I think that you will find ping times are largely irrelavant, most sites
block them and they have a low priority on the network / routers. I'm sure
that this has been mentioned here several times in the past
 
I cannot ping anything (game site or host ) from the LAN here, yet all the
games show ping times !!
This is because the games ping times are acutually calculated from sending
mostly UDP (or TCP) packets across the internet. Again typically UDP is a
not guaranteed for delivery and requires the application to re-transmit the
data. TCP is slightly better in that the Network Layer will re-transmit the
data and re-order the packets and if necessary request re-transmission or
missing packets.
 
Anyway, I get actual ping times to xtra, paradise and jetstream-games of 50
- 80 ms from my external adapter. I wouldn't complain about that.
International sites are typically nearer 200 ms so your gaming will never be
as good as local
 
The corporate networks I have supported are lucky to get less than 100-125
ms AKL - WGL, and the international links are 400-500ms they also pay 2-5
times what ADSL costs for the privilage. (OK its not a fair comparison but
you get the picture)
 
I guess running a business is not as important as killing people as fast as
you can

-----Original Message-----
From: Charismo [mailto:charismo@xtra.co.nz]
Sent: Friday, 24 November 2000 02:44
To: adsl@unixathome.org
Subject: ADSL and interleaving

After a lot of research I discovered that what I wanted to do apparently has
to be done at the DSLAM which is a pity, here's an article which I think
many people may find interesting. If for example, I were to ask telecom
nicely, would they do as other ISP's have done around the world and remove
interleaving for just myself? Or at least reduce it to a much lower level,
as I understand it Telecom New Zealand set it to 30 ms but I could be wrong.
For a very prolific quake player I can tell you that 30 milliseconds makes
all the difference. Ping is the *sole* reason why we have ADSL, there are no
other solutions for where we live that are within our budget (Palmerston
North) that come close, although I suppose if I was in Wellington I could
simply get cable which sports 30 ms like pings... in any case I hope some
lovely person from Telecom reads this and considers my request. If we had to
sign something to get it done then we wouldnt' mind doing that ;). The URL
is here: http://www.dslreports.com/shownews/205
<http://www.dslreports.com/shownews/205> , sorry for posting the whole thing
here but I thought it would be more convenient.
 
In addition... this URL here leads me to believe that this can be done on a
per customer basis, in which case if the customer is happy with the change,
should it not be doable? http://www.dslreports.com/shownews/439
<http://www.dslreports.com/shownews/439>
 
Latency and Interleaving
For internet telephony or interactive applications such as remote
administration over a telnet session, latency is a key (and much discussed)
attribute of the connection.

At the moment, the class of users most obsessed with latency would have to
be the online gaming community. They are often buy entry level residential
ADSL lines, with high download speeds, and are dismayed to read that friends
on slower SDSL or IDSL lines are getting better ping times!

The first reaction of a disappointed gamer is to blame the ISP for routing
inefficiencies or congestion, and although that is often the root cause,
there is more to latency than just many hops and/or long distances.

ADSL modems commonly employ data Interleaving, which is a technique to
increase resistance to noise bursts on a line. Interleaving "smears" out
micro bits of data (interleaves them over time) so that a short burst of
signal destroying noise can only remove part of any given larger block. Data
blocks reserve some space for error-correction data.. which can salvage a
partially damaged block. Interleaving increases the chance that noise on the
line will only cause partial damage, not complete loss. Thats the good news.

The down-side of Interleaving is that it increases latency! this is because
your little (say) quake movement packet is smeared out over several packets
before it can be fully sent or fully received.

ADSL modems with typical Interleaving defaults can be 10-30ms behind in
latency over equivalent speed SDSL modems... this means latency to any point
for some ADSL modems can be at best 50ms! On the same setup, the
aforementioned SDSL modems that typically add only 10ms. So for use of a
nearby server, ADSL Interleaving can be the biggest single source of latency
that you have.

Unfortunately, there is little clear information supplied with, or available
online, about what latency a given DSL modem or ISP connection has built-in.

Some ADSL modems allow the user to turn off Interleaving, or turn it down to
a narrow range, at the expense of possible data-loss on noisy lines. The
Cisco 675, for example, has a full operating system inside it, and one of
the attributes of the ether interface is Interleaving. See Randy Lutton's
<http://www.users.uswest.net/~rlutton/ADSL/Misc.html> US West page). Some
ISPs may be delivering this unit with Interleaving on, and some off. In
other cases, it is the DSLAM (central office equipment) that has the
Interleaving set, and this cannot be changed.

Regards,
Anton Smith
Silicon Dreams Hardware News and Reviews,
 <http://www.challenge-nz.com/silicon-dreams>
http://www.challenge-nz.com/silicon-dreams
 
 

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Received on Fri Nov 24 11:49:25 2000