METHOD AND SYSTEM FOR TELECOMMUNICATION SESSIONS USING ONLY INITIAL SIGNAL MESSAGES

TECHNICAL FIELD The present invention is related to telecommunication, sessions that eliminate the need to send additional signaling messages after initial signaling messages are sent between parties or nodes of the session. More ^■ specifically, the present invention is related to telecommunication sessions that eliminate the 'need to send additional signaling messages after initial signaling messages are sent between parties or nodes of the session, where the session can be multimedia conferencing or Instant Messaging.

BACKGROUND

Multimedia streams are normally signaled using standard protocols such as SIP or IMS. When a multimedia endpoint wishes to send media streams to .another endpoint ^" - the initiating endpoint places ^' the ^{" '} IP . addresses, port^ number, codec type and other stream parameters intτo an Offer' message and sends this to the recipient. ^• If the ^" recipient accepts this multimedia 'call' then it ,.will generate a 'reply' message." This" reply will contain the recipient's address, ports, and other parameters to . match the stream parameters in offer message. When Only ..two parties are involved in a 'call' this is known as a.-point-. to-point (P2P) call. : ,

When more than two parties wish to exchange multimedia streams there are . two basic methods. The <„ older, less flexible method uses a P2P model to send and receive a single- set of multimedia streams between an endpoint' and.; a conference bridge or MCU. The 2 ^nd newer method eliminates-

^■ the bridge' or MCU requirement and uses a ^' direct, media, stream to each party in the call. A very efficient way of streaming to many participants at once is to use multicast technology to minimize network bandwidth requirements. This multicast method is also known as point-to-multipoint (PMP) streaming.

SUMMARY

The present invention pertains to a telecommunications system. The system comprises a telecommunications network. The system comprises ;n nodes, where n is an integer greater -than- or equal to - 3 , in communication with the network. The system comprises a ^" host node that creates a session through the network between the n nodes. The system comprises an additional node in communication with the network, the host node adding the additional node to the - session without any signaling messages being sent from the n nodes.

The present invention perta'ins* " to a method for telecommunicating. The method comprising the steps of forming a session between n parties were n is an integer greater than or equal to 3 thorough a< ' telecommunications network. There is the step of adding an additional party to the session without sending any signaling messages from the n parties.

The present invention pertains to . a method for telecommunicating. The method comprising the steps of conducting a session between a first party, a. second party, a third party and a fourth - party thorough a telecommunications network. There is the step of deleting the first party from the session by sending a bye signal to a host from- the first party, sending-only a~-disconnect of the first party to the second party from the host,

sending _' only a disconnect of the first party to the "third-- party from the host, and sending only -a disconnect of the first party to the fourth party from the host without any additional signals between the parties to delete the first. party from the session.

The present invention pertains to a method for telecommunicating. The method comprising the steps Of conducting a session between a first party, a second, party, a third party and a fourth party tho-rough a telecommunications network. There is the step, of changing session layout behavior of the first party by sending a- behavior change event signal to a host from the. first party, sending only a behavior change- event of the first: party to the second party from the host, sending only a behavior change event of the first party to the ' third- party from the host, and sending only a behavior change event of the first party to the fourth party from the host without any additional signals between -the parties to change the first party from the session.

BRIEF DESCRIPTION OF THE DRAWING.

In the accompanying drawings, the preferred embodiment of the invention and preferred methods of- practicing the invention are illustrated in which: Figure 1 is a representation of a telecommunications system of the present invention.

DETAILED DESCRIPTION

Referring -now to the drawings wherein like reference numerals refer to similar .or identical, parts throughout the several views, and more specifically to' .figure -1

-thereof, there is-- shown- a telecommunications systemr.-lO.

The system 10 comprises a telecommunications network 12,-

The system 10 comprises n riodes 14, where n is an integer- greater .than or equal to 3 , in communication with the network 12. The system 10 comprises a host node 16 that creates a session ..through the network. 12 .between- the _n nodes 14. The system 10 comprises an additional node 18 in communication with the network 12, the host node 16 adding the additional node 18 to -the session without any signaling messages being sent from the n nodes 14.

Preferably, the host sends only (2 plus n) initial signaling messages with session layout behavior "between the nodes 14 without any additional signaling .messages between the nodes 14 to add the additional node 18 to - the session. The nodes 14 preferably . communicate wi-th each other using PMP (point to multipoint) signaling, but are not limited thereto. The session, preferably includes multimedia conferencing. Preferably, the host sends initial signaling messages having audio and video - stream parameters to the parties. 'The additional -party preferably sends its own audio and video stream parameters to the host. One example of a platform regarding multimedia conferencing as described herein is to use the ViPr consoles and associated network sold '-by Ericsson, Inc. The nodes 14 or parties can be computers, ■ servers , videophones or audiophones . Alternatively, the session can include IP Multimedia Subsystem (IMS) conferencing. The session can .include instant messaging (IM).

The present invention pertains to. a method for telecommunicating. The method .comprising the steps of forming a session between n parties were n- is an .-integer greater than or equal to 3 thorough a ..telecommunications network -12. There is the step "of . adding an additional

party to the session without sending any. signaling messages from the n parties.

Preferably, there is a host, and the adding step includes the step of sending the initial ...signaling messages from the host to the parties using PMP (point to multipoint) signaling. The adding step preferably includes the step of sending only - (2 plus n) initial signaling messages with session . layout behavior between the parties without any additional -signaling ^" messages between the parties to add the additional party to the session. . Preferably, the sending step includes,, the step of the host sending initial signaling messages having audio and video stream parameters - to the parties.

The adding step preferably includes the step of ^" the ^• additional party sending its own audio and video stream parameters to the host. Preferably, there is the step of creating per stream inclusion in sets by each party containing desired participants .in. each set. There is preferably the step of creating an.'.exclusion set by each' party to prevent inclusion of certain -streams to the respective party. Preferably, there is - the step of forming dynamic sets using logical intersections or "unions of multiple sets. The conducting step .preferably includes the step of conducting a multimedia conference. The conducting step can include the step of conducting an IP Multimedia Subsystem (IMS) conference. The conducting step can include- the step of conducting instant messaging (IM).

The present invention pertains^- ' to- a method i for .telecommunicating. The method, comprising the steps of. conducting a session between a first, party, a second party, ^• a- third party and a- fourth party ^l thorough', a telecommunications network 12. There is the step _^ jof

deleting ^' the .first party from the -session by sending a. bye' signal to a host from the first party, sending only a disconnect of the first party to the second party from the host, sending. only a disconnect of the first, party to the. third-party from the host, and sending only a disconnect of the first party, to the fourth party from the host without any additional signals between the parties to delete the first party from the session.

The , present . invention pertains to a method for ' telecommunicating. The method comprising the steps of conducting a session, ^■ between .a first party, a second party, a third party and a fourth party thorough a telecommunications network 12. There is the ' step", of changing session layout behavior .of the first party by' sending a behavior change event signal to a host from the ^1' first party, sending only a behavior change event of the", first party to the second party from the host, sending*-, only a behavior change event of 'the first party to the ' third-party from the host, and sending only a behavior' change event of the first party to the fourth party from the ^■ host without 'any additional signals between the parties to change the first party from- the session.

Preferably, no conferencing bridge or MCU is used in- the network 12- for the parties or nodes 14 to communicate^ with each other. Instead, direct streams are. sent between the parties, such as by using multicasting, also know as point to multipoint (PMP) streaming.

In the operation of the invention, to use PMP streaming each endpoint must exchange the lists of addresses,, ports, . codecs, ' and other .parameters' between each endpoint that .is .participating in the call. The ^" , necessity of each endpoint -to communicate with each other endpoint directly would require a full mesh of signaling ^'

channels and would also require sending the same PMP media information to every endpoint. A simple way to reduce the number of signaling channels and signaling messages is to have one endpoint .also become the..conference" signaling 5 'host'. Each party only needs to tell the conference host its PMP information once and then the "host' can send all of the PMP information to each of the endpoints only once.

A rich collaborative multimedia application .can offer each user the ability to choose which audio and .video

10 streams to view or subscribe. This means that every available media stream will NOT necessarily be sent to each party. To make this possible, each -endpoint must provide a per multimedia stream list that states which particular streams are to be subscribed to. This provides

15 a very flexible conferencing architecture, however this flexibility comes at the cost of signaling complexity.

As an example consider when a new party ^V D' is ^' .t invited into an existing 'call' with ^V A', 'B' and ^V C. The following five signaling messages are sent:

20 - 'Host' sends audio and video stream parameters of A, B, and C to ¹ D'

^V D' sends it's own audio and video stream parameters to "Host'

Host sends ^V D' parameters to 'A' 25 - Host sends ^V D' parameters to ^V B' Host 'sends ^V D' parameters to 'C-

Notice that the addition of a participant required 5 initial signaling messages. The actual number of initial signaling messages can be generalized "to be (2

30. + N) messages, where ,N is the number -.of existing participants in the call.

- ^■ All of the parties in" this call now have "air of the. information of all available streams. The final step is to

send back the .list of subscribed streams to the conference 'host' so that .the host can relay these lists to the appropriate parties. The following messages need, to be ^r sent to complete the new party,, addition : - 'A' sends to 'Host' the new list of streams to receive (including 'D')

Host sends to 'D' the stream list from 'A' 'B' sends to 'Host' the new list of streams to receive (including 'D') - Host sends to 'D' the stream list from ^V B'

^V C sends to 'Host', the. new list of -streams to receive (including 'D')

Host sends to ¹ D' the stream list from ^V C So as seen above, the participant addition also. required a secondary group of (6) signaling messages to be sent.. The number of secondary messages can be calculated as (2 * N) , where once again ¹ N' is the number of existing participants .

When the number of conference .participants 'N' is large enough it may require that other received media streams be removed when a new media stream is added. The conference 'Host' will need to send an updated media stream list to all endpoints which were providing - the now dropped streams. The number 'E' of 'extra' secondary signaling messages will vary depending on screen layouts and user preferences.

So, the total number of signaling messages to add a new participant is 2 + (3 * N) + E. The primary purpose of this invention is to eliminate all . of the secondary messages that are currently required .when adding a new participant .

The saving- of at least (6) extra messages for -even a. 3.,party call may not seem like much. However, when .-these

(6) messages are routed through a typical .IMS network 12, these same messages could easily traverse 3 or 4 IMS CSCF Proxies. There is also a minimum of one reply message for each. of these outgoing signaling messages. This means that the real number of signaling messages would be (6 x 2) x 4, or 48 extra signaling messages.

When- this is factored into a large IMS network 12 where many simultaneous calls are active at once, the number. of extra messages is easily in the thousands. This can be a significant savings when calculating IMS server capacity, since the server does not need to be provisioned to handle the load from these extra messages .

One of the ways to eliminate the extra secondary signaling, messages is to impart some of the knowledge iof the default - behavior of adding a party, into tfie conference host and or into the other participant endpoints. First, the conference layout behavior that ¹ Sa participant chooses could be made available in the initial signaling messages. Then each participant .could .use this information to know in advance which streams are to - be received .

Typically, an endpoint has a list of participant audio streams for listening, and a list of video participants to view. The video streams can be further divided into at least two categories. First, the participants that use high resolution video streams, ^■ and next the participants that are displayed using low resolution video 'thumbnails'. These lists of audio and video streams can also be thought of as media .stream 'sets'. This would consist of an ^■ Audio 'set' , a High-Res Video 'set' and a Low-Res Video 'set' . The members or elements of -these 'sets' are the conference participants or a unique identifier representing ^■ them. .If a participant

is a member of a particular media . scream 'set' than that media stream of that participant is to be received.

Guided by .conference layout behaviors and user preferences an endpoint creates per stream inclusion 'sets' containing the desired participants to be included in each set. It is also possible to create an explicit 'exclusion set' to prevent the inclusion of certain streams. But, one of the more useful 'sets' is a set that is 'dynamically' created using logical intersections or unions of multiple sets. For example, a 'dynamic' set can be formed using conference layout rules that state, that the current 'Audio' set is the logical union of the Low- Res set and the High-Res set. Another 'dynamic' set could be formed by defining the Low-Res set as all conference participants NOT included in the High-Res set. Certain constraints can also be applied to further limit the media stream sets. These constraints can be user specified, such as a layout preference of two high resolution videos displayed side by side. Or, a system" constraint can" be used which limits the number of displayed Low-Res videos to be eight.

Even though these 'dynamic' sets can be different for each endpoint, they were formed using layout rules with some additional user and system .10 constraints. If these layout rules and constraints were communicated to each other participant then each endpoint could build the

'dynamic' set for every other endpoint. If every other endpoint knows an endpoint 's stream selections, then that

-endpoint does not need to send a stream selection update message to other endpoints .

The initial layout rules and constraints would "be included in the initial media . parameters so that no extra signaling messages are required. The -only time that a new

signaling message would be required' is when the layout and/ or constraints change.

Since the host is relaying the set and layout information, .the host 'can' .also save the sets . and use them to further optimize the signaling. The host can know exactly which nodes 14 are listening .to a stream sent from another node based on the sets. If the sending node were to send a media format change message, then the host can use the set information to only relay those changes ■ to the nodes 14 who are actually listening. If the host did not have the sets, then it would need to send media format messages to all other nodes 14.

The above showed the signaling messages required to add a new party to the call. The following examples show some other conference call operations (Call currently has 4 participants A, B, C & D) :

1) Deleting a participant from the call

Party 'D' issues a BYE to the 'Host' Host sends 'disconnect' event to 'A' - Host sends 'disconnect' event to 'B'

Host sends 'disconnect' event to 'C The following secondary - signaling messages would NOT be sent when using Dynamic Sets (A savings', of 9 signaling messages) : - Party 'A' sends new media stream receive list to 'Host'

'Host' sends to 'C the updated media stream lists for 'A'

'Host' sends to - 'D' the updated media stream lists for 'A'

Party 'B' sends new media stream receive list to 'Host'

'Host', sends to 'A' the updated media stream lists for 'B'

'Host'' sends to 'C the updated media stream lists for 'B' - Party 'C sends new media stream receive list to 'Host'

'Host' sends to . 'A' the updated media stream lists for 'C

'Host' sends to 'D' the .updated media stream lists for 'C

2 A participant changes their screen layout from a display of '3-Up' to '2-Up':

Party 'D' issues a- 'layout change' event *'to 'Host'

Host sends 'layout change' event to 'A' Host sends 'layout change' event to 'B' Host sends 'layout change' event to 'C .The following secondary signaling messages would NOT be sent when using Dynamic Sets (A savings of 16 signaling messages) :

Party 'A' sends new media stream receive list to 'Host'

'Host' sends to 'B' the updated media stream lists for 'A'

'Host' sends to 'C the updated media stream lists for 'A'

'Host' sends to 'D' the updated media stream lists for 'A' - Party 'B' sends new media stream receive list to 'Host'

'Host' sends to 'A' the updated media stream lists for 'B'

¹ HoSt' sends to ¹ C the updated media stream lists for ¹ B'

^Hosf sends to ¹ D' the updated media stream lists for ¹ B' - Party 'C sends new media stream receive list to ¹ HoSt'

¹ HoSt' sends to ¹ A' the updated media stream lists for ¹ C

¹ HOSt' sends to ¹ B' the updated media stream lists for ¹ C

¹ HoSt' sends to ¹ D' the updated media stream lists for ¹ C Party D' sends new media stream receive list to ¹ HoSt' - ¹ HoSt' sends to ¹ A' the updated media stream lists LOγ ¹ D'

¹ HoSt' sends to ¹ B' the updated medi'a stream lists for ¹ D'

¹ HoSt' sends to ¹ C the updated media stream lists for ¹ D'

The following is the basis for practicing the above.. The "Session Initiation Protocol" (SIP) is described in the IETF RFC-3261, incorporated by reference herein. This is the underlying protocol used in almost all of the worlds "Voice Over Internet Protocol", or VoIP phones. This protocol was designed to completely replace ' the old PSTN phone system with an easily extensible framework that used the vast Internet network 12 as the phone network 12. SIP forms the signaling framework that carries all of the signaling messages used in a call. However, to enable- the easy development of new services, RFC-3261 does NOT.- define, exactly what is contained within these signaling messages.

To enable interoperability between various SIP devices RFC-3264, incorporated by reference herein, was developed at the same time as RFC-3261. RFC-3264 is titled. "An Offer Answer model with SDP". The most popular 'payload' carried within the SIP framework is the "Session Description Protocol" (SDP) which is defined in RFC-4566, incorporated by reference herein. These .3 RFC ' s (RFC-3261, RFC-3264, and RFC-4566) form the signaling basis for nearly every VoIP phone and many conferencing and phone systems. Although the SDP messages contain network 12 information about the media streams, they do NOT carry the actual audio and video streams themselves. The media streams are transported using the "Real Time transport Protocol" or RTP, which is defined in RFC-3550. To define the 'sets' and 'layout behaviors', a - ^' -tew proprietary attributes are added to the SDP message t-hat is used here. The SDP standard documents how to properly format proprietary attributes using an "a=X-" prefix. The following examples show how the extensions described here are applied to SDP. The first example is .an explicit 'inclusion set' that contains a list of participants that have media streams that would be received. The format of this attribute could be "a=X-RxPartyList : 3-5". This- would be interpreted to mean that this participant is interested in receiving media streams from Participant #3 ^■ and Participant #5. The 2nd example is of a 'dynamic set' ¹ formed from the intersection of 'All Participants' and an explicit 'exclusion' list. The format of this attribute could be "a=X-RxExcludeList : 3 5". The actual 'set' of participants . varies depending on -,.how many other- participants are present in this conference session. -If this conference now has six total participants numbered '1' through '6' .then the set of all participants is

defined as " 1 2 3 4 5 6". If the set "3 5" is treated as an exclusion set, then this 'dynamic' set is equal to "1 ,2 4 6", since parties !3' and '5' have been excluded. Since this set is 'dynamic', .if participants '7J and '8' join 5 and participant '4' disconnects,' the new set. would "be "1 2 6 7 8". The important thing to note is that although participants have been added and deleted, no participant needs to send any signaling messages updating their own receive subscription lists, since the other parties , just-

10 use the dynamic set. The last example is an attribute " a=X-ConfLayout : 2 -UpWide" . This attribute is used' 'to; indicate the number of large video windows that a particular participant will be using for their screen layout. This could be used in combination with other

15 participant 'sets' to form a dynamic .'set' that changes based on screen layout. A complete SDP message containing the extensions described here could look like: v=0 o=name 0 0 IN IP4 192.168.10.10 -20 =session

=IN IP4.192.168.10.10 - =0 0

=X-ConfLayout : 2 -UpWide 25 =audio 49170 RTP' AVP 0 =audio 49170 RTP/ AVP 34 =X-RxPartyList : 3 5 =video 49170 RTP/AVP 31 =X-RxExcludeList : 3 5 30

Using 'sets' for Instant Messaging ( IM) . applications : ^■ . Examples of inclusion 'sets'; ¹ would be .a named . buddy/ list, such as 'Family' or ^v Co-workers '. Some ' examples of

exclusion sets would be a 'Blocked' or maybe .a 'Rude People' list.

Here are some examples of simple dynamic sets:

1. Contacts .within a geographic area 2. Contacts who can display video

3. Contacts who have audio

4. Contacts within a buddy .list

5. Contacts that have their presence shown as ¹ On Line ' The dynamic sets can then be used to control which contacts will get your audio and which will get your" video or any other multimedia stream. Of course the real power comes from logical combinations of sets- and the rules that build logical dynamic sets. An IM protocol such as XMPP could be extended to carry these rules, where XMPP is the "Extensible Messaging and Presence Protocol", and' is defined in IETF RFC-3920, incorporated -by refer-ence herein. For example, a dynamic set named 'Contacts 'that can view my video', could be defined as contacts: in my 'Friends' buddy list (set) AND who are in the 'Have. Video capability' set AND are NOT in my 'Bad Hair Day' list.

The IM server could use the sets, rules, ^" and capabilities to build the dynamic 'sets' without secondary signaling from the IM clients. Although the invention has been described in detail in the foregoing embodiments for the . purpose . of illustration, it is to be understood that such detail is solely for that purpose and that variations can" be made therein by those skilled in the art without departing from the spirit and scope of the invention except . ^' as it may be. described by the following claims.