Re: SD: Networking - tell me about it
[Prev][Next][Index][Thread]
Re: SD: Networking - tell me about it
Why the first calc? That's means this hast to know it's the first calc and have
special code to handle this... Why not operate the system peer to peer basis.
Network addressing would be perfomed as follows:-
1) Send an Anonamous Broadcast packet onto the network contrain a string such as
"HELLO TOMC86"
2) Other calculators recive packet, they then send a Sourced Broadcast packet
saying "HI<name>"
3) The others update their list of what calculators are on the network
(distribution list)
4) Calculator recives responses, and from this it can see which net addresses
are in use and pick a free address
5) Unit rountinly sends null packets (Keep Alive) otherwise it will be reomeved
from the others distribution list
6) All calculators on the network now have a list of all other calculaors
network addresses and their textual names
7) User loads a network application, for example a Racing Game
8) Application displays distribution list and User selects for example: MATTH92
9) MATTH92 is sent a packet asking he wants to play the game
10) MATTH92 is also running the game so a message appears asking if he wants to
play. He accepts and a two way diolouge established.
11) ROBINK83P is also running a version of the racing game. He selects MATTH92
from the list.
12) MATTH92 is in the middle of a game, so his calc replies with message to wait
13) MATTH92 finishes his current game, he accepts and ROBINK83P's network
address is passed on to TOMC86. A three way diolouge is established.
14) TOMC86 gets bored of then game and quits. This should be detected using the
top-level (game specific) protcol. Both MATTH92 and ROBINK83P detect this and
remove his car from the game.
15) TOMC86 subsequently turns off his calculator and pulls out the link cable,
thus he stops sending Keep Alive packets. After the Keep Alive Time Limit has
expired all the calculators remove him from their distribution list.
This is an example of a fairly high level protocol, it assumes an underlying
protocol that can facilitate ethernet like packet exchanges. I think in general
directly interconnecting the link cables is a bad idea for this sort or
protocol, though it will still present huge problems for any sort or protocal
attempting to establish 3 way or more communication. For example: collision
detection! A microcontroller (PIC?) and suitable driver circuitary built into an
interface could allow TI calculators to use a far more robust, suitable system
for multi-node communication (such as SHL, Ethernet, Dasiy-Chain Routing, etc).
---Robin Kay---
References: