Transcript of Computer Networking 网络课件 双语教学 模拟实验 计算机网络教研室 Network...
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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 (