I join a game and I have a 100 ping, which means I am 100 milliseconds behind what the server considers real time. An enemy passes in front of me, so I turn and fire, but I am seeing the action delayed by 100 milliseconds. That player is not where I think he is, he's actually 100 milliseconds ahead of where I think he is. This is where the net code comes in. To compensate for the delay, the server knows that I am 100 ms behind the action, so it sends me info that is 100 ms old. That way, what is being displayed on my screen is the position of the enemy player relative to my delay. Basically, I am telling the server "Hey, I'm 100ms behind the action, please tell me where everyone else was 100ms ago."

Cool? Cool.

3. Latency and Bandwidth, or "Why does my ping suck?"

So now that we know how the server and client communicate, we can take a look at the options that Counter-Strike gives us to optimize that communication. Lets start with the 2 most important factors in determining your game experience: Latency, and Bandwidth.

Latency, also referred to as PING, is the amount of time that it takes your information to reach the game server. Bandwidth is the amount of data (packets) that your connection can send and receive at a given time. The less latency between you and the server means the closer you are to real time. Higher bandwidth means you can send and receive more packets from the server, and this keeps your game running smoothly. Latency is out of your control, for the most part, so we will focus on optimizing your bandwidth. Got a calculator? Good, you might need it.

Lets go back to those packets for a second. The packets that are sent back and forth between you and the server vary in size, but seem to average about 64 bytes. Half-life allows you to control the number of bytes that you can send and receive from the server through the rate and cl_rate commands. All of the commands that we discussed are entered through the console.

The rate command controls the amount of bandwidth sent from you to the server (upload) and from the server to you (download). The cl_rate command controls only upload bandwidth. Both commands have a maximum value of 9999, which is representative of the number of bytes per second that your client is allowed to send/receive. I would suggest setting this no higher than the maximum rate that the server can send/receive, which in the case of the KORT game server is 7000. To set the variables, simply pull down your console while in game and enter:

rate x
cl_rate x

Replace 'x' with whatever value you want to use. So now we have told our client "Don't, under any circumstances try to send or receive more than x bytes per second.". Now we need to tell it how many packets to send us per second so that we can stay current. The two commands we use for this are cl_updaterate and cl_cmdrate. cl_updaterate controls how many packets the server will send us per second maximum, and cl_cmdrate controls how many packets we will send the server per second maximum. The maximum values for both of these commands are 99.

The relationship between cl_updaterate, cl_cmdrate and the rate variable is very important. Still have that calculator with you? Good. We already know that the packets that we use to communicate with the server are about 64 bytes. Lets say we tell the server to send us 90 packets per second. 90 x 64 = 5760. So right there we are using about 5.6Kilbytes of bandwidth one way. We could very well be using another 5.6Kilobytes of bandwidth to send info to the server as well. This is all well and good if your connection can handle this kind of bandwidth, but some of us can't. 56k connections max out at about 5Kilobytes a second, and are best suited to handle a constant stream of about 3Kilobytes. Knowing that, you can see that it is best to lower your rate and cl_rate to about 3000, and your cl_updaterate and cl_cmdrate to about 30 - 40. It's all about testing your settings.

4. Net_graph

So how do I test my settings? Easy, by turning on the net_graph. net_graph allows you to see the number of packets sent and received from the server, and the resulting choke and loss. Choke refers to packets that your client is trying to send, but that it can't because your bandwidth is not high enough. It's like trying to fire 100 gallons of water out of a garden hose. The gallons of water are like your packets, and the hose is your bandwidth. The hose will only allow you to send one packet, err, gallon at a time, so the rest have to wait their turn. They are CHOKED off. Get it? Loss refers to packets that the server is trying to send to you that are lost because you are not allowing them in. If the server is using a fire hose to shoot 200 gallons a second at you, you can't expect to catch all of the water in a 5 gallon bucket. Most of the water will be LOST. Same with your connection. If you are requesting 90 packets a second from the server, but you only have enough bandwidth to receive 60, what do you think happens to those other 30 packets?

So what does all this mean? Well, if net_graph shows that you have a high choke, try turning your cl_cmdrate down, or your rate up. Alter those settings until the choke goes away, and your connection remains stable. If net_graph shows that you have high loss, try turning your cl_updaterate down, or your rate up, until the loss disappears.

5. Real Time? I AM Real time!

Unfortunately, none of the bandwidth tweaks listed above will help with your ping, but what they will do is ensure that you are using your bandwidth efficiently, and that your game runs as smooth as possible. Of course, high choke or loss can increase your ping, but in the end you really can't make your connection any faster than it is. However, if you already have a ping that is 40 or less, then you may benefit by having the server send you real time updates, instead of the lag compensated updates described above. There are 2 commands that you can use, cl_lc and cl_lw, to control if you are interacting with the server in real time. cl_lc stands for lagless client and cl_lw stands for lagless weapon. Turning lagless client off by setting cl_lc 0 in console will cause the server to send you current information, i.e. the server does not care how much latency you have, you will always get real time info. With a ping of 40 milliseconds or less, you would not notice the difference with this on or off, so it is best to keep this off. Lagless weapon is a bit different. It relies on server confirmation of your shots fired before displaying those shots on your screen. With lagless weapon on, your gun will fire on your screen the instant you press the trigger. In actuality, this is only how you see it. The server has to wait for the packet containing your shot to reach it, and in some circumstances, this packet might be choked off or dropped and never reach the server at all. Turning lagless weapon off by setting cl_lw 0 in the console will require the server to confirm all of your shots before they are displayed on your screen. This ensures that you see things exactly as the server sees them, and that all your shots are confirmed.

6. Tips of the trade

As a rule of thumb, while adjusting your cl_updaterate and cl_cmdrate settings, you should try to get them to be a multiple of your frames-per-second, plus 1. I.e. If your FPS is 80, try setting your cl_updaterate to:

81 (FPS / 1 + 1)
41 (FPS / 2 + 1)
21 (FPS / 4 + 1)

Also, make sure that if you turn cl_lc off that you also turn cl_lw off. I would not do them independently.