Networking Components WILLIAM NELSON LTEC 4550

HUB  Device that operated on Layer 1 of the OSI stack.  All I/O flows out all other ports besides the incoming port.  Data is sent from one computer to all other computers on the network through these other ports.  Most commonly found with RJ-45 ports.  Can be thought of as a repeaters since it repeats signals from one port to the others.  Sometimes participates in collision detection, but this can slow down the device.  Declining in use, but primarily for very small networks and mostly to connect just a few computers.  Typical cost around $30-50

SWITCH  Device that relays traffic using a layer 2 MAC address in an Ethernet network  Can store a table of MAC addresses for routing purposes  Difference in a hub is that a switch is more intelligent and sends packets only to the ports that contain the computers that need the packets  Can sometimes combine routing into the same platform and route using IP addresses on Layer 3 instead of MAC addresses  Typically used in a network at the access layer, i.e. user connectivity on a Layer 2 level  Costs can range anywhere from $30 to $2000 or more

ROUTER  Much like a switch, but forwards packets from one port to a specific port on the same device based on IP address instead of MAC address  Contains a routing table of IP addresses and where the next “hop” is for the destined package  Sometimes can contain security services, such as firewalls  Flexible due to the fact that it can also function as a switch  This is the most common device in a network as it can be used as a L2/L3 device  Used primarily for the core of the network to do all the heavily lifting as far as traffic between segments of the network. This includes enterprise networks all the way to home networks that need to route internal traffic to the Internet only.  Typical cost is similar to a switch at $30 to $2000 and more.

BRIDGE  Bridges operate in the L1/L2 space and perform similar actions to a router, but unlike a router, the bridge connects to similar network segments, whereas a router connects multiple different networks segments.  Typically bridges are not used in many of today’s networks. In fact, the only time they would be used today would be for separate geographically located sites that need to be on the same LAN.  Also used in the wireless space to connect two buildings together  Typical costs for a bridge are around $50 to $1500

GATEWAY  Node on a TCP/IP network that is the router that is between networks. In other words, the router that connects between different networks.  This is normally just a standard router, but can be a dedicated device.  Typically this sits on the edge of the network in front of the firewall and core router.  When you use this as a separate device, it is normally in larger networks. In home networks, this is something that is built into the router.  Typical costs are the same as a router at $30 to $2000 or more

FIREWALL  This is mostly a L3 and above device. It does a little bit of L2 work, but the majority is routing, etc.  Security is provided in this device for maintaining access from external network to internal network.  Also, responsible for translating external IP addresses to internal IP addresses using Network Address translation  Some will provide anti-virus, anti-spyware abilities at layer 7  Can be a software or hardware device  Firewalls are used in all networks that access the Internet  Anytime that the Internet is used, there have to be safeguards from the external network and that’s what the firewall provides.  Typical costs range from $30 to $4000 or more

WIRELESS AP  This device is for connecting wireless devices into a network. It normally is used in the L2/L3 part of the stack.  Essentially combines wired and wireless networks by being a device that physically connects to the network, but also authorizes users based on wireless credentials.  Can be a standalone device or combined with the router  The standalone device is used in larger networks to add WiFi capabilities, but in a home environment on a smaller scale, combines this with the router.  Typical costs range from $30 to $1500 depending on capabilities

Diagram of Network