Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series IP Phones518Supported header, it indicates that the IP phone can send or receive reliable provisional responses. Whenpresent in a Require header in a reliable provisional response, it indicates that the response is to be sentreliably.Example of a SIP INVITE message:INVITE sip:1024@pbx.test.com:5060 SIP/2.0Via: SIP/2.0/UDP 10.3.6.197:5060;branch=z9hG4bK1708689023From: "1025" :1025@pbx.test.com:5060>;tag=1622206783To: test.com:5060>Call-ID: 0_537569052@10.3.6.197CSeq: 2 INVITEContact: Authorization: Digest username="1025", realm="pbx.test.com", nonce="BroadWorksXi5stub71Ts2nb05BW",uri="sip:1024@pbx.test.com:5060", response="f7e9d35c55af45b3f89beae95e913171", algorithm=MD5,cnonce="0a4f113b", qop=auth, nc=00000001Content-Type: application/sdpAllow: INVITE, INFO, PRACK, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REGISTER, SUBSCRIBE, REFER, PUBLISH,UPDATE, MESSAGEMax-Forwards: 70User-Agent: Yealink SIP-T46G 28.82.0.20Supported: 100relAllow-Events: talk,hold,conference,refer,check-syncContent-Length: 302Topic100 Reliable Retransmission Configuration100 Reliable Retransmission ConfigurationThe following table lists the parameter you can use to configure the 100 reliable retransmission.Parameter account.X.100rel_enable[1] <MAC>.cfgDescription It enables or disables the 100 reliable retransmission feature.PermittedValues0-Disabled1-EnabledDefault 0Web UI Account->Advanced->Retransmission[1]X is the account ID. For T54S/T48S/T48G/T46S/T46G/T29G, X=1-16; for T52S/T42G/T42S, X=1-12; for
