Which SIP response code should be used for maintenance mode
A SIP response code for general maintenance purposes seems not to exist (reference: http://en.wikipedia.org/wiki/开发者_Go百科List_of_SIP_response_codes).
What kind of response code ( 1xx/2xx/3xx/4xx or 5xx ) should be used for maintenance mode?
503 Service Unavailable, see RFC3261, chapter 21.5.4 (Link). BTW, you should retag the question, although the error code scheme is similiar, SIP and HTTP are different protocols
精彩评论