RE: ethernet

From: Jason Sinclair (sinclairj@xxxxxxxxxxxxxxx)
Date: Thu Aug 22 2002 - 21:15:08 GMT-3


   
All,

To clarify this let's define sync versus async:

Sync:
Data is transmitted at a steady consistent rate via the use of a clocking
mechanism.

Async:
Data can be sent at irregular intervals as there is no clocking sync between
devices and another method will be used to provide the synchronisation. This
is usually via start and stop bits.

Ethernet:
There is no clocking between nodes and sync is provided via the preamble of
the Ethernet frame. This is a series of alternating ones and zeros that
denotes the start of the frame. This is used by the receiving node to sync
with the transmitter. Hence Ethernet is defined as asynchronous.

Regards,

Jason Sinclair CCIE #9100
Manager, Network Control Centre
POWERTEL
55 Clarence Street,
SYDNEY NSW 2000
AUSTRALIA
office: + 61 2 8264 3820
mobile: + 61 416 105 858
email: sinclairj@powertel.com.au

 -----Original Message-----
From: Wade Edwards [mailto:wade.edwards@powerupnetworks.com]
Sent: Friday, 23 August 2002 08:20
To: Michael Snyder; Michael Spencer
Cc: ccielab@groupstudy.com
Subject: RE: ethernet

I would submit that Ethernet is asynchronous because it is an ad hoc
medium and synchronization occurs in-band and is per packet. ATM is
synchronous because there are certain timeslots and synchronization
occurs out of band.

L8r

 -----Original Message-----
From: Michael Snyder [mailto:msnyder@ldd.net]
Sent: Thursday, August 22, 2002 4:18 PM
To: 'Michael Spencer'
Cc: ccielab@groupstudy.com
Subject: RE: ethernet

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?

---------------------------------
Do You Yahoo!?
HotJobs, a Yahoo! service - Search Thousands of New Jobs



This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:34 GMT-3