Appendix A-Disconnection Causes
A-8
SIP server error 501 The SIP server sent a SIP Server Error 501 (Not
Implemented) response.
The server does not support the functionality
required to fulfill the request.
SIP server error 502 The SIP server sent a SIP Server Error 502 (Bad
Gateway) response.
The server, while acting as a gateway or proxy,
received an invalid response from the
downstream server it accessed in attempting to
fulfill the request.
SIP server error 503 The SIP server sent a SIP Server Error 503
(Service Unavailable) response.
The server is temporarily unable to process the
request due to a temporary overloading or
maintenance of the server.
SIP server error 504 The SIP server sent a SIP Server Error 504
(Server Time-out) response.
The server did not receive a timely response
from an external server it accessed in attempting
to process the request.
SIP server error 505 The SIP server sent a SIP Server Error 505
(Version Not Supported) response.
The server does not support, or refuses to
support, the SIP protocol version that was used
in the request.
SIP temporarily not
available
The participant's endpoint was contacted
successfully but the participant is currently
unavailable (e.g., not logged in or logged in such
a manner as to preclude communication with the
participant).
SIP remote device did not
respond in the given time
frame
The endpoint did not respond in the given time
frame.
SIP trans error TCP Invite A SIP Invite was sent via TCP, but the endpoint
was not found.
Table A-1 Call Disconnection Causes (Continued)
Disconnection Cause Description