Re: OT Why Ethernet cannot still cross the 10m barrier ?

Technically, yes. As long as you can guarantee it will be full-duplex. I've
had cables linger than 100m work fine.

Of course, at some point, the transmitter strength becomes and issue.

--
Marko Milivojevic - CCIE #18427 (SP R&S)
Senior CCIE Instructor / Managing Partner - IPexpert
On Fri, Jun 14, 2013 at 3:01 PM, John Neiberger <jneiberger_at_gmail.com>wrote:
> That's a good point. If we're running full duplex and collision detection
> is disabled, does that eliminate the 100m restriction since the limiting
> timing factor no longer applies?
>
>
> On Fri, Jun 14, 2013 at 3:51 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar
> >wrote:
>
> > I beg your pardon ?
> > I have not seen any implementation of multiaccess 1G ethernet,
> > and it's ages since I last saw a 100 Mb hub.
> >
> > What's the point of half duplex and colission detection nowadays ?
> >
> > -Carlos
> >
> > John Neiberger @ 14/06/2013 16:03 -0300 dixit:
> > > Exactly what I was thinking. The 100m limit is there because longer
> > cables
> > > mess with synchronization and timing. Here's a snippet I found that
> > > explains it for the OP:
> > >
> > > On 10-Mbps Ethernet one bit at the MAC layer requires 100 nanoseconds
> > (ns)
> > > to transmit. At 100 Mbps that same bit requires 10 ns to transmit and
> at
> > > 1000 Mbps only takes 1 ns. As a rough estimate, 20.3 cm (8 in) per
> > > nanosecond is often used for calculating propagation delay down a UTP
> > > cable. For 100 meters of UTP, this means that it takes just under 5
> > > bit-times for a 10BASE-T signal to travel the length the cable.
> > >
> > > For CSMA/CD Ethernet to operate, the sending station must become aware
> > of a
> > > collision before it has completed transmission of a minimum-sized
> frame.
> > At
> > > 100 Mbps the system timing is barely able to accommodate 100 meter
> > cables.
> > > At 1000 Mbps special adjustments are required as nearly an entire
> > > minimum-sized frame would be transmitted before the first bit reached
> the
> > > end of the first 100 meters of UTP cable. For this reason half duplex
> is
> > > not permitted in 10-Gigabit Ethernet.
> > >
> > > http://ethernettiming.blogspot.com/
> > >
> > >
> > >
> > >
> > > On Fri, Jun 14, 2013 at 11:58 AM, Joe Sanchez <marco207p_at_gmail.com>
> > wrote:
> > >
> > >> Preamble , Preamble
> > >>
> > >> Regards,
> > >>  Joe Sanchez
> > >>
> > >> ( please excuse the brevity of this email as it was sent via a mobile
> > >> device.  Please excuse misspelled words or sentence structure.)
> > >>
> > >> On Jun 14, 2013, at 4:23 AM, marc edwards <renorider_at_gmail.com>
> wrote:
> > >>
> > >>> This isn't distance limitation of Ethernet. Instead this is physical
> > >>> limitation of Ethernet over copper cabling.
> > >>> Law's of Physic's . The signal degrades over length and also you have
> > >> issue
> > >>> with the time the signal takes to both ends. You can push ethernet
> pass
> > >>> 100m, i have personally seen 160m for a connection between console
> > server
> > >>> and device but i would not advise it.
> > >>>
> > >>>
> > >>> On Wed, Jun 12, 2013 at 11:32 PM, Ahmed <ahmedsalim_at_gmail.com>
> wrote:
> > >>>
> > >>>> Is there a history for this 100m barrier ? Even with the modern
> > >> switches ,
> > >>>> cannot this be overcome ?
> > >>>>
> > >>>>
> > >>>> Blogs and organic groups at http://www.ccie.net
> > >>>>
> > >>>>
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> > >
> > >
> >
> > --
> > Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
>
>
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