IEEE 802.3 Ethernet IEEE 802.3u Fast Ethernet IEEE 802.3z Gigabit Ethernet ANSI X3T9 Fibre Channel Ethernet – Table of Contents Part 1: IEEE 802.3 Ethernet Part 2: IEEE 802.3u Fast Ethernet Floor 4 Ethernet / Fast Ethernet Switch Part 3: IEEE 802.3z Gigabit Ethernet Floor 3 Hub Stack Bridge / Router Fast WAN Ethernet Switch Floor 1 Broadband Network Technologies IEEE 802.3 Ethernet 2 Ethernet – History • Developed by Xerox Palo Alto Research Centre • First published by Digital Equipment, Intel, and Xerox as DIX (DEC, Intel, Xerox) standard • Strongly changed and standardised by IEEE in the IEEE 802.3 • Therefore, two different versions are existing: – Ethernet version 2 (DIX) – IEEE 802.3 – differences are mainly in the Media Access frame • Topology of an Ethernet is logically (mostly physically, too) a bus Broadband Network Technologies IEEE 802.3 Ethernet 3 Ethernet – Technological Overview • A lot of standards exist for different Ethernet versions: – 1Base5 (Starlan), 10Base5 (Ethernet), 10Base2 (Cheapernet) – 10BaseT, 10BaseF, 10Broad36 – 100BaseTX, 100BaseFX, 100BaseT2, 100BaseT4 – 1000Base-LX, 1000Base-SX, 1000Base-CX, 1000Base-T – 100BaseVG, 100VG-AnyLAN • First number identifies transfer rate (1=1MBit/s, 10=10MBit/s, ...) • Base = baseband transmission, Broad = broadband transmission • Last digit, number, or character identifies characteristics of the transmission medium: – T = twisted pair, FX/LX/SX = fibre optics, CX = shielded balanced copper, T4 = 4 pair twisted pair, T2 = 2 pair twisted pair – length of a segment - 2=185m, 5=500m Broadband Network Technologies IEEE 802.3 Ethernet 4 Part 1: Survey Part 1: IEEE 802.3 Ethernet – Physical Layer – Medium Access – Configuration Rules Part 2: IEEE 802.3u Fast Ethernet thick coax Part 3: IEEE 802.3z Gigabit Ethernet segment (500m max) coax MAU tap (MDI) 15-pin AUI connector transceiver AUI cable (50m max) Ethernet interface male "N" connector with external MAU 50 Ohm terminator Broadband Network Technologies IEEE 802.3 Ethernet 5 IEEE 802.3 Ethernet – Introduction Applications Management CSMA/CD MAC AUI Interface 10Base5 10Base2 10Base-T 10Base-F (Thick Coax) (Thin Coax) (UTP cat 3,4,5) (Fibre) Ethernet Physical Layer (PHY) Options Broadband Network Technologies IEEE 802.3 Ethernet 6 Physical Layer • Tasks of the physical layer defined as: – send and receive bit streams – collision detection – encoding and decoding of signals – generation of the preamble – generation of clocks for synchronisation – testing of the transmission of data from the station up to the Medium Access Unit (MAU) Broadband Network Technologies IEEE 802.3 Ethernet 7 Physical Layer (cont.) – Architectural Model Higher Protocol Layer Logical Link Control (LLC) Medium Access Control (MAC) PLS standardised in IEEE 802.3 AUI Physical Layer Physical PMA MDI MAU transmission medium PLS Physical Signalling Sub-layer MDI Medium Dependent Interface AUI Attachment Unit Interface MAU Medium Attachment Interface PMA Physical Medium Attachment Broadband Network Technologies IEEE 802.3 Ethernet 8 Medium Access – CSMA/CD • Shared medium access is realised with Carrier Sense Multiple Access with Collision Detection (CSMA/CD) – each station is listening to the carrier (carrier sense) – if no transmission takes place, stations can send data to any other station (multiple access) – if two or more stations send data at the same time, each station has to stop further transmission (collision detection) – after a certain time (random for each station), stations can try to send data again • CSMA/CD needs – multiple stations connected to a segment (multiple access) – sense of the carrier before data is sent (carrier sense) – sense of the carrier during data transmission (collision detection) Broadband Network Technologies IEEE 802.3 Ethernet 9 Medium Access (cont.) – Domains Bridge / Repeater / Router Switch Hub Ethernet Ethernet Ethernet Ethernet Collision Domain Broadcast Domain Broadband Network Technologies IEEE 802.3 Ethernet 1 Medium Access (cont.) – IEEE 802.3 Frames IEEE 802.3 Ethernet MAC frames PA SFD DA SA LEN LLC Data PAD FCS 7 1 646 2 3/4 variable PA preamble LLC logical link control DA destination address PAD padding SA source address FCS frame check sequence (CRC-32) SFD start frame delimiter LEN length Broadband Network Technologies IEEE 802.3 Ethernet 1 Configuration Rules • Basically two models exist for the configuration of multi-segment Ethernet networks: 1. A model employing conservative calculations 2. A model employing IEEE standardised configuration aids with two phase calculation (first the correct round trip signal propagation, than the amount of Interframe Gap shrinkage) • System not built with these guidelines can work, but usually not for a long time • Especially a growing network (by size or traffic load) should not violate this recommendations (IEEE 802.3) Broadband Network Technologies IEEE 802.3 Ethernet 1 Configuration Rules (cont.) – Model 1 10Base-FL link 500m R 500m R 10Base-5 mixing 10Base-FL link 500m 500m DTE 2 10Base-5 mixing 10Base-T link DTE 3 R 100m R DTE 1 185m 10Base-2 mixing R Repeater Broadband Network Technologies IEEE 802.3 Ethernet 1 Configuration Rules (cont.) – Model 2 • Defines two sets of methods, which have to be performed both • First set ensures that the round trip signal propagation is within the limits • Second set verifies the amount of Interframe Gap shrinkage • A simplified network topology (Generalised Transmission Path Model) is used to for the path delay calculation DTE DTE MAU MAU Repeater MAU MAU Repeater MAU MAU 1 2 left segment middle segment right segment Broadband Network Technologies IEEE 802.3 Ethernet 1 Part 2: IEEE 802.3u Fast Ethernet Part 1: IEEE 802.3 Ethernet Part 2: IEEE 802.3u Fast Ethernet – Introduction – 100Base-T Overview – 100Base-TX – 100Base-FX – 100Base-T4 Ethernet / Fast Ethernet / Fast Ethernet Switch Ethernet Switch Part 3: IEEE 802.3z Gigabit Ethernet Fast Ethernet Hub Broadband Network Technologies IEEE 802.3 Ethernet 1 Fast Ethernet – Technological Overview I • Two different technologies exist for 100MBit/s Ethernet – IEEE 802.3u 100Base-T (100Base-TX, 100Base-FX, 100Base-T4, 100Base-T2) – IEEE 802.12 100VG-AnyLAN • 100Base-T – supports the common Ethernet mechanisms (CSMA/CD) • 100VG-AnyLAN – creates an entirely new medium access control mechanism – is based on hubs that control access to the medium using a demand priority – further extended to allow to transport token ring frames Broadband Network Technologies IEEE 802.3 Ethernet 1 Fast Ethernet – Technological Overview II 100 MBit/s Ethernet 100VG-AnyLAN 100Base-T 100Base-T2 100Base-X 100Base-4 100Base-TX 100Base-FX Broadband Network Technologies IEEE 802.3 Ethernet 1 IEEE 802.u Fast Ethernet • Aims of the IEEE 802.3u Fast Ethernet working group – support of CSMA/CD with bit rate of 100 MBit/s – identical MAC frame format – support of twisted pair and fibre optics as physical medium – interoperability between 10Base-T and 100Base-TX components • Fast Ethernet Consortium develops technology and is accepted by the IEEE 802.3u working group • The Fast Ethernet Consortium was formed in December of 1993 and is one of the consortiums at the University of New Hampshire Inter Operability Lab (IOL). The Consortium was formed through the co- operative agreement of vendors interested in testing Fast Ethernet products. Broadband Network Technologies IEEE 802.3 Ethernet 1 IEEE 802.u Fast Ethernet (cont.) – Overview Applications Management CSMA/CD MAC MII Interface 100Base-FX 100Base-TX 100Base-T4 (Fibre) (UTP cat 5) (UTP cat 3,4,5) Fast Ethernet Physical Layer (PHY) Options Broadband Network Technologies IEEE 802.3 Ethernet 1 Physical Layer – 100Base-X Scheme of the 100Base-X standard LLC MAC Reconciliation MII 100Base-X repeater PCS PCS PCS Physical PMA PMA Layer PMA PMD PMD PMD MDI MDI MDI Medium Medium Broadband Network Technologies IEEE 802.3 Ethernet 2 Physical Layer (cont.) – 100Base-T4 Scheme of the 100Base-T4 standard LLC MAC Reconciliation MII PCS PMD MDI Medium Broadband Network Technologies IEEE 802.3 Ethernet 2 Physical Layer (cont.) – 10/100 MBit Hub Scheme of a Fast Ethernet hub supporting different media 10Base-T / 100Base-TX repeater Reconciliation Reconciliation PLS MII MII PCS PCS Physical Layer PMA AUI AUI PMD PMA PMA (= MAU) MDI MDI MDI Medium Medium Medium 100 MBit/s 10 MBit/s 10 MBit/s Broadband Network Technologies IEEE 802.3 Ethernet 2 Media System • 100Base-T is ten times faster than 10Base-T • Common 10Base-T aspects are unchanged – frame format and the amount of data of a frame – media access control • Mechanisms for Auto-Negotiation of media speed added – enables support of dual-speed Ethernet interfaces (10 and 100 MBit/s) • Block diagram of 100Base-T components: Data Terminal Physical Medium Equipment Medium Independent Physical Layer Dependent (DTE) Interface (MII) Medium Device (PHY) Interface (MDI) port 40-pin connector optional Broadband Network Technologies IEEE 802.3 Ethernet 2 100Base-TX – Components I class II four port 100Base-TX repeater hub R II PHY PHY PHY PHY eight pin plugs twisted pair segment (100m max of data graded UTP cat 5 cable) PHY eight pin jack MDI Ethernet interface (100Base-TX) Broadband Network Technologies IEEE 802.3 Ethernet 2 100Base-TX (cont.) – Components II • 100Base-TX segments are link segments • A link segment is defined as a point-to-point medium – connects two and only two MDIs – smallest network would consist of two computers • Typical installation uses multiport repeater hubs or packet switching hubs – provides a