CompTIA A+ 220-1201 (2.5 - Network Devices)

Network devices

• Many different devices and components

- All have different roles

• Some of these functions are combined together

- Wireless router/switch/firewall

• Compare different devices

- Understand when they should be used

Routers

• 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

Switches

• 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

Unmanaged switches

• 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

Managed switches

• VLAN support

- Interconnect with other switches via 802.1Q

• Traffic prioritization

- Voice traffic gets a higher priority

• Redundancy support

- Spanning Tree Protocol (STP)

• Port mirroring

- Capture packets

• External management

- Simple Network Management Protocol (SNMP)

Access point

• Not a wireless router

- A wireless router is a router and an access point in a single device

• An access point is 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

- Permanently punched down to patch panel

• Patch panel to switch can be easily changed

- No special tools - use existing cables

Firewalls

• Filters traffic by port number

- OSI layer 4 (TCP/UDP)

- Some firewalls can filter based on the application

• 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

Power over Ethernet (PoE)

• 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

PoE switch

• Power over Ethernet

- Commonly marked on the switch or interfaces

PoE, PoE+, PoE++

• PoE

- The original PoE specification

- Now part of the 802.3 standard

- 15.4 watts DC power, 350 mA max current

• PoE+

- Now also part of the 802.3 standard

- 25.5 watts DC power, 600 mA max current

• PoE++

- 51 W (Type 3), 600 mA max current

- 71.3 W (Type 4), 960 mA max current

- PoE with 10GBASE-T

• Compare the device with the switch support

- PoE+ won't power a PoE++ device

Cable modem

• Broadband

- Transmission across multiple frequencies

- Different traffic types

• Data on the "cable" network

- DOCSIS (Data Over Cable Service Interface Specification)

• High-speed networking

- Speeds up to 1 Gigabit/s are available

• Multiple services - Data, voice, video

DSL modem

• Digital Subscriber Line - uses telephone lines

• Download speed is faster than the upload speed (asymmetric)

- ~10,000 foot limitation from the central office (CO)

- Faster speeds may be possible if closer to the CO

ONT

• Optical network terminal - fiber to the premises

• Connect the ISP fiber network to the copper network

- Demarcation point (demarc) in the data center

- Terminal box on the side of the building

• Line of responsibility

- One side of the box is the ISP

- Other side of the box is your network

Network Interface Card (NIC)

• 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

• Often built-in to the motherboard

- Or added as an expansion card

• Contains the hardware address

- Media Access Control (MAC) address

- A unique hardware designation