𝗜𝗳 𝘆𝗼𝘂 𝘄𝗼𝗿𝗸 𝘄𝗶𝘁𝗵 𝗜𝗠𝗦… 𝘆𝗼𝘂 𝗺𝘂𝘀𝘁 𝗸𝗻𝗼𝘄 𝘁𝗵𝗲𝘀𝗲 𝗽𝗿𝗼𝘁𝗼𝗰𝗼𝗹𝘀.
IMS is not just architecture.
It’s a combination of protocols working together to deliver voice services.
𝗧𝗵𝗲 𝗰𝗼𝗿𝗲 𝗜𝗠𝗦 𝗽𝗿𝗼𝘁𝗼𝗰𝗼𝗹𝘀
𝗦𝗜𝗣 (Session Initiation Protocol)
Used for call setup, modification, and termination
Core of IMS signaling
𝗗𝗶𝗮𝗺𝗲𝘁𝗲𝗿
Used for authentication, authorization, and policy control
Connects IMS with HSS / PCRF
𝗥𝗧𝗣 (Real-Time Transport Protocol)
Carries the actual voice packets
Works over the user plane
𝗦𝗗𝗣 (Session Description Protocol)
Defines media parameters (codec, IP, ports)
Embedded inside SIP messages
𝗞𝗲𝘆 𝗶𝗻𝘀𝗶𝗴𝗵𝘁
VoLTE / IMS is built on:
SIP (signaling)
Diameter (control)
RTP (media)
SDP (negotiation)
All must work together.
𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻
Which protocol do you find most challenging to troubleshoot?
• SIP
• Diameter
• RTP
• SDP
