and video
over IP networks. To decrease the bandwidth consumed by packet headers, you can enable IPHC
on PPP links to compress RTP (including IP, UDP, and RTP) headers or TCP headers. The following
uses RTP header compression to describe how compression operates.
RTP is a UDP protocol using fixed port number and format. An RTP packet comprises a 40-byte
header and a data section. The 40-byte header, which is composed of a 20-byte IP header, an 8-byte
UDP header, and a 12-byte RTP header, is large compared with the payload, which is usually 20
bytes to 160 bytes in size. To reduce bandwidth consumption, use IPHC to compress RTP packet
headers. After compression, the 40-byte header can be reduced to 2 to 5 bytes. If the payload is 40
bytes, the compression ratio will be (40+40) / (40+5), about 1.78, which is very efficient.
To configure IPHC:
Step
Enter system view.
1.
Enter interface view.
2.
Enable IP header compression.
3.
Set the maximum number of
4.
connections allowed by TCP
header compression.
Set the maximum number of
5.
connections allowed by RTP
header compression.

Configuring Stac LZS compression

Stac LZS compression is a link layer data compression standard developed by Stac Electronics.
Stac LZS is a Lempel-Ziv-based algorithm compressing only packet payloads. It replaces a
continuous data flow with binary codes that can accommodate to the change of data. Though
allowing for more flexibility, this requires more CPU resources.
To configure Stac LZS compression:
Command
interface interface-type
interface-number
ppp mp endpoint string char-string
Command
system-view
interface interface-type
interface-number
ppp compression iphc
[ nonstandard ]
ppp compression iphc
tcp-connections number
ppp compression iphc
rtp-connections number
24
Remarks
N/A
Optional.
Remarks
N/A
N/A
By default, IP header compression
is disabled.
Optional.
The default setting is 16.
Optional.
The default setting is 16.