When the nkmedia_fs backend is selected (either manually, using the backend: "nkmedia_fs" option when creating the session or automatically, depending on the type), the session types described bellow can be created. Freeswitch allows two modes for all types: as an offerer or as an offeree.
As an offerer, you create the session without an offer, and instruct Freeswitch to make one either calling get_offer or using wait_reply: true in the session creation request. Once you have the answer, you must call set_answer to complete the session.
As an offeree, you create the session with an offer, and you get the answer from Freeswitch either calling get_answer or using wait_reply: true in the session creation request.
You can use this session type to place the session at the Freeswitch mediaserver, without yet sending audio or video, and before updating it to any other type.
Sample
{
class: "media",
subclass: "session",
cmd: "start",
data: {
type: "park",
offer: {
sdp: "v=0.."
},
wait_reply: true
}
tid: 1
}-->
{
result: "ok",
data: {
session_id: "54c1b637-36fb-70c2-8080-28f07603cda8",
answer: {
sdp: "v=0..."
}
},
tid: 1
}Allows to create an echo session, sending the audio and video back to the caller.
Sample
{
class: "media",
subclass: "session",
cmd: "create",
data: {
type: "echo",
offer: {
sdp: "v=0.."
},
wait_reply: true
}
tid: 1
}Allows to connect two different Freeswitch sessions together.
Once you have a session of any type, you can start (or switch) any other session and bridge it to the first one through the server. You need to use type bridge and include the field peer_id pointing to the first one.
It is recommended to use the field master_id in the new second session, so that it becomes a slave of the first, master session. This way, if either sessions stops, the other will also stop automatically.
Sample
{
class: "media",
subclass: "session",
cmd: "create",
data: {
type: "bridge",
peer_id: "54c1b637-36fb-70c2-8080-28f07603cda8",
master_id: "54c1b637-36fb-70c2-8080-28f07603cda8",
offer: {
sdp: "v=0.."
},
wait_reply: true
}
tid: 1
}This session type connects the session to a new or existing MCU conference at a Freeswitch instance.
The optional field room_id can be used to connect to an existing room, or create a new one with this name.
Sample
{
class: "media",
subclass: "session",
cmd: "start",
data: {
type: "mcu",
room_id: "41605362-3955-8f28-e371-38c9862f00d9",
offer: {
sdp: "v=0.."
},
wait_reply: true
}
tid: 1
}-->
{
result: "ok",
data: {
session_id: "54c1b637-36fb-70c2-8080-28f07603cda8",
room_id: "41605362-3955-8f28-e371-38c9862f00d9",
answer: {
sdp: "v=0..."
}
},
tid: 1
}See Room Management to learn about operations that can be performed on the room.
Freeswitch has currenly no support for trickle ICE, however NkMEDIA is able to emulate it.
If you want to trickle ICE when sending offfers or answers to the backend, you must use the field trickle_ice: true. You can now use the commands set_candidate and set_candidate_end to send candidates to the backend. NkMEDIA will buffer the candidates and, when either you call set_candidate_end or the trickle_ice_timeout is fired, all of them will be incorporated in the SDP and sent to Freeswitch.
When Freesewitch generates an offer or answer, it will never use trickle ICE.
The Freeswitch backend has full support for SIP.
If the offer you send in has a SIP-like SDP, you must also include the option sdp_type: "rtp" on it. The generated answer will also be SIP compatible. If you want Freeswitch to generate a SIP offer, use the sdp_type: "rtp" parameter in the session creation request. Your answer must also be then SIP compatible.
TBD
Freeswitch allows you to change the session to type to any other type at any moment, calling set_type.
You can for example first park a call, then include it on a bridge or an mcu.
TBD
In the near future, you will be able to perform several updates over any MCU, calling room_action. Currenly the only supported option is to change the layout of the mcu in real time:
Sample
{
class: "media",
subclass: "session",
cmd: "room_action",
data: {
action: "layout"
room_id: "41605362-3955-8f28-e371-38c9862f00d9",
layout: "2x2"
}
tid: 1
}When using the call plugin with this backend, the caller session will be of type park, and the callee session will have type bridge, connected to the first. You will get the answer for the callee inmediately.
You can start several parallel destinations, and each of them is a fully independent session.
You can receive and send calls to SIP endpoints.