RE: Packet delivery on a Ethernet Wire

"So if 1G 1000BASE-T, pairs are bidirectional, full duplex, does that mean
each singe wire in the pair group is doing either transmit or recieve. In
that case I can understand there will be no collision, as each single wire
will be either transmitting or receiving."

That was my understanding yes. 250M of BW in both directions per pair.

From: Irfan Sid [mailto:lifeoverip_at_gmail.com]
Sent: Monday, 1 August 2011 3:02 PM
To: Joe Astorino
Cc: Carlos G Mendioroz; Aaron Riemer; Cisco certification; Cisco
certification
Subject: Re: Packet delivery on a Ethernet Wire

So if 1G 1000BASE-T, pairs are bidirectional, full duplex, does that mean
each singe wire in the pair group is doing either transmit or recieve. In
that case I can understand there will be no collision, as each single wire
will be either transmitting or receiving.

But if a single wire in the pair group is doing both transmitting and
receiving, you have frames going in both directions on a single wire. Its
like cars coming in both directions in a single lane. In this case you will
expect collisions.

Please can someone clarify .....

On 1G 1000BASE-T, pairs are bidirectional, full duplex.
(Like your POTS phone line, you can talk while you listen)
No collisions.

On Sun, Jul 31, 2011 at 9:47 PM, Joe Astorino <joeastorino1982_at_gmail.com>
wrote:

If all 4 pairs are used in 1000Base-T I wonder how POE also rolls into
that...

On Sun, Jul 31, 2011 at 1:55 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar>
wrote:

On 1G 1000BASE-T, pairs are bidirectional, full duplex.
(Like your POTS phone line, you can talk while you listen)
No collisions.
Signal treatment is beyong my current understanding, but it uses 5 levels in
each pair!
Amazing...

Irfan Sid @ 31/07/2011 11:32 -0300 dixit:

 
On 1 Gig link pin 4,5, 7 and 8 are bi-directional meaning the same wire
will be used for Tx and Rx?
 And for 10/100 those pins are not used at all, so 10/100 is serial rather
then parrallel.
 Does that mean that odd collison is possible on both since they are
bidirectional packet streams??

 
http://pinouts.ws/rj-45-pinout.html

 
http://pinouts.ru/Net/Ethernet10BaseT_pinout.shtml

On Sun, Jul 31, 2011 at 2:50 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar
<mailto:tron_at_huapi.ba.ar>> wrote:

   I stand corrected, in 1000BASE-T there are 4 bidirectional signal paths,
   so it's basically a parallel interface.

   Sorry about that.
   -Carlos

   Aaron Riemer @ 31/07/2011 05:36 -0300 dixit:

       Yep. However just doing some reading it looks like Gigabit copper
       (1000BaseT) uses all four pairs and this link seems to suggest
       that data is
       sent in parallel.
 
http://www.cisco.com/en/US/__tech/tk389/tk214/tech___digest09186a0080091a86.
html
 
<http://www.cisco.com/en/US/tech/tk389/tk214/tech_digest09186a0080091a86.htm
l>

       "1000BASE-T works by using all four of the Category 5 pairs to
       achieve 1000
       Mbps operation over the installed Category 5 copper cabling.
       1000 Mbps data
       rates are achieved by sending and receiving a 250 Mbps data
       stream over each
       of the four pairs simultaneously (4 X 250 Mbps = 1 Gbps)."

       Cheers,

       -Aaron.

       -----Original Message-----
       From: nobody_at_groupstudy.com <mailto:nobody_at_groupstudy.com>

       [mailto:nobody_at_groupstudy.com <mailto:nobody_at_groupstudy.com>] On

       Behalf Of
       Irfan Sid
       Sent: Sunday, 31 July 2011 1:02 PM
       To: Aaron Riemer
       Cc: Carlos G Mendioroz; Cisco certification; Cisco certification
       Subject: Re: Packet delivery on a Ethernet Wire

       So does that mean that in copper wire, you have two paths ie
       full duplex,
       one for transmit and one for recieve. One pair of the copper will be
       dedicated to tansmit and one to recieve. Each path transmitting
       serially.

       On Fibre its the same, you have two fibre's one for transmit and
       one for
       receive and data is transmitted serially on them.

       Is this correct?

       On Thu, Jul 28, 2011 at 6:07 AM, Aaron Riemer

       <ariemer_at_amnet.net.au <mailto:ariemer_at_amnet.net.au>> wrote:

           My apologies. I must have misread.

           http://en.wikipedia.org/wiki/__Data_transmission
           <http://en.wikipedia.org/wiki/Data_transmission>

           Thanks for clearing that up.

           Cheers,

           -Aaron.

           -----Original Message-----
           From: nobody_at_groupstudy.com <mailto:nobody_at_groupstudy.com>

           [mailto:nobody_at_groupstudy.com

           <mailto:nobody_at_groupstudy.com>] On Behalf Of
           Carlos G Mendioroz
           Sent: Thursday, 28 July 2011 12:27 AM
           To: Aaron Riemer
           Cc: 'Irfan Sid'; 'Cisco certification'; 'Cisco certification'
           Subject: Re: Packet delivery on a Ethernet Wire

           Aaron,
           copper has "pairs" because you use one wire as a reference
           to the other.
           But there is only one signal path (each way), and it works
           serially.
           -Carlos

           Aaron Riemer @ 27/7/2011 4:09 -0300 dixit:

               Hi Irfan,

               I believe with copper Ethernet (100BaseTX for example)
               since there are
               copper "pairs" the data is sent in parallel. I would
               assume the only way
               parallel data transmission would work with fibre is if a
               different band

           of

               light is used (CWDM for example).

               Queuing on the router/switch only affects packets within
               the router

           itself

               and has no bearing on packets along the wire (unless
               they are dropped).

               Tools such as compression / LFI / DSCP marking are
               examples of the

       router

               manipulating the packets in some way before transmission
               out an

           interface.

               Cheers,

               -Aaron.

               -----Original Message-----
               From: nobody_at_groupstudy.com
               <mailto:nobody_at_groupstudy.com>

               [mailto:nobody_at_groupstudy.com

               <mailto:nobody_at_groupstudy.com>] On Behalf Of
               Irfan Sid
               Sent: Wednesday, 27 July 2011 1:48 PM
               To: Cisco certification; Cisco certification
               Subject: Packet delivery on a Ethernet Wire

               This maybe a stupid question would appreciate if someone
               can clearify:

               Are Ethernet packets delivered serially on the physcial
               medium ie copper

           or

               fibre - one after another in one single file or line if
               you will. Or are
               they delivered in parallel ie. two or more packets can be in

       transmission

               along each other in parallel.

               Also when you enable queueing on Router/switch. Does
               this only effect

           the

               behaviour of how the router treats the packet on the
               inbound or outbound
               interface or does it also effect the behaviour of the
               packet when it is
               actually in transit on the wire itself.

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Received on Mon Aug 01 2011 - 15:15:36 ART