Appendix B: SIP Overview
503
SIP Language
Similarities with HTML and SMTP
SIP shares some common characteristics with HTTP and SMTP. Like the latter two,
SIP is an ASCII text-based protocol which makes it easy to read and troubleshoot. The
text below is a SIP trace that shows a user inviting another use to a session.
Users are identified by a SIP address, known as a Uniform Resource Identifier (URI).
A SIP URI is similar to an email address and is typically built around the user’s phone
number or host name (e.g.,
sip:[your_number]@companyA.vonage.net
). This
allows users to be redirected to another phone as easily as they would be redirected to
another web page.
Types of Messages
SIP communication consists of two types of SIP messages—methods and responses.
Methods are sent from the client to the server and are used to indicate the purpose of
the request. The following six methods are part of RFC 3261.
Table B-1
RFC 3261 Methods
SIP Method
Description
INVITE Establishes a session
ACK Confirms an INVITE request
BYE Ends a session
CANCEL Cancels establishing of a session
REGISTER Registers a user with a proxy/registrar
OPTIONS
Communicates information about the capabilities of the other side
Summary of Contents for ONE IP
Page 4: ......
Page 19: ...Part I Getting Started...
Page 20: ...Part I Getting Started...
Page 47: ...Part II Administering the System...
Page 48: ...Part II Administering the System...
Page 195: ...Deploying the snom ONE IP Telephone System 526...
Page 223: ......