Transcript Network devices

Chapter 3
 Upon
completion of this chapter, you should
be able to:


Select and install network cards to meet network
connection requirements
Connect a media converter
Select and install appropriate networking
hardware
 Select the appropriate device to connect two
networks
 Identify networking and internetworking
devices by name or sight (adapters, hubs,
bridges, routers, switches)

3.1
 How

NIC
 How

do you connect to a wired network?
do you connect to a wireless network?
WLAN NIC
 Both
connect devices to the network
 Converts
digital to
analog/analog to
digital

Modulate/demodulate
 Connects
you to the
Internet through the
ISP
 Cable
modem, DSL
modem, Dial-up
modem
 SFP

Used on routers & switches to convert media
type
 GBIC

Larger sized
 Layer
1 device
 Converts signal type

Ethernet to fiber, for example
 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 #
 Written

0xA4
as 0x
 One
to one communication
 One
to all in a network
 Dest. MAC address will be all F’s
 DHCP & ARP use broadcasts
 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
 How

48 bits
 How

first 6 hex digits are what?
The OUI
 The

many hex digits?
12
 The

many bits in a MAC address?
OUI would then be the 1st ____ bytes.
3
 What
important addresses are encapsulated
into a frame?

Source & destination MAC
 What
kind of message gets sent from one PC
to a group within a network?

Multicast
 Identify
each as unicast, multicast, or
broadcast:
 Works
within your network
LAYER 3 SOURCE IP:
192.168.1.1
LAYER
2
SOURCE
MAC:
AAA
DEST.
MAC:
DESTINATION IP:
192.168.1.2
SOURCE IP:
192.168.1.1
DATA
DEST. IP:
192.168.1.2
DATA
 Each


device has an ARP table of IP/MACs
Added from communication
Added from ARP requests
 Without
a dest. MAC, an ARP request is sent
 ARP request is all F’s in what field?

Destination MAC
 How

Broadcast
 Who

is an ARP request sent?
replies to the ARP request?
Only one with matching dest. IP
 Windows

Arp –a
 TestOut



3.1.3- Select & Install a Network Adapter
3.1.4- Connect a Media Converter
3.1.5- Quiz
 Labs

Handout- Fill out MAC address Chart
3.2
 Simple
Layer 1 device
 Extends network
 Data goes in one port & out all
others


No thinking involved
Relies on devices to decide on
message
 Creates
more network traffic
 Not used anymore
 Separates
segments
 Layer 2 device
 Looks at dest. MAC to decide if data should
cross or not
 Less traffic
 Converts
wired to wireless
 Layer
2 device
 Reads dest. MAC
 Data enters a port, then
sent out the one port


Smarter than bridge
Knows MAC address on
each port
 MAC



Address Table
MAC addresses added
Packaged into a FRAME
Sent to exact port

This basic device extends the network, as it does
not segment it.


Which current networking devices receives data
and sends it out a single port based on MAC
addresses?


Layer 1
What layer does a switch work at?


Switch
What layer does a hub work at?


Hub
Layer 2
A switch builds & maintains what?

MAC address table
 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
 TestOut



3.2.3- Install a Hub
3.2.4- Select a Networking Device
3.2.5- Quiz
 Interactive
 Packet

Activity (together)
Tracer Lab
View MAC address tables
 Draw
network from MAC address table
3.3
 Each
network has a unique set of IP
addresses
 To
connect different networks, you need a
router

What layer do routers work at?


3- Network Layer
What addresses do routers read?
 Connects
different
networks
 Reads
destination
IP addresses


Directs packets to
networks
Doesn’t care about
specific PC’s
 Have
one or more network interfaces
 Has
a table of networks & which interfaces
for data to go out to get to those networks

Routing table
 Usually

at the end of your network
But can be found throughout the inside of your
network
 Protect


network from unauthorized access
Decides what can enter/leave network
Can check packets for source/dest. address
 Hardware


Firewall
A device or integrated in a router
Placed between your network & Internet
 Still
use PC firewall for extra security
 Combines

functions of a switch & router
Switch that also looks at the destination IP
 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 destination
Every NIC looks at it; only one with that IP will
respond with its MAC address
 If
destination IP is outside of network, it gets
sent to the default gateway address

Router port to get out of the network
PC 1
192.168.1.110
AA-AA-AA-AA-AAAA
R1
192.168.1.1
11-11-11-11-11-11
R2
172.16.1.99
22-22-22-22-2222
Web Server
172.16.1.99
AB-CD-EF-1234-56
PC 2
192.168.1.111
BB-BB-BB-BB-BBBB
FTP Server
192.168.1.9
CC-CC-CC-CC-CCCC
 Destination
IP NEVER changes!
 Source & Destination MAC changes at each
router interface
 You

don’t know the destination MAC
ARP can’t be sent outside of the network
 The
DG’s MAC address is substituted
 TestOut


3.3.3 Select a Router Lab
3.3.4 Quiz
 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)
 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
Chapter 3