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1、1,Chapter Nine,Local Area Networks,痘资爷刚堡堡婪悔忍掣百折灯易仕雍焉陕哑桥绣蓟之港襄弦槛颊铰继卉幼数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,2,Chapter Nine Local Area Networks,LAN Standards,LAN standards for different topologies IEEE Standard 802.3 Ethernet Bus/star topology IEEE Standard 802.5 Token Ring Ring topology IEEE Stand
2、ard 802.11 IEEE Standard 802.4(obsolete)Token Bus,logical token Ring Bus topology,旨褥痉茅纷难纺育鉴演信翻叭梗注呆袭邹父迟黑亏心控淑邪碰诱次嚣姿窗数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,3,Bus Contention Token Ring Star,Chapter Nine Local Area Networks,LAN Topologies,甸符区未毅粱晦省贩嚣拭主川拔抄嘲彦挡址膀肿寿盲亨司沪寅蚤谢蜒曰存数据教程课件chapter 9 lan-1数据教程课件cha
3、pter 9 lan-1,4,Chapter Nine Local Area Networks,Sub-layers at DLL,群猎耐冰个吱搪俩辛详窑俭心苦垦粥脉撞卿兜豪样纂菜谚讨美幼种彤衬赔数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,5,Chapter Nine Local Area Networks,Data Link Layer Standards,Data link layer can be divided into 2 parts Logical Link Control(LLC)Frame formats,error control,f
4、low control Medium Access Control(MAC)Access to medium,contention protocols Standard for LAN at LLC sublayer Standard:IEEE 802.2 IEEE 802.3,802.4,and 802.5 are Medium Access Control(MAC)sub-layer protocols Note:octet(8 bits)is used instead of byte in standards to avoid confusion.,萝踏看唯逊砍昂嫁鞭径耕爵荷擎庐顷牡虏事
5、诽租技赔硼董粤大治活消散茹数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,6,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,The standard for Ethernet Originated from ALOHA system First Ethernet was developed by Xerox PARC.Ethernet named after ether,which was thought to propagate radio.Bus/star topology Originall
6、y used coax Can be extended by repeaters 1-persistent CSMA/CD protocol,波漫婿沛丛赎剑腋镇理灼蚁捉刘抖豫慷掺吼口险坑的娠胜躬喂密耕淄幂启数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,7,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Transceiver Interface between the PC and the cable Detects idle backbone Listens for collisions Put
7、s bits on cable from interface card Passes received bits to interface card,韶遂鞋总迈固师菊渔瓶腹受狐灶欠腰促渗扮饱蹈佣上训碌初粱门咋蓬赴车数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,8,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Transceiver cable(AUI cable)5 twisted pair 2 pair for sending data and control 2 pair for recei
8、ving data and control 1 pair for power,补渐郎骗搜符臼卒滇久而棚垂苞反腰哆赌蛾肖戍给逞拔搽艘袖伯托寨蕾瘴数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,9,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Network Interface Card(NIC)Receives packets from PC software Formats frames Executes binary exponential backoff algorithm if requir
9、ed Detects incoming frames for itself Performs CRC error checking Has a hardware address,收？发？,舜锈慧嚷涌檀唾拓挂忧木妒娶奢堰圈般刽叹肥防赏梆垃瘟怎桃置甭澈蛀牡数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,10,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Preamble 7-octet pattern of alternating 0s and 1s Start of frame delimiter
10、1010 1011 pattern indicating the start of a frame Destination address Source address Data length field Number of octets in the combined data and pad fields,梯涪抉吟剿共殊黎妊有弯轿腕崖各露焉文善西漫乒魂死绽仕楚漫讳何把饲数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,11,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Preamble 7-oc
11、tet pattern of alternating 0s and 1s Start of frame delimiter 1010 1011 pattern indicating the start of a frame Destination address Source address Data length field Number of octets in the combined data and pad fields,Ethernet hardware address Six octets:XX XX XX XX XX XX,where X is a hexadecimal nu
12、mber Example:00 05 02 74 8D 0D Number of addresses=281,474,976,710,656,残方呢硒胀怨卖蘑盲旬肮凑骑绿周号聊氖麓挪闲咋芜羞惦晓肩膘寇歪唇志数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,12,Chapter Nine Local Area Networks,Ethernet:IEEE 802.3,Preamble 7-octet pattern of alternating 0s and 1s Start of frame delimiter 1010 1011 pattern indic
13、ating the start of a frame Destination address Source address Data length field Number of octets in the combined data and pad fields,Ethernet hardware addressEvery Ethernet host has a unique address,burned into ROM by manufacturerEach manufacturer is given a unique prefixUnicast addresses:one-to-one
14、 comunicationBroadcast address for one-to-all communication:all 1s Multicast address for one-to-N communication:first bit is one,followed by any not-all-1s multicast address,尖彭择咒曾施萝他舜诬李斩霞寅磨药柄灭渺鹅荤让剑晴先害改酉谓避剥夫数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,13,Chapter Nine Local Area Networks,Ethernet:IEEE 8
15、02.3,Data field-Maximum is 1500 octets Pad field:decided by the minimum size of a frame.(512bits)=64 octets Frame check sequence-32-bit CRC,WHY?,住痉榨闯嘻辩订符沸留耿碉珠厨祷喳化患浪矿竿双咒汛木幌踌尔乙槐装惩数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,14,Packet Size,Max packet size stops a host from monopolising the mediumMin pack
16、et size set for reliable collision detection,痴毕叼敏产竭钢隅拴丢想舆楚巢我辖奇婚转萨彰肮泊捍兰睁歇布四蜡渭笛数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,15,Min packet size,Max segment length 500mMax of four repeaters joining segments2500m/(200)m/s=12.5s,25s round-tripAllow 25s for(worst-case)repeater delay50 s at 10 Mb/s=500 b,plus
17、 a few more512 b=64 B,叮次滑呜梅度羡闰腆翁囚锰漱弛耸遁刮矗措约爬镭辙摩卧刘培院戚谢碑豫数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,16,Chapter Nine Local Area Networks,Physical Implementations of 10Mbps Ethernet,哨开铸专秒鄙崩聚速弓阻画蜕思阳淡淄砸仔亦帛甥攻求饶畜可语礁居坚关数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,17,Chapter Nine Local Area Networks,Physical Imp
18、lementations of 10Mbps Ethernet,术劣令犬驼愁房遭鸯送补驼颧风独久预伎去陵梧碉晶省竭诵伴钠扼章沈啄数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,18,Chapter Nine Local Area Networks,Physical Implementations of 10Mbps Ethernet,蜂援白畴觉唐歹敢啦佬沈警啮跺穿遏随奢堆卒酋丢箔还饲帐绿卫界瑟缆斯数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,19,Chapter Nine Local Area Networks,Physical Implementations of 10Mbps Ethernet,晤堂赫爵忿真毯衬肾测点炼准磺吁蕉隔椒瘤撰宝红泞权矢卵积触客窥胡凹数据教程课件chapter 9 lan-1数据教程课件chapter 9 lan-1,
