C# Developer?UK?tbc

SmartSourcing Ltd

2 days ago

Role details

Contract type

Contract

Employment type

Full-time (> 32 hours)

Working hours

Regular working hours

Languages

English

Experience level

Intermediate

Job location

Tech stack

ASP.NET

.NET

XML Schema

Agile Methodologies

C Sharp (Programming Language)

Protocol Stack

Complex Networks

Continuous Integration

Windows Communication Foundation

Key Management

Multi-Purpose Internet Mail Extensions (MIME)

Network Programming

Object-Oriented Software Development

OpenID

Parsing

Session Management

SignalR

Software Engineering

XML

Data Processing

.NET Core

GIT

Solid Principles

Web Api

Crud

Job description

C# 3GPP Developer

As a Software Engineer in an Agile delivery team, you will move beyond standard CRUD applications to solve complex network and Real Time communication challenges. You will lead the development of expansion products that interface with 3GPP-compliant User Equipment (UE).

Core Responsibilities

SIP Signaling Session Management: Develop C# components for high-concurrency SIP sessions, managing complex headers and MIME bodies to support features like First-to-Answer and Group Regroups.
Real-Time Media Plane: Implement RTP/RTCP media handling for Mission Critical Voice (MCPTT) and Video (MCVideo), ensuring seamless floor control (transmission rights) in half-duplex environments.
Data Configuration: Build handlers for MCData services (SDS, File Distribution) using HTTP and SIP MESSAGE requests, and manage XCAP retrieval logic for XML configuration documents.
Secure Communications: Integrate OIDC authentication flows and MIKEY-SAKKE encryption to ensure media transport remains secure and resilient.

Technical Essentials

C#/.NET Framework/.NET Core Mastery: 3+ years of professional experience with a deep focus on asynchronous network programming.

.NET Frameworks Experience: WCF, SignalR, EF, ASP.NET, WebAPI

Protocol Expertise: A solid understanding of the SIP Protocol Stack (INVITE, PUBLISH, SUBSCRIBE, etc.) and experience with RTP/RTCP stacks.

Data Handling: Proficiency in parsing complex XML schemas (XSD) and handling multipart/mixed MIME bodies.

Software Engineering Principles: Strong grasp of OOP, SOLID principles, and modern CI/CD workflows (Git, Pull Requests, Agile).

Preferred (The Nice to Haves)

3GPP Standards: Familiarity with TS 24.379 (MCPTT) or related MCX standards.

Security: Experience with SRTP, TLS, or Key Management lifecycles (KMS).Domain Knowledge: Previous experience with UK Police Control Room environments or the Emergency Services Network (ESN).

SmartSourcing are a Disability Confident Employer and we promote, celebrate and value diversity, we are committed to promoting equality and inclusion for all.

Requirements