Categories
Voice over IP

SIP Hold – With RFC6337

How SIP hold using RFC6336 is implemented and how it looks in production.

Categories
Voice over IP

FreeSWITCH + ESL = Programmable Voice

An overview of FreeSWITCH’s ESL

Categories
EUTRAN LTE Mobile Networks RFCs & Standards 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 LTE Mobile Networks RFCs & Standards 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 LTE Mobile Networks RFCs & Standards 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 LTE Mobile Networks RFCs & Standards 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 LTE Mobile Networks RFCs & Standards

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
RFCs & Standards Voice over IP

SIP Register – Lesser Known Features

Some of the lesser used / utilized features of the SIP REGISTER method.

Categories
Kamailio Voice over IP

Kamailio Bytes – Multiple Kamailio Instances on a Single Box

Running multiple instances of Kamailio on the same server using init.d

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Kamailio Security Voice over IP

Kamailio Bytes – SIP over TLS (SIPS)

Using Transport Layer Security (TLS) to protect SIP traffic from modification / manipulation and guarantee message authenticity.

Categories
Voice over IP

Automated SIP testing with sipcmd

Using sipcmd to test SIP Services from the command line

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RFCs & Standards Voice over IP

SIP SIMPLE – Instant Messaging with SIP

A look into Instant Messaging using SIP

Categories
Kamailio Voice over IP

Kamailio Bytes – UAC for Remote User Registration to external SIP Server (Originating SIP REGISTER)

Using Kamailio’s UAC module to send outbound SIP REGISTER messages

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Kamailio Voice over IP

Kamailio Bytes – SIP UAC Module to act as a UAC / SIP Client

Using Kamailio UAC module to send a SIP Text Message (MESSAGE) to an administrator when a user dials an emergency services number.

Categories
EPC EUTRAN LTE 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.

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Kamailio Python Voice over IP

Kamailio Bytes – KEMI Intro

Using KEMI to write routing logic using languages like Python, Ruby, Lua and JS

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EPC EUTRAN LTE Security Voice over IP

Using Wireshark to peer inside IPsec ESP VoLTE data from the P-CSCF

Viewing the payload of an Encapsulated Security Payload in Wireshark.

Categories
RFCs & Standards Voice over IP

SIP Supported & Require

Function of Supported & Require headers in SIP.

Categories
Kamailio Software Voice over IP

Kamailio Bytes – Dispatcher States

AP, IX, IP & DX – The meaning of Dispatcher states in Kamailio’s Dispatcher module.

Categories
Kamailio Software Voice over IP

Kamailio Bytes – Rewriting SIP Headers (Caller ID Example)

Stateless Kamailio SIP proxy example for changing Caller ID values