HPE FlexNetwork MSR Series Comware 5 Layer 2 - Wan Access Configuration Guide

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Step Command Remarks
2. Enter interface view.
interface
interface-type
interface-number
N/A
3. Configure the MP endpoint
descriptor.
ppp mp endpoint string
char-string
Optional.
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 Command Remarks
1. Enter system view.
system-view
N/A
2. Enter interface view.
interface
interface-type
interface-number
N/A
3. Enable IP header compression.
ppp compression iphc
[
nonstandard
]
By default, IP header compression
is disabled.
4. Set the maximum number of
connections allowed by TCP
header compression.
ppp compression iphc
tcp-connections
number
Optional.
The default setting is 16.
5. Set the maximum number of
connections allowed by RTP
header compression.
ppp compression iphc
rtp-connections
number
Optional.
The default setting is 16.
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:

HPE FlexNetwork MSR Series Specifications

General

Brand	HPE
Model	FlexNetwork MSR Series
Category	Network Router
Language	English