CompTIA A+ 1101 Network Devices

Routers

- routes traffic between IP subnets

- makes forwarding decisions based on IP addresses

- OSI layer 3 (network layer)

- often connection diverse (LAN, WAN, copper, fiber)

Switches

- bridges devices together

- forwards traffic based on the data link address

- contains many ports and features

- may provide PoE (power over ethernet)

- OSI layer 2 (data link layer)

Multilayer Switches

- contains routing functionality

- OSI layer 3 (network layer)

Unmanaged Switches

- has very few configuration options (plug and play)

- fixed configuration (no VLANs)

- very little integration with other devices (no management protocols)

- low price point

Managed Switches

- provides VLAN support (interconnect with other switches via 802.1Q)

- traffic prioritization

- redundancy support using STP (Spanning Tree Protocol), which prevents loops between multiple switches

- port mirroring (capture packets to troubleshoot or analyze)

- external management options (for example, SNMP, or Simple Network Management Protocol)

Access Points

- provides wireless connectivity for a local network

- provides a link between the wireless network and the wired network (a bridge)

- makes forwarding decisions based on the destination mac address (identical process to a switch)

Firewalls

- filters traffic based on the port number

- may be able to filter based on application traffic (OSI layer 7)

- OSI layer 4 (TCP/UDP layer)

- can encrypt traffic into and out of the network, to protect it between sites

- can proxy traffic

- may also have router functionality (OSI layer 3)

Hubs

- multi-port repeater

- becomes less efficient as network traffic increases

- half-duplex

- succeeded by switches

- speeds of 10 megabit and 100 megabits

Cable Modems

- broadband communication

- transmission across multiple frequencies and different traffic types

- data over a "cable" network (using the DOCSIS, Data over Cable Service Interface Specification)

- provides high-speed networking, with speeds up to 1 gigabit per second

- can support multiple services such as data, voice, and video

DSL (Digital Subscriber Line) Modems

- utilizes telephone lines

- asymmetric, as download speed is faster than the upload speed (hence the acronym, ADSL, or Asymmetric Digital Subscriber Line)

- distance limitations of about 10000 feet from the central office

- common speeds of about 52 megabits per second downstream, and 16 megabits per second upstream

- faster speeds are possible the closer that you are to the central office

ONTs (Optical Network Terminal)