[TI-H] Re: I remember hearing of a ti hub project a few years ago...
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[TI-H] Re: I remember hearing of a ti hub project a few years ago...
>Yes and no, 10BaseT ethernet networks do require a hub, but other networks
>like
>thinnet and token ring don't.
>
>In fact all a Hub does in a 10BaseT network is connect the output of the
>sender
>to the input of the recever(s),
In fact, a hub doesn't even do that. It just connects the cables together,
(with repeating, that is strengthen the signal) so that they all from the
nic:s point of view, is all on the same cable.
a switch, or a router on the other hand, is a bit more smart, and looks on
the reciever and forwards the packet only on the port/segment that has the
reciever. (if it knows where it is, else it sends on all ports)
>but in thinnet all the data is on the same wire,
>and on token ring the output of one host is conneced the input or the next
>host
>until the last host is connected to the first.
Anyway, this was why I proposed an ethernet (both 10baseT and "thinnet" (or
10base2) is ethernet) or token ring sollution. you could probably get away
with a simple hub like this:
(turn on fixed with font, if you don't have it already)
"hub"
_____
| | red
| o--|========================|Calc1
| /| white
| | |
| \|
| |========================|Calc2
| /|
| | |
| \|
| o--|========================|Calc3
|_____|
did you understand? :) connected like an ethernet..
the o is some kind of terminator so you don't get bounced back signals
(just like standard ethernet). Thoose could be tricky with the calc
cables... I for one don't know what value they should have. Could probably
be measured.
for a token ring connection you connect the o:s with eachother instead. (no
terminators, ring network)
Maybe you need some king of amplifying too in the hub, but probably not for
just a few calcs. and the calcs will have to resend everything that comes
on the port so they will in fact handle the amplifying.
This will ofcourse not be compatible with the standard ti link protocol,
but you have to code your own ethernet drivers. could probably use a lot of
methods from standard ethernet like CSMA/CD for cable acsess, and a similar
way of encoding bits on it. and then a stripped down frame format, a bit
overkill with those large adresses for example, to much overhead in this
small lowperformance thing.
Or borrow from token ring if that is what you choose...
I think it could work... with the linkport beeing open collector and all.
(they are, aren't they? I'm quite sure they are) could maybe work even with
using only one of the cables, and not having the calcs resend everything.
I think a token ring could be a quite good choice though. or a kindof-token
ring, where you send a whole packet from one calc to the next all the time,
using a kind of token-system for telling who can send data and such.
Then you don't need to implement CSMA/CD either, since no collisions can
occur...
what do you think?
hmm.. I need more calcs, Only have one :) and vti ofcourse... maybe can
borrow a friends calc too.. hmm.
//Olle
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