Network devices

Routers

• Connects multiple NETWORKS together

• Layer 3 of OSI

• Uses IP addresses to forward packets

Connects diverse network types

• LAN, WAN, copper, fiber

Switches

• Connects multiple devices in a single network

• Layer 2 of OSI model

• Uses MAC address to forward data frames

Unmanaged switches

Very few configuration options

• Plug and play

Fixed configuration

• No VLANs

Very little integration with other devices

• No management protocols

Managed switches

VLAN support

• Interconnect w other switches via 802.1Q
  

Traffic prioritization

• Voice traffic gets higher priority
  

Redundancy support

• Maintain uptime if a switch fails
  

Port mirroring

• Capture packets
  

External management

• Simple network management protocol (SNMP)

Access point

Bridged communication

• Extends the wired network onto wireless network

• Makes forwarding decisions based on MAC address

Not a wireless router (wireless router is a router and an access point on a single device)

Patch panel

Combination of punch-down blocks ad RJ-45 connectors

Runs from desks are made once

• Perma punched down to patch panel

Patch panel to switch can be easily changed

• No special tools, use existing cables

Firewall

Filters traffic by port number

• OSI layer 4 (TCP/UDP)

• Some can filter based on application
  

Can encrypt traffic into/out of the network

Can proxy traffic

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

• 1 wire for both network & electricity

• Phones, cameras, wireless access points

• Useful in difficult-to-power areas

Endspans

When PoE power comes from the switch itself

• Built in power

Midspans

When using an injector

• In-line power injector

PoE switch

Power over Ethernet

• Commonly marked on the switch or interfaces

PoE

Original PoE specification

• 15.4 watts DC power, 350 MA max current

Downwards compatible, but not upwards

• Ex. PoE+ doesn’t power PoE++

PoE+

25.5 watts DC power, 600mA max current

PoE++

• 51 W (Type 3), 600 mA max current

• 71.3 W (Type 4), 960 mA max current

• PoE with 10GBASE-T

Cable modem

• Carries TV signals

• COAXIAL CABLING

• SHARED BANDWIDTH

Broadband

• Transmission across multiple frequencies

• Diff traffic types

Data on the “cable” network

• DOCSIS: Data Over Cable Service Interface Specification

High-speed networking

• Speeds up to 1 Gigabit/s are common

Multiple services

• Data, voice, video

DSL modem

Digital Subscriber line

• Uses telephone lines

• DEDICATED BANDWIDTH

• TWISTED-PAIR COPPER CABLING

• TELEPHONE LINES

Download speed is faster than the upload speed (asymmetric)

• 200Mbit/s downstream | 20 Mbit/s upstream are common

• ~10,000ft limitation from the central office (CO)

• Faster speeds may be possible if closer to CO

ONT

Optical network terminal

• Fiber to the premises

Connect the ISP fiber network to the copper network

• Demarcation point (demarc)

• 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

Specific to the network type

• Ethernet, WAN, wireless, etc.
  

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