Motorola Netopia Embedded Software Handbook page 40

2-24 Administrator's Handbook
bandwidths from 20 kbps to 90 kbps, depending on the CODEC setting – compared to the total throughput bandwidth of the
Gateway and the network. There will usually be fewer than two or three packets pending in the Gateway in any queue in the
Gateway during the conversation. If, during the call, however, a user is surfing and decides to download, or upload, a file
through the Gateway, it is possible that during the file transfer the voice quality of the VoIP call could be degraded. A higher
setting for the lohi-asymmetry will prevent this from occurring.
On the other hand, if 10 or 20 VoIP calls are simultaneously being handled by the Gateway, for example, in an office setting,
then 1000-2000 packets/sec are being throughput at high priority. If one or several of the callers in the office then attempt
to download, 10-15 packets may be pending in the low priority receive queues, with perhaps 2-3 pending in the high. The
corresponding asymmetry in this case would be around 80-86%. If it were found in this situation that the file transfers were
too sluggish, then the lohi-asymmetry threshold could be set to 80%. This would cause more of the low priority traffic to be
throughput, at the expense of the high priority streams. As a result, the file downloads might proceed at a more satisfactory
rate, while the degradation to the 10 or 20 VoIP calls might not be noticeable.
The lo-hi asymmetry parameter is therefore one means of balancing the traffic load to satisfy everyone.
You can then define custom Rules. If your applications do not provide Quality of Service (QoS) control, rules
allow you to define streams for some protocols, port ranges, and between specific end point addresses.
•
To define a Rule, select Add Rules and press Return.
(Once you have added one or more rules, you can edit any of them by returning to this screen and selecting
Show/Change Rules.)
The Diffserv Rule screen appears.
Name:
Protocol...
Priority...
Direction...
Start Port:
End Port:
Inside Ip Address:
Inside Ip Netmask:
Outside Ip Address:
Outside Ip Netmask:
COMMIT
Return accepts * ESC cancels * Left/Right moves insertion point * Del deletes.
•
Name – Enter a name in this field to label the rule.
•
Protocol – Select the protocol from the pop-up menu: TCP (default), UDP, ICMP, or Other. "Other" is
appropriate for setting up rules on protocols with non-standard port definitions. IPSEC and PPTP are
common examples.
Diffserv Rule
TCP
off
outbound
0
0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
CANCEL