Recent Posts

Diameter – Insert Subscriber Data Request / Response

Diameter – Insert Subscriber Data Request / Response

20/06/20212 min read
A look at how the HSS can update the profile of an already in-use subscription using Insert Subscriber Data Request/Response.
PS Data Off

PS Data Off

19/06/20212 min read
How turning mobile data off, doesn’t, in LTE and 5G.
Remember Bash History Forever

Remember Bash History Forever

13/06/20211 min read
A few .bashrc tweaks to improve the ‘history’ command
The Anti-Digit Dialing League

The Anti-Digit Dialing League

12/06/20215 min read
The strange history and triumphs of a group formed to protest the removal of letters from the dialing plan.
Docker & BIND as an ENUM Playground

Docker & BIND as an ENUM Playground

06/06/202114 min read
A Bind environment in a Docker container for experimenting and learning ENUM for DNS based Call Routing.
ENUM – DNS based Call Routing

ENUM – DNS based Call Routing

05/06/20217 min read
Using DNS to resolve E.164 phone numbers to routable SIP URIs
Looking inside the MMS Exchange (With call flow and PCAP)

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

30/05/20215 min read
A look at Multimedia Messaging (MMS) in 3GPP Networks and how it actually works.
Telephony binary-coded decimal (TBCD) in Python with Examples

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

29/05/20215 min read
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 […]
The PLMN Problem for Private LTE / 5G

The PLMN Problem for Private LTE / 5G

23/05/20214 min read
As the number of Private Networks built on LTE and 5G grow, how will PLMN allocation be managed?
How UEs get Time in LTE

How UEs get Time in LTE

22/05/20211 min read
How does “Network Time” actually get to the UE?
Diameter Agents

Diameter Agents

16/05/20213 min read
A look at the 4 types of Diameter Agent
SCTP Parameter Tuning

SCTP Parameter Tuning

15/05/20213 min read
A look at tuning your SCTP parameters to detect failures quickly and reduce dropped packets when they happen.
Australia’s fake Phone Numbers

Australia’s fake Phone Numbers

09/05/20211 min read
Numbers that will never connect, reserved for use in TV/Movies & Books.
IMS Routing with iFCs

IMS Routing with iFCs

08/05/202110 min read
Peer behind the magic curtain at how IMS networks route your VoLTE and VoNR calls, and how iFC (Initial Filter Criteria) achieve this.
Pre-5G Network Slicing

Pre-5G Network Slicing

02/05/20214 min read
5G introduces Network Slicing, or does it? A look at slicing mechanisms widely used in pre-5G networks.