ELTEX TAU-4M.IP, Operation Manual, Page: 56 / 126

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56 TAU-4M.IP Subscriber gateway
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180 Ringing - 180 reply is sending to caller equipment; caller equipment should output
local ringback tone in line after getting this message;
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183 Progress with SDP - 183+SDP reply is sending to caller equipment; used for frequency
path forwarding to callee reply. In this case TAU-4M.IP will remote send ringback tone to
caller.
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Escape Hash Uri —when selected, pass the pound key in SIP URI as an escape sequence ‘%23’,
otherwise – as ‘#’ symbol.
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100rel – utilization of reliable provisional responses (RFC3262):
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Supported – reliable provisional responses are supported;
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Required – reliable provisional responses are mandatory;
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Off — reliable provisional responses are disabled;
SIP protocol defines two types of responses for connection initiating request (INVITE)–
provisional and final. 2хх, 3хх, 4хх, 5хх and 6хх-class responses are final and their transfer is
reliable, with ACK message confirmation. 1хх-class responses, except for
'100 Trying' response,
are provisional, without confirmation (rfc3261). These responses contain information on the
current INVITE request processing step, therefore loss of these responses is unacceptable.
Utilization of reliable provisional responses is also stated in SIP (rfc3262) protocol and defined by
'100rel' tag presence in the initiating request. In this case, provisional responses are confirmed
with PRACK message.
Setting operation for outgoing communications:
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Supported – send the following tag in 'INVITE' request–supported: 100rel. In this case,
communicating gateway may transfer provisional responses reliably or unreliably–as it
deems fit;
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Required – send the following tags in 'INVITE' request–supported: 100rel and required:
100rel. In this case, communicating gateway should perform reliable transfer of
provisional replies. If communicating gateway does not support reliable provisional
responses, it should reject the request with message 420 and provide the following tag–
unsupported: 100rel, In this case, the second INVITE request will be sent without the
following tag–required: 100rel;
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Off – do not send any of the following tags in INVITE request–supported: 100rel and
required: 100rel. In this case, communicating gateway will perform unreliable transfer of
provisional replies.
Setting operation for incoming communications:
–
Supported, Required – when the following tag is received in 'INVITE' request–supported:
100rel, or required: 100rel, perform reliable transfer of provisional replies. If there is no
supported: 100rel tag in INVITE request, the gateway will perform unreliable transfer of
provisional replies;
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Off –when the following tag is received in 'INVITE' request–required: 100rel, reject the
request with message 420 and provide the following tag–unsupported: 100rel. Otherwise,
perform unreliable transfer of provisional replies.

Enable timer – when checked, enables support of SIP session timers (RFC 4028). After connection
establishment, if both sides are supporting timer, one of them periodically send re-INVITE queries
for connection control (if both sides are supporting UPDATE method (it should be pointed in
'Allow' header) session update is being processed by periodical UPDATE messages sending);

Min SE, s – minimal time interval for connection health checks (90 to 1800s, 120s by default);