Categories
GSM Mobile Networks SDM Software

USSD Gateway with Osmocom

Unstructured Supplementary Service Data or “USSD” is the stack used in Cellular Networks to offer interactive text based menus and systems to Subscribers. If you remember topping up your mobile phone credit via a text menu on your flip phone, there’s a good chance that was USSD*. For a period, USSD Services provided Sporting Scores, […]

Categories
Mobile Networks Voice over IP

Demystifying SS7 & Sigtran – Part 5 – What layer to Split

A look at taking SS7 traffic and putting it onto IP / SIGTRAN links on the MTP2 / Layer 2 level.

Categories
EPC LTE Mobile Networks

Evolved Packet Core – Analysis Challenge

This post is one of a series of packet capture analysis challenges designed to test your ability to understand what is going on in a network from packet captures.Download the Packet Capture and see how many of the questions you can answer from the attached packet capture. The answers are at the bottom of this […]

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

The Surprisingly Complicated World of SMS: Apple iPhone MT SMS

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

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FreeSWITCH IMS / VoLTE Kamailio Mobile Networks Voice over IP

FreeSWITCH as an IMS Application Server

Using FreeSWITCH as an IMS Application Server

Categories
Mobile Networks RFCs & Standards

ITU International Point Code Structure

A brief look at International Signaling Point Code numbering and what it all means.

Categories
GSM Mobile Networks RFCs & Standards Software Voice over IP

Demystifying SS7 & Sigtran – Part 4 – Routing with Point Codes

Getting from Point Code A to Point Code Z.

Categories
Mobile Networks RFCs & Standards Voice over IP

Demystifying SS7 & Sigtran – Part 3 – SS7 Lab in GNS3

Setting up our GNS3 environment with a bunch of SS7 Nodes

Categories
Mobile Networks RFCs & Standards Voice over IP

Demystifying SS7 & Sigtran (With Labs!) – Part 2 – Ingredients Needed

Looking at the basic components that make up our SS7 Networks.

Categories
Mobile Networks RFCs & Standards Voice over IP

Demystifying SS7 & Sigtran Networks (With Labs!) – Part 1 – Intro

Taking a look at the basics of the SS7 Protocol Stack.

Categories
EUTRAN LTE Mobile Networks RF

Huawei Baseband Cheat Sheet

Quick reference guide for the types and capacities of Huawei BBU 3900 Series cards

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
5G SA Mobile Networks RFCs & Standards SDM Security

Some thoughts on NRF Security in 5G Core

A look at attack vectors the NRF opens up in #5G Core networks, and the mitigations recommended by 3GPP.

Categories
5G SA Mobile Networks RFCs & Standards SDM

If you like Pina Coladas, and service the control plane – Intro to NRF in 5GC

Looking for Love in the 5G Core?

Let’s look at our matchmaker – The Network Repository Function in 5G Core.

Categories
GSM IMS / VoLTE Mobile Networks

The Surprisingly Complicated World of SMS: Special Characters

A look at how characters are encoded in an SMS.

Categories
5G SA EPC LTE Mobile Networks SDM

Backing up and Restoring Open5GS

How to backup and restore Open5Gs config between servers

Categories
5G SA Mobile Networks

GTP Extension Headers (PDU session user plane protocol) in 5GC

How GTP is extended in 5G Core Networks to support extra QoS functionality like Reflective QoS and Delay Indicators

Categories
GSM IMS / VoLTE Mobile Networks

The Surprisingly Complicated World of SMS: Concatenated / Multipart SMS

Another deep dive into deceptively simple seeming functions to do with SMS.

Categories
5G SA Mobile Networks

Framed Routing in 5G

5GC includes native support for framed-routing.

Categories
5G SA Mobile Networks

Reflective QoS in 5G

A great new feature of #5G Core Networks is Reflective QoS – Where QoS of the traffic coming to a UE is reflected on the QoS coming out.