Ethernet Standards DIX consortium – Mbps 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

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 Ethernet standard

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

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

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)

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

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

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

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

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

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

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

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 is a DEC NIC board ex is SUN –Next 24 bits are a unique serial number

MAC addressing Methods –Static –Configurable –Dynamic

Types of addresses Broadcast Multicast Unicast

Ethernet Frame Format

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

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