Categories
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.

Categories
5G SA Mobile Networks SDM

EIR in 5G Networks (N5g-eir_EquipmentIdentityCheck)

A look at the Equipment Identity Register in 5G Core

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
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.

Categories
EPC LTE Mobile Networks SDM SIM Cards

PS Data Off

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

Categories
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

Categories
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 […]

Categories
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?

Categories
EPC LTE Mobile Networks SDM

Diameter Agents

A look at the 4 types of Diameter Agent

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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
EPC LTE Mobile Networks RFCs & Standards SDM

Diameter Droplets – The Flow-Description AVP and IPFilterRules

Getting to know IPfilterRules and the Flow-Description AVP

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5G SA EPC LTE Mobile Networks SDM Software

Open5Gs Database Schema Change

New database time to support slicing and a migration path for existing users.

Categories
EPC Kamailio LTE Mobile Networks SDM Software

A very unstable Diameter Routing Agent (DRA) with Kamailio

I’d been trying for some time to get Kamailio acting as a Diameter Routing Agent with mixed success, and eventually got it working, after a few changes to the codebase of the ims_diameter_server module. It is rather unstable, in that if it fails to dispatch to a Diameter peer, the whole thing comes crumbling down, […]

Categories
Mobile Networks Security SIM Cards

SIM Card Sniffing with Wireshark

Using Wireshark to sniff communication between your computer and Smart Card / SIM Card

Categories
Mobile Networks Python SIM Cards

SIM / Smart Card Deep Dive – Part 4 – Interacting with Cards IRL

Sending commands/APDUs to a real life Smart Card.

Categories
5G SA GSM LTE Mobile Networks RFCs & Standards SDM Security SIM Cards

Confidentiality Algorithms in 3GPP Networks: MILENAGE, XOR & Comp128

A look at the Confidentiality Algorithms used in 3GPP Networks, MILENAGE, XOR & Comp128

Categories
GSM LTE Mobile Networks Security SIM Cards

SIM / Smart Card Deep Dive – Part 3 – APDUs and Hello Card

A look at APDUs and Interacting with Cards

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GSM LTE Mobile Networks Security SIM Cards

SIM / Smart Card Deep Dive – Part 2 – Meet & Greet

The basics of Smart Cards & their File System

Categories
GSM LTE Mobile Networks Security SIM Cards

SIM / Smart Card Deep Dive – Part 1 – Introduction to Smart Cards

Getting up close and personal with Smart Card / SIM Cards

Categories
SIM Cards

SIMtrace Cases

I put together some laser cut case designs for the Osmocom SIMtrace, Quite happy with the results. If you want to cut your own, I’ve sent the DXF files to the mailing list, and will try and add to the project.