Yealink Yealink SIP-T28P, Руководство администратора

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Administrator’s Guide for SIP-T2xP and SIP-T19P IP Phones
442
SIP uses six request methods:

INVITE—Indicates a user is being invited to participate in a call session.

ACK—Confirms that the client has received a final response to an INVITE request.

BYE—Terminates a call and can be sent by either the caller or the callee.

CANCEL—Cancels any pending searches but does not terminate a call that has
already been accepted.

OPTIONS—Queries the capabilities of servers.

REGISTER—Registers the address listed in the To header field with a SIP server.
The following types of responses are used by SIP and generated by the IP phone or the
SIP server:

SIP 1xx—Informational Responses

SIP 2xx—Successful Responses

SIP 3xx—Redirection Responses

SIP 4xx—Client Failure Responses

SIP 5xx—Server Failure Responses

SIP 6xx—Global Failure Responses
The following figure illustrates the scenario of a successful call. In this scenario, the two
end users are User A and User B. User A and User B are located at Yealink SIP IP
phones.
The call flow scenario is as follows:
1. User A calls User B.
2. User B answers the call.