Assigning static IPs to UEs in Open5GS
Category: Mobile Networks
A look at PFCP for the Sx and N4 Interfaces
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Twenty years of the Nokia 3310
1 September 2000 was when the 3310 was released…
Using Wireshark to filter S1 messaging to find signalling from a specific subscriber,
List of Open Source Evolved Packet Core implementations
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Android Carrier Privileges
Unlocking Carrier Privileges through certificate on a UICC
What’s the deal with Tunnel Endpoint Identifiers and what do they do?
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GSM with Osmocom: Handovers
A look at the Handover process between Cells / BTSs in GSM using the Osmocom stack.
This is part of a series of posts focusing on common Diameter request pairs, looking at what’s inside and what they do. The Authentication Information Request (AIR) and Authentication Information Answer (AIA) are one of the first steps in authenticating a subscriber, and a very common Diameter transaction. The Process The Authentication Information Request (AIR) […]
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GSM with Osmocom: Channel Types
When setting up the timeslots on the TRX for each BTS on your BSC, you’ll notice you have to set a channel type. So what do these acronyms mean, and how do they affect the performance of the network? GSM channels break down into one of to categories, control channels – used for signalling, and […]
Depending on if you’re wearing a tin foil hat or not, silent SMS and silent calls could be a useful tool to for administering the network or a backdoor put in to track citizenry! Regardless of it’s reasons for existence, let’s take a look at what it actually does, and how we can use it. […]
Functionality of eNB MME selection based on Relative Capacity IE
Using SDR hardware to view the LTE System Information Block’s contents.
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GSM with Osmocom: GPRS & Packet Data
So far we’ve focused on building a plain “2G” (voice and SMS only) network, which was all consumers expected twenty years ago. As the number of users accessing the internet through DSL, Dial Up & ISDN grew, the idea of getting this data “on the go” became more appealing. TCP/IP was becoming the dominant standard […]
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GSM with Osmocom: SS7 & Sigtran
SS7 Basics and Osmo-STP as a Signaling Transfer Point
Using the new functionality in Open5Gs to select S-GW based on TAC or eNB ID.
What the Origin-State-Id AVP does and how it is used to track if a Diameter peer restarts.
Why the BaiCells PLMN changes?
A look into the signalling messages between Network elements in an Evolved Packet Core exchanged during the Attach Procedure
These posts focus on the use of Diameter and SIP in an IMS / VoLTE context, however these practices can be equally applied to other networks. The Registration-Termination Request / Answer allow a Diameter Client (S-CSCF) to indicate to the HSS (Diameter Server) that it is no longer serving that user and the registration has […]