數(shù)據(jù)與計(jì)算機(jī)通信ppt課件-wenkub
2023-04-07 00:04:08 本頁(yè)面
【正文】 specifications from FDDI ?Two physical links between nodes ?Transmission and reception ?100BASETX uses STP or Cat. 5 UTP ?May require new cable ?100BASEFX uses optical fiber ?100BASET4 can use Cat. 3, voicegrade UTP ?Uses four twistedpair lines between nodes ?Data transmission uses three pairs in one direction at a time ?Starwire topology ?Similar to 10BASET 23 100Mbps (Fast Ether) ? 100BaseTX 100BaseFX 100BaseT4 ?2 pair, STP 2 pair, Cat 5 UTP 2 optical fiber 4 pair, cat 3,4,5 ?MLT3 MLT3 4B5B,NRZI 8B6T,NRZ 24 100BASEX Data Rate and Encoding ?Unidirectional data rate 100 Mbps over single link ?Single twisted pair, single optical fiber ?Encoding scheme same as FDDI ?4B/5BNRZI ?Modified for each option 25 100BASEX Media ?Two physical medium specifications ?100BASETX ?Two pairs of twistedpair cable ?One pair for transmission and one for reception ?STP and Category 5 UTP allowed ?The MTL3 signaling scheme is used ?100BASEFX ?Two optical fiber cables ?One for transmission and one for reception ?Intensity modulation used to convert 4B/5BNRZI code group stream into optical signals ?1 represented by pulse of light ?0 by either absence of pulse or very low intensity pulse 26 100BASET4 ?100Mbps over lowerquality Cat 3 UTP ? Taking advantage of large installed base ? Cat 5 optional ? Does not transmit continuous signal between packets ? Useful in batterypowered applications ?Can not get 100 Mbps on single twisted pair ? Data stream split into three separate streams ?Each with an effective data rate of Mbps ? Four twisted pairs used ? Data transmitted and received using three pairs ? Two pairs configured for bidirectional transmission ?NRZ encoding not used ? Would require signaling rate of 33 Mbps on each pair ? Does not provide synchronization ? Ternary signaling scheme (8B6T) 27 100BASET Options 28 Full Duplex Operation ?Traditional Ether half duplex ? Either transmit or receive but not both simultaneously ?With fullduplex, station can transmit and receive simultaneously ?100Mbps Ether in fullduplex mode, theoretical transfer rate 200 Mbps ?Attached stations must have fullduplex adapter cards ?Must use switching hub ? Each station constitutes separate collision domain ? In fact, no collisions ? CSMA/CD algorithm no longer needed ? MAC frame format used ? Attached stations can continue CSMA/CD 29 Mixed Configurations ?Fast Ether supports mixture of existing 10Mbps LANs and newer 100Mbps LANs ?. 100Mbps backbone LAN to support 10Mbps hubs ?Stations attach to 10Mbps hubs using 10BASET ?Hubs connected to switching hubs using 100BASET ?Support 10Mbps and 100Mbps ?Highcapacity workstations and servers attach directly to 10/100 switches ?Switches connected to 100Mbps hubs using 100Mbps links ?100Mbps hubs provide building backbone ?Connected to router providing connection to WAN 30 Gigabit Ether Configuration 31 Gigabit Ether Differences ?Carrier extension載波擴(kuò)充 ?At least 4096 bittimes long (512 for 10/100)使傳輸時(shí)間超過(guò) 1Gbps下的傳播時(shí)延 ?Frame bursting幀突發(fā) ?連續(xù)發(fā)送直至達(dá)到最大限度的多個(gè)短幀，避免載波擴(kuò)充所產(chǎn)生的額外開(kāi)銷 32 Gigabit Ether – Physical ?1000BaseSX ?Short wavelength, multimode fiber ?1000BaseLX ?Long wavelength, Multi or single mode fiber ?1000BaseCX ?Copper jumpers 25m, shielded twisted pair ?1000BaseT ?4 pairs, cat 5 UTP ?Signaling 8B/10B 33 Gbit Ether Medium Options(log scale) 34 10Gbps Ether Uses ?Highspeed, local backbone interconnection between largecapacity switches ?Server farm ?Campus wide connectivity ?Enables Inter service providers (ISPs) and work service providers (NSPs) to create very highspeed links at very low cost ?Allows construction of (MANs) and WANs ? Connect geographically dispersed LANs between campuses or points of presence (PoPs) ?Ether petes with ATM and other WAN technologies成為 ATM和其他廣域網(wǎng)技術(shù)的競(jìng)爭(zhēng)對(duì)手 ?10Gbps Ether provides substantial value over ATM價(jià)值遠(yuǎn)超過(guò) ATM 35 10Gbps Ether Advantages ?No expensive, bandwidthconsumin
范文總結(jié)相關(guān)推薦
鄂ICP備17016276號(hào)-1