An overview of FreeSWITCH’s ESL
Using UAC module to authenticate outbound calls where you need to respond to a 401 Unauthorised Response, or a 407 Proxy Authentication required
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 […]
How call routing in GSM works and it’s application in the Osmocom suite
Using Docker to containerize Kamailio instanances
My first Pull / Merge in the Kamailio project was to fix the IMS P-CSCF config
Some of the lesser used / utilized features of the SIP REGISTER method.
Using Kamailio to send HTTP requests (POST & GET) to a HTTP server and store the result.
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 apt package manager to install nightly Kamailio builds
Using Ansible to automate Kamailio deployments at scale
Lessons learned about setting up VoLTE / IMS Networks at small scale.
How the P-CSCF address is assigned to a UE in Protocol Configuration Options (PCO) during bearer establishment.
Using sipcmd to test SIP Services from the command line
An update to PyHSS to support IMS Authentication for VoLTE