My brain hurts! &;-) My point was simply that on a short cable, the issue
of how much "space" a bit takes on the cable is irrelevant, n'est-ce pas??
We all agree that serialization is the real issue. A 100Base-T port can
output bits 10 times as fast.
By the way, I never saw my message posted. Did you? I haven't seen hardly
any of my messages posted lately. It's frustrating.
Priscilla
At 06:08 PM 10/6/00, Kevin L. Kultgen wrote:
>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?
> > > > >
> > > > >
> > > > > **NOTE: New CCNA/CCDA List has been formed. For more information go
>to
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> >
> > ________________________
> >
> > Priscilla Oppenheimer
> > http://www.priscilla.com
> >
> >
________________________
Priscilla Oppenheimer
http://www.priscilla.com
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