> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/sip-and-voip/voip.md).

# VoIP

Voice over Internet Protocol (VoIP) is a means of transmitting voice calls over a packet-based transmission network. It uses [SIP](https://telcobridges.com/learning/sip-trunking/what-is-sip/), H.323, or [BICC](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/protocols/bicc/README.md) as a [signaling](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/sip-voip/signaling-protocols/README.md)/control protocol.

### TelcoBridges and VoIP

TelcoBridges' [Tmedia](https://telcobridges.com/media-gateways/products/tmedia-gateways/) and [Tdev](https://telcobridges.com/products/development-platforms-tdev/) families of devices support VoIP via the SIP signaling protocol as well as via dedicated on-board hardware. This hardware is optional and can be configured at initial purchase or added later via mezzanine board upgrades.

At this time, TelcoBridges does not support VoIP signaling via the H.323 or BICC control protocols.

#### Supported SIP RFCs

TelcoBridges supports the following [RFCs](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/sip-voip/rfc/README.md) for VoIP:

**SIP**

* RFC 3261 Session Initiate Protocol
* RFC 2976 SIP INFO Method
* RFC 3398 ISUP-SIP Mapping (\*)
* RFC 3515 Refer Method (\*)
* RFC 3578 Overlap (\*)
* RFC 2327 Session Description Protocol
* RFC 3581 An Extension to the Session Initiation Protocol (SIP) for Symmetric Response Routing
* RFC 3665 Session Initiation Protocol (SIP) Basic Call Flow Examples
* RFC 3666 Public Switched Telephone Network (PSTN) Call Flows (\*)
* RFC 3892 Referred-By Mechanism (\*)
* RFC 3891 "Replaces" Header (\*)

(\*) TelcoBridges' SIP stack supports the parsing and implementation of the RFC. Not all system-level call flows are necessarily implemented in the routing engine. Contact TelcoBridges' technical support to enquiry about the implementation level of a specific call flow or RFC subsection.

### References

* [Wikipedia article](http://en.wikipedia.org/wiki/VOIP)


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