Network Protocols in Mobile

This section covers critical protocols used in mobile audio calls, spanning signaling, voice transport, and network technologies across generations.

Protocol

Description

Use Case

SIP (Session Initiation Protocol)

A signaling protocol to initiate, maintain, and terminate real-time sessions. Widely used for VoIP and multimedia communications.

VoIP calls, video conferencing, IP telephony.

SS7 (Signaling System No. 7)

Traditional telephony signaling protocol for call setup and control in PSTN. Handles call routing and mobility management.

Circuit-switched calls, roaming, SMS delivery.

VoLTE (Voice over LTE)

Voice service over LTE data networks providing HD voice quality. Allows simultaneous voice and data on LTE.

4G mobile voice calls, improved call setup.

VoNR (Voice over New Radio)

Voice service over 5G NR network enabling native 5G voice calls. Improves latency and voice quality further.

5G voice calls, future-proof mobile telephony.

GSM (Global System for Mobile Communications)

2G cellular standard for voice and basic data services. First widely deployed digital cellular system.

Legacy mobile calls, SMS.

UMTS (Universal Mobile Telecommunications System)

3G cellular technology providing higher data rates. Supports voice and multimedia over cellular.

3G voice calls, video calling.

LTE (Long-Term Evolution)

4G cellular technology offering high-speed data and IP-based voice. Foundation for VoLTE and advanced mobile broadband.

4G mobile data, VoLTE calls.

5G NR (New Radio)

Next-generation 5G wireless standard focused on speed, latency, and capacity. Supports VoNR and enhanced mobile broadband.

5G data and voice services, IoT.

RFC: RFC 3261

Main Features:

  • Initiates, manages, and terminates multimedia sessions

  • Supports presence and user location

  • Text-based, flexible, and extensible

  • Common in VoIP and conferencing platforms

Use Cases:

  • VoIP and IP telephony

  • Video conferencing

  • Unified communication services

Alternative Protocols:

  • H.323 – Older protocol for multimedia

  • MGCP – Media gateway control

Let us learn more about SIP:

Jump to “SIP”

ITU-T Recommendations: Q.700 series

Main Features:

  • Call setup and routing for PSTN and cellular

  • Mobility management, handoff, and SMS delivery

  • Global signaling backbone for telecom

Use Cases:

  • Legacy PSTN voice networks

  • SMS and roaming infrastructure

  • Mobile switching center signaling

Alternative Protocols:

  • SIGTRAN – Transports SS7 over IP

  • Diameter – Modern signaling in IMS

Let us learn more about SS7:

Jump to “SS7”

3GPP Specifications: TS 23.228, TS 24.229

Main Features:

  • IP-based voice service over LTE

  • High-definition (HD) voice quality via AMR-WB

  • Simultaneous voice and data

Use Cases:

  • 4G mobile voice calls

  • Low latency voice setup

  • Transition from legacy voice

Alternative Protocols:

  • CSFB – Circuit-Switched Fallback

  • VoWiFi – Voice over Wi-Fi

Let us learn more about VoLTE:

Jump to “VoLTE”

3GPP Specifications: Release 15+

Main Features:

  • Native 5G voice service

  • Extremely low latency

  • Seamless IMS and NR integration

Use Cases:

  • 5G voice and video calls

  • Advanced mobile communication services

  • Future-ready voice infrastructure

Alternative Protocols:

  • VoLTE – Used during early 5G deployments

  • IMS – Core network platform

Let us learn more about VoNR:

Jump to “VoNR”

Standards Body: 3GPP

Main Features:

  • 2G circuit-switched voice

  • Basic SMS and limited data

  • Widespread global adoption

Use Cases:

  • Legacy mobile voice networks

  • Low-speed text and telemetry services

Alternative Protocols:

  • CDMA – Competing 2G standard

  • UMTS – Successor to GSM

Let us learn more about GSM:

Jump to “GSM”

Standards Body: 3GPP

Main Features:

  • 3G cellular voice and data

  • Higher data rates than GSM

  • Support for circuit- and packet-switched services

Use Cases:

  • Video calls

  • Enhanced voice and mobile browsing

Alternative Protocols:

  • GSM – Legacy fallback

  • LTE – Next-gen replacement

Let us learn more about UMTS:

Jump to “UMTS”

Standards Body: 3GPP

Main Features:

  • All-IP high-speed mobile broadband

  • Foundation for VoLTE and IMS

  • Low-latency access to data and voice

Use Cases:

  • Mobile internet

  • VoIP over LTE (VoLTE)

  • Streaming and multimedia

Alternative Protocols:

  • UMTS – 3G predecessor

  • 5G NR – Next-gen successor

Let us learn more about LTE:

Jump to “LTE”

Standards Body: 3GPP Release 15+

Main Features:

  • Ultra-fast wireless connectivity

  • Supports massive IoT and enhanced mobile broadband

  • Foundation for VoNR and future services

Use Cases:

  • 5G voice and video

  • Smart devices and IoT

  • Edge computing and ultra-low latency

Alternative Protocols:

  • LTE – Legacy 4G platform

  • Wi-Fi 6/6E – Competing wireless access

Let us learn more about 5G NR:

Jump to “5G NR”