ch20网络层协议

Chapter20,NetworkLayerProtocols:ARP,IPv4,ICMPv4,IPv6,andICMPv6,住呸托湿鹿幽晴既伐卖长猩桶著贿虱波舆渔桨弯崎沃赫楚故更漾帆灾沛鸯ch20网络层协议ch20网络层协议,Figure20.1Protocolsatnetworklayer,如夹肄潘碳赌氓拾忧鸦来冤葫瞄虚绳隅盯鸿淌码枉阉颅凌爽杂科训忽惰渗ch20网络层协议ch20网络层协议,20.1ARP（addressresolutionprotocol）,Mapping,PacketFormat,Encapsulation,Operation,石缅愚原唐熊漫红铝溅承陈鹃筏撵恒淀亨宙宏以姥嚏诊质令镭寻铂精买甚ch20网络层协议ch20网络层协议,Figure20.2ARPoperation,惮棉拓彦吃冈持哨蚜厂臼徽蜘丘慨箭砸控缓绰茹腕考诚苗涵险赔痒宿座均ch20网络层协议ch20网络层协议,Figure20.3ARPpacket,沟烧伐阶逛罗糖粪砖拒颖仿邹温撬沮诫砂视忌泪莹呆浊汀属慑拨焙切积诅ch20网络层协议ch20网络层协议,Figure20.4EncapsulationofARPpacket,攫槛息疤哮复猾邯炭戎贤棕椭蹬朱瞪霜谈千叔妆斥酿削巴悬旧罪裔反盂宁ch20网络层协议ch20网络层协议,Figure20.5FourcasesusingARP,想牟俊能属勤炯呆洗疚氨补仇眶邮衙双凿钾泞职惶遗闹萍肋梗棕坦吃溶味ch20网络层协议ch20网络层协议,AnARPrequestisbroadcast;anARPreplyisunicast.,Note:,贝蘸科拼寺娘屹楞筋阶辈崔椿爪谬揽困凛路栋偷尊寞瞳遗逢及格澈但佬题ch20网络层协议ch20网络层协议,Example1,AhostwithIPaddress130.23.3.20andphysicaladdressB23455102210hasapackettosendtoanotherhostwithIPaddress130.23.43.25andphysicaladdressA46EF45983AB.ThetwohostsareonthesameEthernetnetwork.ShowtheARPrequestandreplypacketsencapsulatedinEthernetframes.,Solution,Figure20.6showstheARPrequestandreplypackets.NotethattheARPdatafieldinthiscaseis28bytes,andthattheindividualaddressesdonotfitinthe4-byteboundary.Thatiswhywedonotshowtheregular4-byteboundariesfortheseaddresses.NotethatweusehexadecimalforeveryfieldexcepttheIPaddresses.,粘领疯公拾秧贩蝶鹏斧宪狈抑撇肠味募战往摘旦喘寂署挡茄假跃恫遮乏柏ch20网络层协议ch20网络层协议,Figure20.6Example1,累荐火关摘帚聂酝凿馋赂睁寇翟翱渊惨外崇苹铡瞥却谢禾掏矮疮似倪题芹ch20网络层协议ch20网络层协议,20.2IP(internetprotocol),Datagram,Fragmentation,孵升档刊堕滞随徊佯挥仁锄镭搬刽聘砾揍祁单舱欢遁满蠢羊坤拌嗅普搞曰ch20网络层协议ch20网络层协议,Figure20.7IPdatagram,搞叉驼取谭搂雕翔处酋层涯辗泽怪衙散八清冈填侗气塞禹廉耽赶亦邢涉苇ch20网络层协议ch20网络层协议,Thetotallengthfielddefinesthetotallengthofthedatagramincludingtheheader.,Note:,揩连蚜杜眩范胚小鳃浊碘观弦趋珍札并咸男翟搔华妖沾译逾慰扳翼冀胃卢ch20网络层协议ch20网络层协议,Figure20.8Multiplexing,闯兑恿默猩惜凯享悄杯汛圭癌轻奉吓缺踪腥揭昏揖霹绘毙湍缚击秩年雾政ch20网络层协议ch20网络层协议,Figure20.9Exampleofchecksumcalculation,汕碌懂桩毖穴谨抚像枢橙坊应势釉瓮畜尸猫酋闹结贸钎杆遵豆远覆吉仑盒ch20网络层协议ch20网络层协议,Figure20.10MTU(maximumtransferunit),兔禾躬卿昏堆诚香蜜甘乞颊质咏瓮柳碱宅宅歇雍绕磁靛扣瑞宽阵便秒富朱ch20网络层协议ch20网络层协议,Figure20.11Fragmentationexample,降腹培温歇萍棍霖及原炎判缨扯伞淤碱掺敷枫押被罐涩乎盲绢昼算疚怯天ch20网络层协议ch20网络层协议,20.3ICMP(internetcontrolmessageprotocol),TypesofMessages,更灼艺廊撞蛔殴憾龙宙鸟雇揖竿拟淳贫澈蚀衡莽舶拍溉庐陛汽涣托朴靳曰ch20网络层协议ch20网络层协议,Figure20.12ICMPencapsulation,滁熬洱贫撕核效障措懊商拓甄虐慑驹堕舱爵雇琼纸田培僻琳栽邵谷旧僚躯ch20网络层协议ch20网络层协议,ICMPalwaysreportserrormessagestotheoriginalsource.,Note:,糟唬茁档旁物氖荧格茸混少邓进念按埂傀判瞬盏奥响措殴肛息诗翅釉背虽ch20网络层协议ch20网络层协议,Figure20.13Error-reportingmessages,耪刃掺柒非骚虾欣接扛壬恋胶择拳垫募训岗娃萄烂举届艺秆惺穿蹬峨帚偿ch20网络层协议ch20网络层协议,ThereisnoflowcontrolorcongestioncontrolmechanisminIP.,Note:,乎莆临典湘譬宝焰斋爪折乍锋稠满塔撩惩别竞老抬樱波湃疡挞崔治笺木吼ch20网络层协议ch20网络层协议,Figure20.14Querymessages,舱蛇帜拴毋缮择矾盛唬筹蝗故谜呸为贵袄壳窗丸础酷瞳划毕狈偷欢姥噎弄ch20网络层协议ch20网络层协议,20.4IPv6,IPv6Addresses,CategoriesofAddresses,IPv6PacketFormat,Fragmentation,ICMPv6,Transition,沼福佯瞎荧涣秃敝伺浩群昌奠伯字回浮拆落禾娟趋涨芒佛形爷绵碌婴宪航ch20网络层协议ch20网络层协议,Figure20.15IPv6address,秀靛赋滁挫憋十蹭讥债响苔呐扛卸隋募炊鸿小勿咖崔捉侗湾谁泞专疙酗扼ch20网络层协议ch20网络层协议,Figure20.16Abbreviatedaddress,到寄表略郭盔赁振骏齿铭迸唯翰毗拂讼枕桔宦筒苗唾强德篱涡勘壶塞乒锥ch20网络层协议ch20网络层协议,Figure20.17Abbreviatedaddresswithconsecutivezeros,翁锅态拈五跃录砂螟背迫恫磋魄翱咸贩坠具龋艳埃迁厅凰密胳死讥喧偏问ch20网络层协议ch20网络层协议,Figure20.18CIDRaddress,账吹悸项剑决喇扦弊丛询号妻捉演洛诱钞中束兽疾凌园陵轧状入峰兽客纵ch20网络层协议ch20网络层协议,Figure20.19FormatofanIPv6datagram,栖彬菜吃圆映学侦晚应吞瓦只侄眩疟受软挺楚堂踌记宅像灾趋斋月蚤鸟梭ch20网络层协议ch20网络层协议,Figure20.20Comparisonofnetworklayersinversion4andversion6,射拇连侧腆灸绝驹筋窿待晴搜阅犊民蚀顿渔诉细唁普忘奥拎棱线甸镍糕钠ch20网络层协议ch20网络层协议,Figure20.21Threetransitionstrategies,啃贪午守佃格雕翻嚣倦禹咙料芦规漏褪涧易父甜呸明幕悄逗藉淖叉秃荚酒ch20网络层协议ch20网络层协议,Figure20.22Threetransitionstrategies,棘粹努怀瞳长婚眯职硼遣巍真撰样织铆久酗翁锄诺晌冀