Instruction manual

Networking and connectivity
555-233-767144 Issue 4 May 2003
QoS for call control
Communication Manager allows QoS for the signaling packets coming from
gatekeepers such as the C-LAN by employing the same standards based DiffServ
and 802.1p/Q schemes as with audio channels. This QoS services further improve
the users VoIP audio experience.
QoS for VoIP
Communication Manager implements QoS through the selection of audio codec
such as G.711, G.723 and G.729, and by requesting network prioritization through
the layer 3 differentiated services (DiffServ) scheme, as well as the layer 2 IEEE
802.1p/Q prioritization. Diffserv and 802.1p/Q are supported on voice packets
coming to/from the gateway, all the way down to the endpoints such as IP
telephones. Dynamic jitter buffers are also used.
QoS to endpoints
Users can set operating parameters to optimize the audio performance, or quality
of service (QoS), on calls made over your IP network. These parameters include
the audio codec, network priority through DiffServ capability, and the IEEE
802.1p/Q MAC-layer prioritization and segregation.
Default QoS parameters are downloaded to the IP telephone R1.5 and the IP
softphone R3 when the values are not provided by the endpoint installer or the
user. Certain options can be set locally by the endpoints or through the gatekeeper.
The endpoints receive the parameters when the endpoints register, and once they
are registered, whenever the administered values of the QoS parameters are
modified.
Resource Reservation Protocol (RSVP)
Resource Reservation Protocol (RSVP) is a protocol that allows an endpoint to
negotiate with a RSVP-capable network to allocate protected resources for traffic
that the endpoint will generate. RSVP provides protection for traffic flows, which
is also essential for providing the quality of service required by VoIP.
One of the primary purposes of RSVP is to mediate between an end-point and the
set of routers on the path to another end-point to reserve resources to provide a
guaranteed QoS for a session. RSVP is used for IP endpoints and is supported for
configurations including servers running Communication Manager and Avaya
media gateways.
Administrators can configure RSVP settings in Communication Manager. When
the
RSVP enable field in the IP NETWORK REGION form is set to ‘y’, the RSVP
Reservation Parameters
appear.