Network Addressing
Networking for Home and Small Businesses – Chapter 5
ITE PC v4.0
Chapter 1
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1
Purpose of an IP Address
 A logical network address that identifies a host
 A host (end-user) must have a NIC card
– workstations
– servers
– printers
– router interface
 Each packet will contain a source and destination IP
address
Packet Tracer Activity Cisco I 5.1.1.2
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IP addresses
 IP Version 4
– most common form of IP addresses
 32 binary digits
 4 octets
 Dotted decimal notation
 Over 4 billion possible IP addresses
 IP Version 6 will soon become the standard to ensure we
have enough addresses to use
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Binary Numbers
 The IP address is made up of binary numbers (1 or 0)
 Humans must be able to talk computer language to
send data
 We do this by converting our numbering system
(Base 10 to binary)
 Let’s try some . . .
Convert 140 to binary
Convert 10 to binary
Convert 11010111 to Base 10
Convert 11111110 to Base 10
Time to play a game -- Online Activity 5.1.2.3
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Parts of an IP Address
 Hierarchical
– made up of 2 parts
• network
• host(Id’s the specific device)
– determined by IP class
 Similar to your phone number
– Area code = network
– phone number = host(specific location)
 Go to page 5.1.2.3 to see how network addresses are
used
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Purpose of the Subnet Mask
 Helps identify the network
 Boolean math or “ANDING”
 What happens if both source and destination IP are on
the same network?? What happens if they are not??
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Copy Into Your Notes
 On page 5.2.1.1 copy the chart of IP Address Classes
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Types of IP Addresses
 Class A
– Range 1-127
– N.H.H.H
– First bit in octet will be a 0
– Default subnet mask
• 255.0.0.0
– can create over 16 million host addresses – the most host
addresses available in networking
• 224 – 2 = 16,777,214 to be exact
• why do you subtract 2???
– Used in large organizations
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Types of IP Addresses
 Class B
– Range 128-191
– N.N.H.H
– 16 bits for network and 16 bits for host
– Default subnet mask
• 255.255.0.0
– can create over 65,000 host addresses
• 216 – 2 = 65,534 to be exact
– Used in medium-sized organizations
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Types of IP Addresses
 Class C
– Range 192 -223
– N.N.N.H
– First two bits in octet will be a 11
– Default subnet mask
• 255.255.255.0
– can create 254 useable hosts
• 28 – 2 = 254 to be exact
– Used in small organizations
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Types of IP Addresses
 Class D
– Range 224 - 239
– used for multicasting
– not for commercial use
 Class E
– Range 240 - 255
– reserved for experimental use
– not for commercial use
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Activity
 On page 5.2.1.2 use the activity to test your skills
looking at IP addresses and determining their default
subnet mask.
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Private IP Addresses
 Solves the issue of a finite number of available public IP addresses
 Allows hosts to communicate locally without each device needing a
public IP address
 Not routed on the Internet; blocked by the ISP router
 Private address ranges
 Class A – 10.0.0.0
 Class B – 172.16.0.0 – 172.31.0.0
 Class C – 192.168.0.0 – 192.168.255.0
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Activity
 On page 5.2.2.3 can you determine which addresses
are private and need to be blocked and which
addresses are public and need to be passed through
the router?
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Unicast Address
 Most common type of address
 Intended for a specific host, has a specific IP Address
 Talking to a person on the phone is an example
 Must have both destination IP and MAC in the header
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Broadcast Address
 All ones in the host portion of the IP address
– Class C address: 204.33.4.0 (N.N.N.H)
– Broadcast address: 204.33.4.255
 MAC address all Fs
– FF-FF-FF-FF-FF-FF
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Multicast Address
 Send packet to a group of devices
 Must use multicast address range
 Range 224.0.0.0 – 239.255.255.255
 Used for remote gaming
 Destination MAC address begins with:
– 01-00-5E
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Activity
 On page 5.2.3.4 can you determine who the message
will go to based on the address. Is the message a unicast, multicast or broadcast. Think back to how we
identified these items on the last few slides.
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Using Static IP Addressing
 Manually configured by the network administrator
 Advantages
– useful for printers, servers, etc
– increased control of resources (security)
 Disadvantages
– time consuming
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Using Dynamic IP Addressing
 Automatic assignment of IP addresses
 Useful if frequent change in users (wireless hotspot)
 Uses DHCP (Dynamic Host Configuration Protocol)
server
 IP addresses leased for a period of time
– if host is removed from the network (turned off), the IP
address goes back into the pool of IP address
 Preferred method for large networks
– reduces the burden of network support
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DHCP
 DHCP dynamically assigns an IP address to a host
 A PC obtains its IP address from a DHCP server. If the
PC is taken off the network for repair, what happens to
the IP address configuration?
The addresses is returned to the pool for reuse when the lease
expires.
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Configuring DHCP
 If host is configured as DHCP client, it will not have a
– IP address
– Subnet Mask
– Default Gateway
 Clients send a DHCP Discover Message
–The message comes from a client seeking an IP address
–The destination IP address of the message is 255.255.255.255.
– All hosts receive the message, but only a DHCP server replies
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Obtaining an IP address from DHCP server
 Multifunction device (Linksys Router) provides services
to clients (SOHO network)
 If a host connects to a Linksys integrated router that is
also a DHCP server and receives an IP address from it.
Which address does the host need to access the ISP
and the Internet?
- Internal IP address of the integrated router that connects to the
local network
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Packet Tracer
 Configure a DHCP Server within a network. Open
packet tracer and open the file Cisco I 5.3.3.3 and
follow the instructions for successful completion.
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Purpose of a Gateway
 Used by the router to provide the path through which hosts on one
network can communicate with hosts on a different network
 Default gateway address
– IP address of the router interface
 If DHCP is being used
– the DHCP server will automatically send the correct IP interface to
the host to use as the default gateway
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Address Assignment
 ISR (Integrated Services Router)
 Default IP address
– Class C Private Address
– Configured on router interface
 Internal hosts must be assigned addresses within the
same network
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Address Management
 Direct Connection
– direct connection from PC to ISP through modem
– public address assigned to the host
 Connection through Integrated Router
– more than one host needs access to the Internet
– modem connected to ISR
 Connection through Gateway Device
– ISR and modem in one unit
– connect directly to ISP
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Using NAT with a Home or Small Business
Network
 NAT (Network Address Translation)
 Packets that stay local are not translated using NAT
 Only packets destined for different network use NAT
 NAT Prevents external users from detecting the IP
addresses used on a network
 With NAT, a private (local) source IP address is
translated to a public (global) address. The process is
reversed for incoming packets.
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 Refer to the graphic. NAT and DHCP are installed on
the Linksys integrated router. Which IP address is most
likely to be assigned to the local computer, Host1?
10.0.0.17
128.107.1.2
192.135.250.0
209.165.201.1
 Why would this address be chosen? 10.0.0.17 because
it is the only private IP address within the range.
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Chapter Quiz
 Take the chapter 5 quiz found on page 5.6.1.1 to test
your knowledge over IP addresses and the uses of the
address in most networks around the world.
© 2007 Cisco Systems, Inc. All rights reserved.
Cisco Public
© 2007 Cisco Systems, Inc. All rights reserved.
Cisco Public