Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks

Lifecycle of a Dedicated Bearer – From Flow-Description AVP to Traffic Flow Templates

To support Dedicated Bearers we first have to have a way of profiling the traffic, to classify the traffic as being the type we want to provide the Dedicated Bearer for. The first step involves a request from an Application Function (AF) to the PCRF via the Rx interface. The most common type of AF […]

Categories
EPC LTE Mobile Networks RFCs & Standards SDM Voice over IP

Basics of EPC/LTE Online Charging (OCS)

A glimpse into the complexities of prepaid billing (Online Charging) Diameter based networks.

Categories
FreeSWITCH Voice over IP

HTTP PUT call recordings from FreeSWITCH

Using mod_httpapi to HTTP POST call recordings to a remote server

Categories
EPC Mobile Networks RFCs & Standards Voice over IP

Docker & BIND as an ENUM Playground

A Bind environment in a Docker container for experimenting and learning ENUM for DNS based Call Routing.

Categories
5G SA EPC IMS / VoLTE LTE Mobile Networks SDM Voice over IP

IMS Routing with iFCs

Peer behind the magic curtain at how IMS networks route your VoLTE and VoNR calls, and how iFC (Initial Filter Criteria) achieve this.

Categories
FreeSWITCH IMS / VoLTE Mobile Networks Voice over IP

Adding support for AMR Codec in FreeSWITCH

Adding support for AMR Codec in FreeSWITCH

Categories
EPC GSM IMS / VoLTE LTE Mobile Networks RFCs & Standards

The Surprisingly Complicated world of MO SMS in IMS/VoLTE

Short messaging can be anything but simple…

Categories
EUTRAN IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM Voice over IP

Diameter and SIP: Registration-Termination-Request / Answer

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 […]

Categories
EPC IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM Voice over IP

Diameter and SIP: User-Authorization-Request/Answer

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.

Categories
EPC IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM Voice over IP

Diameter and SIP: Server-Assignment-Request/Answer

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. […]

Categories
EPC IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM Voice over IP

Diameter and SIP: Location-Info-Request / Answer

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 […]

Categories
EPC IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM

Diameter and SIP: Multimedia-Authentication-Request/Answer

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 […]

Categories
EPC IMS / VoLTE Kamailio LTE Mobile Networks Software Voice over IP

Kamailio Proxy-CSCF Pull

My first Pull / Merge in the Kamailio project was to fix the IMS P-CSCF config

Categories
EPC EUTRAN IMS / VoLTE Kamailio LTE Mobile Networks RFCs & Standards SDM SIM Cards Voice over IP

Things I wish I knew about setting up private VoLTE Networks

Lessons learned about setting up VoLTE / IMS Networks at small scale.

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks SDM Security Voice over IP

VoLTE / IMS – P-CSCF Assignment

How the P-CSCF address is assigned to a UE in Protocol Configuration Options (PCO) during bearer establishment.

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks Python RFCs & Standards SDM Software Voice over IP

PyHSS Update – IMS Cx Support!

An update to PyHSS to support IMS Authentication for VoLTE

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks RFCs & Standards Voice over IP

IMS / VoLTE IPsec on the Gm Interface

The exchange between a UE and P-CSCF to put SIP traffic into IPsec encapsulated payloads.

Categories
IMS / VoLTE LTE Mobile Networks Security Software

Reverse Engineering Samsung Sysdump Utils to Unlock IMS Debug & TCPdump on Samsung Phones

Reverse Engineering the Samsung Sysdump app to unlock IMS Debug and TCPdump functions

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks Security Software Voice over IP

VoLTE/IMS Debugging on Samsung Handsets using Sysdump & Samsung IMS Logger

Unlocking the built in IMS Debugging tool in Samsung’s Sysdump Utility

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks RFCs & Standards Voice over IP

The case for Header Compression in VoIP/VoLTE

Robust Header Compression (ROHC) and it’s use for compressing RTP / VoLTE traffic headers.