【文章內(nèi)容簡介】 ?連線過程 ?建立連線 ?通話 ?斷線 SIP訊息 – 範例 SIP SDP INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 v=0 o=Alice 2897654321 2897654321 IN IP4 s=Phone Call c=IN IP4 t=0 0 m=audio 49170 RTP/AVP 0 a=rtpmap:0 PCMU/8000 SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 Method 即 命令 Request URI SIP 協(xié)定版本 SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 所有經(jīng)過的 SIP設備都會被列在這裡 ‘ branch’用來識別不同的連線分支 在所有 SIP Requests中都是必要的欄位 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 最多可以被幾個 Server轉(zhuǎn)傳 SIP Headers 在所有 SIP Requests之中除了 INFO都是必要的欄位 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 目的地位址 SIP Headers 在所有 SIP Requests中都是必要的欄位 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 來源位址 虛擬的隨機亂數(shù) (當作是 ID使用 ) SIP Headers 在所有 SIP Requests中都是必要的欄位 James Polk 20050503 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 在網(wǎng)域內(nèi)獨一無二的識別碼 SIP Headers 在所有 SIP Requests中都是必要的欄位 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 遞增的序號 SIP Headers 在所有 SIP Requests中都是必要的欄位 James Polk 20050503 INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 直接可以路由到來源位址的完整網(wǎng)域名稱或 IP位址 SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 用來描述附加的訊息主體格式 (如果有的話 ) SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp ContentLength: 142 用來描述附加的訊息主體的內(nèi)容長度 (Octets) SIP Headers INVITE sip: SIP/ Via: SIP/。branch=z9hG4bK776asdhds MaxForwards: 70 To: Bob sip: From: Alice sip:。tag=1928301774 CallID: CSeq: 314159 INVITE Contact: sip: ContentType: application/sdp Content