Chapter 3 Upon completion of this chapter you

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 � Both NIC 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 GBIC �Small sized; 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 � 48 -bits into NIC hardware / 12 hex digits / 6 bytes � 1 st 24 bits OUI; 2 nd 24 bits serial #

� Written as 0 x � 0 x. A 4 � Ipconfig /all

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

� How � 48 many bits in a MAC address? bits � How many hex digits? � 12 � The first 6 hex digits are what? �The � The OUI would then be the 1 st ____ 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:

� Finds destination MAC 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 � How MAC is an ARP request sent? �Broadcast � Who replies to the ARP request? �Only one with matching dest. IP

� Windows �Arp –a

� Test. Out � 3. 1. 3 - Select & Install a Network Adapter � 3. 1. 4 - Connect a Media Converter � 3. 1. 5 - Practice Questions (10) � Lab �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

� Allows wireless devices to connect to wired network �Uses � Like radio waves 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

� 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 � What layer does a switch work at? � Layer �A 1 2 switch builds & maintains what? � MAC address table

� Test. Out � 3. 2. 3 - Install a Hub � 3. 2. 4 - Select a Networking Device � 3. 2. 5 - Practice Questions (5) � Interactive � Packet �View � Draw Activity (together) Tracer Lab MAC address tables 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 � Usually �But table at the end of your network 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 �Switch functions of a switch & router 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 PC 1 192. 168. 1. 110 AA-AA-AAAA port to get out of the network R 1 192. 168. 1. 1 11 -11 -11 -11 R 2 172. 16. 1. 99 22 -22 -2222 Web Server 172. 16. 1. 99 AB-CD-EF-12 -3456 PC 2 192. 168. 1. 111 BB-BB-BBBB FTP Server 192. 168. 1. 9 CC-CC-CCCC

� Destination IP NEVER changes! � Source & Destination MAC changes at each router interface

� You don’t know the destination MAC �ARP � The can’t be sent outside of the network DG’s MAC address is substituted

� Test. Out � 3. 3. 3 Select a Router Lab � 3. 3. 4 Practice Questions (5)

� What addresses do you need to communicate? �Source � What & Destination IP and MAC specific addresses do routers read? �Destination IP � To communicate outside of your network, each PC needs this address configured. �Default � What gateway 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