Re: Session tracking

Thomas Maslen (
Wed, 19 Apr 1995 18:28:16 +0500

> This can be implemented in about 500 lines of C code so it's not
> really as complex as it might sound.

This is not one of the more reassuring comments I've seen in WWW design

We're not just implementing a client or a server; we're doing protocol
design. Protocol design is hard. (Well, good protocol design is hard).

The best example I know of this is a message that Van Jacobson sent (in
1988?) describing modifications to TCP to deal with congestion (slow-start
and congestion detection/backoff). It's a pretty long and dense E-mail
message. Almost all of the message is an analysis of the problem and a
solution; the code to implement it is something like two variables and half
a dozen lines of code (and, I think, no changes to the bits in the protocol
spec, just a change in the way that implementations use it). It's a small
change, but it makes all the difference to how the net runs (a small matter
of avoiding meltdown).

So... "it's only 500 lines of C" may provide a reasonable comfort level
for, say, a discussion about a whizzy new GUI feature, but when it's about
a protocol it's pretty scary.

Thomas Maslen My opinions, not Verity's