Thoughts on How to Improve On-line Connections

by Ron Ayton

Note from Alison: GPL 1.2, which supersedes GPL 1.1 which Ron refers to in this article, eliminates some of the issues which Ron discusses, particularly issues around client-server synchronization. Nevertheless, many of Ron's comments are still quite applicable. For more information about GPL 1.1 and GPL 1.2, see the FAQs at VROC.

I have updated this article I posted a while back, regarding connection issues with GPL, to include a few thoughts and help notes for GPL 1.1, which seems to be causing a few headaches for a few people. The following is mainly for those new-comers to GPL on-line, who are having trouble with poor connections and disconnection problems etc. Hope it helps out a bit...

- Ron

Most of us are not blessed with Cable etc. so we have to make the most of dial-up modem connections, so this is a brief idea on how to improve your analogue, dial-up modem connections.... This is simply to give you some idea of where to begin and what to play with to try to improve your on-line gaming connections, using an analogue modem.

Firstly, the DUN you use for the Internet is NOT suitable for on-line gaming. It most likely would be using Data Compression, Error Correction, Maximum FIFO Buffers and probably going as hard as your poor little modem can peddle, or harder if i believe half of the tales i hear about....

All of the above is VERY bad news for on-line gaming.

You should make up another DUN for on-line gaming, with Data Compression and Error Correction turned OFF. Also, turn down the maximum connect speed of your modem to 24000, 26400 or 28800 at a maximum.

The quality of the lines in your area, will dictate the best speed for you.

This can be done in the Modem Properties tab of your DUN for the designated Modem. Read the booklet that comes with your modem for the initialization strings you need.


Some people are under the mistaken belief that a slower connect speed will take longer to get to the host, resulting in higher latencys (pings) etc. This is totally false.!!!

The connection speed of your modem, is a false analogy, as the connection speed only refers to how much bandwidth the modem is capable of sending at any given time, NOT how fast it can send it.

Hence, the ammount of data that a GPL host requires from a client, will get to the host at exactly the same time, whether the client is using 26400 baud or 56000 baud, and 99.9% of the time, the 26400 baud rate from the client will have a lot less errors and be a lot more stable than the 56000 baud's best effort, unless you are lucky enough to live in a area where optical fibre abounds, all the way from you to the host, which is very unlikely. :)

I only ever use a maximum of 26400 on-line with GPL, as the lines in my area, leave a bit to be desired, but with my normal internet dun, i use 33 to 56k baud, and let the error correction fix any problems i encounter, which is fine for surfing and general internet use etc. (error correction is a definite no-no for GPL on-line)

To make more than one DUN with different modem initialization strings, you will need to go to the MODEMS in the control panel and ADD another modem. This will not overwrite your present modem settings, but will add another modem to the modems you have listed in the modem list. As you add more modems to the list, Windows will simply add a #2 #3 #4 etc etc to the end of the modem name. That way you can set up as many DUN's as you have modem names, each one with different initialization strings.

Once you have your on-line DUNS and modem set up correctly, you will actually find that disco's, error filled connections and high latency's will simply become a bad memory..


The FIFO buffers should be set no higher than the 2nd mark from the left, unfortunately these are global settings, so if you set them at the 2nd setting from the left, that is where they will remain, regardless of which DUN you are using. I have not noticed any lesser performance in surfing or downloading with the buffers set there anyway, so i just leave them there all the time.

Make sure you turn Error Correction off, also turn off the Data Compression and select Hardware Flow Control in you modem's properties tab for the On-Line gaming DUN. If you are a paranoid type, as i am, you could also add those commands to the extra settings in the modem initialization string, just in case you don't trust windows to carry out your wishes and let's face it, who trusts windows to do anything right when it comes to gaming anyway..

I have included the following line for my US Robotics modem in my On-Line Gaming DUN..


&F1 Resets modem to standard, in case windows messed it up.
&K0 Disables Data Compression, in case windows forgot.
&M0 Disables Error Correction, as per above scenario..
&U10 Sets the floor connect speed to 19200.
&N13 Sets the ceiling connect speed to 26400.

The above is an example for the US Robotics modem, different modems will vary slightly in the initialization strings, so read your manual for further details to achieve similiar results.

Secondly.. Windows in it's infinite wisdom sets up the Port settings on the extra conservative side by default. This needs to be changed manually.

To do this:

Go to the Control Panel, go to System, go to Device Manager, go to Ports (com & lpt).
Select Com1 , go to Port Settings, and adjust the following to read as follows:
Bits per second 115200
Data 8
Parity none
Stop Bits 1
Flow Control Hardware
Go to Advanced and adjust the FIFO Buffers so they are 1 mark from the left side.

Do the same for Com Port 2.

The following topics are relevant to the new CORE.INI file, that ships with GPL 1.1


This file is called: COREINI.SAMPLE and must be re-named to: CORE.INI before GPL 1.1 can make use of it.

It is located in the: SIERRA\GPL\ folder, after the GPL 1.1 patch has been installed...

A couple of slight adjustments are needed to get the best out of the new CORE.INI file.

Following is a brief example of a couple of changes I made to my CORE.INI file, to suit on-line play on VROC.

The parts you need to alter from the CORE.INI that ships with GPL1.1 are the two lines concerned with band width: net_mdm_client_send =2 & net_mdm_server_send_every =2

Change both of those to 3, like below in the pasted example.

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 = 84 ; Server packet size on dialup

That is the standardized band settings that VROC uses, for clients and hosts, and everyone running on VROC, should alter the relevant lines to match the above criteria.

Also, for me, the new Synch method does not work well... The best way to tell if the new synch method is working for you, is to race on-line, and if you are noticing a lot of slow motion & speed-up effects, then the new synch method is not working well for you. The new synch method does not use the: clock_adj_delay = 4 line either, as that is disabled when the synch_method is set to 1.

I have changed the line:

synch_method =1


synch_method = 0

(which re-enables the old version of synchronization)

By altering that line back to 0, GPL 1.1, uses the following line:

clock_adj_delay = 4 ; How often may client adjust clock?

The number of 4, did not work for me at all, so after much experimenting with different values, both locally here in Australia, and to overseas hosts, I settled for a value of: 16 eg: clock_adj_delay = 16 ; How often may client adjust clock?

That cured all my slow-mo problems, and 99 % of my warping problems. Anything under 14, began to give me frame stuttering, so i left it at 16, which seems strange, as before with version 1.000 of GPL, the default delay setting of 12, and even 10 seemd to work best. However, with the new GPL 1.1, a clock setting of 16 seems to be much more stable and stutter/warp free.

You may need to experiment with this line, to suit your own local and overseas conditions, but generally, if you have good low pings to your regular hosts, a value of 8 to 10, seems to work well enough. If latency is an issue, then a higher value of 12 14 or 16, seems to do a better job of keeping the client's computer in synchronization with the hosting computer.


This line does not effect the hosting computer, or the other clients, it is simply a localized, client based, instruction set. The only way this line could effect the other clients and host, is if you alter this value to some ridiculous ammount, which causes your own computer to fall out of synchronization with the hosting computer at a much larger rate, and then, the other clients would notice your car disappearing (warping) around more than usual, however, this does not effect the other clients in any other way.


Things may change for the better, when the patch for the patch is released, in regards to what synch method we will end up using, but for the moment, the older (original) version of: snych_method = 0 seems to work best for the majority of us.. Hopefully, when the patch for the patch is released, we can go back to the new method: synch_method = 1 which should allow for a more seamless adjustment of the timing, between the hosting and client's computer.


GSB2 & VROC2 allows the setting up and use of the old synchronization method in the joining screen, if you would rather do it from there, than make the designated changes in your CORE.INI file...

Another line you may want to change is the line that says:

disable_modem = 0 ; Don't look for/use modems

If you change that line to:

disable_modem = 1 ; Don't look for/use modems

By disabling modem lookup, GPL 1.1, will start up a lot quicker.. This only effects the modem to modem dial-up playing between two players, and will not effect GPL's Internet play....

The only other line you might need to alter, is the line:

alternate_ip_addr_lookup = 0 ; Find IP addresses another way

If GPL cannot find your ip address, to enable you to join on-line races, change that line to 1..

eg: alternate_ip_addr_lookup = 1 ; Find IP addresses another way

Finally, why do people insist on having to run at 1024x768 with all the eye candy on for on-line racing. Frame rates DO matter as far as warping and good on-line play go.

If you are not seeing 36fps in on-line play, then your CPU is being taxed. Give your CPU a rest and turn down the resolution a bit, turn off some eye candy untill you are seeing 36 fps or as close to it as you can. You might be surprised at the difference it makes. Another thing to keep in mind as well, is to not have back ground programs running when you intend to play on-line.

Just to finish this novel off, Windows 98 is superior to Windows 95 when it comes to Networking, Serial Control, Internet functionability, DUN protocols and on-line gaming, so if all else fails, consider that much dreaded upgrade. It may just make that final difference to having a good connection or a so so connection..