Skip to main content

Short note: Soft switching

Short answer

Soft switching separates call control (software on a softswitch) from media hardware. A softswitch handles call setup, routing, and signalling, while media gateways convert TDM voice to IP packets. It uses protocols like H.248/MGCP and SIGTRAN, offering lower cost and faster service introduction.

Write a short note on soft switching.

Soft switching is a switching technique in which call control is performed by software on a server called a softswitch, separated from the hardware that carries the voice. It is the core of next-generation (IP-based) networks.

     [Softswitch / Call agent]
      |H.248/MGCP     |SIGTRAN
 [Media gateway] [Signalling gateway]
      |                 |
 PSTN trunks        SS7 network
      \_____ IP / MPLS core ____/

Main elements

  • Softswitch (Media Gateway Controller): call setup, routing, signalling and billing records.
  • Media gateway: converts TDM voice to IP packets (RTP).
  • Signalling gateway: carries SS7 signalling over IP.
  • Application and media servers: services, announcements, conferencing.

Protocols: SIP, H.323, H.248/Megaco, MGCP, SIGTRAN.

Advantages

  • Lower cost and space than circuit switches.
  • Open, standard interfaces; vendor independence.
  • Fast introduction of new services.
  • Same network carries voice, video and data.
  • Easy to scale by adding servers and gateways.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Telecommunications chapter 8 questions →