Re: Clarify the differences between Ethernet & IEEE 802.3
Actually it was called "Aloha Protocol", with a successor called "Slotted Aloha" developed at the University of Hawai'i. Alloah is the Islamic version of this protocol ;-). Cheers, Gernot Phil Barker wrote: > > IEEE 802.3 does indeed define the operation of > CSMA/CD, which I believe is media - independent. > I seem to recall that CSMA/CD was first tried out with > a project called 'Alloah' in the 1970's between > several islands, one being Hawaii, so radio was the > medium here. > > http://www.smarthomeforum.com/ethernet.shtml > See link > > Phil. > > --- Billy Monroe <[EMAIL PROTECTED]> wrote: > > I see a description of the differences between them > > but I can't really > > understand that in practical terms. > > Is the IEEE 802.3 the CSMA/CD ? > > > > > > > > > > _ > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to > [EMAIL PROTECTED] > > > Do You Yahoo!? > Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk > or your free @yahoo.ie address at http://mail.yahoo.ie > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
During the initial installation of your network interface card driver your upper layer protocols like IP or IPX/SPX was binded to a frame type of your choice , in your case either IEEE 802.3 or Ethernet II. So the packet will be encapsulated with the frame type of your choice. -Original Message- From: Billy Monroe <[EMAIL PROTECTED]> Newsgroups: groupstudy.cisco To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Sunday, February 04, 2001 9:27 PM Subject: Re: Clarify the differences between Ethernet & IEEE 802.3 >Thanks. >I mean, during encapsulation how IEEE 802.3 or Ethernet will be selected ? >"Who" decides that ? > > >"Curtis Call" <[EMAIL PROTECTED]> wrote in message >4.3.2.7.0.20010204110556.00ab6100@mail">news:4.3.2.7.0.20010204110556.00ab6100@mail... >> They are different standards for ethernet. They both use CSMA/CD. 802.3 >> was defined by the IEEE and Ethernet was defined by Xerox I believe. >> >> The difference is in the packet format: >> >> Ethernet: >> Destination Address (6 octets) - Source Address (6) - Protocol (2) - Data >> (Variable) - FCS (4) >> >> 802.3 >> Destination Address (6 octets) - Source Address (6) - Length (2) - Data >> (Variable) - FCS (4) >> >> A node can tell the difference between the two protocols because the >Length >> of a packet can never be more than 1518 bytes so if that value is more >than >> 1518 the node can tell that it is an Ethernet packet and that that >> particular spot is the protocol type field not the length. >> >> Given that 802.3 packets don't contain the protocol type field they cannot >> transport different network layer protocols without using additional >> information which is why 802.2 and SNAP was defined. The 802.2 or SNAP >> fields occur at the beginning of the Data portion of the packet and are >> used to specify which protocol is sending the packet. >> >> Did that answer your question? >> >> At 09:43 AM 2/4/01 -0800, you wrote: >> >I see a description of the differences between them but I can't really >> >understand that in practical terms. >> >Is the IEEE 802.3 the CSMA/CD ? >> > >> > >> > >> > >> >_ >> >FAQ, list archives, and subscription info: >> >http://www.groupstudy.com/list/cisco.html >> >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] >> >> _ >> FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] >> > > >_ >FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
"Billy Monroe" <[EMAIL PROTECTED]> wrote, >I see a description of the differences between them but I can't really >understand that in practical terms. Depends what you mean by "practical." Ethernet II is an older standard. >Is the IEEE 802.3 the CSMA/CD ? No. Both use CSMA/CD (ignoring special cases of Fast and Gigabit speeds) > The February CCIE paper at http://www.certificationzone.com, CCIE Switching Part 1 by Dan Farkas, goes into this in more detail. Briefly, both the original Ethernet and 802.3 cover more than one OSI layer, although 802.3 assumes 802.2 will run on top to complete the data link layer. Layer 1 differences: minor. Ethernet has an interface signal variously called SQE or heartbeat, which 802.3 does not. Layer 2 differences: after the preamble, both Ethernet and 802.3 have a destination MAC address, a source MAC address, followed by a two-byte field. The usage of this two-byte field is different in the two protocols. In Ethernet, it carries an Ethertype code that identifies the protocol of the payload in the user data field. In 802.3, it carries the frame length. Protocol identification is the job of the 802.2 header, which occupies the first few bytes of the user data field. Note: there is one Novell variant in which there is no 802.2. 802.1Q VLANs and other 802 standards can complicate things, but are beyond the scope of this answer. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
Well, take Cisco routers for instance. You configure the interface to use either 802.3 or Ethernet II (or 802.2 or SNAP). So in this case it is you that decides which encapsulation to use and the router just follows your instructions. In other cases a program might be explicitly set up to only use one certain encapsulation but generally they let you choose which one you want to use. At 10:19 AM 2/4/01 -0800, you wrote: >Thanks. >I mean, during encapsulation how IEEE 802.3 or Ethernet will be selected ? >"Who" decides that ? > > >"Curtis Call" <[EMAIL PROTECTED]> wrote in message >4.3.2.7.0.20010204110556.00ab6100@mail">news:4.3.2.7.0.20010204110556.00ab6100@mail... > > They are different standards for ethernet. They both use CSMA/CD. 802.3 > > was defined by the IEEE and Ethernet was defined by Xerox I believe. > > > > The difference is in the packet format: > > > > Ethernet: > > Destination Address (6 octets) - Source Address (6) - Protocol (2) - Data > > (Variable) - FCS (4) > > > > 802.3 > > Destination Address (6 octets) - Source Address (6) - Length (2) - Data > > (Variable) - FCS (4) > > > > A node can tell the difference between the two protocols because the >Length > > of a packet can never be more than 1518 bytes so if that value is more >than > > 1518 the node can tell that it is an Ethernet packet and that that > > particular spot is the protocol type field not the length. > > > > Given that 802.3 packets don't contain the protocol type field they cannot > > transport different network layer protocols without using additional > > information which is why 802.2 and SNAP was defined. The 802.2 or SNAP > > fields occur at the beginning of the Data portion of the packet and are > > used to specify which protocol is sending the packet. > > > > Did that answer your question? > > > > At 09:43 AM 2/4/01 -0800, you wrote: > > >I see a description of the differences between them but I can't really > > >understand that in practical terms. > > >Is the IEEE 802.3 the CSMA/CD ? > > > > > > > > > > > > > > >_ > > >FAQ, list archives, and subscription info: > > >http://www.groupstudy.com/list/cisco.html > > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > > > _ > > FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > > > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
Thanks. I mean, during encapsulation how IEEE 802.3 or Ethernet will be selected ? "Who" decides that ? "Curtis Call" <[EMAIL PROTECTED]> wrote in message 4.3.2.7.0.20010204110556.00ab6100@mail">news:4.3.2.7.0.20010204110556.00ab6100@mail... > They are different standards for ethernet. They both use CSMA/CD. 802.3 > was defined by the IEEE and Ethernet was defined by Xerox I believe. > > The difference is in the packet format: > > Ethernet: > Destination Address (6 octets) - Source Address (6) - Protocol (2) - Data > (Variable) - FCS (4) > > 802.3 > Destination Address (6 octets) - Source Address (6) - Length (2) - Data > (Variable) - FCS (4) > > A node can tell the difference between the two protocols because the Length > of a packet can never be more than 1518 bytes so if that value is more than > 1518 the node can tell that it is an Ethernet packet and that that > particular spot is the protocol type field not the length. > > Given that 802.3 packets don't contain the protocol type field they cannot > transport different network layer protocols without using additional > information which is why 802.2 and SNAP was defined. The 802.2 or SNAP > fields occur at the beginning of the Data portion of the packet and are > used to specify which protocol is sending the packet. > > Did that answer your question? > > At 09:43 AM 2/4/01 -0800, you wrote: > >I see a description of the differences between them but I can't really > >understand that in practical terms. > >Is the IEEE 802.3 the CSMA/CD ? > > > > > > > > > >_ > >FAQ, list archives, and subscription info: > >http://www.groupstudy.com/list/cisco.html > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
IEEE 802.3 does indeed define the operation of CSMA/CD, which I believe is media - independent. I seem to recall that CSMA/CD was first tried out with a project called 'Alloah' in the 1970's between several islands, one being Hawaii, so radio was the medium here. http://www.smarthomeforum.com/ethernet.shtml See link Phil. --- Billy Monroe <[EMAIL PROTECTED]> wrote: > I see a description of the differences between them > but I can't really > understand that in practical terms. > Is the IEEE 802.3 the CSMA/CD ? > > > > > _ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Clarify the differences between Ethernet & IEEE 802.3
They are different standards for ethernet. They both use CSMA/CD. 802.3 was defined by the IEEE and Ethernet was defined by Xerox I believe. The difference is in the packet format: Ethernet: Destination Address (6 octets) - Source Address (6) - Protocol (2) - Data (Variable) - FCS (4) 802.3 Destination Address (6 octets) - Source Address (6) - Length (2) - Data (Variable) - FCS (4) A node can tell the difference between the two protocols because the Length of a packet can never be more than 1518 bytes so if that value is more than 1518 the node can tell that it is an Ethernet packet and that that particular spot is the protocol type field not the length. Given that 802.3 packets don't contain the protocol type field they cannot transport different network layer protocols without using additional information which is why 802.2 and SNAP was defined. The 802.2 or SNAP fields occur at the beginning of the Data portion of the packet and are used to specify which protocol is sending the packet. Did that answer your question? At 09:43 AM 2/4/01 -0800, you wrote: >I see a description of the differences between them but I can't really >understand that in practical terms. >Is the IEEE 802.3 the CSMA/CD ? > > > > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Clarify the differences between Ethernet & IEEE 802.3
I see a description of the differences between them but I can't really understand that in practical terms. Is the IEEE 802.3 the CSMA/CD ? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
