I'm not sure I stated my view properly. The first bits would get there at
the same time but the last bits of 100bT would arrive wayyy before the last
bits of the 10bT frame. The 100bT could send (almost) 10 frames in the same
amount of time that the 10bT sent its one.
I know Priscilla already has her CNX so she should be treated as a higher
(final?) authority.
Kevin L. Kultgen
----- Original Message -----
From: "Priscilla Oppenheimer" <[EMAIL PROTECTED]>
To: "Kevin L. Kultgen" <[EMAIL PROTECTED]>; "Tim O'Brien"
<[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Friday, October 06, 2000 6:01 PM
Subject: Re: Ethernet Trivia
> Kevin,
>
> Great analysis.
>
> Does this help at all? Speed of light in twisted-pair cable is 177,000
> km/sec. So a bit occupies 177,000 divided by 10 million bits per second,
or
> 17.7 meters, in 10 Mbps Ethernet.
>
> 177,000 divided by 100 million bits per second is 1.77 meters for 100 Mbps
> Ethernet. (I'm sure you figured that one out already.)
>
> It would have to be a pretty long cable for the 100 Mbps versus 10 Mbps to
> make any difference!
>
> Priscilla
>
> At 10:12 AM 10/5/00, Kevin L. Kultgen wrote:
> >They would both start at the same time. The 100bT interface would be
> >placing bits on the wire faster than the 10bT interface and would
complete
> >placing bits on the wire in 1/10 the time. But those bits can't actually
> >move any faster through the copper medium. The copper isn't more
conductive
> >(it's still Cat 5(e)) and the speed of light hasn't increased. So the
bits
> >that are placed on the wire will move through the wire at exactly the
same
> >rate. If the bits for 10bT consume 5 meters of cable megth before the
NIC
> >moves the the next bit then a bit for 100bT will be 1/2 meter (.5 meters)
> >before the next bit is placed on the wire. This is just an example, I'm
not
> >sure of the exact lengths of the bits on the wire, but the point is that
the
> >bits can't move any faster because the speed of electricity through
copper
> >is fixed. The difference is that the 100bT card is placing bits on the
wire
> >10x faster than the 10bT card. And 1000bT (gigabit ethernet) places bits
on
> >the wire 100x faster than the 10bT card (or each bit would be .05 meters
(5
> >centimeters), given the above example).
> >
> >So, on 100bT the end of the packet (the whole packet) would arrive before
> >the 10bT would be done (in fact depending on the size of the packet 10bT
> >might still be sending the preamble or headers), but the start of the
> >packets (first bit of the preamble) would arrive at the same time.
> >
> >HTH,
> >
> >Thanx
> >
> >Kevin L. Kultgen
> >
> >Disclaimer: YMMV, the 5/.5/.05 meters are all fictional, I was told at
one
> >point how long a bit is on the wire but I forgot it. If I have anything
> >that needs clarification (or correction) then please feel free to add it
or
> >request it. This is helping me too, because I'm looking at taking the
> >CNX-Ethernet exam (http://www.mycnx2000.com, http://www.cnx2000.com).
> >
> >----- Original Message -----
> >From: "Tim O'Brien" <[EMAIL PROTECTED]>
> >To: "Kevin L. Kultgen" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>;
> ><[EMAIL PROTECTED]>
> >Sent: Thursday, October 05, 2000 5:49 AM
> >Subject: Re: Ethernet Trivia
> >
> >
> > > So if this were the case, and they both started at the same time and
used
> > > the same size frame/packet I would think that the 100Mbps interface
would
> > > get the packet onto the wire faster hence it would arrive sooner than
the
> > > 10Mbps interface which would probably still be putting the data on the
> >wire.
> > > Correct?
> > >
> > > Tim
> > >
> > > ----- Original Message -----
> > > From: "Kevin L. Kultgen" <[EMAIL PROTECTED]>
> > > Newsgroups: groupstudy.cisco
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Wednesday, October 04, 2000 12:35 PM
> > > Subject: Re: Ethernet Trivia
> > >
> > >
> > > They would bith reach the destination at the same time (speed of
> >electricity
> > > through copper). The difference is in the rate at which the bits are
> >placed
> > > on the wire, the Fast Ethernet would be placing 20 bits of information
> > > (actually encoded as 24 bits) on the wire for every 2 bits that the
10bT
> > > would place on the wire. At least his is my understanding of 100bT vs
> > > 10bT..
> > >
> > > Anybody else have different(better?) interpretations?
> > >
> > > --
> > > Kevin L. Kultgen
> > >
> > >
> > > ""Frank"" <[EMAIL PROTECTED]> wrote in message
> > > 8rfksm$l2s$[EMAIL PROTECTED]">news:8rfksm$l2s$[EMAIL PROTECTED]...
> > > > Let's say we have a 10Mbps and 100Mbps interface. Both transmit the
> >same
> > > > sized
> > > > frame over the same type of media and over the same distance and
neither
> > > > experience
> > > > a collision. Which will get to the destination first?
> > > >
> > > >
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> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
>
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