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 do you connect to a wired network?  NIC  How 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  1 st 24 bits OUI; 2 nd 24 bits serial #

 Written as 0x  0xA4

 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  Dest. MAC will begin with E

 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 1 st ____ bytes. 3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 3SOURCE IP: DESTINATION IP: DATA LAYER 2 SOURCE MAC: AAA DEST. MAC: SOURCE IP: DEST. IP: 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 is an ARP request sent?  Broadcast  Who replies to the ARP request?  Only one with matching dest. IP

 Windows  Arp –a

 TestOut  Select & Install a Network Adapter  Connect a Media Converter  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.  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

 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  Install a Hub  Select a Networking Device  Quiz  Interactive Activity (together) Interactive Activity (together)  Packet 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 AA-AA-AA-AA-AA- AA PC BB-BB-BB-BB-BB- BB FTP Server CC-CC-CC-CC-CC- CC R R Web Server AB-CD-EF

 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  Select a Router Lab  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