What is "lag"?

[Biggles]

Just came off a 13 car 600 PP on Suzuka with severe lag.

Can anyone explain what exactly lag is? Why do cars appear to hop all over the place, clearly not showing the actual line they are following? Is every participant in the race seeing the same thing?

 

[McLaren]

It's due to their connection. Bad connections can cause the cars to jump.

 

[Vaxen]

Simple explanation:
The internet isn't like a highway you can drive on. It's a series of tubes, see...

Let me try that again:
Sometimes a networking device somewhere in the internet will be temporarily overwhelmed by a flood of traffic. These devices deal with this by throwing away some of these packets at random. In the case of GT5p, this is usually either the host's PS3, his router/modem, or his service provider.

However, the game can't wait for each packet before drawing the next frame. When it doesn't hear from one of the clients for a while (a few frames), it has to guess where the player's car will be. (This is called dead reckoning.) After it gets an update from the player, it now has a new position which is accurate. If it's guess was off by only a little bit, the game software can smoothly morph the car to the accurate position, so players won't notice.

However, if there is no possible way for the car to move that far and still obey the laws of physics, the game will force it to move more radically. This is when you see the cars ghost out with tires squealing. If it's even further off, it will simply warp the car to the correct position, and carry on.

 

[Shaun]

Simple explanation:
The internet isn't like a highway you can drive on. It's a series of tubes, see...

Let me try that again:
Sometimes a networking device somewhere in the internet will be temporarily overwhelmed by a flood of traffic. These devices deal with this by throwing away some of these packets at random. In the case of GT5p, this is usually either the host's PS3, his router/modem, or his service provider.

However, the game can't wait for each packet before drawing the next frame. When it doesn't hear from one of the clients for a while (a few frames), it has to guess where the player's car will be. (This is called dead reckoning.) After it gets an update from the player, it now has a new position which is accurate. If it's guess was off by only a little bit, the game software can smoothly morph the car to the accurate position, so players won't notice.

However, if there is no possible way for the car to move that far and still obey the laws of physics, the game will force it to move more radically. This is when you see the cars ghost out with tires squealing. If it's even further off, it will simply warp the car to the correct position, and carry on.

Thanks good simple explanation for someone new to online gaming.

 

[GT Pro]

Simple explanation:
The internet isn't like a highway you can drive on. It's a series of tubes, see...

Let me try that again:
Sometimes a networking device somewhere in the internet will be temporarily overwhelmed by a flood of traffic. These devices deal with this by throwing away some of these packets at random. In the case of GT5p, this is usually either the host's PS3, his router/modem, or his service provider.

However, the game can't wait for each packet before drawing the next frame. When it doesn't hear from one of the clients for a while (a few frames), it has to guess where the player's car will be. (This is called dead reckoning.) After it gets an update from the player, it now has a new position which is accurate. If it's guess was off by only a little bit, the game software can smoothly morph the car to the accurate position, so players won't notice.

However, if there is no possible way for the car to move that far and still obey the laws of physics, the game will force it to move more radically. This is when you see the cars ghost out with tires squealing. If it's even further off, it will simply warp the car to the correct position, and carry on.

Would it not be reasonable to suggest that the software should still make an attempt to 'morph' the vehicles back into place, regardless of breaking the laws of physics in doing so; it would allow a much smoother gameplay experience. And dare I say, more realistic since the vehicles atleast aren't mysteriously 'jumping' from position to position.

 

[Denur]

Would it not be reasonable to suggest that the software should still make an attempt to 'morph' the vehicles back into place, regardless of breaking the laws of physics in doing so; it would allow a much smoother gameplay experience. And dare I say, more realistic since the vehicles atleast aren't mysteriously 'jumping' from position to position.

The jumping will be less when the AI engine would kick in to make a more educated guess of where a laggy car will be. Now the engine assumes that the car will continue in a staight line (with its current speed), which results in the severe jumping about on a track's curvy part.

 

[Biggles]

Simple explanation:
The internet isn't like a highway you can drive on. It's a series of tubes, see...

Let me try that again:
Sometimes a networking device somewhere in the internet will be temporarily overwhelmed by a flood of traffic. These devices deal with this by throwing away some of these packets at random. In the case of GT5p, this is usually either the host's PS3, his router/modem, or his service provider.

However, the game can't wait for each packet before drawing the next frame. When it doesn't hear from one of the clients for a while (a few frames), it has to guess where the player's car will be. (This is called dead reckoning.) After it gets an update from the player, it now has a new position which is accurate. If it's guess was off by only a little bit, the game software can smoothly morph the car to the accurate position, so players won't notice.

However, if there is no possible way for the car to move that far and still obey the laws of physics, the game will force it to move more radically. This is when you see the cars ghost out with tires squealing. If it's even further off, it will simply warp the car to the correct position, and carry on.

Thank you! Good explanation.

What I find weird, is the way the cars often seem to go back & forth off the track, or even take a whole corner in the dirt. It doesn't seem logical, even based on your explanation...