LAG

***** LAG *****

The "ping" command shows your lag, or network latency.  The "lagstat"
command gives the average lag per chess move over all players on the
ICC.  If your lag is much worse than the average, there are problems
local to you.

There are sites such as http://www.internettrafficreport.com  and
http://www.internetpulse.net that give latency and packet loss
statistics for various internet connections around the world.

Basic info about lag:

"Lag" occurs when there is a delay in receiving a response to a
command you have sent out over the internet.  When you send a
command to the ICC, it travels through a variety of computers and
communications equipment to the ICC, gets processed by the ICC,
and then gets sent back to you.  Your signal has to go through
many machines and cables on the way to and from ICC.  With the
number of people using the internet growing every day, many of
these machines ("routers" that redirect data) and cables are being
overloaded, and delays occur.  It's similar to rush-hour automobile
traffic in a big city.

Most of the time, by far the most latency is in your connection
to your local Internet Service Provider (ISP), especially if you
use a dial-up connection.  Upgrading to DSL, cable modem, or other
high-speed digital service is the best thing you can do to
reduce your lag.

The Flexible Lag Compensation system determines how much lag time you
will be compensated for during games.  In regular games on ICC, you will 
be compensated for up to one second (1000 milliseconds) of lag per move.  
If your lag is less than one second, as it is for 98% or 99% of players, 
none of the lag will be charged to your clock. If it exceeds one second 
during any move, your first second of lag time is "free" and any 
additional lag time will be charged to your clock. "help LagCompensation"

Questions about lag:

1) Why is lag good on some days, and bad other days?

Sometimes there are problems on the network regionally or globally,
e.g. if a backhoe cuts a cable, or a denial-of-service attack
clogs a gateway.  And sometimes the ICC server is a little
slower when we're making backups.

2) Why do some people on ICC have lots of lag, and other people don't?

The main factor is what kind of connection they have to their ISP (dialup
or broadband) and the quality of that connection.  An important
secondary factor is where they live, what ISP they use and how good
their ISP's connection is to the backbone of the internet in the USA
that day.  E.g. a satellite connection adds almost 250 ms extra latency,
because takes a signal that long to get up to the satellite and back,
even at the speed of light.

A traceroute utility can show you the routers along the your path to ICC,
and may give some indications of where the problems lie.  At the MS-DOS
prompt try "tracert chessclub.com".  For a traceroute the other direction
(from ICC to your site), visit
http://king.chessclub.com/cgi-bin/nph-traceroute

3) Why doesn't the ICC buy a bigger, more powerful computer?
   Why don't people stop shouting, so lag will get better?
   There are too many people logged into ICC, and it's causing lag!

We do upgrade our hardware regularly.  But the server's CPU load is
rarely a significant factor in the lag.  Packet loss is by far
the larger factor.  If you are stuck in rush-hour traffic, driving a
Ferrari won't help :-)

Nor is the bandwidth used when a couple thousand ICC users are
logged in and playing games really significant in causing any
network congestion, since it's a small amount of data compared
to all the images and videos transmitted by other sites.

4) What can I do about lag?

Be sure to use ICC's "timestamp" system, which effectively ensures
that your clock doesn't run while your move is in transit.  It's
automatically included in Blitzin and most other interfaces.
"help timestamp" for more information.  The "ping" command will
tell you if you don't have timestamp.

When you are playing chess, it is best not to be receiving a lot
of other data such as shouts and channel chatter, because there
is one stream of data from the server to you, and your computer
has to receive and process all of that data in its correct order
before it can get to the crucial information:  what move your
opponent just made.  "set quietplay 1" helps by blocking the
chatter while you are playing.

Also, it's best not to be doing a lot of downloading of data
while playing, as that will congest your internet connection.

You can try different internet providers, to see if there is one
that gives you less lag.  Different providers are connected to
the internet at different places, so their lag can vary.  You can
also try playing at different times of day; often there is a bit
less lag after working hours and on weekends.

You can use our backup server at queen.chessclub.com, which we have
provided for our members.  You might have less lag on that machine.

See also: lagstats, quietplay, timestamp