Rtp Ports - Snom ONE IP Technical Manual

Deploying the snom ONE IP Telephone System
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be consulted by the system before consulting/using the operating system).
Whenever the system wants to find the IP address that is being used when
sending a SIP packet, it steps through the list and looks for a match (using
the netmask mask) to a destination address (DAdr). If a match is found, the
system uses the provided IP address (LAdr). The mask must be in the form of
an IP address, e.g.,

RTP Ports

The Real Time Protocol (RTP) ports are used for sending and receiving media. Be sure
to specify a reasonable port range so that you have enough ports for all open calls. A
port range of 100 ports is not unusual.
Most user agents send RTP media data from the same port on which they expect to re-
ceive data. This is useful when a user agent sends media from behind NAT. The system
can use this mechanism to establish a two-way media path, even if the user agent is not
able to determine its public IP address for media and is behind NAT.
•
Port Range Start: This setting represents the starting RTP port that the sys-
tem will use for media sessions. If the system is behind a firewall, these ports
should be open.
•
Port Range End: This setting represents the end RTP port that the system
will use for the media sessions. RTP uses UDP for transport, whereas SIP can
use UDP, TCP, and/or TLS.
255.255.255.0
.