ping times

Koopa

This is taken from Utumno's column on barrysworld.com...

begin quote:
Myth 1 - compression lowers pings
Not true. You are not decreasing the latency of your connection by applying payload compression, you are just getting more data through in each packet because the data is compressed. Your ping may be reported lower in the online game of your choice but that doesn`t mean it`s *actually* lower. That is the ping that is being reported to you by the server and it`s not actually a ping, it`s a calculated latency that the server works out depending on how much data it`s sending you. This is why your ping can go down at higher RATE settings because the server thinks you`re on a fatter connection than you actually are and reports it as such.
--(rest got boring so its gone)--

right, this might explain why ppl from colleges etc. get ping times of 25, when in actual fact its nothing like a LAN connect... and why i get a ping of 111 on my modem when it feels like a 250 ping connect..
next time im gonna use the dos 'ping' command in-game to check my ping <IMG SRC="http://lacerta.ucg.ie/boards/smile.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":)">
also modem muppets are NEVER LPB's...because of that ping thing.... dont moan at me if i play you with a 100 ping on my modem cos its still GAY for me

FreaK_BrutheR

The ping and pl in nethouse is very low. Where were u ya big (ish) muppet (type)????


o yeah and <IMG SRC="http://lacerta.ucg.ie/boards/tongue.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":P">

VisHnU

Latency (which ping measures) is a function of the frequency of your data link point to point. A V.34+ (33,600 bps) analogue modem has a frequency of 3.4 KHZ (8 bits for data 2 bits for stop/start). A standard analogue phone line has an available frequency of roughy 4KHZ. Since the standard ping packet is of size 64 bytes it takes roughly 0.019 seconds to reach its destination and the same time to come back (a standard echo). Thusly in theory a round trip time from modem to POP should be close to 0.038 seconds or 38 miliseconds. In reality this is usually closer to 90-100 miliseconds. Does anyone know why ? (There is a prize for the winner).
ViShNu......

Dr_Teeth

Umm. dunno. Modulation maybe? Enlighten us. <IMG SRC="http://lacerta.ucg.ie/boards/smile.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":)">

Teeth.

MindPhuck

Whats this? Two posts in one day Conor! WoW <IMG SRC="http://lacerta.ucg.ie/boards/smile.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":)">

Btw I know why, but, err, im not telling you. err honestly <IMG SRC="http://lacerta.ucg.ie/boards/tongue.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":P">

Koopa

right heres my guess..
The computer at the isp's end has to identify what the data received by its modem was, and decide how to deal with it.

DeVore

Modulation and Demodulation I reckon.

that would explain why isdn has such a good ping and still gets crap d/l speeds.
(about 7.5 kps on a good day)

compression will actually slightly LAG your game as the data is quite compressed to begin with and the extra decompression will have to be done by a cpu already busy with 3d stuff. Its nearly a philosophical effect tho so i wouldnt go bananas about it.

DeV.

Koopa

mm im obviously not sure bout this, but isnt the modulation/demodulation bit accounted for already? isnt that what the 33600bps/10bits = 3.36khz 'frequency' is, which is giving the 38ms latency in the first place? <IMG SRC="http://lacerta.ucg.ie/boards/smile.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":)">

Von

I have a modem.

VisHnU

Yes, the 2 extra bits per byte account for the stop/start bits. The extra latency comes from a number of sources. One is the fact that most routers/POP (unless they are modem banks) will try to priorties traffic, typically ICMP traffic is assigned the lowest priority. Two is something that isn't mentioned much, error correction. By default most modems will try to negotiate one of two types of error correction routines, LAPM (V.42) or MNP (1-4). These will introduce between 1-4 extra bits per byte and whilst playing Quake will cause packet retransmissions which can slow down or cause undue LAG. In short turn of error correction Baby. Another issue sorely missed is async/sync connections, I have no hard stats to hand but I have a gut feeling that synchronous connections may suit Quake better ?
VisHnU

P.S OH and the prize was/is honour membership to the IGN inner council ....

Dr_Teeth

Damn, foiled. <IMG SRC="http://lacerta.ucg.ie/boards/smile.gif&quot; WIDTH=15 HEIGHT=15 BORDER=0 ALT=":)">

D.

VisHnU

Oh and Eric Mooney wets the bed ......

Koopa

rofl..
yes i know eric mooney ruins beds.. but hes absolutely vicious in the sack.... just like his mother that lad is..

TAAKE IT eric..(heh)

oh yeah, i turned off error correction on my pace modem, and started getting constant 500-600 pings... strange..