Reply by David Hawkins●November 24, 20052005-11-24
Hi Bruce,
> I have implemented a SLIP-like application on a
MC68360 in the past.
> SLIP is really incredibly simple. It's the IP packets straight out
of
> the TCP/IP stack with a checksum shoved on the end. I suspect PLIP may
> be as trivial.
It looks pretty straightforward from what I have seen so far.
First I'm just trying to understand this stuff, and then I want
to figure out if I should take PLIP and port it to a faster parallel
interface, or create a tty interface over something that actually
uses a parallel bus (and can run at MB/s, not kB/s) and then
run SLIP over that.
Hence if someone had already got LwIP working with SLIP, I
would obviously lean towards the tty approach. (Actually
I haven't had a chance to ask that on an LwIP message group
yet ... since I haven't played with the LwIP stuff yet).
> The SLIP I was using wasn't normal...it could
communicate multidrop
> using cascaded devices all talking synchronously (it was a multi-point
> IP network). It never made it out to the real world, but it certainly
> all worked.
>
> At the time the processor was running pSOS+ (a thing of the past now)
> which had a TCP/IP stack and an poorly/undocumented network interface
> layer so I was able to plug in there. pSOS+ = $$$$ and I'd never go
> there now.
Yeah, we had some 68k's running pSOS around here until recently.
> Despite the fact the 68360 had dedicated
communications engines and very
> cool serial port support, the power of the LPC main processors is huge
> by comparison. You should have no problem.
>
> It's worth including compressed header SLIP support if you're
going that
> way. It cuts down the traffic by removing redundant TCP/IP packet
> headers and replacing them with a token to refers back to the original
> header.
I was reading the 'Linux Network Administrator's Guide' and it
mentioned
SLIP and CSLIP. I found the RFC for SLIP, but haven't looked for
CSLIP stuff.
I managed to get a PLIP setup working with the non-ethernetworked
machine being able to surf the web, so I have a much better
understanding of the network configuration now; point-to-point
setup, gateway machine configuration, ARP proxy - all new to me.
I'll play with SLIP after I take a look at the lower-levels
of the Linux PLIP driver to see how the hardware layer works.
>>Happy Thanksgiving! (to all the Americans out
there anyway)
>
> Oh yeah this is the time of year all you Yanks die from badly cooked
> turkeys :)
Actually, they like deep frying them now-a-days. Its nice since
it keeps the fire deparment busy. (I'm from New Zealand,
I just happen to live here, so technically not a Yank :).
Reply by Bruce Paterson●November 24, 20052005-11-24
> I haven't played with LwIP yet, I have an Olimex board that > I'll use at some point with the CS8900
interface.
> But I was wondering if anyone had used SLIP or PLIP in
> applications (LPC or not really)?
I have implemented a SLIP-like application on a MC68360 in the past.
SLIP is really incredibly simple. It's the IP packets straight out of
the TCP/IP stack with a checksum shoved on the end. I suspect PLIP may
be as trivial.
The SLIP I was using wasn't normal...it could communicate multidrop
using cascaded devices all talking synchronously (it was a multi-point
IP network). It never made it out to the real world, but it certainly
all worked.
At the time the processor was running pSOS+ (a thing of the past now)
which had a TCP/IP stack and an poorly/undocumented network interface
layer so I was able to plug in there. pSOS+ = $$$$ and I'd never go
there now.
Despite the fact the 68360 had dedicated communications engines and very
cool serial port support, the power of the LPC main processors is huge
by comparison. You should have no problem.
It's worth including compressed header SLIP support if you're going
that
way. It cuts down the traffic by removing redundant TCP/IP packet
headers and replacing them with a token to refers back to the original
header.
> Happy Thanksgiving! (to all the Americans out
there anyway)
Oh yeah this is the time of year all you Yanks die from badly cooked
turkeys :)
Cheers,
Bruce
Reply by David Hawkins●November 24, 20052005-11-24
Reply by David Hawkins●November 24, 20052005-11-24
>>To see how PLIP works, I've just setup a
couple of
>>Linux boxes and I can ping between them. I have a way
>>to go before understanding all the low-level details, but
>>at least I have a starting point to 'hack on'.
> Why hacking ?
Oh, well I want to start with something that works; PLIP,
and 'port' it over to a DSP running on a PCI board. So, if
I replace the PLIP data transfer routines with my PCI
transfers, I should be able to move from something
working, to something working :)
> Why not reading the RFCs ??
Thats a good point. This is the first time I have played
with the lower-levels of networking layers, so hadn't
even thought of that. I'll make sure to find the relevent
ones.
>>I haven't played with LwIP yet, I have an
Olimex board
>>that I'll use at some point with the CS8900 interface.
>>But I was wondering if anyone had used SLIP or PLIP
>>in applications (LPC or not really)?
> SLIP or PLIP encapsulates IP packet for transfer. Same does Ethernet.
> You just need to know where LwIP starts working with IP packets.
>
That's what I figured. So in much the same way as I am
going to hook into the lowest layer of the PLIP driver,
I'll hook into the lower layer of the LwIP layers.
I just figured I'd see if anyone else out there had
tinkered with this stuff.
Dave
Reply by 42Bastian Schick●November 24, 20052005-11-24
David Hawkins <dwh@dwh@...> schrieb am Wed, 23 Nov 2005 21:50:14
-0800:
> To see how PLIP works, I've just setup a
couple of
> Linux boxes and I can ping between them. I have a way
> to go before understanding all the low-level details, but
> at least I have a starting point to 'hack on'.
Why hacking ? Why not reading the RFCs ??
> I haven't played with LwIP yet, I have an
Olimex board
> that I'll use at some point with the CS8900 interface.
> But I was wondering if anyone had used SLIP or PLIP
> in applications (LPC or not really)?
SLIP or PLIP encapsulates IP packet for transfer. Same does Ethernet.
You just need to know where LwIP starts working with IP packets.
--
42Bastian Schick
Reply by Joel Winarske●November 24, 20052005-11-24
> Yeah yeah, not the most efficient way to deal with > things, this is purely for entertainment at the
moment.
> I can however think of applications where it would make
> sense to waste a little processing power to gain the
> advantage of having multiple independent socket
> communications between devices. (For example;
> communicating between a host processor and another
> processor running on a PCI board - networking
> without a network interface).
An interesting fit for the LPC214x series is the USB Ethernet Emulation
Model. Linux directly supports it, and Win32 via an inf file.
Reply by David Hawkins●November 24, 20052005-11-24
Hi all,
Since there are a bunch of knowledgable microcontroller
and Linux developers that read this list, I want to
describe a concept and see if anyone has developed
parts.
I want to look into connecting devices using networking
interfaces. In some cases the 'network' will be a
simple point-to-point link using a serial port (PLIP)
or the parallel port (PLIP), or a real network controller
(eg. like the CS8900's on the Olimex boards and others).
To see how PLIP works, I've just setup a couple of
Linux boxes and I can ping between them. I have a way
to go before understanding all the low-level details, but
at least I have a starting point to 'hack on'.
Now, at some point I'd like to replace the second
Linux box with an LPC. The caveat is now the LPC needs
to implement the other side of the PLIP protocol,
and include a TCP/IP stack for dealing with packets.
Yeah yeah, not the most efficient way to deal with
things, this is purely for entertainment at the moment.
I can however think of applications where it would make
sense to waste a little processing power to gain the
advantage of having multiple independent socket
communications between devices. (For example;
communicating between a host processor and another
processor running on a PCI board - networking
without a network interface).
I haven't played with LwIP yet, I have an Olimex board
that I'll use at some point with the CS8900 interface.
But I was wondering if anyone had used SLIP or PLIP
in applications (LPC or not really)?
Of course I will share my results.
Happy Thanksgiving! (to all the Americans out there anyway)
