Network ComponentsLTEC4550 – GEORGE SWEETNAM

Typical Network Components:• Hub• Switch• Router• Bridge• Gateway• Firewall• Wireless AP

Hub

• Hubs are used in small offices to extend connectivity to a few additional devices. They are often confused with Switches because they look similar and operate on network layer 2.• Their major advantage over Switches is cost.• They are typically used homes or small offices and typically

cost than switches and range from $50 to $100.• Hubs can cause collisions on a network because network

traffic is broadcast to each port on the hub due to it having no MAC address.

Switch• Switches operate on network layer 2. There are some high-end switches which offer layer3 capability (ip routing).• Their main benefit is they provide intelligence for network data delivery because they have a MAC address for

each port. Switches send data ONLY to the port of a destination device (as opposed to a hub which sends to all ports).

• Higher end switches have the capability to segment portions of a network into VLANs for increased security.• They are found in all sizes of businesses and are often scalable to meet expanding needs of the organization.• Switches cost from the $100’s well into the thousands. The Cisco 3750 48 port switch on this page costs close to

$10,000.

RouterRouters are the workhorses of a network. They provide the layer3 transit between networks. Typically they are used to join together a Local Area Network and a Wide Area Network (the internet).

• Routers function send packets of data between networks.• Routers support different network protocols but the two

locations communicating always use the same method (IP to IP).

• Routers typically have interface connections to connect to methods of transit such as cable, DSL, Satellite, cellular or even dialup service.

• All sizes of businesses and homes use routers.• They typically cost from $150 to many thousands of dollars.

The Cisco 3945 above could easily cost in excess of $10,000 depending on the modules installed in it.

Bridge• Bridges are used to connect to locations together as if they are one contiguous

network.• They can be wired or wireless (image above is of a Cisco 1410 series wireless

bridge). • It operates like a switch and passes traffic destined for a MAC address on the far

side of the bridge as if it was located in the same physical network.• It works well in campuses and business locations where there are physically

divided buildings.• Power line Ethernet adapters in homes are an example of a network bridge.• Costs range from $100 to a few thousand dollars for wireless solutions.

Gateway

• A Gateway is found on at the edge of a network. • Often they are combined with other features such as firewalls and VPNs.• A Gateway sends traffic between two differing network types (main difference from

a Router).• It may operation across different network layers.• Costs range from $150 to $1000.

Firewall• Firewalls are used to protect networks by allowing or rejecting traffic.• Smaller network devices often include simple firewalls which block traffic by type.

Larger networks have devices which inspect traffic using Intrusion Detection Systems (IDS) and then implement policies to reject suspect traffic through Intrusion Prevention Systems (IPS).

• Prices range from a few hundred up to tens of thousands for enterprise grade protection systems.

• They are typically deployed after the router, but some devices have integrated firewalls in their router or gateway devices.

Wireless Access Point• Wireless Access Points (APs) allow connection to a network without maintaining a

physical connection.• Businesses use them to deploy connectivity nodes in buildings and campuses to

allow portable devices to have network connectivity.• The most common frequencies used to connect are 2.4Ghz and 5Ghz. The

channels are named a/b/g and n.• Many corporate installation allow client devices to handoff between access points

and the user never knows they’ve moved to another device.• Enterprise grade APs Costs range from about $500 to $1000 each.

Network Diagram of Discussion Items

To the right is an example of how all the devices discussed could be connected together.