Home Computer Networks

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THIS GUIDE IS A GENERAL INTRODUCTION TO COMPUTER HOME NETWORKS. IF YOU HAVE ANY QUESTIONS AFTER READING THIS GUIDE PLEASE CONTACT US. BRAVO AV CONSULTING STANDS READY TO HANDLE ALL OF YOUR HOME COMPUTER NETWORK NEEDS.

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Bravo AV Computer Networking Capabilities

Bravo AV Consulting stands ready to handle all of your home computer network needs. Our services areas include:

• Physical wiring. See www.BravoAV.com and our papers on: “Bravo AV Consulting’s Structured Wiring approach” and “Classification of low voltage wiring.”
• Setup and configuration of: modem, router, firewall, switch, PC, printer etc.
• Data Backup
• Wireless Network Configuration
• Network Security

Benefits of Networking

A network is two or more computers linked together. There are various methods to connect or link networked devices referred to as a “topology” or “architecture.” Networks allow your computers to connect to the Internet, talk to each other, and share resources like files and printers.

Network Classification

Ways to classify networks:

• Client server
• Peer-to-Peer
• Wired vs. wireless
• Wireless Network Configuration
• LAN vs. WAN

Most home networks are peer-to-peer (P2P) networks. In a P2P network, all PCs are connected to the network to communicate and share resources as equals.

LAN

A Local Area Network (LAN) supplies networking capability to a group of computers in close proximity to each other, as in an office, school, or home. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN can connect to other LANs, the Internet or to a WAN.

LANs can be wired or wireless. Wired networks are connected by cabling (commonly referred to as “Cat 5" or “Cat6” cable) and can transfer data at a rate of 100Mb/s to 1000Mb/s. In the past, typically only computers and computer peripheral would be connected. Today more and more devices are connected to home networks, including these devices: TV’s, cell phones, Audio/Video equipment, control panels and video games. By connecting these devices to a LAN with a router you will be able to take advantage of advance features such as streaming music (internet radio, Rhapsody, Sirius/XM) and movies (Netflix, YouTube, home movies stored on a local computer).

LAN speeds
Fast Ethernet: 100BASE-T: 100 Mbit/s Ethernet over Category 5e cable. Gigabit Ethernet: 1000BASE-T: 1 Gbit/s Ethernet over Category 5e cable.

WLAN

A Wireless Local Area Network (WLAN) provides wireless network communication over short distances using radio or infrared signals instead of traditional network cabling. A WLAN typically extends an existing wired local area network. WLANs are built by attaching a device called the access point (“AP”) sometime referred to as a wireless access point (“WAP”) to the edge of the wired network. Clients communicate with the “AP” using a wireless network adapter similar in function to a traditional Ethernet adapter. Network security remains an important issue for WLANs. Random wireless clients must usually be prohibited from joining the WLAN. Technologies like WEP/WPA/WPA-2 raise the level of security on wireless networks to rival that of traditional wired networks.

WAN

A Wide Area Network (WAN) spans a large geographic area. WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs). The world's most popular WAN is the Internet. Some segments of the Internet, like VPN-based extranets, are themselves WANs.

VPN

A Virtual Private Network (VPN) is a secure connection between two computers (VPN server and VPN client.) You can think of the connection as a tunnel across the Internet. Only the two computers on the ends of the tunnel can see what is being transported in the tunnel. A firewall can be set up to allow VPN connections to the VPN server (the router in our case) but block other types of connections. The VPN is how you securely connect to your network from home or while traveling.

ISP

An Internet Service Provider (ISP) is a company that provides internet access. You must have an ISP to connect to the internet. An ISP is like a gateway. Your computer connects to the ISP and the ISP connects to the Internet. Examples of ISPs are: cable companies and phone companies (Verizon FIOS).

Internet Protocol (IP)

IP addresses, both public and private, are used to identify devices and data as it travels across the internet. Although IP addresses are stored as binary numbers, they are usually displayed in human-readable notations, such as 208.77.188.166.

Media Access Control (MAC)

The Media Access Control (MAC) address is a globally unique 40-bit address consisting of a manufacturer’s code and a serial number. The MAC address allows networked devices to communicate directly with each other. The switch (see below) keeps a table (directory) of the devices connected to the switch using the MAC address.

Network protocols used in home networks include:

Domain Name Services (DNS). Translates domain names (i.e. www.Yahoo.com) into IP addresses (i.e. 192.168.1.0)
Dynamic Host Configuration Protocol (DHCP). DHCP is a protocol used by the router to assign internal addresses to network devices on an as needed or dynamic basis. DHCP allows users to attach multiple devices to a home network using a single leased address for the ISP. These internal addresses are assigned by the router using a private network number. The address sequences set aside are for use on internal networks only and are not valid addresses for the use across the public Internet.
Network Address Translations (NAT). Translates internal private IP addresses to an external public address, provided by the ISP, for the use on the public Internet.

Network Hardware

Network Adaptor

Allows your computers to connect to the network. Many modern computers already have a wireless or network adapter pre-installed. Modem

A modem is a device that provides the first level of connectivity between the ISP and the end user location. Router

This is your network's "air traffic controller". It routes all the data on your network to the proper place. It also assigns unique network addresses to all the computers (IP addresses). Routers can also “hide” the computer and other devices from the outside world (using Network Address Translation (NAT). To people on the Internet, your entire network looks like one computer (one IP address). This adds another layer of protection to the computers on your network. A router may contain a VPN server and/or a firewall. Wireless Router

This performs the same function as the router, but for computers and devices not wired to the network. There are several different wireless protocols (802.11a, 802.11b, 802.11g, and 802.11N). These protocols differ in bandwidth (11mb/s - 300mb/s) and/or radio frequency (2.5 GHz and 5 GHz). Wireless networks (WLAN) are inherently less secure than wired networks (LAN). It is important to understand how to secure a WLAN. (See Appendix B for more information on protocols and WLAN’s) Network Switch

A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at Layer Two (Data Link Layer) of the OSI model. Network switches are capable of inspecting data packets as they are received, determining the source and destination device of each packet, and forwarding them appropriately. Ethernet implementations of network switches are the most common. Mainstream Ethernet network switches support either 10/100 Mbps Fast Ethernet or Gigabit Ethernet (10/100/1000) standards. Different models of network switches support differing numbers of connected devices. Most consumer-grade network switches provide either 4, 8 or 16 connections for Ethernet devices. Switches can be connected to each other, a so-called daisy chaining method to add progressively larger number of devices to a LAN. Firewall

The term firewall is a blanket term describing security measures that protect a network. A network firewall performs the same function as the firewall in your car. The firewall in your car keeps things in the engine compartment from coming into the passenger compartment. The firewall in your network stops bad things from the Internet coming into your network. A firewall is critical for a secure network.

Protecting Your Network

Linksys by Cisco routers offer a variety of security features that help to protect your networked computers and put you at ease.

Network Address Translation (NAT) Technology
NAT prevents hackers from seeing and attacking your network address while you are surfing the web. NAT takes a public IP address and translates it into several private IP addresses, so a computer behind a router with NAT technology is difficult for outside hackers to see. All Linksys by Cisco routers include NAT security.

Network Address Translation (NAT) technology translates IP addresses of a local area network to a different IP address for the Internet. Each computer on your network has a local IP address. When the router gets the data transmission to forward out to the Internet, the router puts a different IP address on the transmission. This way, whoever receives the data transmission doesn't know the computer’s actual IP address. The computer is hidden from prying eyes.

Stateful Packet Inspection (SPI) Firewall
An SPI Firewall inspects packets of information coming into your system to make sure they are not part of a hacker attack. When information is requested from a Web site, it is sent out through the SPI router and is noted as a request destination. Any unfamiliar or unlisted destinations are rejected. Some Linksys by Cisco routers include this security feature, so check your product documentation.

Because the router is your network's connection to the Internet, a built-in firewall helps protect your entire local network, like an alarm system for your house. An SPI is a type of firewall that inspects incoming data packets to make sure they correspond to an outgoing request. Unsolicited and potentially harmful packets are rejected.

An SPI firewall is considered to be more advanced than NAT because it is able to examine the information that is coming through to your network from the Internet.

Virtual Private Network (VPN)
VPN enables communication over the Internet with another computer on your network using a secure, encrypted connection. VPNs are frequently used by businesses and home offices. It is commonly used by people traveling or working from their home, who want to connect to their company's network to check email or access business applications.

How to Secure Your Wireless Network

The information in this section is from the Linksys website, but applies to most wireless manufacturer’s equipment. With a wireless network, your information is traveling through the airwaves, not physical wires, so anyone within range can "listen in" on your network. There are five security measures essential to securing a wireless network.

1. Change the default password
Access points and routers have a default password set by the factory. You will be asked for a password when you want to change their settings. (The Linksys by Cisco default password is “admin”). Hackers know these defaults and will use them to access your wireless device. Create your own hard-to-guess password.

2. Change the default SSID
Your wireless devices have a default SSID (Service Set Identifier) set by the factory. The SSID is the name of your wireless network, and can be up to 32 characters. Linksys wireless products use “Linksys” as the default SSID. Hackers know these defaults and can use them to join your network. Change your network's SSID to something unique, and make sure it doesn't refer to the networking products you use. As an added precaution, be sure to change the SSID on a regular basis, so any hacker who may have figured out your network's SSID in the past will have to figure out the SSID again and again. This will deter future intrusion attempts.

3. Enable WPA Encryption
Encryption allows protection for data that is transmitted over a wireless network. Wired Equivalency Privacy (WEP) and Wi-Fi Protected Access (WPA) offer different levels of security for wireless communication. WPA is considered to be more secure than WEP, because it uses dynamic key encryption. To protect your information as it passes over the airwaves, you should enable the highest level of encryption that is supported by your network equipment.

4. Disable SSID broadcast
For convenience, most wireless networking devices are set by default to broadcast the SSID, so anyone can easily join the wireless network with just this information. Hackers will also be able to connect, so unless you're running a public hotspot, it's best to disable SSID broadcast. You may think it is more convenient to broadcast your SSID so that you can click on it to join your network, but you can configure the devices on your network to automatically connect to a specific SSID without broadcasting the SSID from your router. You might ask "If it's easier for hackers, why broadcast SSID in the first place?" The answer is because setup is easier if you can see it. After setup you should disable SSID Broadcast.

5. Enable MAC address filtering
Linksys by Cisco routers give you the ability to enable MAC (Media Access Control) address filtering. MAC address filtering allows you to specify which computers can access your network.

The MAC address is a unique series of numbers and letters assigned to every networking device. With MAC address filtering enabled, wireless network access is available only to devices with particular MAC addresses, i.e. the computers in your house. It would be very difficult for a hacker to access your network using a random MAC address.

Resources

www.Iwebtools.com
www.linksysbycisco.com/US/en/learningcenter

 

Contact TOM CURNIN at 908-304-0555 or Tom@BravoAV.com.  Your Professional AV Expert.

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