GXE502X User Manual 7/9/2008
45
Version 03
o Max Concurrent Calls: This field specifies the maximum number of concurrent calls
allowed between the peer systems.
o Prefix: The prefix digits for outbound calls to be recognized and routed to this peer
system. When the call is sent to the networked peer system, the prefix digit is NOT
removed. This is done slightly different than dialing out using other trunks on the
GXE502X. Users may specify multiple prefixes for a peer system by separating them
with a semicolon (i.e. 6;7).
o IPPBX Number: This parameter is used to route calls based on the country or area
code4.
o Heart Beat: if set to Yes, the GXE502X will send a SIP OPTIONS Request
periodically to check whether the peer system is still online. If the peer does not
respond with a SIP 200 OK then the GXE502X will consider this trunk or peer as
disconnected. This feature is also used to keep UDP ports open when the GXE502X
is behind a NAT firewall.
o Session Keep Alive: This field allows users to enable or disable the session timer.
This is set to Automatic/Session Timer in the factory default settings.
o Session Expiration: The session timer enables SIP sessions to be periodically
“refreshed” via a SIP request. If enabled, before the session interval expires, the
GXE502X will send a SIP re-INVITE message to the SIP server. If this message is
not replied to the session will be terminated. This will avoid dropped sessions
occupying the channel/bandwidth. Session Expiration is the timer (in seconds) at
which the session is considered timed out if no successful session refresh
transaction occurs beforehand. The default value is 180 seconds. Incorrect
configuration could cause calls to be dropped or suspended.
o Min-SE: The minimum session expiration time (in seconds). The default value is 90
seconds.
When done, click the Submit button to add the extension or Cancel to go back.
• Modify: Click the Modify button to the right of the row to select the peer system to be
modified. The modify peer system page will be load. This page allows users to modify all
of the peer system’s settings. When done, click the Submit button to save changes or
Cancel to go back.
• Delete: Click the Delete button on the far right to remove a peer system. Users will be
prompted for confirmation via a dialog box; click OK to confirm or Cancel to go back.
4 Note: (Dial Plan/dynamic routing(pending)) will be used in the future.