[lwip-users] Re: [lwip] Specifications

[Kieran Mansley]

On Wed, 26 Jun 2002, Jim Purbrick wrote:

> Hi,
>
> I'm developing a TCP like protocol over UDP and have been using LWIP as an
> exemplar alongside the RFCs, but there seems to be quite a lot of
> differences between the RFCs and what LWIP is doing. Where does LWIP differ
> from the TCP specificiations, which specs is it based on and what are the
> current TCP specs?

I can't speak for Adam, but you should be aware that a lot of the TCP
related specs are extensions or additions for higher performance.  lwIP in
general has implemented a fairly minimal set of TCP functionality, but
should be compatible with more "complete" stacks.  lwIP implements a
subset of RFC1122.  All those parts that are required for host to host
communication are included, but some of the requirements for communication
between the application and network stack are not.  (eg. Soft error
reporting and type-of-service bits).  Section 4 of Adam's paper "Full
TCP/IP in 8 Bits" explains this in more detail, and is a good read if
you're doing lwIP stuff.

http://www.sics.se/~adam/publications.html

Kieran



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