2.2 - Network Devices

Question 1

Network Interface Card (NIC)

Answer 1

The fundamental network device
• Every device on the network has a NIC
• Computers, servers, printers, routers, switches, phones,
tablets, cameras, etc.
• Specific to the network type
• Ethernet, WAN, wireless, etc.
• Often built-in to the motherboard
• Or added as an expansion card
• Many options
• Single port, multi-port, copper, fiber

Question 2

Repeater

Answer 2

Receive signal, regenerate, resend
• No forwarding decisions to make
• Common use
• Boost copper or fiber connections
• Convert one network media to another
• Extend wireless network reach

Question 3

Hub

Answer 3

“Multi-port repeater”
• Traffic going in one port is repeated to every other port
• Everything is half-duplex
• Becomes less efficient as network speeds increase
• 10 megabit / 100 megabit
• Difficult to find today

Question 4

Bridge

Answer 4

Imagine a switch with two to four ports
• Makes forwarding decisions in software
• Connects different physical networks
• Can connect different topologies
• Gets around physical network size limitations /
collisions
• Distributes traffic based on MAC address
• A modern bridge is a wireless access point
• Bridges wired Ethernet to wireless

Question 5

Switches

Answer 5

Bridging done in hardware
• Application-specific integrated circuit (ASIC)
• Forwards traffic based on data link address
• Many ports and features
• The core of an enterprise network
• May provide Power over Ethernet (PoE)
• Multilayer switch - Includes routing functionality

Question 6

Unmanaged switches

Answer 6

Very few configuration options
• Plug and play
• Fixed configuration
• No VLANs
• Very little integration with other devices
• No management protocols
• Low price point
• Simple is less expensive

Question 7

Managed switches

Answer 7

• VLAN support
• Interconnect with other switches via 802.1Q
• Traffic prioritization
• Voice traffic gets a higher priority
• Redundancy support
• Spanning Tree Protocol (STP)
• External management
• Simple Network Management Protocol (SNMP)
• Port mirroring
• Capture packets

Question 8

Routers

Answer 8

• Routes traffic between IP subnets
• Makes forwarding decisions based on IP address
• Routers inside of switches sometimes called
“layer 3 switches”
• Often connects diverse network types
• LAN, WAN, copper, fiber

Question 9

Wireless access point (WAP)

Answer 9

• Not a wireless router
• A wireless router is a router and a WAP
in a single device
• WAP is a bridge
• Extends the wired network
onto the wireless network
• Makes forwarding decisions
based on MAC address

Question 10

Wireless LAN controllers

Answer 10

• Centralized management of WAPs
• A single “pane of glass”
• Management functions
• Deploy new access points
• Performance and security monitoring
• Configure and deploy changes to all sites
• Report on access point use
• Usually a proprietary system
• The wireless controller is paired
with the access points
• Can also be cloud-based
• Manage the console from anywhere

Question 11

Firewalls

Answer 11

• Filters traffic by port number
• OSI layer 4 (TCP/UDP)
• Some firewalls can filter through OSI layer 7
• Can encrypt traffic into/out of the network
• Protect your traffic between sites
• Can proxy traffic
• A common security technique
• Most firewalls can be layer 3 devices (routers)
• Usually sits on the ingress/egress of the network

Question 12

Cable modem

Answer 12

• Broadband
• Transmission across multiple frequencies
• Different traffic types
• Data on the “cable” network
• DOCSIS (Data Over Cable Service Interface Specification)
• High-speed networking
• 4 Mbits/s through 250 Mbits/s are common
• Gigabit speeds are possible
• Multiple services
• Data, voice

Question 13

DSL modem

Answer 13

• ADSL (Asymmetric Digital Subscriber Line)
• Uses telephone lines
• Download speed is faster than the upload speed
(asymmetric)
• ~10,000 foot limitation from the central office (CO)
• 52 Mbit/s downstream / 16 Mbit/s upstream
are common
• Faster speeds may be possible if closer to the CO

Question 14

Patch panels

Answer 14

• Combination of punch-down blocks and RJ-45 connectors
• Runs from desks are made once
• Permanently punched down to patch panel
• Patch panel to switch can be easily changed
• No special tools
• Use existing cables

Question 15

Power over Ethernet

Answer 15

• Power provided on an Ethernet cable
• One wire for both network and electricity
• Phones, cameras, wireless access points
• Useful in difficult-to-power areas
• Power provided at the switch
• Built-in power - Endspans
• In-line power injector - Midspans

Question 16

PoE switch

Answer 16

• Power over Ethernet

* Commonly marked on the switch or interfaces

Question 17

Ethernet over Power (EOP)

Answer 17

• Also called Power-line communication (PLC)
• IEEE standard 1901
• 500 megabits per second
• Standard includes links to the premise, intra-building
networking, vehicles, smart energy devices, and more