Reading Journal 9 - Shadowsarespooky/TechJournal GitHub Wiki

Networking Overview

Networks are connections between many devices, however in relation to computers, it is when two or more devices connect and share information. Networks are divided into categories based on size and type. It ranges from small to large, listing as: Personal (PAN), Local(LAN), Metropolitan(MAN), Wide Area(WAN), and the biggest so far Wireless as (WLAN or WWAN). Networks can be found anywhere.

Network Topologies

With a physical network, there many methods on how to wire the computers together to be the most sufficient. The methods are called topologies, such as Star, Hierarchical, Ring, Bus, and Mesh. Ethernet is the most used type of LAN. With a Star topology, there is a central hub that all devices are connected to, although a switch can be used too. A hub a switch are very similar but both do different things. A hub will send out the data it receive to all other connections except the one it received the data from. A switch will receive the data and look up the address it needs to send it to and send it only to that one. With a star topology, if one device fails, all other device can still function.

The OSI Model

OSI stands for "Open Systems Interconnect". It is a standard for transferring information across a network. It has a lot of guidelines determining how media is arranged when sent, how devices of different languages connect, how a network connects with another network, and how a network knows if it received the information. The OSI model divides its networks into different layers, which each can be treated differently. Each layer of the system adds information being sent with the data. The bottom layers work with the physical functions while the top four work with the data delivery between computers.

The TCP/IP Model

Transmission Control Protocol/Internet Protocol is the most used protocol suite when using the internet. This Model only has four layers, Application, Transport, Internet, and Network Access. It tells how the layers how the data should be translated through to the other devices.

Network Addressing

Network adapters have two types of addresses assigned to them, a MAC and an IP address. A MAC address is a unique 48-bit number that is burned into the chip. The MAC address is on Layer 2. An IP address is located on Layer 3. There are two types of IP addresses, IPv4 and IPv6. The IPv4 is most used on LANs and is 32 bits. The IPv6s are 128 bits and are shown in hexadecimal. Many devices have a IPv6 address but will end up not using it most of the time. IPv4 addresses have five classes; AA, B, C, D, and E. A, B, and C addresses are used by network devices. Class D is used for multicasting and Class E is used for experiments.

More IPv4 Addressing

An IP address has two major parts, a network number and host number. The network number shows what network the computer is on. The host number represents a computer on a network. With the classes A, B, and C there are variances in how they represent computers with A using the first 8 bits, B using the first 16 bits and C using the first 32 bits. A subnet mask determines what part of the IP number represents the network and what represents the host.

Network Troubleshooting

One way to determine the problem of a network is to see how many devices are affected. If only one is affected, than it may just be the computer. The ping command is used to check the connectivity around a network. If the ping command does not work, then the problem may lie in the connection between the server and computer. The ping command can also be used to do other things to figure out the problem with other commands like ping -t or ping localhost. The next step is to use the ipconfig command, with its variants of ipconfig /release and ipconfig /renew. These are used when a device may not be configured for DHCP. Other commands include the tracert command used in Windows and Linux computers. The nslookup command is used to help wit DNS servers. And finally the net command is used to manage a network. A similar command "netdom" is used to manage workstations.

How would you classify Champlain's network (for example, is it a PAN, LAN, or WAN)? Justify your answer.

I would call it a Local LAN, because it's not quite big enough to be a Metropolitan MAN. It connects several computer together to a big network.

Between the OSI and TCP/IP Model, which one seems more useful for describing networks? Justify your answer.

I would say a TCP/IP Model as it has less layers and would be easier to explain to someone who does not have any previous knowledge of networks. Especially when explaining how the physical interfaces connect to the virtual is hard to explain.

Suppose Champlain College was given a Class A network ID for its network (i.e., it had 224 addresses to assign to computers). Give one reason why this would be a good thing, and one reason why this might be a bad thing.

A class A network ID would definitely work for a network to connect 224 computers in a certain area like the game labs. However, considering how many labs are at Champlain, I think there are more than 224 computers so a Class B or C would work better.