计算机网络第五版英文第五章-网络层ppt课件

我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011The Network LayerChapter 5Computer Networks,Fifth Editi1我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Network Layer Design IssuesStore-and-forward packet switchingServices provided to transport layerImplementation of connectionless serviceImplementation of connection-oriented serviceComparison of virtual-circuit and datagram networksComputer Networks,Fifth Editi2我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Store-and-Forward Packet SwitchingThe environment of the network layer protocols.ISPs equipmentComputer Networks,Fifth Editi3我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Services Provided to the Transport Layer1.Services independent of router technology.2.Transport layer shielded from number,type,topology of routers.3.Network addresses available to transport layer use uniform numbering planeven across LANs and WANsComputer Networks,Fifth Editi4我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Implementation of Connectionless ServiceRouting within a datagram networkISPs equipmentAs table(initially)As table(later)Cs Table Es TableComputer Networks,Fifth Editi5我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Implementation of Connection-Oriented ServiceRouting within a virtual-circuit networkISPs equipmentAs table Cs Table Es TableComputer Networks,Fifth Editi6我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Comparison of Virtual-Circuit and Datagram NetworksComparison of datagram and virtual-circuit networksComputer Networks,Fifth Editi7我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Routing Algorithms(1)Optimality principleShortest path algorithmFloodingDistance vector routingLink state routingRouting in ad hoc networksComputer Networks,Fifth Editi8我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Routing Algorithms(2)Broadcast routingMulticast routingAnycast routingRouting for mobile hostsRouting in ad hoc networksComputer Networks,Fifth Editi9我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Fairness vs.EfficiencyNetwork with a conflict between fairness and efficiency.Computer Networks,Fifth Editi10我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011The Optimality Principle(a)A network.(b)A sink tree for router B.Computer Networks,Fifth Editi11我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Shortest Path Algorithm(1)The first five steps used in computing the shortest path from A to D.The arrows indicate the working nodeComputer Networks,Fifth Editi12我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Shortest Path Algorithm(2)Dijkstras algorithm to compute the shortest path through a graph.Computer Networks,Fifth Editi13我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Shortest Path Algorithm(3)Dijkstras algorithm to compute the shortest path through a graph.Computer Networks,Fifth Editi14我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Shortest Path Algorithm(4)Dijkstras algorithm to compute the shortest path through a graph.Computer Networks,Fifth Editi15我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011(a)A network.(b)Input from A,I,H,K,and the new routing table for J.Distance Vector RoutingComputer Networks,Fifth Editi16我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011The Count-to-Infinity ProblemThe count-to-infinity problemComputer Networks,Fifth Editi17我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Link State Routing1.Discover neighbors,learn network addresses.2.Set distance/cost metric to each neighbor.3.Construct packet telling all learned.4.Send packet to,receive packets from other routers.5.Compute shortest path to every other router.Computer Networks,Fifth Editi18我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Learning about the Neighbors(1)Nine routers and a broadcast LAN.Computer Networks,Fifth Editi19我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Learning about the Neighbors(2)A graph model of previous slide.Computer Networks,Fifth Editi20我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Building Link State Packets(a)A network.(b)The link state packets for this network.Computer Networks,Fifth Editi21我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Distributing the Link State PacketsThe packet buffer for router B in previous slideComputer Networks,Fifth Editi22我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Hierarchical RoutingHierarchical routing.Computer Networks,Fifth Editi23我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Broadcast RoutingReverse path forwarding.(a)A network.(b)A sink tree.(c)The tree built by reverse path forwarding.Computer Networks,Fifth Editi24我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Multicast Routing(1)(a)A network.(b)A spanning tree for the leftmost router.(c)Amulticast tree for group 1.(d)A multicast tree for group 2.Computer Networks,Fifth Editi25我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Multicast Routing(2)(a)Core-based tree for group 1.(b)Sending to group 1.Computer Networks,Fifth Editi26我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Anycast Routing(a)Anycast routes to group 1.(b)Topology seen by the routing protocol.Computer Networks,Fifth Editi27我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Routing for Mobile HostsPacket routing for mobile hostsComputer Networks,Fifth Editi28我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Routing in Ad Hoc Networks(a)Range of As broadcast.(b)After B and D receive it.(c)After C,F,and G receive it.(d)After E,H,and I receive it.The shaded nodes are new recipients.The dashed lines show possible reverse routes.The solid lines show the discovered route.Computer Networks,Fifth Editi29我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Congestion Control Algorithms(1)Approaches to congestion controlTraffic-aware routingAdmission controlTraffic throttlingLoad sheddingComputer Networks,Fifth Editi30我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Congestion Control Algorithms(2)When too much traffic is offered,congestion sets in and performance degrades sharply.Computer Networks,Fifth Editi31我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Approaches to Congestion ControlTimescales of approaches to congestion controlComputer Networks,Fifth Editi32我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic-Aware RoutingA network in which the East and West parts are connected by two links.Computer Networks,Fifth Editi33我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic Throttling(1)(a)A congested network.(b)The portion of the network that is not congested.A virtual circuit from A to B is also shown.Computer Networks,Fifth Editi34我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic Throttling(2)Explicit congestion notificationComputer Networks,Fifth Editi35我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Load Shedding(1)A choke packet that affects only the source.Computer Networks,Fifth Editi36我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Load Shedding(2)A choke packet that affects each hop it passes through.Computer Networks,Fifth Editi37我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Quality of ServiceApplication requirementsTraffic shapingPacket schedulingAdmission controlIntegrated servicesDifferentiated servicesComputer Networks,Fifth Editi38我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Application Requirements(1)How stringent the quality-of-service requirements are.Computer Networks,Fifth Editi39我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Categories of QoS and ExamplesConstant bit rateTelephonyReal-time variable bit rateCompressed videoconferencingNon-real-time variable bit rateWatching a movie on demandAvailable bit rate File transferComputer Networks,Fifth Editi40我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic Shaping(1)(a)Shaping packets.(b)A leaky bucket.(c)A token bucketComputer Networks,Fifth Editi41我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic Shaping(2)(a)Traffic from a host.Output shaped by a token bucket of rate 200 Mbps and capacity(b)9600 KB,(c)0 KB.Computer Networks,Fifth Editi42我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Traffic Shaping(3)Token bucket level for shaping with rate 200 Mbps and capacity(d)16000 KB,(e)9600 KB,and(f)0KB.Computer Networks,Fifth Editi43我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Scheduling(1)Kinds of resources can potentially be reserved for different flows:Bandwidth.Buffer space.CPU cycles.Computer Networks,Fifth Editi44我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Scheduling(2)Round-robin Fair QueuingComputer Networks,Fifth Editi45我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Scheduling(3)(a)Weighted Fair Queueing.(b)Finishing times for the packets.Computer Networks,Fifth Editi46我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Admission Control(1)An example flow specificationComputer Networks,Fifth Editi47我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Admission Control(2)Bandwidth and delay guarantees with token buckets and WFQ.Computer Networks,Fifth Editi48我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Integrated Services(1)(a)A network.(b)The multicast spanning tree for host 1.(c)The multicast spanning tree for host 2.Computer Networks,Fifth Editi49我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Integrated Services(2)(a)Host 3 requests a channel to host 1.(b)Host 3 then requests a second channel,to host 2.(c)Host 5 requests a channel to host 1.Computer Networks,Fifth Editi50我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Differentiated Services(1)Expedited packets experience a traffic-free networkComputer Networks,Fifth Editi51我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Differentiated Services(2)A possible implementation of assured forwardingComputer Networks,Fifth Editi52我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011InternetworkingHow networks differHow networks can be connectedTunnelingInternetwork routingPacket fragmentationComputer Networks,Fifth Editi53我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011How Networks DifferSome of the many ways networks can differComputer Networks,Fifth Editi54我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011How Networks Can Be Connected(a)A packet crossing different networks.(b)Network and link layer protocol processing.Computer Networks,Fifth Editi55我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Tunneling(1)Tunneling a packet from Paris to London.Computer Networks,Fifth Editi56我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Tunneling(2)Tunneling a car from France to EnglandComputer Networks,Fifth Editi57我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(1)Packet size issues:HardwareOperating systemProtocolsCompliance with(inter)national standard.Reduce error-induced retransmissionsPrevent packet occupying channel too long.Computer Networks,Fifth Editi58我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(2)(a)Transparent fragmentation.(b)Nontransparent fragmentationComputer Networks,Fifth Editi59我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(3)Fragmentation when the elementary data size is 1 byte.(a)Original packet,containing 10 data bytes.Computer Networks,Fifth Editi60我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(4)Fragmentation when the elementary data size is 1 byte(b)Fragments after passing through a networkwith maximum packet size of 8 payload bytes plus header.Computer Networks,Fifth Editi61我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(5)Fragmentation when the elementary data size is 1 byte(c)Fragments after passing through a size 5 gateway.Computer Networks,Fifth Editi62我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011Packet Fragmentation(6)Path MTU DiscoveryComputer Networks,Fifth Editi63我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放在这样一个美丽的世界里呢？但是我也感到愉快，证实我的猜测没有错：表里边有一个活的生物Computer Networks,Fifth Edition by Andrew Tanenbaum and David Wetherall,Pearson Education-Prentice Hall,2011The Network Layer Principles(1)Make sure it worksKeep it simpleMake clear choicesExploit modularityExpect heterogeneity.Computer Networks,Fifth Editi64我吓了一跳，蝎子是多么丑恶和恐怖的东西，为什么把它放