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RE: T3 Vs OC3 Vs DS3 ??? Whats the diff??? [7:78910] posted 11/12/2003
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At 3:01 AM +0000 11/12/03, John Brandis wrote:
>Does any one have one of these at home
>
>OC-192= 9.952 Gbps
>
>How much would they cost?
>Who (outside of the phone company) uses them?

OC-192 and "10 Gigabit Ethernet" actually use the same physical 
layer. Beyond phone companies, they are used in major data carrier 
interconnects, although it's more likely to be used in TDM.  Using 
wavelength division multiplexing, many OC-192's can go onto a single 
fiber.


>Are they only available in the US and between US Cities?

Multiple OC-192 lambdas are multiplexed onto the newer transoceanic cables.

>
>
>Really interesting stuff. If I can create a business case, I will see if
>I can get one at home.
>
>-----Original Message-----
>From: Tom@xxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]
>Sent: Wednesday, 12 November 2003 11:35 AM
>To: cisco@xxxxxxxxxxxxxx
>Subject: RE: T3 Vs OC3 Vs DS3 ??? Whats the diff??? [7:78910]
>
>You are most definatly splitting hairs at best.  SONET is defined as
>Synchronous Optical Network, therefore it is optical.  If someone uses
>the
>same encoding methods but changes the transport medium, the definition
>changes.  Besides, we were talking about OC (Optical Carrier).
>
>OC defined:
>
>Short for Optical Carrier, used to specify the speed of fiber optic
>networks
>conforming to the SONET standard. The table shows the speeds for common
>OC
>levels.
>
>  OC =  Speed
>  OC-1 = 51.85  Mbps
>  OC-3 = 155.52 Mbps
>  OC-12 = 622.08 Mbps
>  OC-24 = 1.244  Gbps
>  OC-48 = 2.488 Gbps
>  OC-192= 9.952 Gbps
>
>
>
>>  -----Original Message-----
>>  From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]
>>  Sent: Tuesday, November 11, 2003 2:06 PM
>>  To: cisco@xxxxxxxxxxxxxx
>>  Subject: RE: T3 Vs OC3 Vs DS3 ??? Whats the diff??? [7:78910]
>>
>>
>>  Tom@xxxxxxxxxx wrote:
>>  >
>>  > T3 is simply the "transport" for a DS3, they are often (if not
>>  > incorrectly)
>>  > used interchangibly.  It is based on the T-Carrier system
>>  > developed by,
>>  > "Gulp", Bell.  A T3 is 28 T-1s which is 24 channels of 64k each.
>>  > Interestingly the 64k comes from sampling the analog voice 8000
>>  > times per
>>  > second and representing each sample with an 8 bit word.
>>  > 8x8000=64000!
>>  >
>>  > DS3 is described very accuratly below.
>>  >
>>  > An OC3 is an optical carrier and is ALWAYs delievered over
>>  > fiber,
>>
>>  I may be splitting hairs, but I have to disagree somewhat.  SONET
>branched
>>  out beyond fiber years ago.  Microwave radios exist that not only can
>>  transport SONET payloads, but can act as SONET Add/Drop Muxes, etc.
>too.
>>  They just happen to have RF transmitters/receivers at the physical
>layer
>>  instead of laser trasmitter/receivers.  SONET rings with SATCOM shots
>>  between nodes exist too.  Not that common, but they do exist.
>>
>>  SONET is just another way of arranging ones and zeros that almost any
>>  physical layer can be made to transport.  There need only be a
>>  business case
>>  to bring something to market.
>>
>>  >but can
>>  > carry ATM or POS (maybe other layer 2 Protocols too)  An OC3
>>  > can be
>>  > delivered two ways, OC3 which is broken down as three distinct
>>  > DS3s or an
>>  > OC3c which is concatonated and therefore looked at as one
>>  > pipe.  An OC3 is
>>  > 155Mbps (+/-)
>>  >
>>  > Tom
>>  >
>>  >
>>  > > -----Original Message-----
>>  > > From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]On
>>  > Behalf Of
>>  > > Howard C. Berkowitz
>>  > > Sent: Monday, November 10, 2003 7:02 PM
>>  > > To: cisco@xxxxxxxxxxxxxx
>>  > > Subject: Re: T3 Vs OC3 Vs DS3 ??? Whats the diff??? [7:78910]
>>  > >
>>  > >
>>  > > At 3:18 PM +0000 11/10/03, neal rauhauser wrote:
>  > > > >DS3 is the 45 mbit signaling standard used in the US.
>>  > >
>>  > > 44.736 Mbps, but who's counting? :-)
>>  > >
>>  > > >It can carry 28
>>  > > >T1s in a bundle, seven six mbit T2s (logical construct,
>>  > somewhat rare,
>>  > > >think E1s transiting US facilties), 672 DS0s (64k channels),
>>  > or as in
>>  > > >ISP type applications it can be just a clear channel.
>>  > > >
>>  > > >    No one uses 'T3' any more - I think the 'T' indicates
>  > > some sort of
>>  > > >telco signaling and implicitly telco content.
>>  > >
>>  > > The T series are the mechanisms for carrying a particular DS
>>  > > bitstream over a specific medium.  T1, for example, defines
>>  > carrying
>>  > > DS1 over two twisted pairs with various characteristics, and
>>  > > typically a repeater every 6000 wire feet (except on 26 gauge
>>  > wire,
>>  > > which requires repeaters every 4000 feet). Electrical power
>>  > for the
>>  > > repeaters, nominally 135 volts, goes across the wire.  This
>>  > is 135
>>  > > volts referenced to the power supply, not ground, so the
>>  > peak-to-peak
>>  > > voltage can hit 270. I've been knocked flat by touching the
>>  > wire.
>>  > >
>>  > > FT1 carried a DS1 over fiber, the details of which I forget.
>>  > The
>>  > > original Data under Voice microwave system, IIRC, carried a
>>  > DS1.
>>  > >
>>  > > T3 was defined for coaxial cable.
>>  > >
>>  > > >    OC3 is a 155mbit ATM stream. It is usually delivered via
>>  > fiber, but
>>  > > >there are 155mbit ATM copper interfaces on some switches.
>>  > The fact that
>>  > > >'OC' is there indicates ATM, not optical transport. An OC3
>>  > rides inside
>>  > > >an STM1 sonet stream - you can get PA-POS-OC3 which does
>>  > packet over
>>  > > >sonet instead of ATM. Why this is called an 'OC3' PA escapes
>>  > me.
>>  > > >
>>  > > >
>>  > > >    The details on all of this stuff are found in the Cisco
>>  > CCNA WAN
>>  > > >Switching book ... mine walked off years ago so I can't give
>>  > you chapter
>>  > > >& verse but I strongly recommend reading this book, even if
>>  > you're not
>>  > > >getting the WAN CCNA - its full of valuable background
>>  > information.
>>  > > >
>>  > > >
>>  > > >
>>  > > >Steven Aiello wrote:
>>  > > >>  Can some one help me out here for a second.  What is the
>>  > difference
>>  > > >>  between a T3 and an OC3 and a DS3?  I'm going to take a
>>  > shot
>>  > > and say the
>>  > > >>  T3 os run over Copper, and the OC3 is run over fiber, my
>>  > guess is that
>>  > > >>  the only difference.  Is the "DS" in the DS3 the
>>  > signaling protocol?
>>  > > >>  Does this kind of relate to how you can run Ethernet over
>>  > Fiber or Cat
>>  > > >>  Whatever or STP?  If someone can give me  brief over view
>>  > of supply me
>>  > > >>  with a good link I would be thankful.
>>  > > >>
>>  > > >>  Thanks,
>>  > > >>  Steve
>>  > > >>  **Please support GroupStudy by purchasing from the
>>  > GroupStudy Store:
>>  > > >>  http://shop.groupstudy.com
>>  > > >>  FAQ, list archives, and subscription info:
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>>  > > >>
>>  > > >>
>>  > > >>
>>  > > >
>>  > > >
>>  > > >--
>>  > > >mailto:neal@xxxxxxxxxxxxxxxxxxx
>>  > > >phone:402-301-9555
>>  > > >IM:Neal R Rauhauser
>>  > > >"After all that I've been through, you're the only one who
>>  > matters,
>>  > > >you never left me in the dark here on my own" - Widespread
>>  > Panic
>>  > > >**Please support GroupStudy by purchasing from the
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