====== Media ======
Real-time media (audio and video) is sent between the clients once a call has been established. In webRTC media is always encrypted.

===== Direct =====
{{ :ixnx:wrtc:description:ingate_media_block_diagram.png?direct&400 |}}
Whenever possible audio and video media is sent directly between clients.

When client **B** wants to call client **C** it sends [[ixnx:wrtc:description:diagram:signaling|signaling]] through Ingate unit's websocket server. Once the call is established audio and video media is sent directly between the clients.

The same goes for clients **A** and **D**, it doesn't matter one of them are on the LAN and the other on the Internet. Audio and video media is sent directly between the clients, through the firewall (that automatically opens requested ports to let the media stream through).

===== QTURN =====
{{ :ixnx:wrtc:description:nat_block_diagram.png?direct&400 |}}
If remote client **D** is behind a NAT (thus it has not public IP address it can be reached at) direct media transmit is not possible. In such case wrtc_kit automatically reroutes media to go through the QTURN server. It receives media streams from the clients and forwards it to other client. The Q in QTURN stands for Quality - real-time media streams are given priority over data transmissions.

The web socket connections sends periodic ping transmissions to keep the ports on the remote NAT open.

===== Voice Bridge =====
{{ :ixnx:wrtc:description:sip_block_diagram.png?direct&400 |}}
If one of the clients is a SIP phone the Ingate unit uses one of its **SIP UA**-s to translate between [[ixnx:wrtc:rtcgate:start|RTCgate]] and [[https://en.wikipedia.org/wiki/Session_Initiation_Protocol|SIP]] signaling protocols. It is carried out completely seamless when client **B** tries to call a SIP address.

If possible media is sent directly between the webRTC and SIP clients. Some SIP clients do however not support encrypted media. In such cases **B** sends its media to Ingate unit's **Voice Bridge** that decrypts it before forwarding it to SIP client **C**.

One or both clients can be on the Internet, the Ingate can handle all combinations. The QTURN server may also be used if any of the clients are behind NAT.


Next page: **[[ixnx:wrtc:description:diagram:sip_services|SIP Services]]**