1. Ethernet Standards DIX consortium – 1979 10Mbps Ethernet 1 st Blue book – 1980 IEEE group takes over – Project 802 –802.1 – High Level Interface –HLI – Focused on high level inter-network protocols & management –802.2 – Logic Link Control –802.3 – Data Link & Medium Access Control DLMAC

2. Ethernet Standards 1982 – DLMAC – 3 groups –802.3 – CSMA/CD – driven by DIX –802.4 – Token Bus – burroughs, concorde, –802.5 – Token – Ring - IBM 1982 – DIX & IEEE merges –1 st version of 802.3 Ethernet standard

3. Ethernet Standards IEEE 802.3 – series of specifications for 10Mbps –Thick coaxial – thicknet – 10Base5 –Thin coaxial – thinnet- cheapernet –10Base2 –UTP XBaseT –Fibre XBaseF –Broadband version XBroad36

4. Ethernet Standards Other specifications –100 Mbs – fast Ethernet –1000 Mbps – gigabit Ethernet –Switched Ethernet –Proposal for 100MBps – 1982 –IEEE 802 focused on 1- 20 MBps –ANSI took up 100 Mbps - led to FDDI

5. Ethernet Popularity Result –Shift in Ethernet shared access – to switched Ethernet –Subsequent – Fast Ethernet – 100BASE-T (1995) –High bit rate interconnectivity requirement Gigabit Ethernet 10 9 bits per second –(Ethernet frame format maintained)

6. Network Connection Network Interface Card – NIC Attachment Unit Interface – AUI Medium Attachment Unit – MAU PHY + MAC – HW LLC - SW

7. Network Connection MAU – Transceiver –Transmit data –Receive data –Loopback –Collision detection –SQE test –Jabber protection

8. 10BASE5 Thicknet Early 80s standard Tapped Bus topology – 50 ohm coax cable Maximum 500 m segment length 100/200 users per segment Max 4 repeaters

9. 10BASE2 Thinnet 1989 standard BNC ( British Navel Connector) Less expensive cable – flexible – to the desktop Max segment size 185m, max nodes 30 Max length with repeaters – 925 m Min distance between MAU = 0.5m

10. 10BASE-T Twisted Pair Uses standard voice grade telephone cable 1990 – IEEE 802.3i UTP standard 4 twisted pairs Star topology – logically bus Hub – repeater at the centre –Signal restoration –Repeated incoming signal in all output ports

11. 10BASE-FL Runs over 2 strands of single/multimode fibre Fibre distance between MAU – 2000m Point-to-point links

12. Functions of a NIC Physical Addressing Encoding Data Access to Physical Medium Connection to Physical Medium Framing - encapsulate & decapsulate data Create and Check CRC - error detection Transceiver - translates signal to medium specific signal

13. Physical MAC addresses Unique Addresses assigned by the IEEE 48 bit address in two parts –First 24 bits specify the vendor (block number) ex. AA-00-00 is a DEC NIC board ex. 08-20-00 is SUN –Next 24 bits are a unique serial number

14. MAC addressing Methods –Static –Configurable –Dynamic

15. Types of addresses Broadcast Multicast Unicast

16. Ethernet Frame Format

17. Ethernet Operation Broadcast/half duplex network –On a bus topology Listen first then transmit if clear What to do if you collide –Backoff and try again

18. CSMA/CD LAN transmissions operate on the idea of a bit period For 10baseT this is 100ns (10,000,000 bits/sec) 3 times to keep track of –Slot time –Interframe gap –Jam period