Networking Devices | CompTIA Network+ N10-007 | 2.2

In this video you will learn about various networking devices such as firewalls, routers, switches, hubs, bridges, modems, wireless access points, media converters, wireless range extenders, & VoIP endpoints.

Firewall

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.  A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the internet. Firewalls can be either software or hardware.  Firewalls are frequently incorporated into wireless routers, Microsoft Windows & mac OS. Software firewalls are also known as host firewalls.

Firewalls work like this:  A computer from outside the network attempts to gain access to a server on the network that has a firewall.  The firewall blocks the incoming traffic from that computer because no computer from inside the network has sent a request to the outside computer.  A computer on the network sends a request to a remote server hosting a website. The remote server responds back to the computer on the network. Because the remote server is responding to a request from the network, the firewall permits the incoming traffic.

Router

A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (i.e. the internet) until it reaches its destination node. Devices that are connected to a LAN via a router connected to a cable modem or DLS modem allows for these devices to share a broadband connection to the internet. A router has at least two network connections that use RJ-45 cables.  The port labeled WAN connects the router to a modem. The port labeled LAN connects the router to a switch. If the router has a built-in switch, it has multiple LAN ports numbered starting at 1. Most routers today are wireless routers (use the 802.11 WiFi standards) that combine a router, a switch, and an access point. A router has two IP addresses because it has two network connections.  One network connection uses a private IP address and is used to attach to the LAN (ports numbered 1-4 or higher).  The other network connection is the one used to connect to the internet via a modem. This is a public IP address.

Switch

A switch is a high-speed device that receives incoming data packets and redirects them to their destination on a local area network (LAN). Essentially, switches are the traffic cops of a simple local area network. A switch enables direct connections between any two computers or devices on a network. A switch makes a direct connection between the sending and receiving devices by identifying the Media Access Control (MAC) address of each device. Switches are available with as few as four or five RJ-45 ports or with dozens of ports.  Switches can be connected to each other (stacked or daisy-chained) so that a small network can grow without needing to replace existing switches. Most switches support at least Fast Ethernet (100Mbps) signaling, with Gigabit Ethernet (1000Mbps) becoming common in home and small-office networking.  10G Ethernet switches (10Gbps) are now used in enterprise-networks. Low-cost switches used in SOHO networks cannot be configured to perform complex switching functions and are considered unmanaged. A managed switch can organize its switch ports into several logical networks (virtual LANs or VLANs) that cannot interfere with each other which enables different companies or departments to have independent networks in the same physical location to keep their traffic separated. Managed switches also support SNMP for diagnostics & performance measurements. To enable a switched network to connect to the internet, connect a switch to a router.  Many routers made for home or small offices include a multi-port switch and a wireless access point.

Hub

A hub is a network hardware device for connecting multiple Ethernet devices together and making them act as a single network segment. Hubs were used to connect computers together and to boost the communication signal between computers. It has multiple I/O ports, in which a signal introduced at the input of any port appears at the output of every port except the original incoming. A network hub is considered an unsophisticated device in comparison with a switch. A hub cannot examine or manage any of the traffic that comes through it. A hub has no memory to store data, can handle only one transmission at a time, splits the bandwidth of a connection among all computers connected to it, and broadcasts data to all computers connected to it. When it comes to the splitting of bandwidth, a five-port 10/100 Ethernet hub will divide the 100Mbps speed of the Fast Ethernet amongst the five ports, therefore only providing 20Mbps of bandwidth to each port for Fast Ethernet. With that being said, hubs have become rare in networks.

Bridge

A wireless bridge (or a setting on many access points) connects two wired networks together over WiFi. The wireless bridge acts as a client, logging in to the primary router and getting an internet connection, which it passes on to the devices connected to its LAN.

Modems

A modem (modulator/demodulator) is a hardware device that converts data into a format suitable for a transmission medium so that it can be transmitted from one computer to another (historically along telephone wires). A modem modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded reliably to reproduce the original digital data. Modems connect a LAN to an ISP. Dial-up modems allow computers to gain access to the internet by converting the computer’s digital signals to analog signals used by a land-based phone line. The issue with dial-up modems is that they are slow devices and are typically used if no other internet option is available. The most common modems in use today are cable & DSL modems.

Wireless Access Point (WAP)

A WAP is a networking hardware device that allows other WiFi devices to connect to a wired network based on IEEE 802.11 standards.  The WAP usually connects to a router (via a wired network) as a standalone device, but it can also be an integral component of the router itself.  WAPs act as central connecting points for computers equipped with wireless network adapters by identifying each computer by its MAC address. To connect a wireless network to a wired network, connect the RJ-45 port on the WAP to a switch on a wired network. If the wired network is connected to a router with internet access, the wireless network will also have internet access.

Media Converter

A fiber media converter is a simple networking device that makes it possible to connect two dissimilar media types such as twisted pair with fiber optic cabling. They were introduced to the industry in the 1990s, and are important in interconnecting fiber optic cabling-based systems with existing copper-based, structured cabling systems. They are used in metropolitan area network (MAN) access and data transport services to enterprise customers.

Wireless Range Extender

A repeater/extender is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Wireless signals can be blocked by a variety of objects such as bricks, steel, & concrete walls. Distance can also weaken signals as well. Wireless repeaters can look similar to wireless routers and some even include a switch component, but instead of connecting to a cable or DSL modem, a repeater connects wirelessly to a wireless router.

VoIP Endpoint

Voice over Internet Protocol (VoIP) is a method & group fo technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. VoIP & SIP (Session Initiation Protocol) phones are examples of VoIP endpoints.