[CLUE-Tech] Need help with kppp Statistics window

[Dave Anselmi]

Charlie Oriez wrote:

[...]


> Other 6 entries aren't so clear.  wtf are "non-vj, vjerr, vjunc
> in/out, and vjcomp in/out" and what should I expect to see grow at
> what reasonable rates as I download the 27M install for NS 6.2.1?
> vjerr sits at 0, which I suspect is a good thing.  non-vj is growing.
> Same with the others.  I can make guesses on them, but I'd really
> like to know for sure.

One option on PPP connections is called Van Jacobsen header compression.
In short, since a PPP link doesn't require all the routing overhead of
TCP/IP, this saves bytes in each packet by stripping them out at one end
and adding them back in at the other.  There are some RFCs listed here:

http://www.acn.purdue.edu/dp/doc/ppp.html

or you can find more through google.

So, non-vj are packets that don't use vj compression.  vjerr is errors,
and the others are vj packets with uncompressed and compressed headers.
(IIRC, early packets in a connection aren't compressed because the far
end needs the info.  Once the info is on both ends it can be stripped
going through the PPP pipe.)

How vjc is used is configurable (on Linux anyway) and may not be
worthwhile on fast links.

(I made most of this up, but it's as good a guess as I have and I'm
pretty sure I'm close.  Obviously my lack of social skills is due to the
large amounts of clutter in my head, like the fact that vj has to do with
compression in the context of ppp - this is my first use of that info,
but it's still in there from years ago when I started networking with
winsock.  Sigh.)

HTH,
Dave