4600 Series IP Telephone LAN Administrator’s Guide
QoS
4-22
encodings that do not terminate in 000. The specific treatment intended by these custom DSCPs
will not necessarily be carried out by routers outside the customer’s own network.
To support DiffServ, the 4600 Series IP Telephones are administered at the switch in accordance
with the documentation for the switch.
UDP Port Selection 4
Some data networks include equipment that can perform UDP port selection. This is a mechanism
by which packets with port numbers in a given range are given priority over packets with port
numbers outside that range.
To support UDP port selection, the 4600 Series IP Telephones can be administer ed either from the
network, via appropriate administration of the DHCP or TFTP servers, or at the telephone itself, via
dialpad input. Specific implementation details for local administration are in the 4600 Series IP
Telephone Installation Guide, and, for remote administr ation, in 4600 Series IP Telephone Scripts
and Application Files on page 4-18. In summary, the system value MCPORT represents the port
on the TN2302AP board. This port number can be used to administer routers, etc. that support
UDP port selection, to maximize the priority given to the voice packets being exchanged between
the PBX and the telephone.
The default value for MCPORT is 1719. The switch must be administered to use a port within the
proper range for the specific LAN, and the IP Telephone(s) will copy that port. A related parameter
is PORTAUD, which is the RTP port used by the switch. In accordance with standards RFC 1889
and 1890, the IP Telephone uses a default value for PORTAUD of 5004. MCPORT and PORTAUD
are both administrable (see Administering Options for the 4600 Series IP Telephones on page
4-24).
QoS with 4620 and 4630 IP Telephones 4
As of Release 1.7, both the 4620 and 4630 telephones offer the end user an opportunity to monitor
network audio performance while on a call. The user guides for each phone go into specific details
on how the user gets to the appropriate screen; this document tells you what the end user can see,
and what it means. Specifically, the following parameters are displayed in real-time to users on the
appropriate screens, while on a call:
Parameter Possible Values
Audio Connection Present? Yes (if a receive RTP stream has been established)
No (if a receive RTP stream has not been established)
Received Audio Coding G.711 or G.729
Silence Suppression Yes (if the telephone knows the far-end has silence
suppression Enabled)
No (if the telephone knows the far-end has silence
suppression Disabled, or the telephone does not know
either way)