From: Asim Khan (asimmegawatt@xxxxxxxxx)
Date: Fri Aug 23 2002 - 04:42:32 GMT-3
I think ethernet is synchronous. The reason is in any
synchronous transmission, the receiver uses a clock
which is synchronized to the transmitter clock. The
clock may be transferred by either:
1)A seperate interface circuite.
2)Encoded in the data (like Manchester encoding,AMI
encoding).
Now in ethernet an encoded clock is used.
Regards.
Asim Khan
--- Przemyslaw Karwasiecki <karwas@bellsouth.net>
wrote:
> Ethernet is using something called Manchester
> encoding.
> It basically means, that in order to provide clock
> synchronization
> between frame transmitter and receiver, each zero is
> represented
> by sequence of 01 and each one is represented by 10.
> By doing so, it makes it possible to maintain clock
> synchronization
> even in case frame contains long sequence of zeroes
> or ones.
> And, yes, before each frame, there is a short
> sequence send
> called preamble (but I believe this is layer 1 not
> 2),
> which makes it possible to delineate beginning of
> the frame.
>
> Is it synchronous -- IMHO yes, but it depends on
> definition
> of the term synchronous.
>
> Przemek
>
>
> On Thu, 2002-08-22 at 17:17, Michael Snyder wrote:
> > Where's the clock?
> >
> > Believe every Ethernet transmission starts with a
> series of one's and
> > zero's sent before the packet header.
> >
> > This layer two header provides the clock. So it
> it's async before the
> > packet is transmited, and synced as the packet is
> transmited.
> >
> > Does this help?
> >
> > I have a better question for you, is ATM sync or
> async. Really? You
> > don't think there's a sync'ed clock signal on the
> fiber cables. About
> > as clear as mud huh?
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> > Michael Spencer
> > Sent: Thursday, August 22, 2002 1:04 PM
> > To: ccielab@groupstudy.com
> > Subject: ethernet
> >
> > Is ethernet synchronous or asynchronous?
> >
> >
> > ---------------------------------
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