ACCESS Product Manual
93
A
dvAnced
n/AciP t
oPics
Warning: Advanced Topic
The basic entries provided will allow support for the vast majority of
N/ACIP SIP based applications. But there are inevitably situations where
the defaults don’t work, and we’ve provided some advanced options that
can help. As always, these options are located in the Systems Settings and
can be made visible by selecting the
Advanced
box.
1)
IP Port
- Universally, SIP connections are supposed to use UDP port
5060 to negotiate calls between devices (and between servers and devices).
Note this is only the negotiation channel--actual audio data is passed on
the RTP ports. Changing this port number will change which incoming
ports are used to initiate connections, and to which ports connection re-
quests are sent. Obviously, the change must be made on both devices, and
this change will essentially make your codec incompatible with industry-
standard VoIP devices.
2)
RTP Port
- This is one of two port numbers used for audio data trans-
fer (the port number directly above this is used as well). Because this port
number is negotiated at the beginning of a call (over the IP port), this port
may be changed without breaking compatibility. Note that many SIP stan-
dard devices use port 5004 for this function. Due to the negotiation, it is
not important that these numbers match on each end. Changing this port
to 5004 can actually have an adverse effect, since 5004 is the default port
for other services on Comrex codecs.
3)
Public IP Override
- See the next section,
SIP t
roubleShootIng
, for more
information on this option.
4)
Use STUN Server
- See the next section,
SIP t
roubleShootIng
, for more
information on this option.
5)
SIP Proxy Keepalive
- Only applies to
Registered
mode. This variable
determines how often the codec “phones home” if registered with a SIP
server. It’s important that the codec periodically “ping” the server, so the
server can find the codec for incoming calls. It can be adjusted primarily to
compensate for firewall routers that have shorter or longer binding tim-
ings, i.e. the router may have a tendency to “forget” that the codec is ready
to accept incoming calls and block them.