Chapter 13: Networking - 11/1/20

Networking Overview

A network connects computers together, and can be many different things. PAN (Personal Area Network): A PAN is a personal network, usually consisting of the devices directly connected to your computer via bluetooth like a keyboard or a mouse. LAN (Local Area Network): A LAN is the most common network, consisting of multiple computers connected to each other in some capacity. A LAN ends when a packet must use a router to leave. WAN (Wide Area Network): A WAN is two LANs that connect over a large geographical distance.

Copper Media

The most common media to connect computers is copper wiring. Twisted pair cabling is the most common wiring in the cable. CAT 5e: A very common and reliable ethernet cable used to connect two computers. CAT 6: Supports gigabit ethernet, thick cable that can transfer data the fastest. It is possible to purchase parts and create your own cables for specific purposes.

Ethernet Concepts

A LAN connected via ethernet cables is very common and is found in many workplaces. Some issues with this can be low bandwidth or half & full duplex transmission problems. Full Duplex: A type of ethernet cable meaning transmissions can go both ways simultaneously, found in efficient networks. Ethernet naming conventions look like this: 10baseT (10 mb/s) and 10GbaseSR (10 gb/s).

OSI Model

The OSI (Open Systems Interconnect) Model is a universal standard model for data transfer. Its layers are: 1.Physical , 2.Data Link , 3.Network , 4.Transport , 5.Session , 6.Presentation , 7.Application. The lower layers deal with MAC addresses, physical connections, and then up to IP addresses for the network layer. The top deals with how data is presented to the user via a GUI and other applications.

The TCP/IP Model

Network Protocol: a data communication language. TCP/IP is the standard protocol currently used today in networks to transfer data. The TCP/IP Model layers are: 1.Network access , 2.Internet , 3.Transport , 4.Application. The TCP/IP model generally follows the same idea as the OSI Model.

More IPv4 Addressing

An IP address is a 32-bit number that consists of two parts, the first: network bits, and the second: host bits. The network bits correspond with the bits turned on by the subnet mask, and the host bits correspond to the individual device. IP addresses have classes A, B, and C. Class A has the most host bits available, and class C has the least host bits available. Broadcast address: The 2nd to last host address of a subnet, used to to communicate with all devices on a similar network. A VLAN (Virtual Local Area Network) is a common way to use a switch to create multiple LANs on one switch. The subnet mask is a crucial part of an IP address, and usually looks like this: 255.255.255.0. A subnet mask denotes the number of network bits using a 32-bit binary number where a 1 means that that specific bit is being used for the network, and any 0 bits are to be used for the host.

Wireless Networks Overview

A wireless network is a network that exists without physical connections, and communicates most commonly using radio waves. Wi-fi is the more common term for a wireless network, and are very common in homes and public areas.

Wireless Network Standards

Standards follow the naming convention: 802.11xx, with the xx denoting a letter corresponding with the speed of the wireless frequency. The current fastest being 802.11ad, running in the 60hz range with speeds up to 6.76 gb/s.

Bluetooth

Bluetooth is a wireless technology that is most commonly found in Personal Area Networks, and connects devices like a keyboard or a mouse. Bluetooth usually falls in a range of less than 30 feet to the desired host.

Wireless Network Components

Access Point: A common connecting point for a wireless network that usually connects to a wired network. Wireless bridge: A physical device or software that connects two or more networks, usually a wired and wireless network.

Wireless Network Design

An access point can be compared to a hub, except that it connects wireless devices together that share the same bandwidth. Access points can connect to a wireless repeater, that helps to boost the signal to increase speeds of the network.