Grandstream Networks HT881

Primary IP The main IP address used for communication and control.
Backup IP1 The secondary IP address used as a backup for communication in case the Primary IP fails.
Backup IP2
The third IP address used as an additional backup for communication in case both the Primary IP and Backup
IP1 fail.
NAT Traversal
Indicates type of NAT for each account. This parameter congures whether the NAT traversal mechanism is
activated. Users could select the mechanism from No, Keep-alive, STUN, UPnP.
Default setting isNo.
Use NAT IP Denes NAT IP address used in SIP/SDP messages. It should only be used if required by ITSP.
Proxy-Require Determines a SIP Extension to notify the SIP server that the HT841/HT881 is behind a NAT/Firewall.
SIP Settings
SIP Basic Settings
SIP Registration
Controls whether the HT841/HT881 needs to send REGISTER messages to the proxy server. The default
setting isYes.
SIP Transport
Selects transport protocol for SIP packets; UDP or TCP or TLS. Please make sure your SIP Server or network
environment supports SIP over the selected transport method. Default is UDP.
Unregister On Reboot
Controls whether to clear SIP user’s information by sending un-register request to the proxy server. The un-
registration is performed by sending a REGISTER message with “Expires=0” parameter to the SIP server. This
will unregister the SIP account under the concerned FXS page.Unregister on reboot option can be set to "No",
"All" or "Instance".
1. Set to "No":If the "Unregister on reboot" option is set to "No", it means that the SIP user's information will
not be cleared when the device reboots. In other words, the SIP account will remain registered with the
server even after the device is rebooted.
2. Set to "All":If the "Unregister on reboot" option is set to "All", it means that all SIP accounts associated with
the device will be unregistered when the device reboots. This option clears the SIP user's information for
all the FXS ports on the device.
3. Set to "Instance":If the "Unregister on reboot" option is set to "Instance", it means that only the SIP
account associated with the concerned FXS port will be unregistered when the device reboots. This option
clears the SIP user's information for only the specic FXS port that is affected by the reboot.
Default value is set to "No"
Outgoing Call without Registration
Enables the ability to place outgoing calls even if the account is not registered (if allowed by ITSP); device will
not be able to receive incoming calls. Default is No.
Register Expiration
Refreshes registration periodically with specied SIP proxy (in minutes). Maximum interval is 65535 minutes
(about 45 days).
Default is60minutes (or 1 hour).
Reregister before Expiration
Sends re-register request after specic time (in seconds) to renew registration before the previous registration
expires.
SIP Registration Failure Retry Wait
Time
Sends re-register request after specic time (in seconds) when registration process fails. Maximum interval is
3600 seconds (1 hour).
Default is20seconds.
SIP Registration Failure Retry Wait
Time upon 403 Forbidden
Sends re-register request after specic time (in seconds) when registration process fails with error 403
Forbidden. Maximum interval is 3600 seconds (1 hour). Default is 1200 seconds.