Yealink SIP-T2 SERIES Administrator's Manual page 517

3. Select the desired value from the pull-down list of Unregister When Reboot.
4. Click Confirm to accept the change.
As described in RFC 3262, 100rel tag is for reliability of provisional responses. When
present in a Supported header, it indicates that the IP phone can send or receive
reliable provisional responses. When present in a Require header in a reliable
provisional response, it indicates that the response is to be sent reliably.
Example of a SIP INVITE message:
INVITE sip:1024@pbx.yealink.com:5060 SIP/2.0
Via: SIP/2.0/UDP 10.3.6.197:5060;branch=z9hG4bK1708689023
From: "1025" <sip:1025@pbx.yealink.com:5060>;tag=1622206783
To: <sip:1024@pbx.yealink.com:5060>
Call-ID: 0_537569052@10.3.6.197
CSeq: 2 INVITE
Contact: <sip:1025@10.3.6.197:5060>
Authorization: Digest username="1025", realm="pbx.yealink.com",
nonce="BroadWorksXi5stub71Ts2nb05BW", uri="sip:1024@pbx.yealink.com:5060",
response="f7e9d35c55af45b3f89beae95e913171", algorithm=MD5, cnonce="0a4f113b", qop=auth,
nc=00000001
Content-Type: application/sdp
Allow: INVITE, INFO, PRACK, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REGISTER, SUBSCRIBE, REFER,
PUBLISH, UPDATE, MESSAGE
Max-Forwards: 70
Configuring Basic Features
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