g 182 Call Queued response, 109 response, 117 183 Session Progress response, 415 Unsupported Media Type response, 117 200 OK response, 112 416 Unsupported URI Scheme 202 Accepted response, 112 response, 117 300 Multiple Choices response, 420 Bad Extension response, 117 421 Extension Required response, 301 Moved Permanently response, 117-18 422 Session Timer Interval 302 Moved Temporarily response, Too Small response, 118 423 Interval Too Brief response, 305 Use Proxy response, 113 380 Alternative Service 428 Use Authentication Token response, 113 response, 118 400 Bad Request response, 114 429 Provide Referror Identity 401 Unauthorized response, 114 response, 118-19 SIP: Understanding the Session Initiation Protocol 480 Temporarily Unavailable addresses response, 119 e-mail-like names, 26 481 Dialog/Transaction Does IP, 25-26, 202 Not Exist response, 119 MAC, 10 482 Loop Detected response, 119 address of record (AOR), 26 483 Too Many Hops response, 119-20 Alert-Info header field, 128-29 484 Address Incomplete response, Allow-Events header field, 129 Allow header field, 158 485 Ambiguous response, 120-21 application design team, 263 486 Busy Here response, 121 application layer, 8-9 487 Request Terminated response, Augmented Backus-Naur Format (ABNF), 1 comments, 14 488 Not Acceptable Here representation, 13-14 response, 122 token definition, 14 489 Bad Event response, 122 authentication, 57-59 491 Request Pending response, 122 digest call flow, 59 493 Request Undecipherable forms, 57-58 response, 122-23 HTTP Digest, 58 501 Not Implemented response, 124 lightweight, 58 502 Bad Gateway response, 124 multiproxy, 146 503 Service Unavailable response, robust, 58 of user agent, 58 504 Gateway Timeout response, 124 Authentication-Info header field, 505 Version Not Supported 153-54 response, 124 Authorization header field, 142 513 Message Too Large response, back-to-back user agents (B2BUA), 45 BYE method, 76-77 600 Busy Everywhere response, 125 603 Decline response, 125 defined, 76 604 Does Not Exist Anywhere example, 7