Re: [lwip-users] lwip + profinet ... possible?

[Simon Goldschmidt]

"Claudius Zingerli" <address@hidden>
> On 2014-02-14 18:44, Pomeroy, Marty wrote:
>> Bandu
>>> Is there anyone successfully implement profinet with lwip?

That depends on what you exactly want. You can't use lwIP to implement profinet 
since it is implemented
on a different level, but you can run lwIP for UDP/TCP things in parallel to 
profinet. This works.

>>> (couldn't find any opensource on google related to profinet stack except 
>>> expensive 3rd party stacks)

Of course not. You won't. No need in searching on.

>> From http://us.profinet.com/technology/profinet/: "Real Time (PROFINET
>> RT): Here the TCP/IP layers are bypassed in order to give deterministic
>> performance...".
> 
> IMHO, there is no point in that. The same stuff is claimed by Ethercat,
> but as I understand it, any protocol - including TCP - would be
> deterministic, given there is a full duplex path, no packet loss and no
> congestion...

Exactly. But as soon as it comes to packet loss, TCP fails while UDP-based
protocols (or Profinet RT) still work. This *is* the point (keeping easier
implementation of the cyclic traffic aside if UDP/TCP/IP is not used).



Simon