Configuring AastraLink Pro 160 System and Network Parameters
Configuring Network Settings
•SIP Registration Expiration
Specifies the time, in seconds, that the SIP phone and AastraLink SIP trunks use for their SIP registration renewal timer.
Usually no change is required for this parameter, but some SIP trunk service providers may refuse registration if the period is set shorter than a specified value, for example 3600 seconds. Default is 120.
•RTP/RTCP Port Count
Specifies the total number of media stream ports the AastraLink can support simultaneously for remote phone users.
Each incoming or outgoing call requires one media stream; each media stream uses one RTP port and one RTCP port. To set this parameter, multiply the maximum numbers of simultaneous calls supported on the AastraLink by two.
For example, the default setting of 20 allows the AastraLink to support 10 incoming or outgoing calls simultaneously.
Notes:
•Aastra recommends accepting the RTP/RTCP Port Count default setting of 20. Increasing the default setting beyond 20 may result in call degradation or service outage.
•When UPnP is enabled, then RTP/RTCP Port Count is the maximum number of ports forwarded. Some UPnP router implementations limit the number of ports that may be forwarded. If fewer ports are forwarded, then the number of simultaneous calls supported by the AastraLink is restricted.
•If UPnP is not enabled, then you should manually forward ports:
RTP Port Start through (RTP Port Start + RTCP Port Count
