Panasonic KX-TDA0480 Installation Manual page 148

Appendices
FR, F/T1, and T1), and the Internet Service Provider (ISP) facilities also affect performance.
Transmission delays are caused by excessive packet collisions. The probability that this
condition will affect the KX-TDA0480 performance can be minimised by taking steps to
provide the KX-TDA0480 with clear transmission paths.
KX-TDA0480 Location
One preventative measure is to install the KX-TDA0480 so that the number of transmission
hops is kept to a minimum. In the figure below, the KX-TDA0480 is located as close to the
WAN interface as possible.
Priority Control
Some routers permit the configuration of priority control features. This allows the router to be
configured to give higher priority to packets with high priority flags.
The priority control feature should be used when available. The KX-TDA0480 port numbering
for the various packet types is presented in the following table.
Item
No.
1
2
3
4
5
148
Too many HOPS!
Router
Switch
Switch
Hub
IP PBX
Type of Communication
Q.931
H.245
RAS
RTP / RTCP
Telnet, FTP
Better!
(IP PBX located nearest
WAN access point)
Router
Switch
Switch
Hub
Port No.
1720
1721, 1722, 1723, 1724
1718, 1719
5004 - 5011
21, 23
IP PBX
TCP /
UDP
TCP
TCP
UDP
UDP
TCP
Installation Manual