Re: Java applet - UDP or TCP?

[Kevin Hawkins <lists@xxxxxxxxxxxxxxxxx>]

xAP being UDP is intended for LAN operations. If you wish to reliably
pass xAP between devices on the internet (cf intranet) then you should
use TCP.  There are two routes to this , firstly you could use one of
the existing xAP router applications or secondly you should create a
socket level connection at your application level. You can still send
the xAP packet exactly as you did for UDP.  The difference is that once
you move to TCP you forfeit the broadcast nature of xAP If this is
important, and in most cases it will be,  then you should  repeat
received packets locally at each end of the internet link using UDP and
a broadcast address.   This is effectively what the xAP router does,
although often they have some added features to support multiple
endpoints, security and selective message filtering across the link.

Kevin

James has the XServer router..
http://www.mi4.biz/modules.php?name=Content&pa=showpage&pid=37

& Patrick has a router ...
http://patrick.lidstone.net/haweb/router.htm


Kevin


estratosapiens wrote:
> I was planning to develop a Java Web applet that should stablish a
> communication socket with the Web server. This Web server already
> "speaks" xAP, so, I thought about the possibility of using
xAP between
> the Web server and the Java applet (instead of the typical TCP socket
> connection). I have some doubts:
>
> Using UDP instead of TCP is not (maybe) a good idea when communicating
> over Internet. Here I have no more idea than what I've read in some
> posts. Has anyone get xAP to work over Internet? Problems with
routers?
>
> If I decide not to use xAP or UDP for this application, is there any
> communication standard for home/industrial automation and related with
> TCP client/server connections? I know Modbus but I'm not sure whether
> it's TCP oriented.
>
> As you see, I'd like to avoid dealing with different communication
> protocols. Nevertheless, I know that every thing has its place.
>
> Any light over this subject is wellcome.
>
> Thanks in advance,
>
> Daniel.
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