So far with most of our discussions about Kamailio we’ve talked about routing the initial SIP request (INVITE, REGISTER, SUBSCRIBE, etc), but SIP is not a one-message protocol, there’s a whole series of SIP messages that go into a SIP Dialog. Sure the call may start with an INVITE, but there’s the 180 RINGING, the […]
How SIP hold using RFC6336 is implemented and how it looks in production.
An overview of FreeSWITCH’s ESL
These posts focus on the use of Diameter and SIP in an IMS / VoLTE context, however these practices can be equally applied to other networks. The Registration-Termination Request / Answer allow a Diameter Client (S-CSCF) to indicate to the HSS (Diameter Server) that it is no longer serving that user and the registration has […]
The Diameter User-Authorization-Request and User-Authorization-Answer commands are used as the first line of authorization of a user and to determine which Serving-CSCF to forward a request to.
These posts focus on the use of Diameter and SIP in an IMS / VoLTE context, however these practices can be equally applied to other networks. The Server-Assignment-Request/Answer commands are used so a SIP Server can indicate to a Diameter server that it is serving a subscriber and pull the profile information of the subscriber. […]
These posts focus on the use of Diameter and SIP in an IMS / VoLTE context, however these practices can be equally applied to other networks. The Location-Information-Request/Answer commands are used so a SIP Server query a Diameter to find which P-CSCF a Subscriber is being served by Basics: The RFC’s definition is actually pretty […]
These posts focus on the use of Diameter and SIP in an IMS / VoLTE context, however these practices can be equally applied to other networks. The Multimedia-Authentication-Request/Answer commands are used to Authenticate subscribers / UAs using a variety of mechanisms such as straight MD5 and AKAv1-MD5. Basics: When a SIP Server (S-CSCF) receives a […]
Some of the lesser used / utilized features of the SIP REGISTER method.
Running multiple instances of Kamailio on the same server using init.d
Using Transport Layer Security (TLS) to protect SIP traffic from modification / manipulation and guarantee message authenticity.
Using sipcmd to test SIP Services from the command line
A look into Instant Messaging using SIP
Using Kamailio’s UAC module to send outbound SIP REGISTER messages
Using Kamailio UAC module to send a SIP Text Message (MESSAGE) to an administrator when a user dials an emergency services number.
The exchange between a UE and P-CSCF to put SIP traffic into IPsec encapsulated payloads.
Using KEMI to write routing logic using languages like Python, Ruby, Lua and JS
Viewing the payload of an Encapsulated Security Payload in Wireshark.
Function of Supported & Require headers in SIP.
AP, IX, IP & DX – The meaning of Dispatcher states in Kamailio’s Dispatcher module.