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T12 · T12-R35 · Open alternatives

Kamailio is a SIP server

Kamailio is signaling. The article calls it a SIP proxy aimed at large real-time services, not a media mixer you assume is in the path. RTP may go around it. That is the same split as RFC 3261 and RFC 3550.

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Counts on this page

4boxes
5opened sources
2confirm rows
5study lines

Opened sources

Confirm rows, no URL

Learn it in 5 minutes

  • Wikipedia says Kamailio, formerly OpenSER, is a GPL-licensed SIP server that can be a registrar, proxy, or redirect server.
  • The feature list includes a SIP security firewall, least-cost routing, IMS and VoLTE, a SIP-WebRTC gateway, and MSRP relay.
  • The article says a large public deployment, with several million users, is at the German ISP 1&1, and another is at sipgate.
  • The documentation page links module docs for series including 6.0.x and 6.1.x, and older series.
  • The wiki says its front page links documents for latest stable versions, 5.2 or newer, and points older releases elsewhere.

Visual

Kamailio is a SIP server Kamailio. Teaching sketch. Confirm a live system. Proxy Registrar WebRTC 6.1 Names come from pages opened in 2026-10. A missing name stays confirm.

Count the boxes: 4. Each label is a name from a page or a study label marked on the drawing.

Flow

Kamailio is a SIP server Caller SIP Called session setup session setup RTP, not required to hairpin Teaching sketch from RFC 3261 and RFC 3550. Not a packet capture.

What is going on

Kamailio is signaling. The article calls it a SIP proxy aimed at large real-time services, not a media mixer you assume is in the path. RTP may go around it. That is the same split as RFC 3261 and RFC 3550.

The version folders on the docs site are real labels: 6.1.x was linked. They are not a statement that you should skip a release. Least-cost routing is a feature name, not a tariff this lab copied.

Worked example

Place Kamailio on the SIP arrows only. Place RTP beside it, dashed. If the design needs a WebRTC gateway, cite the feature list and then confirm the module name in the version you run.

Quiz

1. The Kamailio article says it can be a registrar, a proxy, or a redirect server.

2. The article includes a price for least-cost routing.

Ecosystem

Sister pieces sit on the ecosystem page: the glossary, the mind map, the integration map, and the bridges.

  • Redirect server — One of the three SIP roles the Kamailio article lists.
  • OpenSIPS — The article's fork of the older SER line. It is named so you do not mix the projects. Its current docs were not opened.

Config. Record the version folder you read, such as 6.1.x, next to any module name. A 5.x example may not match.

Troubleshooting. If SIP completes and audio fails, do not keep adding Kamailio routes. Move to RTP. The proxy is not required to be on the media path.

Bridge. A SIP-WebRTC gateway feature is the open bridge toward the browser rooms. Jitsi and LiveKit are different projects.

Mind map, sister technologies, and future hooks live on the ecosystem page.

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

sources.json Markdown