Re: Packet delivery on a Ethernet Wire

So then my last statement is also true :

"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."

On Mon, Aug 1, 2011 at 10:15 AM, Aaron Riemer <ariemer_at_amnet.net.au> wrote:

> 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.h
tml
> <
>
http://www.cisco.com/en/US/tech/tk389/tk214/tech_digest09186a0080091a86.html
> >
>
> "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.
>
>
> Blogs and organic groups at http://www.ccie.net
> <http://www.ccie.net/>
>
>
>
Received on Mon Aug 01 2011 - 12:04:25 ART