Configuring Iphc - 3Com MSR 50 Series Configuration Manual

378 C 19: PPP
HAPTER AND

Configuring IPHC

MP C
ONFIGURATION
cause block and delay, consequently, the remote end cannot hear continuous
speech. It is required by the interactive voice that the end-to-end delay cannot be
larger than 100-150 ms.
Dispatching a large packet of 1500 bytes through a 56-kbps line, perhaps will take
215 ms, this will exceed the delay point that one can tolerate. LFI is a method for
fragmenting larger packets and adding both the smaller packets and fragments of
the large packet to the queue. The fragmented datagrams are reassembled at the
destination. LFI can reduce delay of real-time packets on relatively slow bandwidth
links.
The following figure describes the process of link fragmentation and interleaving.
When large packets and small voice packets arrives at an interface at the same
time, the large packets are fragmented into small fragments. If the interface is
configured with WFQ, the voice packets and these small fragments are interleaved
together and put into the WFQ.
Figure 95 Link fragmentation and interleaving
Large packet
Voice packet
Follow these steps to configure IPHC:
To do...
Enter system view
Create an MP-group
Exit to system view
Enter the specified interface view
Configure Enable IPHC
IPHC
(optional)
Configure the maximum number of
TCP header compression connections
Configure the maximum number of
RTP header compression connections
Fragmentation
Traffic
classifying
WFQ
WFQ
Use the
command... Remarks
system-view -
interface mp-group Required
number
quit -
interface -
interface-type
interface-number
ppp compression Required
iphc
[ nonstandard ]
ppp compression Optional
iphc
16 by default
tcp-connections
number
ppp compression Optional
iphc
16 by default
rtp-connections
number
Output queue