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Computer Networking

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Network Management and Operation Department of Computer Networking Application 1 The first section 2 Exercises 3 Online lecture CHAPTER 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 Chapter 2 Network Classification Many ways that networks can be classified 1 2 Distinguish among WAN,MAN,and LAN Describe voice network 3 Explain the concept of internetworking 4

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Network Management and Operation 2.2 definition of network A communications network is an interconnected system of computers, terminals, and other hardware established for the purpose of exchanging information or services between individuals, groups, or institutions. www.gxmu.edu.cn medium DATA PC Chapter 2 Network Classification

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Network Management and Operation NODE A node on a network is a point of connection into a network, or a point at which one or more transmission lines (circuits) interconnect, such as where a router or a switch connects into the network. www.gxmu.edu.cn five node network Chapter 2 Network Classification

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Network Management and Operation Nodes are points of entry into a network or interconnection within in www.gxmu.edu.cn For example computer terminal modem, hub, bridge or switch Print Scanner five node network Chapter 2 Network Classification

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Network Management and Operation Topology Ownership Other types of networks Line Configuration Transmission Mode Internetworks www.gxmu.edu.cn Chapter 2 Network Classification NETWORKS CLASSIFIED B F C D A Geography Topology Ownership Transmission Mode Other types of networks E Internetworks

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Network Management and Operation 2-3 NETWORKS CLASSIFIED BY GEOGRAPHY Networks that cover a small geographic area are called LANs. www.gxmu.edu.cn 2.3.1 LAN (Local Area Networks) / LAN network could be installed in a home. LAN is useful for sharing resources like files, printers, games or other applications. Chapter 2 Network Classification

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Network Management and Operation Key attribute of LAN Its limited geographic scope. Don`t care the number of nodes. much higher data-transfer rates. LANs are frequently found in business offices. And lack of a need for leased telecommunication lines. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Metropolitan Area Networks (MANs) MAN covers an intermediate area, such as a city and usually links several LANS. MAN standard :IEEE.802.6 IEEE: Institute of Electrical and Electronics Engineers, Inc www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Figure 2-2 A MAN. www.gxmu.edu.cn MANs normally operate at high speed. Chapter 2 Network Classification

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Network Management and Operation Dark fiber: www.gxmu.edu.cn * The term dark fiber refers to fiber that has been manufactured with black pigment to improve its reflectivity. F It is optical fiber that has been installed (typically in the ground) but which does not have the necessary electronics installed at each end to make it usable. Chapter 2 Network Classification

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Network Management and Operation DQDB:Distributed Queue Dual Bus IEEE 802.6 Cancelled A MAN technology early. have not been large-scale application. www.gxmu.edu.cn DQDB Buses and Nodes Chapter 2 Network Classification

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Network Management and Operation Fiber IP MAN WDM FIBER www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation CAN (Campus Area Network ) A network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Wide Area Networks(WANs) Networks that cover a broad geographic area are called WANs. WANs usually crosses public rights of way. The Internet is the largest WAN, spanning the Earth. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 The world's largest WAN is the Internet. WAN usually uses circuits provided by one or more communication carriers. Chapter 2 Network Classification

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Network Management and Operation Why do WANs not operate at as high speed as LANs do ? The communication circuits that make up A WAN exist in a much harsher environment Than those of a LAN. more likely to experience errors. Expensive leased lines. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.4 NETWORKS CLASSIFIED BY TOPOLOGY Network Topology : The configuration of a communication network- the way the circuits are connected together. www.gxmu.edu.cn *The primary purpose of the network topology isn't to indicate the technology used by the network. Chapter 2 Network Classification

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Network Management and Operation 2.4.1 Star network All circuits radiate from a central node, which is often a cluster of servers or a host computer. It is still often used for voice network. www.gxmu.edu.cn Star networks can have a maximum of six arms F Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn ease to manage and control network. Protocol was relatively simple. Star configuration was easy to implement. Chapter 2 Network Classification If central node is down, network is out of service. In times of peak traffic, Central node may become overloaded. Advance and Disadvance

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Network Management and Operation 2.4.2 Hierarchical network A network in which the top node in the structure is called the root node is called a hierarchical network. It has a tree structure. At least three levels in the hierarchy.WHY? Two levels= equality www.gxmu.edu.cn tree Chapter 2 Network Classification

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Network Management and Operation It can be compared to a corporate organization chart. Figure 2-4 A hierarchical network. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Advantages www.gxmu.edu.cn Chapter 2 Network Classification No single point of failure in the network If one division's network fails, the other division are not affected. Easy to extend

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Network Management and Operation 2.4.3Mesh network It is similar to a hierarchical network, except that there are more interconnections between nodes at different levels-or even at the same level. ADVS: provides redundant connection. No single point of failure that cause entire network to fail. WAN and PSTN are configured in a mesh topology. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Figure 2-5 A mesh network. www.gxmu.edu.cn Fully interconnected mesh network. In a partially interconnected mesh network each node is connected to every other node each node isn`t connected to every other node. Major nodes are connected. For high cost reasons, Fully interconnected mesh network.seldom implemented. Chapter 2 Network Classification

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Network Management and Operation 2.4.4 Bus Network It is a communication medium to which multiple nodes are attached. www.gxmu.edu.cn Figure 2-6 A bus network. Bus topologies are frequently used for LANs. Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Ethernet networking technologies for LAN Local talk Apple Computer Inc. invented the use of a bus topology of the LAN. Chapter 2 Network Classification

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Network Management and Operation. Local talkApple Computer Inc. invented the use of a bus topology of the LAN. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Advantages: www.gxmu.edu.cn Very high speed transmission. High reliability, All stations are independent of one another. Are limited in the distance they can traverse. Easy to implement and extend. Requires less cable length than a star topology Well suited for LAN. Cheaper than other topologies. Chapter 2 Network Classification

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Network Management and Operation Disadvantages Limited cable length. If there is a problem with BUS, the entire network goes down. faults can be difficult to locate.. It works best with limited number of nodes. Performance degrades as additional computers are added or on heavy traffic. collision. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation CSMA/CD (Carrier Sense Multiple Access/Collision Detect) www.gxmu.edu.cn or wait for free. if free transmit examines signal- Send message Chapter 2 Network Classification

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Network Management and Operation CSMA/CD (Carrier Sense Multiple Access/Collision Detect) www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.4.5 Ring Network A ring network is a network topology in which each node connects to exactly two other nodes, forming a circular pathway for signals - a ring. Data travels from node to node, with each node handling every packet. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Token-Ring 1970,IBM Token-Ring www.gxmu.edu.cn When to send a message, they must wait for the free tokens through the station, and then will be busy token status, and sending data to the ring.AB C D A->C A->C Chapter 2 Network Classification

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Network Management and Operation The stations on a ring network: are equal. regenerate a signal before passing it on. check the address of all incoming signals. are connected to the ring with a tap. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Example IBM Token Ring FDDI Fiber Distributed Data Interface Once a backbone level of mainstream technology, has been suspended SDH RPR www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Advantages Very orderly network where every device has access to the token and the opportunity to transmit. Performs better than a bus network under heavy network load (no Collision ), Can create much larger network Regeneration the signal. Device check the signal for errors www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Disadvantages One malfunctioning workstation can create problems for the entire network. Moves, adds and changes of devices can affect the network. Network adapter cards and MAU's are much more expensive than Ethernet cards and hubs. Much slower than an Ethernet network under normal load. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation A ring network with two channels. www.gxmu.edu.cn Links fails,reconfigure themselves to begin to transmit data. Why have two rings and in opposite directions ? Transmit the data in opposite directions. Chapter 2 Network Classification

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Network Management and Operation 2-5 NETWORKS CLASSIFIED BY OWNERSHIP 2.5.1Private Networks It is usually built by an organization for its exclusive use. a network that uses private IP address space www.gxmu.edu.cn *A private network is a network built and owned by a communications company, a common carrier, or another organization for use by its customers or other constituency.F Chapter 2 Network Classification

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Network Management and Operation Advantages And Disadvantages It can make better use of circuits than a public network could. Can be made from circuits acquired from a communications carrier. It give the company full control of the network's operation and provides better security. May be connected to a public network. May be more expensive on communication than public networks. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.5.2 Public Networks It is a network built and owned by a communications company, a common carrier, or another organization for use by its customers. Uses Public IP. INTERNET www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation VPNVirtual Private Network As public and private networks have merits, the merits of a combination of the two new technologies emerged www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.6 Other Types Of Networks 2.6.1 VAN (value added networks) It is a particular type of public data network that,in addition to offering transmission facilities, Contains intelligence. Van in the application of e-commerce Bank SWIFT Airline SITA Insurance IVANS www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.6.2 Wireless network www.gxmu.edu.cn Networks classified by the transmission medium A wireless network always uses unguided medium. Wireline networks wireless network Chapter 2 Network Classification

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Network Management and Operation WSN Wireless networksWSN are among the most rapidly growing segments of networking technology today. A wireless network uses radio frequency technology as an extension of, or as an alternative to, a wired network. Wireless networks don't cause interference to commercial radio stations. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation WLAN WIFI WLAN: Wireless Local Area Network WIFI: Wireless Fidelity www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation 2.6.3 Backbone Network It is the main network in an organization or a location. Carries the most traffic and is the most critical. Backbone is relative. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn 2.5G CERNET Backbone at 2.5G Mbps /155 Mbps CERNET Backbone at 2.5G Mbps /155 Mbps 155M 2.5G 155M When looking at a network topology, it is always easy to pick out the backbone network. Chapter 2 Network Classification

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Network Management and Operation NETWORKS CLASSIFIED BY SERVER FUNCTION Server-Based To transit server. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Client/Server www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Peer-to-Peer NO SERVEREach other. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation NETWORKS CLASSIFIED BY DATA TRANSMISSION Unicast Multicast BROADCAST www.gxmu.edu.cn Unicast communication is one-to-one. Multicast communication is one-to-many. Broadcast communication is one-to-all. Chapter 2 Network Classification

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Network Management and Operation Unicast vs. Multicast www.gxmu.edu.cn Server Router Unicast Server Router Multicast Chapter 2 Network Classification

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Network Management and Operation NETWORKS CLASSIFIED BY LINE CONFIGURATION LINE CONFIGURATION www.gxmu.edu.cn POINT TO POINT MULTIPOINT Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 Point-to-Point Line Configuration Chapter 2 Network Classification

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Network Management and Operation shortcomings Too many connections www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 Multipoint Line Configuration Sharing communication channel Sharing to avoid Repeatability Reduce costs Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn NETWORKS CLASSIFIED BYTRANSMISSION MODE Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Simplex Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Half-Duplex Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Full-Duplex Chapter 2 Network Classification

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Network Management and Operation 2.7 Voice network Telephone Network PSTN: Public Switched Telephone Network. Sometimes call Public Telephone Network. PSTN is diverse and is highly redundant. PSTN is an example of a mesh network. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation Importance of a CO CO:central office. Call swithes that route and connect telephone call. A serving CO is one that serves telephone customers. www.gxmu.edu.cn Chapter 2 Network Classification

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Network Management and Operation www.gxmu.edu.cn Figure 2-9 Residential telephone cabling. Drop wire < Distribution cable< Feeder cable Circuit : connects to tele, pc, or other. feeder cable Chapter 2 Network Classification

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Network Management and Operation Figure 2-10 The connection of the COs in the nationwide telephone network. www.gxmu.edu.cn End office=Tolloffic e Trunk Trunk : as a circuit, connecting telephone swithes or swithing locations. PSTN is an example of a mesh network. mesh network makes the PSTN so redundant and fail-safe. Chapter 2 Network Classification

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Network Management and Operation Local loop In telephony, the local loop is the physical link or circuit, that connects from the demarcation point of the customer premises to the edge of telecommunications service provider www.gxmu.edu.cn *A loop is defined as a circuit that connects telephone switches or switching locations. F Chapter 2 Network Classification

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Network Management and Operation Modem Using voice band (