At 03:20 PM 1/11/02, Joseba Izaga wrote: >It is true that 10Base-T and 100Base-T unshielded twisted-pair cabling uses >two pairs, both full duplex and half duplex. > >It is true that It's not the cabling that distinguishes half-duplex and >full-duplex. It's the logical topology, hardware, and configuration. > >But, if you want to run 100Base-T and full-duplex depend you must take care >on the cable4s length and quality. It functions better if you have CAT-5 or >CAT-5E cable.
That statement applies if you want to run 100Base-T with half duplex also. In fact, 100Base-TX requires Cat 5 or better. I just checked the standard. 10Base-T, on the other hand, does not say that. He asked about cabling requirements for half versus full. He didn't ask about cabling requirements for 10 Mbps versus 100 Mbps. Priscilla >----- Original Message ----- >From: "Priscilla Oppenheimer" >To: >Sent: Friday, January 11, 2002 9:59 AM >Subject: Re: full-duplex Ethernet cable? [7:31643] > > > > At 11:56 AM 1/11/02, mlh wrote: > > >how many pairs of two-twisted cable are used for full-duplex Ethernet ? >what > > >is the > > >difference between full- and half- duplex cable? > > > > 10Base-T and 100Base-T unshielded twisted-pair cabling uses two pairs, for > > both full duplex and half duplex. There's a transmit pair and a receive > > pair. A station's transmit pair gets crossed over at the hub or switch to > > mean receive at the hub or switch. The hub or switch's transmit pair > > becomes receive at the station. > > > > It's not the cabling that distinguishes half-duplex and full-duplex. It's > > the logical topology, hardware, and configuration. > > > > With half-duplex, if a station receives bits on its receive pair while > > transmitting bits on its transmit pair, this is considered a collision. >The > > station must stop transmitting, back off, and retransmit. A half-duplex > > network is shared. Every device on the hub (or coax cable) shares the > > bandwidth and must obey the rules of Carrier Sense Multiple Access, > > Collision Detect. Listen before sending. Listen while sending to see if > > another station started sending at the same time and back off if that's >the > > case. > > > > Full duplex works on a point-to-point link between a station and a switch. > > Bandwidth is not shared. In this case, receiving while you are sending it > > perfectly legitimate. > > > > So, to upgrade a network from half-duplex to full-duplex doesn't require > > new cabling, but it does require a new logical topology and possibly new > > hardware: switches and Network Interface Cards (NICs) that support full > > duplex. It also requires that the administrator configure everything for > > full duplex (or use auto-negotiation which is risky because it's buggy.) > > > > Hope that helps. > > > > Priscilla > > > > > > > > >Thank you in advance. > > > > > > > > > > > >Regrads, > > > > > >mlh > > ________________________ > > > > Priscilla Oppenheimer > > http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=31683&t=31643 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
