Sip Audio Session Timeout; Alg Screen; Figure 214 Advanced > Alg; Table 103 Advanced > Alg - ZyXEL Communications ZYWALL P1 User Manual

If the SIP client does not have this mechanism and makes no calls during the ZyWALL SIP
timeout default (60 minutes), the ZyWALL SIP ALG drops any incoming calls after the
timeout period.

20.5.4 SIP Audio Session Timeout

If no voice packets go through the SIP ALG before the timeout period (default 5 minutes)
expires, the SIP ALG does not drop the call but blocks all voice traffic and deletes the audio
session. You cannot hear anything and you will need to make a new call to continue your
conversation.

20.6 ALG Screen

Click ADVANCED > ALG to open the ALG screen. Use the ALG screen to turn individual
ALGs off or on and set the SIP timeout.
Figure 214 ADVANCED > ALG
The following table describes the labels in this screen.
Table 103 ADVANCED > ALG
LABEL
Enable FTP
ALG
Enable H.323
ALG
Enable SIP
ALG
SIP Timeout
Apply
Reset
ZyWALL P1 User's Guide
DESCRIPTION
Select this check box to allow FTP sessions to pass through the ZyWALL. FTP (File
Transfer Program) is a program that enables fast transfer of files, including large
files that may not be possible by e-mail.
Select this check box to allow H.323 sessions to pass through the ZyWALL. H.323 is
a protocol used for audio communications over networks.
Select this check box to allow SIP sessions to pass through the ZyWALL. SIP is a
signaling protocol used in VoIP (Voice over IP), the sending of voice signals over
Internet Protocol.
Most SIP clients have an "expire" mechanism indicating the lifetime of signaling
sessions. The SIP user agent sends registration packets to the SIP server
periodically and keeps the session alive in the ZyWALL.
If the SIP client does not have this mechanism and makes no calls during the
ZyWALL SIP timeout (default 60 minutes), the ZyWALL SIP ALG drops any
incoming calls after the timeout period. Enter the SIP signaling session timeout
value.
Click Apply to save your changes back to the ZyWALL.
Click Reset to begin configuring this screen afresh.
Chapter 20 ALG Screen
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