Intro to Network Design & Analysis: COMPUTER SKILL Unit 2 ALL SOLUTION LATEST EDITION 100% CORRECT GUARANTEED GRADE A+

Logical Design Layer: OSI (Open Systems Interconnection) model 7. Application 6. Presentation 5. Session 4. Transport 3. Network 2. Data Link 1. Physical Networking The interconnection of workstations, peripherals, terminals and other devices. The Evolution of Data Networks -Sneaker-Net -Local Area Network: Peer-to-Peer -LANs: Client/Server -Wide Area Networks -Cloud Computing Semiconductor Transistors Invented in 1947 NIC (Network Interface Card) Each end user device is provided with a unique MAC address that is usually not changed. Hubs -Physical Layer devices that logically function as a shared bus, or a multiport repeater -All devices connected to a hub belong to the same collision domain -a physical switch/toggle normally mounted under an uplink port, allows devices to be connected directly or it can support an additional host The 5-4-3 Rule 5. the number of network segments 4. the number of repeaters needed to join the segments into one collision domain 3. the number of network segments that have active (transmitting) devices attached 2. the number of network segments that do not have active devices attached 1. the number of collision domains Bridges -Designed to create multiple physical LAN segments but only one logical network to extend the size of a network. -operate at the MAC (media access control) sublayer of the OSI Data Link Layer -they examine each destination NIC address or MAC address -they use an internal table of addresses to decide whether to forward a frame to the rest of the network -they should control segment or workgroup access to the backbone -performance is measured in frames per second (fps) Bridge advantages -they can connect networks running different high-level protocols -they form logically single networks Bridge disadvantages -they create broadcast traffic that congests the network -they cannot prevent broadcast storms -the cannot take simultaneous advantage of redundant paths in a network -they cannot convert protocols above the Data Link Layer Routers -Used to separate or segment one network from another network. -Operate at the Network Layer of the OSI reference model -they use specialized routing protocols to maintain and exchange network path information in their internal routing tables -they segment networks into separate broadcast domains -the provide firewall service and economical WAN access Router advantages -they select the best forwarding path based on several factors in addition to the destination network address -they are the only internetworking devices that can provide efficient WAN access Router disadvantages -the additional software processing can increase packet latency, reducing performance when compared to simpler switch architecture -if an architecture lacks a Network Layer, the protocols must be bridged When to Use Routers -when network applications require limiting broadcast traffic -support for redundant paths -intelligent packet forwarding -WAN access Router considerations -what you get in the base configuration -hardware upgrade costs -software upgrade costs -support for multiple protocols or a single protocol -network connectivity support -performance (packets per second) -network management capabilities -LAN architectures supported -latency Physical topology Actual layout of the wire or media Logical topology Defines how the media is accessed by the hosts or sending data Examples of physical topology -Bus -Star -Extended Star -Ring Examples of logical topology -Broadcast or multi-access -token passing Bus topology Uses a single backbone segment (length of cable) that all the hosts connect to directly Ring topology -connects one host to the next and the last to the first -this creates a physical ring of cable Token Ring topology -use a token passing method -wired in a physical star but produce a logical ring Star topology -connects all cables to a central point of concentration -this point is usually a hub or switch, and is the most common type of topology Extended star topology -links individual stars together by linking the hubs or switches Hierarchical topology -similar to an extended star but instead of linking hubs or switches together, the system is linked to a device that controls the traffic on the topology -implements a layered approach to networking Layers of hierarchical topology Core Distribution Access Mesh topology -used when there can be absolutely no break in communications -each device has its own connection to all other hosts -reflects Internet design, which has multiple paths to any one location Network Protocols A set of rules and conventions that govern a particular aspect of how devices on a network communicate Protocol suites -collections of protocols that enable network communication from one host through the network to another host Protocols Without them, the computer cannot make or rebuild the stream of incoming bits from another computer into the original format. LAN Local Area Network WAN Wide Area Network: -Modems (asynchronous) -ISDN -DSL -T1 -Can/US -E1 -Europe -Frame Relay -SONET ISDN Integrated Digital Services Network DSL Digital Subscriber Line MAN Metropolitan Area Network: -usually consists of two or more LANs in a common geographic area SAN Storage Area Network: -a dedicated, high-performance network used to move data between servers and storage resources -allows high-speed connectivity -offers performance, availability and scalability VPN Virtual Private Network: -constructed within a public network such as the global Internet -a single user or remote office can obtain access to the office LAN using the Internet Intranets Remote sites or local users that all belong to the same organization. Extranets Remote access granted to other organizations to perform a required service (e.g. Software maintenance, network monitoring) ISO International Organization for Standardization: -released the Open Systems Interconnection Reference Model in 1984 -ISO. A network of national standards institutes from 140 countries working in partnership with international organizations, governments, industry, business and consumer representatives. A bridge between public and private sectors. Protocols in the Application Layer of the OSI Model The following communicate with TCP: -FTP, Telnet, SMTP, POP3, IMAP4, HTTP, X-Window The following communicate with UDP: -SNMP, TFTP, BOOTP, DHCP Protocols in the Session Layer of the OSI Model NETBIOS, DNS Protocols in the Transport Layer TCP, UDP Protocols in the Network Layer of the OSI Model IP, ICMP, RIP, IGMP Protocols in the Data Link Layer of the OSI Model LLC, ARP/RARP The Physical Layer of the OSI Model LAN/WAN Physical Media The OSI reference model Allows you to: -view the network functions that occur at each layer -use a framework to understand how information travels throughout a network -understand, visualize, and troubleshoot the sending and receiving of data on a network -visualize how information, or data packets, travel from application programs, through a network medium, to another application program that is located in another computer on a network. Even if the sender and receiver have different types of network media Application Layer function User functionality CONTINUED...