Routers
A router is a type of internetworking device that passes data packets between networks based on Layer 3 addresses. A router has the ability to make intelligent decisions regarding the best path for delivery of data on the network. In this chapter, you will learn how routers use a Layer 3 addressing scheme to make forwarding decisions. In addition, you will learn how devices on local-area networks (LANs) use Address Resolution Protocol (ARP) before forwarding data to a destination. You will learn what happens when a device on one network does not know the MAC address of a device on another network. You will learn that Reverse Address Resolution Protocol (RARP) is the protocol a device uses when it does not know its own IP address. Lastly, you will learn the difference between routing and routed protocols and how routers track distance between locations. You will also learn about distance-vector, link-state, and hybrid routing approaches and how each resolves common routing problems. In networking, there are two addressing schemes: one uses the MAC address, a data link (Layer 2) address; the other uses an address located at the network layer (Layer 3) of the OSI model. An example of a Layer 3 address is an IP address. A router is a type of internetworking device that passes data packets between networks, based on Layer 3 addresses. A router has the ability to make intelligent decisions regarding the best path for delivery of data on the network. Bridges and switches use physical, or MAC addresses, to make data forwarding decisions. Routers use a Layer 3 addressing scheme to make forwarding decisions. They use IP, or logical addresses, rather than MAC addresses. Because IP addresses are implemented in software, and refer t...
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... device that originated a RARP request receives a RARP reply, it copies its IP address into its memory cache, where it will reside for as long as the session lasts. · routers, like every other device on the network, send and receive data on the network, and build ARP tables that map IP addresses to MAC addresses · if the source resides on a network that has a different network number than the desired destination, and if the source does not know the MAC address of the destination, it will have to use the router as a default gateway for its data to reach the destination · routed protocols direct user traffic, whereas routing protocols work between routers to maintain path tables · network discovery for distance-vector routing involves exchange of routing tables The next chapter discusses the functions of the transport layer.
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When using routers, you need many routers in order to route the information to the correct location, as one router will not be able to manage this task. Explain how the routing schemes handle this problem.
What is done to information to send it from one location to another on the Internet? It is broken into packets that travel across the internet and the packets take the most avaiable and efficient path and eventually all come together where they are suppose to be.
In the networking of computers and devices, the Internet Protocol (IP) plays a very important role. The IP, found at the internet layer of the Department of Defence (DoD) model provides the means for the devices to communicate using logical addresses called IP addresses. The importance of an IP address to communication will be felt in the analogy of a surface mail. How possible would it be to send a letter to someone whose address we do not know? The IP address enables us to know the source of a packet and the destination for proper delivery by the IP protocol.
When a home is connected to the Internet, residential communications infrastructure serves as the "last mile" of the connection between the home computer and the rest of the computers on the Internet. This section describes the Internet technology involved in that connection.
1) The relationship between information systems, Internet Technology and Cisco’s business strategy was quite intriguing. Cisco’s company worked hand in hand directly with the Internet and their IS system was supported by almost 45% by digital means. Their sales were all Internet driven by almost half of their production.
Network Address Translation (NAT) is a standard used to allow multiple PCs on a private network to share a single, globally routable IPv4 address. NAT enables a user to have a large set of addresses internally and usually one address externally. The main reason NAT is often deployed is because IPv4 addresses are getting scarce. NAT is an immediate, but temporary, solution to the IPv4 address exhaustion problem that will eventually be rendered unnecessary with the deployment of the IPv6. The Internet Engineering Task Force has been aware of the impending depletion of the current address space for almost a decade.
Wireless local area networks (WLANs) have the potential to improve the flexibility, productivity, and the quality of work life of an enterprise (Sage Research Staff, 2001). Berean Institute is a typical two year college with about a staff of sixty eight employees and 250 students per semester. Berean teaches cosmetology, barbering and the latest software and hardware technology, which is located in Philadelphia, Pennsylvania. Berean currently has two locations in the Philadelphia area and using a Local Area Network (LAN).
In most cases cable or DSL companies such as Comcast or DirectPC are just a single type of Internet connection company. But sometimes companies acquire these one-connection companies to make their companies bigger and better such as AOL buying Time Warner. As these companies get bigger and start to offer more types of connections they also start to have more security conflicts. AOL’s software for its dial up connection has a firewall built in to it, the firewall protects it users from hackers and unwanted programs from running. And the software works almost perfectly for keeping unwanted people or programs out, but the only catch is you have use their software. Road Runner, which is now part of AOL, is a cable company, which only provides high-speed Internet access, not full proof security. This problem leaves you open for hackers that are randomly barraging Internet connected PC’s with “pings” or “port scans”, probing to find unprotected PCs. Once found, a hacker can compromise your PC with a dangerous Internet threat such as a Trojan horse, spyware or even a malicious worm (Zone Labs).
There are many types of routing or data/packet retransmitting hardware and devices that networks can utilize for security purposes. Some use one or a combination for data transfer. However, each poses a level or type of vulnerabilities, additional unwanted threats, and countless types of risk. The quintessential design is to provide a means to controlling the flow of packet transfer. The main function of the switch, router, gateways, or hubs is having the ability to process and forward data packets on the network. The creation and function is to ensure that each having their own unique functions and configurations which makes one a more viable optional choice over the next for ensuring data forwarding. For example, large networks will need routing protocols that will send the data packet to the intended destination and not broadcast it throughout the entire network.
TCP/IP is composed of four layers. All this layers are meant to provide different functionalities in order for the packets to reach their destination. The diagram below represents a TCP/IP protocol. In this diagram, it clearly shows the TCP/I...
Local Area Networks also called LANs have been a major player in industrialization of computers. In the past 20 or so years the worlds industry has be invaded with new computer technology. It has made such an impact on the way we do business that it has become essential with an ever-growing need for improvement. LANs give an employer the ability to share information between computers with a simple relatively inexpensive system of network cards and software. It also lets the user or users share hardware such as Printers and scanners. The speed of access between the computers is lighting fast because the data has a short distance to cover. In most cases a LAN only occupies one or a group of buildings located next to each other. For larger area need there are several other types of networks such as the Internet.
ABSTRACT : This paper describes the basic threats to the network security and the basic issues of interest in designing a secure network. it describes the important aspects of network security. A secure network is one which is free of unauthorized entries and hackers. INTRODUCTION
A network computer or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices transmit data to each other using data connections. These connections are established with nodes using either cable or through wireless media. The most famous and interesting computer network is the internet network. There are many types of computer networks, local area networks (LANs) to wide area networks (WAN) campus area networks ( containers ) metropolitan area network MAN ) and home area networks (HANs). With massive uprising in pc’s in the early eighties, the LAN system expanded rapidly. The LAN system on a workstation can be functioned via a short networking cable. LANs consist of computer units linked to a control computer called server. Network technology is the way by which the numerous stations are linked with one another. LAN can be linked to greater networks including mainframe. This provides LAN users with the access to enormous computing power and excellent communication facilities. Computerization in the banking system is the best example of the network LAN.
In general, wireless technology works a lot like wired technology. The user inputs data onto device, connection software translates the data into a format for transmission, and transmission protocols determine the method and route the data into a format for transmission. The method and route the data will take is determined by transmission protocols. Once more, connection software re-translates the data into a format that the new user can perceive.
TCP/IP is a network model which enables the communication across the Internet. The most fundamental protocol on which the Internet is built. This is made up of the 2 common networking protocols, TCP, for Transmission Control Protocol, and IP, for Internet Protocol. TCP maintains and handles packet flow linking the systems and IP protocol has the ability to handle the routing of packets. However The TCP/IP stack consists of 5 layers first being application layer, the transport layer, then the network layer, the link layer and finally the physical layer. The assignment focuses on the three middle layers and is divided into five parts. Firstly explaining how the TCP and UDP the most vital protocols needed to deliver and communicate.