NETWORKING COMPONENTS By Scott H. Bowers

HUB A hub can be easily mistaken for a switch, physically there are no defining characteristics, both have power in and multiple Ethernet in ports. The key difference is in the layer the device operates at, the hub will broadcast to all hosts connected meaning it does not even attempt to discern whose traffic is whose. Normally a hub is found closest to host devices, and can be purchased for under twenty dollars.

SWITCH A switch operates at layer two (data link) and channels traffic based on the MAC address of a host’s connected interface. This device can be found at the floor, or department level depending on business size. An enterprise switch with 48 ports can cost anywhere from 4,000 to 12,000 dollars is often stacked with other switches as part of a scalable solution.

ROUTER The router operates at level 3 ( network layer ) transferring packets based on IP address and can often be found most readily in a personal home network, because in an enterprise environment physical access to a router is highly secure. The router delineates a personal home’s “inside” LAN from the ISP’s “outside” WAN, but in a business it may only separate one functional unit’s LAN from another, though both would still be considered “inside” the company. A router has a dedicated interface for connection to the WAN while reserving a number of other ports for internal use. Personal Routers often cost under or near 100 dollars.

BRIDGE A network bridge is a device that allows two separate networks to intercommunicate. Connecting two collision domains requires a bridge of some sort, and one example of this is might be a router connecting the physical and wireless LANS configured in it.

GATEWAY A gateway acts as a network node that is configured to communicate with other networks that may be utilizing different network protocols. Another name for these is protocol converters and they are often found between ISP or Companies. The price varies on these, but once again the trusted enterprise solutions range from 1,000 dollars to very high.

FIREWALL A firewall is a piece of hardware that inspects, and directs traffic based upon a defined ruleset of expressly allowed content or expressly blocked content. This device is set up between a trusted network and some other presumed unsecure network. An enterprise level firewall will run near 1,000 dollars, but can reach as high as 40,000.

WIRELESS AP A wireless access point operates as an extended arm of the wired network which casts out radio frequencies in order to communicate with Wireless Network Interface Cards. This AP can be contained in a router, or simply connected to one in order to allow wireless access to the wired LAN. These, like routers, often cost 100 dollars or less.

DIAGRAM OF DEVICES Gateway