CompTIA A+ 1101 - 2.2 Network Devices

Routers

routes traffic between IP subnets, makes forwarding decisions based on IP address

Switches

application-specific integrated circuit (ASIC), forwards traffic based on data link address

Unmanaged Switches

very few configuration options, fixed configuration, no VLAN, very little integration with other devices, low price

Managed Switches

VLAN support, traffic prioritization, redundancy support (STP), port mirroring, external management (SNMP)

Access Point

not a wireless router (more like a bridge), extends the wired network onto the wireless network, makes forwarding decisions based on MAC address

Patch Panels

combination of punch-down blocks and RJ-45 connectors, runs from desks are made once

Firewalls

filters traffic by port number, can encrypt traffic into/out of network, can proxy traffic

Power over Ethernet (PoE)

power provided on an Ethernet cable, one wire for both network and electricityI

Injector

midspan in-line power for PoE

PoE

IEEE 802.3af-2003, original PoE specification, now part of 802.3 standard, 15.4 watts DC power, 350 mA max current

PoE+

IEEE 802.3at-2009, also part of 802.3 standard, 25.5 watts DC power, 600 mA max current

PoE++

IEEE 802.3bt-2018, Type 3 - 51W 600mA, Type 4 - 71.3W 960mA

Hub

multi-port reader, everything is half duplex, becomes less efficient as network traffic increases, only available in 10 megabit or 100 megabit speeds, difficult to find today

Cable Modem

broadband, data on the “cable” network, high-speed networking, multiple services (data, voice, video)

DSL Modem

ADSL, uses telephone lines, download speed is faster than upload speed

ONT (Optical Network Terminal)

fiber to the premises, connect the ISP fiber network to the copper network, demarcation point (demarc) in the data center, line of responsibility (one side of the box is ISP, other side is network)

NIC (Network Interface Card)

fundamental network device, specific to the network type (Ethernet, WAN, wireless), often built-in to the motherboard