Categories
IMS / VoLTE Mobile Networks RFCs & Standards SDM SIM Cards Software

SQN Sync in IMS Auth

A look at how the SQN resync procedure is performed in the IMS Authentication flows

Categories
IMS / VoLTE Kamailio Mobile Networks VoIP

Failures in cobbling together a USSD Gateway

Adventures in setting up a non-working USSD Gateway for IMS

Categories
IMS / VoLTE Mobile Networks RFCs & Standards

SMS-over-IP Message Efficiency – K

How much overhead is used to send the message “K” back to an SMS?

Categories
EPC IMS / VoLTE Mobile Networks Python SDM Software

Diameter Routing Agents – Part 5 – AVP Transformations with FreeDiameter and Python in rt_pyform

Using FreeDiameter, Python and our newly released “rt_pyform” module to rewrite AVPs in your FreeDiameter based Diameter Routing Agent.

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

Diameter Routing Agents – Part 5 – AVP Transformations

A look at why we’d want to apply translations to Diameter AVPs inside a Diameter Routing Agent

Categories
EPC IMS / VoLTE LTE Mobile Networks SDM Software

Diameter Routing Agents – Part 4 – Advanced FreeDiameter DRA Routing

Looking at overriding the default Diameter routing logic in FreeDiameter with rt_default

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

Diameter Routing Agents (Why you need them, and how to build them) – Part 2 – Routing

Diving back into the world of Diameter Routing Agents with a look at the logic that defines how a DRA routes traffic from one place to another.

Categories
IMS / VoLTE Kamailio Mobile Networks RFCs & Standards VoIP

Kamailio I-CSCF – SRV Lookup Behaviour

Recently I had a strange issue I thought I’d share. Using Kamailio as an Interrogating-CSCF, Kamailio was getting the S-CSCF details from the User-Authorization-Answer’s “Server-Name” (602) AVP. The value was set to: sip:scscf.mnc001.mcc001.3gppnetwork.org:5060 But the I-CSCF was only looking up A-Records for scscf.mnc001.mcc001.3gppnetwork.org, not using DNS-SRV. The problem? The Server-Name I had configured as a […]

Categories
GSM IMS / VoLTE Mobile Networks VoIP

Sending SMS with an alphanumeric String as the Source

If you’ve ever received an SMS from your operator, and the sender was the Operator name for example, you may be left wondering how it’s done. In IMS you’d think this could be quite simple – You’d set the From header to be the name rather than the MSISDN, but for most SMSoIP deployments, the […]

Categories
FreeSWITCH IMS / VoLTE Mobile Networks VoIP

FreeSWITCH – Incompatible Destination

A quick look at a possible cause for “INCOMPATIBLE DESTINATION” errors in FreeSWITCH.

Categories
IMS / VoLTE Kamailio Mobile Networks VoIP

Kamailio, IMS & DNS Headches

A quick post on a lesson that took me a while to learn with DNS, Kamailio and IMS.

Categories
FreeSWITCH IMS / VoLTE Kamailio Mobile Networks VoIP

FreeSWITCH, Kamailio & IMS Extensions

Bad Extension is nothing to do with the Dialplan…

Categories
5G SA IMS / VoLTE Kamailio LTE Mobile Networks VoIP

The Surprisingly Complicated World of SMS: Apple iPhone MT SMS

Quirks and gotchas of working with SMS on IMS on iPhones.

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks

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

A look at how Dedicated Bearers get established for VoLTE.

Categories
EPC LTE Mobile Networks RFCs & Standards SDM VoIP

Basics of EPC/LTE Online Charging (OCS)

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

Categories
FreeSWITCH VoIP

HTTP PUT call recordings from FreeSWITCH

Using mod_httpapi to HTTP POST call recordings to a remote server

Categories
EPC Mobile Networks RFCs & Standards VoIP

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 VoIP

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 VoIP

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…