5G SA EPC LTE Mobile Networks 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.

5G SA EPC EUTRAN GSM LTE Mobile Networks RFCs & Standards

Pre-5G Network Slicing

5G introduces Network Slicing, or does it? A look at slicing mechanisms widely used in pre-5G networks.


Adding Vlans to VMware Workstation

Just discovered you can add VLANs to Realtek NICs on Windows PCs, I have a fairly grunty desktop I use for running anything that needs Windows, running VMware Workstation and occasional gaming, I do have a big Dell machine running ESXi which supports VLAN tagging and trunking, but I try and avoid using it as […]

Mobile Networks Voice over IP

Adding support for AMR Codec in FreeSWITCH

Adding support for AMR Codec in FreeSWITCH


K8s multiple objects in YAML File

Defining multiple K8 objects in the same YAML file

EPC LTE Mobile Networks RFCs & Standards

Diameter Droplets – The Flow-Description AVP and IPFilterRules

Getting to know IPfilterRules and the Flow-Description AVP

EPC GSM LTE Mobile Networks RFCs & Standards

The Surprisingly Complicated world of MO SMS in IMS/VoLTE

Since the beginning of time, SIP has used the 2xx responses to confirm all went OK. If you thought sending an SMS in a VoLTE/IMS network would see a 2xx OK response and then that’s the end of it, you’d be wrong. So let’s take a look into sending SMS over VoLTE/IMS networks! So our […]

5G SA Mobile Networks RFCs & Standards

5Gethernet? – Transporting Non-IP data in 5G

A look at non-IP transport for 5G including Ethernet.

5G SA EPC LTE Mobile Networks Software

Open5Gs Database Schema Change

As Open5Gs has introduced network slicing, which led to a change in the database used, Alas many users had subscribers provisioned in the old DB schema and no way to migrate the SDM data between the old and new schema, If you’ve created subscribers on the old schema, and now after the updates your Subscriber […]

EPC Kamailio LTE Mobile Networks 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, […]

Notes RFCs & Standards Software

Diff + Wireshark

Comparing packet contents with Wireshark and a diff utility

EPC LTE Mobile Networks Python Software

PyHSS Update – YAML Config Files

Introducing YAML based config files for defining how PyHSS should be setup


Offtopic – HDMI & USB over Twisted Pair

I wanted to be able to use my desktop computer which lives in my office, on the TV in the living room. Long HDMI cables would involve me climbing around under the house, and making more holes in the walls, and most wireless keyboard/mouse combos wouldn’t reach that far and USB has a limit of […]

EPC LTE RFCs & Standards

MSISDN Encoding in Diameter AVPs – Brought to you by the letter F

Peculiar padding problem perplexes poor programmer.


How AT&T tried (and failed) at mmWave Deployments the 1960s before 5G

Lessons in mmWave from the 1960s.

Linux Notes Software

Being mean to Mikrotiks – Pushing SMB File Share

I’d tried in the past to use the USB port on the Mikrotik, an external HDD and the SMB server in RouterOS, to act as a simple NAS for sharing files on the home network. And the performance was terrible. This is because the device is a Router. Not a NAS (duh). And everything I […]

EPC LTE Mobile Networks Python

PyHSS Update – SCTP Support

Info on PyHSS new support for SCTP as well as TCP.

5G SA EPC EUTRAN GSM LTE Mobile Networks RFCs & Standards Security

And the call was coming from… INSIDE THE HOUSE. A look at finding UE Locations in LTE

How to find a subscriber location within the network.

5G SA LTE Mobile Networks Python Security Software

PyHSS New Features

Thanks to some recent developments, PyHSS has had a major overhaul recently, and is getting better than ever, Some features that are almost ready for public release are: Config File Instead of having everything defined all over the place a single YAML config file is used to define how the HSS should function. SCTP Support […]

5G SA EPC LTE Mobile Networks

MTU in LTE & 5G Transmission Networks – Part 1

A look at MTU and its role in LTE and 5G Transmission.