Yealink SIP-T19 E2 — administrator's Guide for SIP IP Phones: Request Methods Explained [800/841]

Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series IP Phones

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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.

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.