SIP Blog - Page 6

http://siproxd.sourceforge.net/ From the website: Siprox is an proxy/masquerading daemon for the SIP protocol. It handles registrations of SIP clients on a private IP network and performs rewriting of the SIP message bodies to make SIP connections possible via…

From RFC 2848: When a SUBSCRIBE request is sent to a PINT Server, it indicates that a user wishes to receive information about the status of a service session. The request identifies the session of interest by including…

sipsak is a small command line tool for developers and administrators of SIP applications. It can be used for some simple tests on SIP applications and devices. Features sending OPTIONS request sending text files (which should contain SIP…

From the Abstract of RFC 3428: Instant Messaging (IM) refers to the transfer of messages between users in near real-time. These messages are usually, but not required to be, short. IMs are often used in a conversational mode,…

SIP responses, class 4: Request failures 400 Bad Request 401 Unauthorized: Used only by registrars. Proxys should use proxy authorization 407 402 Payment Required (Reserved for future use) 403 Forbidden 404 Not Found: User not found 405 Method…

The response codes are consistent with, and extend, HTTP/1.1 response codes. Not all HTTP/1.1 response codes are appropriate, and only those that are appropriate are given here. Other HTTP/1.1 response codes should not be used. Also, SIP defines…

SIP implements a three-way handshake. The caller sends an INVITE The callee sends an 200 OK to accept the call The caller sends an ACK to indicate that the handshake is done and a call is going to…

From the SIP RFC: SIP Proxy, Proxy Server: An intermediary entity that acts as both a server and a client for the purpose of making requests on behalf of other clients. A proxy server primarily plays the role…

SIP security is a vast and somewhat challenging field. Authentication: Can users steal other users identity? Integrity: Is the SIP message received the same as the one sent? Confidentiality: Is someone else listening on your SIP call setup?…

From RFC 2848: During the subscription period, the Gateway may, from time to time, send a spontaneous NOTIFY request to the entity indicated in the Contact: header of the “opening” SUBSCRIBE request. Normally this will happen as a…

From the SIP RFC 3261: All SIP elements MUST implement UDP and TCP. SIP elements MAY implement other protocols. Making TCP mandatory for the UA is a substantial change from RFC 2543. It has arisen out of the…

SIP can be auto-configured using DHCP both in IPv4 and in IPv6 From RFC 3361: Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for Session Initiation Protocol (SIP) Servers This document specifies a DHCP option that allows SIP clients to…

SIMPLE is the SIP package for Presence and Instant messaging. It’s defined by the IETF and used in the IMS platform defined by the 3gpp forum. From the SIMPLE IETF Working group charter: This working group focuses on…

From RFC 3311: UPDATE allows a client to update parameters of a session (such as the set of media streams and their codecs) but has no impact on the state of a dialog. In that sense, it is…