5G SA Mobile Networks RFCs & Standards

5G Online Charging with the Nchf_ConvergedCharging SBI

There’s no such thing as a free lunch, and 5G is the same – services running through a 5G Standalone core need to be billed. In 5G Core Networks, the SMF (Session Management Function) reaches out to the CHF (Charging Function) to perform online charging, via the Nchf_ConvergedCharging Service Based Interface (aka reference point). Like […]

EPC Mobile Networks SDM

Jaffa Cakes explain the nuances between Centralized vs Decentralized Online Charging in 3GPP Networks

A look at Centralized vs DeCentralized Online Charging with the aid of sugar.

Mobile Networks RF

Converting Elevation Data (DEM) for Forsk Atoll

After headaches importing elevation (DEM) data into Forsk Atoll, I found a better mechanism for converting them, I’d been having issues with as soon as the elevation passed 255 meters, resetting to 0 in the PNG as it didn’t understand values beyond this. I was able to open the elevation data in GlobalMapper (You can […]

5G SA Mobile Networks SDM

EIR in 5G Networks (N5g-eir_EquipmentIdentityCheck)

A look at the Equipment Identity Register in 5G Core

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.

FreeSWITCH Voice over IP

HTTP PUT call recordings from FreeSWITCH

Using mod_httpapi to HTTP POST call recordings to a remote server

5G SA EPC Linux LTE Mobile Networks

Open5GS without NAT

Setting up Open5Gs without a NAT requirement, and the routing required to do so.

Kamailio Voice over IP

ENUM in Practice with Kamailio

Using ENUM to resolve E.164 numbers into SIP URIs using Kamailio.

EPC LTE Mobile Networks RFCs & Standards SDM

Diameter – Insert Subscriber Data Request / Response

A look at how the HSS can update the profile of an already in-use subscription using Insert Subscriber Data Request/Response.

EPC LTE Mobile Networks SDM SIM Cards

PS Data Off

How turning mobile data off, doesn’t, in LTE and 5G.


Remember Bash History Forever

A few .bashrc tweaks to improve the ‘history’ command


The Anti-Digit Dialing League

The strange history and triumphs of a group formed to protest the removal of letters from the dialing plan.

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.

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

ENUM – DNS based Call Routing

Using DNS to resolve E.164 phone numbers to routable SIP URIs

GSM LTE Mobile Networks RFCs & Standards

Looking inside the MMS Exchange (With call flow and PCAP)

A look at Multimedia Messaging (MMS) in 3GPP Networks and how it actually works.

EPC LTE Mobile Networks Python RFCs & Standards SDM Software

Telephony binary-coded decimal (TBCD) in Python with Examples

Chances are if you’re reading this, you’re trying to work out what Telephony Binary-Coded Decimal encoding is. I got you. Again I found myself staring at encoding trying to guess how it worked, reading references that looped into other references, in this case I was encoding MSISDN AVPs in Diameter. How to Encode a number […]

5G SA EPC EUTRAN LTE Mobile Networks RFCs & Standards SDM Security SIM Cards

The PLMN Problem for Private LTE / 5G

As the number of Private Networks built on LTE and 5G grow, how will PLMN allocation be managed?

EPC LTE Mobile Networks

How UEs get Time in LTE

How does “Network Time” actually get to the UE?

EPC LTE Mobile Networks SDM

Diameter Agents

A look at the 4 types of Diameter Agent

EPC LTE Mobile Networks RFCs & Standards

SCTP Parameter Tuning

A look at tuning your SCTP parameters to detect failures quickly and reduce dropped packets when they happen.