1 Implementing a WebRTC Web Based Vide Cnference Slutin Ricard Vicente, Amaral Carval, André Sants Edubx Abstract Current dcument cntains the prpsal f a framewrk that allws building Web Vide Cnference applicatins. It is prpsed that this framewrk uses HTML5, JavaScript and WebRTC t implement all its features. With this slutin it must be used a TURN and STUN Server, t slve the NAT prblems that are nt yet slved by WebRTC technlgy. It will be develped a Client Javascript Library that will be respnsible t prvide a public service allwing receiving and bradcasting all peer s messages prir t the peer-t-peer cmmunicatin channel establishment. TURN and STUN Server will be respnsible fr allwing peers t gather their public infrmatin and create a WebRTC cmmunicatin channel. Client Library will implement all cnnectin and stream management features. This Library can be used t develp any web-based slutin cntaining vide and audi cnferences, data exchange and an Instant Messaging Service. The framewrk has been tested in a real case scenari, and prved that is wrking. V I. INTRODUCTION ide and audi cnference as well as Instant Messaging slutins are currently widely used by users t interact with each ther using an Internet cnnectin. Slutins such as Skype, Ggle Hanguts, and Facebk Messenger are a nice example f the previus statement. The implementatin f these slutins with all f these features is cmplex because the vide/audi prtcls are mainly private. The use f these slutins is hwever increasing at the same time as the quality f Internet Cnnectins and s there is an increasing demand n slutins that prvide a gd user experience and that can be accessed frm different devices, such as smartphnes, tablets, desktps and smart TVs. This brader scpe f pssible devices brings even mre cmplexity. The different devices hardware and sftware pses different challenges and restrictins t the develpment f a vide and audi slutin. Develping a slutin fr each device independently besides being cmplex, will als be incredibly time cnsuming and therefre substantially expensive. II. PROPOSED SOLUTION The current sectin will present the prpsed slutin and will explain pssible prblems and slutins regarding the implementatin f a web based vide and audi cnference framewrk. It is purpse f the current dcument t define the slutin architecture, mdules, features t be implemented and technlgies t be used. It will therefre be presented the WebRTC architecture in general and where it can be used. Nwadays the main prblem fr this type f slutins, is that peple want t access t thse frm anywhere and frm any device. It is prpsed a web slutin t slve these prblems and minimize future prblems with new devices t supprt. With the evlutin f web brwsers in all devices, is nw pssible t prvide rich web applicatin slutins. Nwadays the slutins develped are managed t wrk in all devices, this way is pssible t adapt the same slutin fr different devices. Fr example, a desktp slutin can fully wrk in a device mdule adapting the slutin t the device screen because the cre f the slutin is nly brwser dependent. With that, it is pssible t develp appealing and intuitive slutins reaching all the devices, by develping a slutin that is device and perative system agnstic. Fr this apprach is nly necessary t make sure that the brwser is fully functinal and updated. Besides this, building an adaptive interface will allw with less effrt but withut discarding functinality r usability t build an unique slutin that will target all available platfrms. HTML5 is anther technlgy that intrduced new fixtures t the web. Using this technlgy it is nw pssible t have elements such as vide and audi directly in the HTML cde. This new elements are respnsible t play media streams t the users, withut adding any plugin t the brwser. All mdern brwsers currently supprt these features being pssible t use these elements in smartphnes, tablets and desktps. HTML5 als enabled the appearance f ther framewrks, such as WebRTC. With WebRTC is nw pssible t implement vide and audi sharing features. This technlgy cnsists in an API defined by Wrld Wide Web Cnsrtium (W3C) as well as a set f prtcls specified by the Internet Engineering Task Frce s (IEFT). With WebRTC is pssible t have cmmunicatin ver vide, audi and data, in a direct peer-t-peer cnnectin channel, allwing these peers t exchange infrmatin directly. T create that channel between peers is first necessary t exchange infrmatin ver a server, and fr this, WebSckets can be used.
2 After negtiating the terms f the cnnectin ver SDP (Sessin Descriptin Prtcl), the channel peer-t-peer is created, and can be further updated, by renegtiating the streams. Currently the fllwing brwsers have native supprt fr WebRTC: Desktp PC Andrid ios Ggle Chrme (v23 r higher) Mzilla Firefx (v22 r higher) Opera (v18 r higher) Ggle Chrme (v28 r higher) Mzilla Firefx (v24 r higher) Opera Mbile (v12 r higher) Ggle Chrme (v28 r higher) Mzilla Firefx (v24 r higher) Regarding the previus supprt infrmatin it is pssible t see that nt all platfrms will be able t use the develped slutin. Internet Explrer r Safari s brwsers currently d nt have native supprt t a WebRTC based slutin. But cnsidering that users can have different brwsers n their devices, it is still crrect t say that the slutin can be used in any device. A. General View Figure 1 - General View Bellw is displayed an image cntaining the general view f the slutin t implement. Framewrk will cnsist n tw internal dependent entities and an external independent entity, being all these entities able t interact with each ther. With the cmmunicatin between all these three entities, it is pssible the establishment and maintenance f a peer cnnectin used t exchange media stream infrmatin. Client Library will be able t be embedded at any web applicatin t prvide all features assciated with the WebRTC technlgy. TURN and STUN entities will cnsist n standalne server applicatins that will allw users t pass thrugh NAT and cmmunicate withut any prblem. The NdeJS, is anther standalne server applicatin that will prvide lgic t exchange SDP infrmatin between peers allwing the creatin f a peer cnnectin. This cmpnent is als respnsible fr the Instant Messaging service, prviding lgic t exchange messages between peers thrugh a scket channel. 1) NdeJS Server Cnsists n an individual service that will allw peers t send private, public and instant messages amng ther cnnected peers. The clients that are cnnected t this service thrugh the Client Library using a scket cnnectin will be able t create a bi-directinal channel used t send and receive messages. NdeJS server will accept scket cnnectins and will allw bradcasting messages t all targeted peers. It will be pssible t exchange infrmatin that will be used t create a direct cmmunicatin channel by using webrtc specificatin and brwser s native implementatin allwing the further sharing f media streams. a) Rm Management The NdeJS Server includes a Rm Management mdule that allws creating a rm where multiple users can jin and bradcast messages, allwing that nly interested users in that channel will receive its messages. Users will then be able t either register r enter in a pre-created rm being scheduled t receive all ntificatins and public messages assciated with the registered rm. Features assciated t the management f a rm: Register t Rm Check if Rm is created Discnnect frm Rm Return current users in a given Rm It is prpsed that the server will nt handle rm id generatin as well as permissin management. In this way is pssible t prvide a service with quick respnse system. Figure 2 - General View By prviding a rm management apprach is pssible t bradcast messages thrugh users, making easier t knw wh enters r exit the rm, r even wh is sending a message.
3 b) Chat Bradcaster This cmpnent frm the NdeJS server is respnsible t bradcast Instant Messages thrugh users that are at the same rm. In this case nly exist the cncept f public messages, because the cntext is a rm with ne r mre persns. If it s needed t send a private message t a specific user, is pssible t create a rm between nly tw peers, in that way is pssible t send private messages, because in that rm nly exist tw persns.. 2) TURN and STUN Server One f the biggest prblems with the WebRTC technlgy is hw t enable peers t have a direct cmmunicatin channel between them. In a cntext where they are in different netwrks arises the need t pass thrugh their respective NATs, s is nly pssible t create a direct channel knwing their respective public IP address. TURN and STUN Server will prvide a public endpint and allw client s t retrieve their public IP address, type f NAT and ICE candidates that will enable tw clients t create a direct cmmunicatin channel using WebRTC API and prtcls. The mdules respnsible fr that are STUN (Sessin Transversal Utilities fr NAT) and TURN (Transversal Using Relays arund NAT). STUN server will reply t client requests with their public address and sme additinal infrmatin, like the type f NAT f their netwrks. The specificatin f this mdule is nt in the cntext f the current dcument. There are bth third party services as well pen surce implementatins, that prvide this service and s, n new pints r cnclusins can be retrieved r accmplished in the develpment f a service that already is widely available and dcumented. 3) Client Client Framewrk will cnsist in a Javascript Library that will allw using WebRTC features. By ding this, it is pssible t create a web app with the WebRTC features, in an easier way. The features f webrtc will be encapsulated in the Cliente Framewrk. T make it wrk it, Client must be able t cnnect t the NdeJS server ver sckets, enabling clients t cmmunicate and negtiate all the necessary sessin descriptrs t have a peer cnnectin, and d a vide audi cnference. a) Streams Management This mdule will be respnsible t capture and manage streams. This mdule will manage all the lgic assciated t with bth lcal and remte streams. It will be pssible t share audi, vide r audi/vide. The fllwing features will be prvided: Enable lcal audi nly Enable lcal vide nly Enable lcal audi and vide Disable all lcal streams Receive remte streams Receive ntificatins frm streams changing Renegtiate sessin descriptin Enable remte user s stream receptin Disable remte user s stream receptin Users will be able t tell frm their third party applicatins which media streams the user desires t share and receive any ntificatin abut the changes that ccur at the same time that they are in a cnference. In rder t implement these features, getusermedia brwser functin will be used. All current scped brwsers (Opera, Chrme, Firefx) wh supprt WebRTC features d prvide this functin. Every time a user changes lcal sharing streams all users currently registered at the same rm will be ntified f the change. Fr each peer cnnectin that was currently used t share lcal stream, the re-negtiatin peer cnnectin rutine will be restarted in rder t re-create a new cmmunicatin channel with the updated streams. Will be pssible fr the users t tell the third party applicatins which type f stream they want t receive. S if a user is sharing audi and vide at the same time, the peer can chse if wants t have audi and vide, vide r just audi. b) Cnnectin Management Cnnectin Management s purpse is t bradcast public and send private messages, implementing the fllwing features: Bradcast message Public messages will be sent t users that are in the target rm. This feature will be mainly used t send ntificatins. Send private message T establish a channel peer-t-peer is needed that the at least tw users cmmunicate with each ther. This part f the Cnnectin Management is respnsible fr manage the private messages between tw users. By ding this is pssible t exchange infrmatin abut the sessin descriptin assciated t the sessin that they will have, making sure that n ne receives r intercept this infrmatin. All the messages that are sent and received (public r private) will be nt stred, s the histry f the cnversatins will be nt accessible. T implement this part f the Framewrk is prpsed t use Nde.js technlgy. Nde.js is a platfrm built n Chrme's
4 JavaScript runtime fr easily building fast, scalable netwrk applicatins. Nde.js uses an event-driven, nn-blcking I/O mdel that makes it lightweight and efficient, perfect fr dataintensive real-time applicatins that run acrss distributed devices. Scket.IO is a mdule that is supprted by Nde.js and is specially targeted t real time web applicatins. Nde.js is highly qualified fr applicatins that have a high number f cncurrent cnnectins and capable f manage each request with a lw prcessing time assciated. c) Peer Cnnectin Management This mdule will be respnsible t manage each peer cnnectin in a cnference. All the events assciated t a peer cnnectin are managed by this mdule, such as if a user cnnects/discnnects r even share streams (remte r lcal). This mdule will be respnsible t establish r re-establish cnnectins. The direct interactin with TURN/STUN Server will be made by this mdule t, and use the native WebRTC features t d that. Each time that sme event related t the cnnectin ccurs it will be respnsible t ntify the users ver the third party web applicatins. 4) Slutin Wrkflw descriptin has been exchanged. T renegtiate streams and sessin descriptin. When this WebRTC channel is created is pssible t have a audi, vide r audi and vide cnference. B. Develpment f the framewrk In rder t validate and test the prpsed slutin, a framewrk was develped using the prvided specificatin. Nde.js technlgy was used t develp the defined features, allwing users t create/enter rms and send private/public messages. An pen-surce TURN and STUN Server prvided by an external entity was used as well. Javascript was used t develp the Client library and all features assciated with the specified mdules. A Library was made t prvide an abstractin t all webrtc and stream management implementatin using a ntificatin system. This way it is pssible t enter/leave a rm while als sending ntificatins t the clients in that rm. The ntificatin system is als implemented t lcal/remte streams t display thse at the third party web applicatin. By using this library, third party slutin will nly have t implement bth ntificatins and HTML5 vide/audi displays systems that will use streams prvided by the Client library. C. Third Party Applicatin T test the develped framewrk, it was necessary t create a third party applicatin that uses all the cncepts f this framewrk. It was develped an applicatin where is included the vide and audi cnference cmpnent. This applicatin was develped targeting all the devices that were mentined befre in this paper, such as smartphnes, desktp and tablets. This is an adaptive applicatin that is ptimized t all screen sizes, and was nly wrte nce. Figure 3 - Peer cnnectin establishment Figure 3 explain the general wrkflw f the general Framewrk: 1. Alice create a rm and enter in the rm. 2. After that Bb enter in the same rm as Alice 3. The NdeJS server send a bradcast t all users registered in that rm 4. Alice receive that ntificatin cmmunicates with TURN and STUN server t retrieve its infrmatin abut its public IP. 5. Bb receive that ntificatin cmmunicates with TURN and STUN server t retrieve its infrmatin abut its public IP. 6. After that the infrmatin retrieved with the TURN and STUN service is sent ver the NdeJS Server, fr the specific peers by the private messaging service. A new peer cnnectin is created between Alice and Bb using the sessin Figure 4 Big screens view
5 [2] http://www.w3.rg/tr/html401/ [3] http://dev.w3.rg/2011/webrtc/editr/getusermedia.html [4] http://tls.ietf.rg/html/rfc5245 [5] http://www.webrtc.rg/reference/architecture#toc-stun-ice [6] A. Bergkvist, D. Burnett, C. Jennings, A. Arayanan, Webrtc 1.0: Realtime cmmunicatin between brwsers, 2012 [7] Thmas Sandhlm, Bris Magnussn, Bjrn A. Jhnssn, On-Demand WebRTC Tunneling in Restricted Netwrks, 2014 [8] Max Jnas Werner, WebRTC Security in the cntext f a DHT Implementatin, 2013 [9] Hitendra Patil, Amar Buchade, Review and Study f Real Time Vide Cllabratin Framewrk WEBRTC, 2014 [10] Justin Uberti, Cullen Jennings, Javascript Sessin Establishment Prtcl, 2013 Figure 5 Small screens The previus figure shws that the slutin has the all features that were prpsed. Prvides slutins fr: Vide Cnference Audi Cnference Vide and audi Cnference Smartphne Slutin Desktp Slutin Tablet Slutin This slutins enables user t cmmunicate with each ther, ie, the users can be in different devices, withut having t cncern all the prblems assciated with creating, managing peer cnnectins amng users and WebRTC features. D. Cnclusins The Prpsed framewrk, allws t have a generic implementatin f WebRTC features, such as vide and audi cnference. This framewrk can be used fr web based slutins, and can be implemented t different devices, having cmmunicatin with each ther. The specificatin presented in the dcument, is a valid apprach and was prved by develping the prpsed framewrk and a Third Party applicatin, withut needing any further specificatin r changes. The third party applicatin prved that is pssible t integrate the framewrk in a real case scenari, prviding all the features that where described. REFERENCES [1] http://www.w3.rg/security/wiki/same_origin_plicy