Re: Session tracking

> 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
discussions.

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
tmaslen@verity.com				My opinions, not Verity's

Received on Wednesday, 19 April 1995 18:20:18 UTC