WebRTC: Possible? Don McGregor Research Associate MOVES Institute.

Transcription

1 WebRTC: Possible? Don McGregor Research Associate MOVES Institute

2 The World Classic simulation applications: can we do them in the web browser? Pretty much. I think. 2

3 1990s Start: Classic Applications Classic PC/Unix application UDP and TCP network updates Classic applications It works A classic! 3

4 Classic 4

5 Classic Display Display App Logic App Logic C++/Java C++/Java N hosts that receive and send data. The logic in the applications is extensive and tricky, app is usually installed Hosts are classic workstations No web server needed; can do classic image displays Clients use TCP or UDP Network 5

6 Classic Works pretty well since circa 1995 or before! Network updates fine; no HTML web browsers needed at all, just get the classic message exchanges in DIS or HLA Sims can be kind of complex, but it all works Can use HLA, DIS, etc; it s all fairly cheap and straight forward 6

7 Modern Improvement Thinking? Web-based apps unrelated to DoD simulations : facebook Many Google apps for writing, etc Modern Microsoft Live, etc What they re up to seems like web-driven apps using TCP Do something similar but for sim apps; practical? Yes, some apps similar for web apps Compelling concept for nearly all apps, still catching on OK, lets do this for DoD simulations as well 7

8 DoD Simulations Install sim web app on local host (similar to facebook et all web apps with TCP updates) Web-based sim applications are compelling Go to URL, app loads No official installation other than web-based app Sim can run on desktops or phones, indifferent about OS OK performance for some apps 8

9 Web-Based The web browsers load the web app code from the server side, run the application. New code is loaded every time Some indifference to browser vendor Classically TCP socket updates; a web app contacts the server over TCP At least some commercial support for web sims, mostly mapping Server Side Client Side 9

10 Desktop v. Web Classic Desktop Web-Based High Performance Classic TCP/IP networks Long upgrade cycles for apps Stable PC platforms It works Cheaper Good enough for some apps Apps use Javascript variant Mobile-friendly Fast upgrade cycles, app is always downloaded from the HTML server Thousands of sources for other types of data on the web Web apps starting to go down this 10

11 Javascript Logic So far so good! We have a basic web implementation that can Send & receive TCP updates A compelling update for custom apps Do standard web apps 3D, 2D mapping Classic real time updates Works well for a lot of things All using web app updates for the user Compelling arguments in some ways 11

12 But! Classically we receive entity model messages from the sever over TCP Works OK for some, but can fall apart if there are classic TCP message delivery problems Questionable support for UDP at best Should also get classic message format updates over UDP because using TCP has some inherent drawbacks What do we want? 12

13 Web App Sim updates via classic TCP In Web Sim updates via UDP in Web In principle an app can receive web updates via both TCP and UDP

14 To Do We want a web application that Gets UDP-style updates in web browser In broadcast Doing classic sim app Makes it look a lot like a classic simulation application, only in a web browser app Can we? So far, yes, still working on this 14

15 Details Apps should receive classic UDP bcast updates Probably in DIS format DIS is stupid simple, already there, binary HLA doesn t work well in Javascript Try to stick to classic formats for this instead of inventing yet another format Solve classic real time apps 15

16 To Do: UDP Updates We can do that (probably) by getting update messages over UDP, in addition to TCP updates WebRTC is an emerging classic, intended to do UDP to clients, vs TCP over classic web apps Do we have that for UDP updates? Probably. WebRTC implemented most media aspects only in the last few months 16

17 DIS: WebRTC 17

18 WebRTC Support by browsers for WebRTC--MS Edge: April 2017; Firefox: March 2017; Chrome: since April 2016; some Android mobile support since Spring 2017 Global platform support for WebRTC at ~60% now, higher inevitable HTML clients can receive and send UDP updates for data. (I think. If this goes horribly wrong we can also eventually use QUIC, may do it eventually anyway) 18

19 To Do: Web Implementation Application DIS binary Javascript implementation: easy to do; text updates kinda bad, classic binary updates preferred No need for text format message contents; does not scale as well, binary updates compelling for large apps 19

20 Classic Desktop vs Web Classic Desktop Web-Based High Performance Classic TCP/IP networks Long upgrade cycles for apps Stable PC platforms It works Classic apps with DIS updates Using UDP (for some) Sort of OK for some applications Pretty compelling for simulations 20

21 Web: TCP or UDP? Old: all web updates go over TCP Newer: can send & receive web updates on UDP as well Sorta works for some things. I suspect I will discover some problems Single thread for whole Javascript app? Recover if anything goes wrong? Even in UDP, can we recover if sockets dry up? 21

22 Solution? Looks promising in some ways Industry did UDP support for web-based, but I suspect they did that only for some things Still figuring this stuff out 22

23 Other Things Unrelated: Writeup of DIS for multiple languages Only a few hundred K lines to go! Multiple programming languages Java, C++, Javascript, C#, Python Multiple explanations Way more than I thought at first 23