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Re: [OM] (OM) OT Internet connection speed

Subject: Re: [OM] (OM) OT Internet connection speed
From: "Carlos J. Santisteban" <zuiko21@xxxxxxxxx>
Date: Fri, 21 Jan 2011 17:54:25 +0100
Hi Brian and all,

Just for the record...

There are three different speeds involved in any internet connection:

a) The speed of the interface between the computer and the access device
(modem, cable-modem, router...)

b) The speed of the link between the access device and the ISP (Internet
Service Provider) via a suitable medium (phone lines, ISDN, broadband
cable...)

c) The actual transfer speed, as measured by the browser.

The first factor (a) has to be the fastest of them all. With dial-up
connections, it's a serial port (RS-232) which usually works at 115 kb/s.
Broadband devices may be connected via Ethernet (formerly 10 Mb/s, now 100
MB/s, even 1 Gb/s), USB (1.1 = 12 Mb/s; 2.0 = 480 Mb/s) or WiFi (usually up
to 11 or *54* Mb/s) among other interfaces.

Please note that actual data will be transferred slower; not continuously,
but in 'chunks', each of them transmitted at full interface speed... This is
usually fixed by configuration; the exception being wireless, going thru a
"dirty" medium may occasionally negotiate a slower speed, should the signal
strength impair.

The (b) factor is what you see every time you connect via dial-up -- I've
seen from 14.4 kb/s to (rarely) 56 kb/s, depending on line quality. Cable
and DSL may depend on purchased service, the latter being also affected by
the distance between the computer and the Phone central (sp?) -- from
hundreds to tens of thousands of kb/s.

As already mentioned in other posts, cable performance may depend on
neighbour's activity -- link speed may be the same, but the 'chunks' will be
transferred sparsely. Something akin may happen if the access device is
shared in a Network with heavy traffic.

Finally, (c) is the actual transfer speed, up to (b) in ideal conditions.
There's a lot of factors going here: server load, server connection
bandwidth, Internet traffic... Unlike the other speeds, this is usually
mesured in multiples of *bytes* per second (kB/s, MB/s), not _bits_ (kb/s,
Mb/s)

By the way... my cable-modem connection seems to work fine every time, I
think I can get full bandwidth (12.24 Mb/s, a bit over 1.5 MB/s download and
a solid 68 kB/s upload) anytime I want -- maybe my neighbours are inactive
most of the time ;-)

To me, the great advantage of Cable vs. DSL is the lack of the "dreaded"
PPPoE.

Disclaimer: this post may not be 100% accurate, for the sake of clarity...
I'll welcome any correction/clarification from the network experts here.

Cheers,
-- 
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
-- 
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