rec.autos.simulators

Here's hoping Randy Cassidy will chime in...

I am curious, in the FAQ's and discussions it has been said that both
client and host need to have the same settings in their core.ini file.
However, this does not seem "necessary" in order for online connections
to work.  The big question is, whose settings take precedence, the
host's or the client's?  

The reason I am asking, is that it would appear (though I maybe greatly
mistaken), that a host running via cable, ADSL or T1 with enough upload
bandwidth could maximize performance by setting the core.ini as follows:

net_mdm_client_send_every = 3    ; Client packet freq on dialup
net_mdm_client_send_size = 84    ; Client packet size on dialup
net_mdm_server_send_every = 3    ; Server packet freq on dialup
net_mdm_server_send_size = 340   ; Server packet size on dialup

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

Both :-)  The host uses the server_send values to determine how much
and how often it can send data to each client.  The host uses the
client_send values to determine how much and how often it should expect
to see data from each client.  (Note that the sizes are maximums -
frequently it won't be necessary to send that much data, so smaller
packets will be sent (ever notice that your modem lights glow brighter
while in a race with several cars than when selecting parameters for
the race?))

Similarly, the client uses the client_send values to determine how
much/often it can send to the server, and the server_send values to
determine how much/often it can expect to see from the server.

It's critical that the client_send_size on the client be no greater
than the client_send_size on the host.  If this is not the case, the
client may send a packet to the host that is larger than the host
believes is possible, and this will cause the host to disconnect the
client.  Similarly, it is critical that the server_send_size on the
host be no larger than the server_send_size on the client.  Otherwise
the client may see a packet from the server that is larger than it
believes is possible, and disconnect from the server.

It's best to have the send_every's match, but it's not critical.  A GPL
host will disconnect a client if it receives less than 50% of the
number of packets it expects to see from that client (that'd be a
pretty crappy connection).  But, if the client had a client_send_every
of 3, and the server had a client_send_every of 2, then with a perfect
connection the server would only be seeing 67% of what it was expecting
to see from the client.  This doesn't leave much margin for packet loss
before the server dumps the client.  (This also works in reverse - if a
client isn't getting 50% of the number of packets it expects to see
from the server, it will disconnect from the server).

While the cable/ADSL/T1 line may have enough upload bandwidth to allow
the server to send a 340 byte packet to each of several clients, if the
clients are only connected to the Internet with 28.8 modems, they won't
have the download bandwidth to accept it

340bytes/packet*10bits/byte*36cycles/second*0.333packets/cycle=40800bits
/sec

before accounting for IP overhead (which is significant).

Randy

This would not maximise performance. If net_mdm_server_send_size is greater
than 84, at most 84 bytes are sent. This amounts to 4 cars being visible in
front and 1 car behind for each client.
If you set net_use_mdm_bandwidth_for_tcp_ip = 0 and use the net_lan_
parameters instead of the net_mdm_ parameters, larger packets will be sent,
amounting to more surrounding cars being visible to each client. Although
this would help to avoid crashes, it will put an extra burden on the
resources so performance will suffer from it unless resources are plenty.

See http://people.A2000.nl/bcwes/gplol.htm for details.

Regards,
Bart Westra