Categories
EPC EUTRAN LTE Mobile Networks

S1AP – Relative Capacity (87) on MME

Functionality of eNB MME selection based on Relative Capacity IE

Categories
EPC EUTRAN LTE Mobile Networks RFCs & Standards

LTE UE Attach Procedures in Evolved Packet Core (EPC)

A look into the signalling messages between Network elements in an Evolved Packet Core exchanged during the Attach Procedure

Categories
EUTRAN LTE Mobile Networks RFCs & Standards Voice over IP

Diameter and SIP: Registration-Termination-Request / Answer

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 […]

Categories
EPC LTE Mobile Networks RFCs & Standards Voice over IP

Diameter and SIP: User-Authorization-Request/Answer

The Diameter User-Authorization-Request and User-Authorization-Answer commands are used as the first line of authorization of a user and to determine which Serving-CSCF to forward a request to.

Categories
EPC LTE Mobile Networks RFCs & Standards Voice over IP

Diameter and SIP: Server-Assignment-Request/Answer

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 Server-Assignment-Request/Answer commands are used so a SIP Server can indicate to a Diameter server that it is serving a subscriber and pull the profile information of the subscriber. […]

Categories
EPC LTE Mobile Networks RFCs & Standards Voice over IP

Diameter and SIP: Location-Info-Request / Answer

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 Location-Information-Request/Answer commands are used so a SIP Server query a Diameter to find which P-CSCF a Subscriber is being served by Basics: The RFC’s definition is actually pretty […]

Categories
EPC LTE Mobile Networks RFCs & Standards

Diameter and SIP: Multimedia-Authentication-Request/Answer

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 Multimedia-Authentication-Request/Answer commands are used to Authenticate subscribers / UAs using a variety of mechanisms such as straight MD5 and AKAv1-MD5. Basics: When a SIP Server (S-CSCF) receives a […]

Categories
EPC EUTRAN GSM LTE Mobile Networks

Sending SMS in Open5GS LTE Networks using the SGs Interface and OsmoMSC with SMSoS

Sending SMS over LTE using OsmoMSC and OsmoHLR and the SGs interface for SMSoS

Categories
EPC EUTRAN GSM LTE Mobile Networks

OsmoMSC and Open5GS MME – SGs Interface for CSCF / InterRAT Handover

Looking into the SGi interface for Circuit Switched Fallback in LTE to use GSM/UMTS networks for Calls & SMS

Categories
EUTRAN LTE Mobile Networks

BaiCells Neutrino eNB Setup

Configuring BaiCells Neutrino eNB

Categories
EPC EUTRAN LTE Mobile Networks Python RFCs & Standards Software

PLMN Identifier Calculation (MCC & MNC to PLMN)

How to encode and decode MCC and MNC as PLMN Identifiers

Categories
Australian Telco EUTRAN Mobile Networks Software

Making use of Australian Elevation Data in Forsk Atoll

Importing Elevation data from ELVIS into Forsk Atoll

Categories
EPC LTE Mobile Networks RFCs & Standards

Why GTP for LTE?

Why and How GTP is used in LTE networks to carry user data.

Categories
EPC EUTRAN LTE Mobile Networks Security

Roll your own USIMs for Private LTE Networks

Adventures in getting USIMs to use on private LTE networks.

Categories
EPC EUTRAN LTE Mobile Networks

LTE / EUTRAN – Idle Detach

Overview of the packet flow for a UE Idle detach from the network.

Categories
EPC EUTRAN LTE Mobile Networks RFCs & Standards Voice over IP

The case for Header Compression in VoIP/VoLTE

Robust Header Compression (ROHC) and it’s use for compressing RTP / VoLTE traffic headers.

Categories
EPC LTE Mobile Networks Python RF

Open5Gs- Python HSS Interface

Note: NextEPC the Open Source project rebranded as Open5Gs in 2019 due to a naming issue. The remaining software called NextEPC is a branch of an old version of Open5Gs. This post was written before the rebranding. I’ve been working for some time on Private LTE networks, the packet core I’m using is NextEPC, it’s […]

Categories
EPC LTE Mobile Networks Software

Open5GS – Splitting Network Elements

Separating Network Elements (NEs) in NextEPC packet core.

Categories
EPC EUTRAN GSM LTE Mobile Networks Software

Building Android APN / Carrier Config

How Android OS autoprovisions APN settings and how to set your own for your unique MCC & MNC.

Categories
EPC EUTRAN LTE Mobile Networks RF

Qos in LTE (4G) – ARP

ARP in LTE is not the Ethernet standard for address resolution, but rather the Allocation and Retention Policy. A scenario may arise where on a congested cell another bearer is requested to be setup. The P-GW, S-GW or eNB have to make a decision to either drop an existing bearer, or to refuse the request […]