tag:blogger.com,1999:blog-3608259233956699628Wed, 11 Sep 2024 17:42:05 +0000Networking ConceptsNetworking TechnologiesIP AddressComputer Network and Wireless Networkhttp://blogpcnet.blogspot.com/noreply@blogger.com (Unknown)Blogger28125en-usnoLearn about Computer Network and Wirelessnoreply@blogger.comtag:blogger.com,1999:blog-3608259233956699628.post-5403220607682032774Fri, 14 May 2010 09:00:00 +00002010-05-14T10:00:02.763+01:00IP AddressTransport Layer The TCP/IP transport layer is responsible for providing a logical connection between two devices and can provide these two functions: ■ Flow control (through the use of windowing or acknowledgements) ■ Reliable connections (through the use of sequence numbers and acknowledgements) The transport layer packages application layer data into segments to send to a destination device. http://blogpcnet.blogspot.com/2010/05/tcpip-protocol-stack-transport-layer.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-6678634539073267739Fri, 14 May 2010 07:00:00 +00002010-05-14T08:00:03.951+01:00IP Address The Transmission Control Protocol/Internet Protocol (TCP/IP) is a standard that includes many protocols. It defines how machines on an internetwork can communicate with each other. It was initially funded by and developed for DARPA (Defense Advanced Research Protects Agency), which is a conglomeration of U.S. military and government organizations. Developed initially for the government, it was http://blogpcnet.blogspot.com/2010/05/tcpip-protocol-stack-application-layer.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1544508421884357857Fri, 14 May 2010 05:00:00 +00002010-05-12T16:10:57.829+01:00Networking ConceptsCisco has developed a three-layer hierarchical model to help you design campus networks. Cisco uses this model to simplify designing, implementing, and managing large-scale networks. With traditional network designs, it was common practice to place the networking services at the center of the network and the users at the periphery. However, many things in networking have changed over the past http://blogpcnet.blogspot.com/2010/05/hierarchical-network-model.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-3146638057518098193Fri, 14 May 2010 03:00:00 +00002010-05-14T04:00:01.574+01:00Networking ConceptsGoing Down the Protocol Stack This section covers the basic mechanics as to how information is processed as it is sent down the protocol stack on a computer. I’ll use the diagram shown in Figure 2-10 to illustrate this process as PC-A sends information to PC-B. In this example, assume that the data link layer is Ethernet and the physical layer is copper. The first thing that occurs on PC-A is http://blogpcnet.blogspot.com/2010/05/going-down-and-up-protocol-stack.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-710968932690409067Fri, 14 May 2010 00:00:00 +00002010-05-14T01:00:06.508+01:00Networking ConceptsBefore delving into the mechanics of how information is transferred between computers, you must grow familiar with the terminology used to describe the transmitted data. Many of the layers of the OSI Reference Model use their own specific terms to describe data transferred back and forth. As this information is passed from higher to lower layers, each layer adds information to the original data—http://blogpcnet.blogspot.com/2010/05/transferring-information-between.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1359409265614418877Thu, 13 May 2010 10:00:00 +00002010-05-13T11:00:10.852+01:00Networking ConceptsOne of the issues of connection-oriented services is that they must always go through a three-way handshake before you can transfer data. In some instances, like file transfers, this makes sense, because you want to make sure that all data for the file is transferred successfully. However, in other cases, when you want to send only one piece of information and get a reply back, going through the http://blogpcnet.blogspot.com/2010/05/transport-layer-unreliable-connections.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-2694066823925162065Thu, 13 May 2010 08:00:00 +00002010-05-13T09:00:02.589+01:00Networking ConceptsThe fourth layer of the OSI Reference Model is the transport layer. The transport layer has four main functions: ■ It sets up and maintains a session connection between two devices. ■ It can provide for the reliable or unreliable delivery of data across this connection. ■ It can implement flow control through ready/not ready signals or windowing to ensure one device doesn’t overflow another http://blogpcnet.blogspot.com/2010/05/transport-layer-reliable-connections.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-4507181065573197850Thu, 13 May 2010 05:00:00 +00002010-05-13T06:00:00.629+01:00Networking ConceptsBecause routers operate at a higher layer than the network layer and use logical addressing, they provide many advantages over bridges and switches, including: ■ Logical addressing at layer-3 allows you to build hierarchical networks that scale to very large sizes. This is discussed in Chapter 12. ■ They contain broadcasts and multicasts. When a broadcast or multicast is received on an interfacehttp://blogpcnet.blogspot.com/2010/05/advantages-of-routers.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-8211624461638012036Thu, 13 May 2010 02:00:00 +00002010-05-13T03:00:03.257+01:00Networking ConceptsRouters are devices that function at the network layer; they use network numbers to make routing decisions: how to get a packet to its destination. Routers build a routing table, which contains path information. This information includes the network number, which interface the router should use to reach the network number, the metric of the path (what it costs to reach the destination), and how http://blogpcnet.blogspot.com/2010/05/routing-tables.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-162631073026704600Thu, 13 May 2010 00:00:00 +00002010-05-13T01:00:10.944+01:00Networking ConceptsNetwork Layer Layer 3 of the OSI Reference Model is the network layer. This layer is responsible for three main functions: ■ Defines logical addresses used at layer-3 ■ Finds paths, based on the network numbers of logical addresses, to reach destination devices ■ Connects different data link types together, such as Ethernet, FDDI, Serial, and Token Ring The following sections cover the network http://blogpcnet.blogspot.com/2010/05/network-layer-layer-3-addressing.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-7285016412040485142Wed, 12 May 2010 22:50:00 +00002010-05-12T23:50:00.801+01:00Networking ConceptsBridges are data link layer devices that switch frames between different layer-2 segments. They perform their switching in software, and their switching decisions are based on the destination MAC address in the header of the data link layer frame. Bridges perform three main functions: ■ They learn where devices are located by placing the MAC address of a device and the identifier of the port ithttp://blogpcnet.blogspot.com/2010/05/bridge-data-link-devices.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-4382266348448379438Wed, 12 May 2010 21:00:00 +00002010-05-12T22:00:01.999+01:00Networking ConceptsEthernet II is the original Ethernet frame type. Ethernet II and 802.3 are very similar: they both use CSMA/CD to determine their operations. Their main difference is the frames used to transmit information between NICs. The bottom part of earlier Figure 2-3 shows the fields in an Ethernet II frame. Here are the two main differences between an Ethernet II and IEEE: ■ Ethernet II does not have http://blogpcnet.blogspot.com/2010/05/ethernet-iis-version-of-ethernet.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-4472894030579956454Wed, 12 May 2010 19:00:00 +00002010-05-12T20:00:01.053+01:00Networking ConceptsThere are actually two variants of Ethernet: IEEE’s implementation and the DIX implementation. Ethernet was developed by three different companies in the early 1980s: Digital, Intel, and Xerox, or DIX for short. This implementation of Ethernet has evolved over time; its current version is called Ethernet II. Devices running TCP/IP typically use the Ethernet II implementation. The second version http://blogpcnet.blogspot.com/2010/05/ieees-version-of-ethernet.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-3085547147895439238Wed, 12 May 2010 09:51:00 +00002010-05-12T10:53:47.184+01:00Networking ConceptsLayer 2 of the OSI Reference Model is the data link layer. This layer is responsible for defining the format of layer-2 frames as well as the mechanics of how devices communicate with each other over the physical layer. Here are the components the data link layer is responsible for: ■ Defining the Media Access Control (MAC) or hardware addresses ■ Defining the physical or hardware topology for http://blogpcnet.blogspot.com/2010/05/data-link-layer.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1959159183023593955Wed, 12 May 2010 09:36:00 +00002010-05-12T10:36:35.462+01:00Networking ConceptsWireless transmission has been used for a very long time to transmit data by using infrared radiation, microwaves, or radio waves through a medium like air. With this type of connection, no wires are used. Typically, three terms are used to group different wireless technologies: narrowband, broadband, and circuit/packet data. Whenever you are choosing a wireless solution for your WAN or LAN, you http://blogpcnet.blogspot.com/2010/05/wireless-concept-basic.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1729452674119008457Wed, 12 May 2010 08:47:00 +00002010-05-12T09:49:10.314+01:00Networking ConceptsLANs typically use either copper or fiber-optic cabling. Copper cabling is discussed in more depth in the section “Ethernet” later in this chapter. Fiber-optic cabling uses light-emitting diodes (LEDs) and lasers to transmit data. With this transmission, light is used to represent binary 1’s and 0’s: if there is light on the wire, this represents a 1; if there is no light, this represents a 0. http://blogpcnet.blogspot.com/2010/05/fiber-cabling.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-7216368165882456064Wed, 12 May 2010 08:23:00 +00002010-05-12T11:15:43.849+01:00Networking ConceptsNetwork Layer The third layer of the OSI Reference Model is the network layer. The network layer provides quite a few functions. First, it provides for a logical topology of your network using logical, or layer-3, addresses. These addresses are used to group machines together. The network component is used to group devices together. Layer-3 addresses allow devices that are on the same or http://blogpcnet.blogspot.com/2010/05/osi-reference-model-3.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-8047417495272753770Wed, 12 May 2010 08:02:00 +00002010-05-12T11:15:43.849+01:00Networking ConceptsLayer Definitions There are seven layers in the OSI Reference Model, shown in Figure 2-1: application, presentation, session, transport, network, data link, and physical. The functions of the application, presentation, and session layers are typically part of the user’s application. The transport, network, data link, and physical layers are responsible for moving information back and forth http://blogpcnet.blogspot.com/2010/05/osi-reference-model-2.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-4666677114190346216Tue, 11 May 2010 23:00:00 +00002010-05-12T11:26:00.429+01:00Ethernet is a LAN media type that functions at the data link layer. Ethernet uses the Carrier Sense Multiple Access/Collision Detection (CSMA/CD) mechanism to send information in a shared environment. Ethernet was initially developed with the idea that many devices would be connected to the same physical piece of wiring. The acronym CSMA/CD describes the actual process of how Ethernet functions. http://blogpcnet.blogspot.com/2010/05/ethernet.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-4579661221851813465Tue, 11 May 2010 23:00:00 +00002010-05-12T11:15:43.849+01:00Networking ConceptsUnicast A frame with a destination unicast MAC address is intended for just one device on a segment. The top part of Figure 2-2 shows an example of a unicast. In this example, PC-A creates an Ethernet frame with a destination MAC address that contains PC-C’s address. When PC-A places this data link layer frame on the wire, all the devices on the segment receive. Each of the NICs of PC-B, PC-C, http://blogpcnet.blogspot.com/2010/05/unicast-multicast-broadcast.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-6221940170076011696Tue, 11 May 2010 20:53:00 +00002010-05-11T21:53:30.218+01:00Networking ConceptsThe International Organization for Standardization (ISO) developed the Open Systems Interconnection (OSI) Reference Model to describe how information is transferred from one machine to another, from the point when a user enters information using a keyboard and mouse to when that information is converted to electrical or light signals transferred along a piece of wire or radio waves transferred http://blogpcnet.blogspot.com/2010/05/osi-reference-model-1.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-78638247140166547Mon, 10 May 2010 20:01:00 +00002010-05-12T11:14:30.385+01:00Networking Technologies Content Networks Content networks (CNs) were developed to ease users’ access to Internet resources. CNs are aware of layers 4–7 of the OSI Reference Model and use this information to make intelligent decisions about how to obtain the information for the user or users. CNs come in the following categories: content distribution, content routing, content switching, content management, content http://blogpcnet.blogspot.com/2010/05/network-types-3.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-275568455004746686Mon, 10 May 2010 19:45:00 +00002010-05-12T11:14:30.385+01:00Networking TechnologiesMetropolitan Area Networks A metropolitan area network (MAN) is a hybrid between a LAN and a WAN. Like a WAN, it connects two or more LANs in the same geographic area. A MAN, for example, might connect two different buildings or offices in the same city. However, whereas WANs typically provide low- to medium-speed access, MANs provide high-speed connections, such as T1 (1.544 Mbps) and optical http://blogpcnet.blogspot.com/2010/05/network-types-2.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1021194374875010677Mon, 10 May 2010 19:29:00 +00002010-05-12T11:14:30.385+01:00Networking TechnologiesNetworks come in a wide variety of types. The most common are LANs and WANs, but there are many other types of networks, including metropolitan area networks (MANs), storage area networks (SANs), content networks (CNs), intranets and extranets, VPNs, and others. The following sections provide a brief overview of each of these network types. Local Area Networks Local area networks (LANs) are http://blogpcnet.blogspot.com/2010/05/network-types-1.htmlnoreply@blogger.com (Unknown)0tag:blogger.com,1999:blog-3608259233956699628.post-1675287238347600768Mon, 10 May 2010 19:16:00 +00002010-05-12T11:14:30.386+01:00Networking Technologies Meshing generically describes how devices are connected together. There are two types of meshed topologies: partial and full. In a partially meshed environment, every device is not connected to every other device. In a fully meshed environment, every device is connected to every other device. Figure 1-3 shows examples of these two types of topologies. Note that like the topologies in the http://blogpcnet.blogspot.com/2010/05/mesh-topology.htmlnoreply@blogger.com (Unknown)1