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Subject: 
Lego Network Protocol questions
Newsgroups: 
lugnet.robotics.rcx.legos, lugnet.robotics
Date: 
Fri, 30 Apr 1999 16:31:27 GMT
Viewed: 
1878 times
  
Hi all. I came to the discussions on the LNP a bit late and was wondering if
the following questions had been discussed (I flipped through an old
Communications course book and noted some thoughts):

- Can we do Carrier Sense *whilst* we are transmitting? This would help in the
sensing of collisions.

- What is a reasonable segment size? This relates to expected interference.
I've yet to start my own experimentation and I was wondering if anyone knew
just what the noise was in a "friendly" and "hostile" environment.

- Is the protocol slotted? By this I mean: can any RCX transmit when it feels
like it or does it have to start/end within the boundary of some slot? If we
were to use slots I think the throughput would be higher (slotted protocols are
generally better than non-slotted ones in terms of collisions). To have slots
we'd need some sort of synchronization signal, perhaps through one embedded in
the wire-line signal? If no such synchronization signal is available, we could
possibly establish a group clock through an initial community-time protocol.

- If we do have slots, can we get non-data messages to fit in? That is, say an
irpd wanted to do its thang with the IR as a sensor medium, could we get it to
play ball and only transmit in it's own slot? How frequently does the irpd
blurt out as compared to how often we send segments (and hence how big a slot
is)?

- In general, I was wondering what the low-level protocol details were, apart
from the frame/segment details that I have seen?

Much Thanks,

Mike



Message has 2 Replies:
  Re: Lego Network Protocol questions
 
(...) Transmit whenever you feel like it and hope you didn't obliterate data coming from the other direction. Rudimentary, but still quite effective given the typical use pattern with is host driven command/response. With RCX to RCX communication (...) (25 years ago, 30-Apr-99, to lugnet.robotics.rcx.legos, lugnet.robotics)
  RE: Lego Network Protocol questions
 
Sorry, I have been out of the loop for quite some time now on the protocol. Next time will someone smack me when I voluntarily take a compiler theory course on top of 3 other computer sciences courses. I had no life for over a month. I am currently (...) (25 years ago, 5-Jun-99, to lugnet.robotics.rcx.legos, lugnet.robotics)

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