RE: [Embedlets-dev] Peer-to-peer or master/slave
Status: Alpha
Brought to you by:
tkosan
|
From: James C. <ca...@vi...> - 2003-06-29 06:26:03
|
Hi All, I2C of course offers peer-to-peer in with multi-master modes and collision detection. It is the natural contender for a true peer-to-peer protocol as it is already an industry standard. I have no problem with Teds idea of using I2C for peer-to-peer when it is absolutely a must. It is also a fast protocol, as fast as SPI, has a specification for collision detection with hardware support for this.=20 I see two things emerging here UART/SLIP for medium performance Master/Slave Client/Server polling applications which will cover about 80% of the application space. It has the huge advantage as Ted noticed of being able to plug into the PC making it easy to test application etc. I2C/SLIP for high performance peer-to-peer networking Client/Server/UDP which allows applications to also have nodes generate asynchronous events. This is of course only the lowest layers of the Networking Stack so toplevel interfaces can be na=EFve about what's going on down below. James Caska www.muvium.com uVM - =91Java Bred for Embedded=92 -----Original Message----- From: emb...@li... [mailto:emb...@li...] On Behalf Of Bruce Boyes Sent: Friday, 27 June 2003 10:31 PM To: emb...@li... Subject: [Embedlets-dev] Peer-to-peer or master/slave Topic tags:[ARCH][JAPL][WIRING][DOCS][MGMT][STRATEGY][NEWBIE] _______________________________________________ At 01:01 PM 6/27/2003 -0700,=20 emb...@li... wrote: >It is just an idea, but it will work just fine. It will provide a=20 >network exactly like you would see with a TCP/IP switched network, in=20 >terms of topology. Broadcast networks are fine for one or two users,=20 >but degrade quickly... There's plenty of experience that says about=20 >20% utilization is all that you can count on before you get a dramatic=20 >degradation for each percentage above that. > >Clearly there is research going on that has shown some ways to make the >degradation less dramatic (search google for 'CSMA degradation'). =20 >LonWorks has a proprietary solution as do others specific to their use. >The easies and simplest is the round-robin, equal time, equal access=20 >mechanism that I described. It will provide dependable, predictable=20 >data transfer from one peer to another. ...only if there is a reliable master, if I understand your idea. In a true=20 peer-to-peer ad-hoc (I realize I added that just now) network you can't=20 count on any node being present at any time. In fact, in any realtime=20 control network I think that is a good assumption. Whatever nodes happen to=20 be present carry on as best they can, rather than the whole network just crashing. So if a master is required to facilitate all communication amongst slaves=20 there can be no true peers. Only the master and slave(s), and the network=20 should not be called a peer network. Bruce=20 ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01 _______________________________________________ Embedlets-developer mailing list Emb...@li... https://lists.sourceforge.net/lists/listinfo/embedlets-developer |