Level 1 - Network devices and functions

Router

Route traffic between IP subnets

Layer 3 switch

Connects deiverse network types (LAN, WAN, copper, fiber)

Switches

Bridging hardware that forwards traffic based on data link address

Uses application-specfic integrated circuit (ASIC)

Many ports and features - core of enterprise networks, may provide PoE

Multilayer switches have routing functionality

Unmanaged switches

Very few configuration options

Fixed configuration, no VLANS possible

Simple, less expensive

Managed switches

Traffic prioritization

Redundancy support via Spanning Tree Protocol (STP)

Port mirroring

External management via (SNMP)

VLAN supported

Access point

A bridge that extends wired network to wireless network

NOT a wireless router

Makes forwarding decisions based on MAC address

Patch panels

Punch-down blocks and RJ-45 connectors

Cables are made once and permanently punched down to panel

Can be easily changed

Firewalls

Filter traffic by port number, some can filter by application

OSI layer 4

Can encrypt traffic into/outside network

Can proxy traffic - common security

More firewalls can be layer 3 devices (built into routers)

Power over Ethernet (PoE)

One wire for network and electricity, used in difficult to power areas

Power provided at the switch:

Built-in power: Endspans

In-line power injector: Midspans

PoE, PoE+, PoE++

PoE - IEEE 802.3af-2003
Original specification - 802.3 standard
15.4 watts DC power, 350mA max current

PoE+ - IEEE 802.3at-2009
802.3 standard
25.5watts DC power, 600 mA max current

PoE++ - IEEE 802.3bt-2018
PoE with 10GBASE-T
Type 3: 51W, 600 mA max current
Type 4: 71.3W, 960 mA max current

Hub

Traffic going in one port is repeated to all ports

Low efficiency at high network traffic

Obsolete

10 megabit - 100 megabit data transfer

Cable modem

Broadband - transmission across multiple frequencies

DOCSIS - data over cable service

High speed networking - up to 1 Gigabit/s

multiple services - data, voice, video

DSL modem (Digital subscriber line)

ADSL - asymmetric, uses telephone lines
Download speed faster than upload
52 Mbit/s downstream, 16Mbit/s upstream

Optical network terminal (ONT)

Connect ISP fiber network to copper network

Demarc point in the data center

Terminal box on side of the building

Network Interface Card (NIC)

Every device in a network must have NIC

Ex: Computer, server, printer, router, switches, phones, tablets, etc

Specific NIC for specific networks (Ex: Ethernet, WAN, wireless, etc)

Often built-in to motherboard, sometimes added as an expansion card

Options - single port, multi-port, copper, fiber