AudioCodes MediaPack MP-40 series, Руководство пользователя

Страница: 129 / 180

User's Manual 6. Configuring the MediaPack
Version 2.2 129 July 2007
6.3.1.6 QoS Source Classes and Packet Tagging
Every packet has a source class or Class of Service (CoS). The available source classes
are listed below:
„
local-voice: locally generated RTP packets
„
local-default: other locally generated traffic
„
default: default for all routed packets (packets are assigned a class of service based
on their origin)
„
user-define: a user defined source class
(Note that the term Source Class is synonymously used with Class of Service.)
By default, the packet has one of the first three source classes. The tree source class
assigned to the packet is defined by the packet origin.
The ACL can be used to override the CoS of a packet and assigns a new CoS. If the ACL
does not assign a CoS, the packet keeps its default CoS.
In addition to the internal prioritization, the CoS contains tagging attributes. Each CoS
defines the following parameters:
Each CoS is defined by the following parameters:
„
Priority: the priority can be set to True or False . If the priority is set to True, the
packet bypasses the WFQ scheduler and uses a priority queue. Packets in this queue
have absolute priority over packets in the WFQ queues. If priority is set to False, you
must configure a share for the WQF scheduler.
„
Share: if the Priority is set to false, the packet is scheduled by the WFQ scheduler.
The scheduler prioritizes packets according to their share value, for example:
•
Local-voice: priority
•
Local-default: 90%
•
Default: 10%
„
L3 Tagging: packets scheduled by the QoS scheduler can be tagged. These tags can
be used by subsequent routers to treat the packets according to their priority tag
value. Tagging can be defined according to the following standards.
•
Diff Serve according to RFC 2474
•
TOS and Precedence according to RFC 1349
Diff serve and TOS/Precedence use the same field in the IP header. Setting DSCP
takes preference. If a DSCP values is defined, the TOS and Preference values are
ignored.