Polycom RMX 2000 Administrator's Manual page 124

Chapter 8-Network Services
8-18
Table 8-8 Default IP Service – Conferencing – QoS Parameters
(Continued)
Field
Type
Audio / Video
Description
DiffServ and Precedence are two methods for
encoding packet priority. The priority set here for
audio and video packets should match the priority
set in the router.
•
DiffServ: Select when the network router uses
DiffServ for priority encoding.
The default priority is 4 for both audio and video
packets.
Note: If you select DiffServ but your router does
not support this standard, IP packets queue on
the same communication links with data packets.
This non-prioritized queueing greatly increases
the latency and jitter in their delivery.
• Precedence: Select when the network router
uses Precedence for priority encoding, or when
you are not sure which method is used by the
router. Precedence should be combined with
None in the TOS field.
Note: Precedence is the default mode as it is
capable of providing priority services to all types
of routers, as well as being currently the most
common mechanism.
You can prioritize audio and video IP packets to
ensure that all participants in the conference hear
and see each other clearly. Select the desired
priority. The scale is from 0 to 5, where 0 is the
lowest priority and 5 is the highest. The
recommended priority is 4 for audio and 4 for video
to ensure that the delay for both packet types is the
same and that audio and video packets are
synchronized and to ensure lip sync.