NETWORKING DEVICES

Chapter 3

OBJECTIVES Upon completion of this chapter, you

should be able to:Select and install network cards to meet

network connection requirementsConnect a media converterSelect and install appropriate

networking hardwareSelect the appropriate device to connect

two networksIdentify networking and internetworking

devices by name or sight (adapters, hubs, bridges, routers, switches)

NETWORK ADAPTERS

3.1

NETWORK INTERFACE CARDS How do you connect to a wired network?

NIC How do you connect to a wireless

network?WLAN NIC

Both connect devices to the network

MODEM Converts digital to

analog/analog to digitalModulate/demodulate

Connects you to the Internet through the ISP

Cable modem, DSL modem, Dial-up modem

MODULES SFP

Used on routers & switches to convert media type

GBICLarger sized

MEDIA CONVERTERS Layer 1 device Converts signal type

Ethernet to fiber, for example

MAC ADDRESSES Used to identify frame Each host has a unique address

Burned into NIC hardware 48-bits / 12 hex digits / 6 bytes 1st 24 bits OUI; 2nd 24 bits serial #

FORWARDING FRAMES

HOW MAC ADDRESSES ARE SHOWN Written as 0x

0xA4

UNICAST MAC ADDRESS One to one communication

BROADCAST MAC ADDRESS One to all in a network Dest. MAC address will be all F’s DHCP & ARP use broadcasts

MULTICAST MAC ADDRESS One to a group in a network Remote gaming or video conference Dest. IP will be 224.0.0.0 -

239.255.255.255 Dest. MAC will begin with 01-00-5E

REVIEW- 5Q How many bits in a MAC address?

48 bits How many hex digits?

12 The first 6 hex digits are what?

The OUI The OUI would then be the 1st ____ bytes.

3 What important addresses are

encapsulated into a frame?Source & destination MAC

REVIEW- 2Q What kind of message gets sent from

one PC to a group within a network?Multicast

Identify each as unicast, multicast, or broadcast:

ARP Works within your network

LAYER 3

SOURCE IP:192.168.1.1

DESTINATION IP:192.168.1.2

DATA

LAYER 2

SOURCE MAC:AAA

DEST. MAC:

SOURCE IP:192.168.1.1

DEST. IP:192.168.1.2

DATA

HOW ARP WORKS Each device has an ARP table of IP/MACs

Added from communicationAdded from ARP requests

Without a dest. MAC, an ARP request is sent

ARP request is all F’s in what field?Destination MAC

How is an ARP request sent?Broadcast

Who replies to the ARP request?Only one with matching dest. IP

ARP REQUEST & REPLY

HOW ARP WORKS- LOCAL

VIEWING THE ARP TABLE Windows

Arp –a

ACTIVITY TestOut

3.1.3- Select & Install a Network Adapter3.1.4- Connect a Media Converter3.1.5- Quiz

LabsHandout- Fill out MAC address Chart

NETWORK DEVICES

3.2

HUBS Simple Layer 1 device Extends network Data goes in one port & out

all othersNo thinking involvedRelies on devices to decide

on message Creates more network

traffic Not used anymore

HUB NETWORK

BRIDGE Separates segments Layer 2 device Looks at dest. MAC to decide if data

should cross or not Less traffic

WIRELESS BRIDGE Converts wired to wireless

SWITCH Layer 2 device Reads dest. MAC Data enters a port, then

sent out the one port Smarter than bridgeKnows MAC address

on each port MAC Address Table

MAC addresses added Packaged into a FRAME Sent to exact port

HOW A SWITCH WORKS

BUILDING A SWITCH TABLE

WHAT WILL HAPPEN?

REVIEW- 5Q This basic device extends the network, as it

does not segment it. Hub

Which current networking devices receives data and sends it out a single port based on MAC addresses? Switch

What layer does a hub work at? Layer 1

What layer does a switch work at? Layer 2

A switch builds & maintains what? MAC address table

WIRELESS ACCESS POINT (WAP) Allows wireless

devices to connect to wired network Uses radio waves

Like a hub as signal goes to all; dest. MAC accepts

Like a bridge to connect to wired network

WAP reads MAC if you use MAC Filtering

ACTIVITY TestOut

3.2.3- Install a Hub3.2.4- Select a Networking Device3.2.5- Quiz

Interactive Activity (together)

Packet Tracer LabView MAC address tables

Draw network from MAC address table

INTERNETWORK DEVICES

3.3

CONNECTING NETWORKS Each network has a unique set of IP

addresses

To connect different networks, you need a routerWhat layer do routers work at?

3- Network Layer

What addresses do routers read?

ROUTERS Connects different

networks

Reads destination IP addressesDirects packets to

networksDoesn’t care about

specific PC’s

ROUTERS Have one or more network interfaces

Has a table of networks & which interfaces for data to go out to get to those networksRouting table

Usually at the end of your networkBut can be found throughout the inside of

your network

SAMPLE NETWORK 1

SAMPLE NETWORK 2

FIREWALLS Protect network from unauthorized

accessDecides what can enter/leave networkCan check packets for source/dest. address

Hardware FirewallA device or integrated in a routerPlaced between your network & Internet

Still use PC firewall for extra security

LAYER 3 SWITCH Combines functions of a switch & router

Switch that also looks at the destination IP

COMMUNICATE WITHINYOUR NETWORK

COMMUNICATE WITHINYOUR NETWORK- ARP REQUEST

To find the MAC address of a device within your network…ARP request sent as a broadcast

DOES NOT GO OUTSIDE A NETWORK Includes the IP of the destinationEvery NIC looks at it; only one with that IP

will respond with its MAC address

COMMUNICATE OUTSIDE OF YOUR NETWORK If destination IP is outside of network, it

gets sent to the default gateway addressRouter port to get out of the network

PC 1192.168.1.110AA-AA-AA-AA-AA-AA

PC 2192.168.1.111BB-BB-BB-BB-BB-BB

FTP Server192.168.1.9CC-CC-CC-CC-CC-CC

R1192.168.1.111-11-11-11-11-11

R2172.16.1.9922-22-22-22-22-22

Web Server172.16.1.99AB-CD-EF-12-34-56

MAC & IP- TO OTHER NETWORKS Destination IP NEVER changes! Source & Destination MAC changes at

each router interface

COMMUNICATE OUTSIDE YOUR NETWORK- PROXY ARP You don’t know the destination MAC

ARP can’t be sent outside of the network The DG’s MAC address is substituted

ACTIVITY TestOut

3.3.3 Select a Router Lab3.3.4 Quiz

REVIEW- 4Q What addresses do you need to

communicate?Source & Destination IP and MAC

What specific addresses do routers read?Destination IP

To communicate outside of your network, each PC needs this address configured.Default gateway

What is the default gateway?Router port you connect to (way out of your

network)

REVIEW- 3Q When communicating within your

network segment, how does a device find the destination MAC?ARP request

What device inspects packets and protects the network from unauthorized access?Firewall

What device combines layer 2 & 3 functionality?Layer 3 switch

NETWORKING DEVICES

Chapter 3