SIP User's Manual  124  Document #: LTRT-12804 
  Mediant 800 MSBG 
 
Parameter  Description 
  [0] Standard = INVITE messages that are generated as a 
result of Transfer or Redirect are sent directly to the URI, 
according to the Refer-To header in the REFER message or 
Contact header in the 3xx response (default). 
  [1] Proxy = Sends a new INVITE to the Proxy.  
Note: Applicable only if a Proxy server is used and the 
parameter AlwaysSendtoProxy is set to 0. 
  [2] Routing Table = Uses the Routing table to locate the 
destination and then sends a new INVITE to this destination.
Notes:  
  When this parameter is set to [1] and the INVITE sent to the 
Proxy fails, the device re-routes the call according to the 
Standard mode [0]. 
  When this parameter is set to [2] and the INVITE fails, the 
device re-routes the call according to the Standard mode 
[0]. If DNS resolution fails, the device attempts to route the 
call to the Proxy. If routing to the Proxy also fails, the 
Redirect / Transfer request is rejected. 
  When this parameter is set to [2], the XferPrefix parameter 
can be used to define different routing rules for redirected 
calls. 
  This parameter is ignored if the parameter 
AlwaysSendToProxy is set to 1. 
Enable Survivability 
[IPGroup_EnableSurvivability] 
Determines whether Survivability mode is enabled for USER-
type IP Groups. 
  [0] Disable (default). 
  [1] Enable if Necessary = Survivability mode is enabled. The 
device records in its database the registration messages 
sent by the clients belonging to the USER-type IP Group. If 
communication with the Serving IP Group (e.g., IP-PBX) 
fails, the USER-type IP Group enters into Survivability mode 
in which the device uses its database for routing calls 
between the clients (e.g., IP phones) of the USER-type IP 
Group. The RTP packets between the IP phones in 
Survivability mode always traverse through the device. In 
Survivability mode, the device is capable of receiving new 
registrations. When the Serving IP Group is available again, 
the device returns to normal mode, sending INVITE and 
REGISTER messages to the Serving IP Group. 
  [2] Always Enable = Survivability mode is always enabled. 
The communication with the Serving IP Group (e.g., IP-PBX) 
is always considered as failed. The device uses its database 
for routing calls between the clients (e.g., IP phones) of the 
USER-type IP Group. 
Notes: 
  This field is available only if the SBC or IP-to-IP application 
is enabled. (The IP-to-IP application will be supported in the 
next applicable release.) 
  This parameter is applicable only to USER-type IP Groups.