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
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.

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IMS / VoLTE Mobile Networks RFCs & Standards SDM Voice over IP

ENUM – DNS based Call Routing

Using DNS to resolve E.164 phone numbers to routable SIP URIs

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5G SA EPC IMS / VoLTE LTE Mobile Networks SDM 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.

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FreeSWITCH IMS / VoLTE Mobile Networks Voice over IP

Adding support for AMR Codec in FreeSWITCH

Adding support for AMR Codec in FreeSWITCH

Categories
EPC GSM IMS / VoLTE LTE Mobile Networks RFCs & Standards

The Surprisingly Complicated world of MO SMS in IMS/VoLTE

Short messaging can be anything but simple…

Categories
GSM IMS / VoLTE LTE Mobile Networks SDM Software

Android Carrier Privileges

Unlocking Carrier Privileges through certificate on a UICC

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EUTRAN IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM 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 IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM 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 IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM 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 IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM 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 IMS / VoLTE LTE Mobile Networks RFCs & Standards SDM

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 IMS / VoLTE 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
GSM IMS / VoLTE Mobile Networks Voice over IP

GSM with Osmocom: Call routing in GSM

How call routing in GSM works and it’s application in the Osmocom suite

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GSM IMS / VoLTE Mobile Networks RF

GSM with Osmocom Part 9: Calls & SMS at last!

So now we’ve covered the basics of what’s involved let’s get some traffic on our network. For starters we’ll need to start each of our network elements and bring up whichever BTS hardware we’re using. In order for our calls to have audio, we’ll need to set a parameter on the Media Gateway. We’ll cover […]

Categories
EPC IMS / VoLTE Kamailio LTE Mobile Networks Software Voice over IP

Kamailio Proxy-CSCF Pull

My first Pull / Merge in the Kamailio project was to fix the IMS P-CSCF config

Categories
EPC EUTRAN IMS / VoLTE Kamailio LTE Mobile Networks RFCs & Standards SDM SIM Cards Voice over IP

Things I wish I knew about setting up private VoLTE Networks

Lessons learned about setting up VoLTE / IMS Networks at small scale.

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks SDM Security Voice over IP

VoLTE / IMS – P-CSCF Assignment

How the P-CSCF address is assigned to a UE in Protocol Configuration Options (PCO) during bearer establishment.

Categories
EPC EUTRAN IMS / VoLTE LTE Mobile Networks Python RFCs & Standards SDM Software Voice over IP

PyHSS Update – IMS Cx Support!

An update to PyHSS to support IMS Authentication for VoLTE

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

IMS / VoLTE IPsec on the Gm Interface

The exchange between a UE and P-CSCF to put SIP traffic into IPsec encapsulated payloads.