Chapter 3 - Page 1
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
IP ADDRESSING&SUBNETTING
Chapter 3 - Page 2
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
TOPICS
•Numbering Systems
•What is IP Addressing?
–The Hierarchical IP Addressing Scheme
–Additional Classes of Networks
–Who Assigns Network Addresses?
•Subnetting a Network
–Implementing Subnetting
–How to Implement Subnetting
–Subnet Masks
–Can This Be Make Easier?
Chapter 3 - Page 3
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
NUMBERING SYSTEMS
•Decimal – base 10
–Digits 0-9
–Example: 163
•Binary – base 2
–Digits 0-1
–Example: 1010 0011
•Hexadecimal – base 16
–Digits 0-9, a-f
–Example: a3
Chapter 3 - Page 4
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
DECIMAL NUMBERING SYSTEM
•Each position in a Decimal number represents a value
•Decimal digits – 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9
163
100
10
1
1-100
6 - 10s
3 - 1s
Chapter 3 - Page 5
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
BINARY NUMBERING SYSTEM
•Each position in a Binary Number represents a value
•Binary Digits – 1 and 0
1 0 1 0 0 0 1 1
128
1
64
32
16
8
4
2
128 +
32 +
2 +
1 =
Chapter 3 - Page 6
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CONVERT BINARY TO DECIMAL
•To Convert:
–Identify the place holder value
–Add all the values
1 0 1 0 0 0 1 1
128
1
64
32
16
8
4
2
1-128
1-32
1-2
1-1
128 + 32 + 2 + 1 = 163
Chapter 3 - Page 7
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CONVERT DECIMAL TO BINARY
163
-128
35
128
64
32
16
8
4
2
1
Chapter 3 - Page 8
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CONVERSION EXERCISES
Convert the following decimal numbers to binary
128
64
32
16
8
4
2
1
11
45
72
168
195
234
255
Convert the following binary numbers to decimal
Chapter 3 - Page 9
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CONVERSION SHORTCUT CHART
IP ADDRESSING SCHEME
•Addresses are fixed length of four octets (32-bits)
–An address begins with a network number
–An address ends with a local address (host/node number)
•There are three methods for depicting an IP address
–Dotted-decimal – 130.57.30.56
–Binary – 10000010.00111001.00011110.00111000
–Hexadecimal – 82 39 1E 38
All of these examples represent the same IP address
Chapter 3 - Page 10
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
IP ADDRESS CLASSES
Address
Class
Leading
Bit Pattern
128 | 64 | 32
Decimal
Range
(1st Octet)
Address
Template
Number
Of Networks
Hosts
Per Network
2^ Host Bits-2
A
0
1 – 126
B
10
128 – 191
C
110
192 - 223
CLASS A IP ADDRESS
•Class A: Net.Node.Node.Host
•The first bit of the first octet is always 0
•Decimal range of first byte: 1-126
•Note: Network number 127 is reserved for diagnostics
•Maximum networks: 126
•Maximum nodes per network: 16,777,216
0
Network ID
Host ID
Chapter 3 - Page 11
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CLASS B IP ADDRESS
•Class B: Net.Net.Node.Host
•The first two bits of the first octet are always 10
•Decimal range of first byte: 128-191
•Maximum networks: 16,384
•Maximum nodes per network: 65,534
1
0
Network ID
Host ID
CLASS C IP ADDRESS
1
1
0
Network ID
Host ID
•Class C: Net.Net.Net.Host
•The first three bits of the first octet are always 110
•Decimal range of first byte: 192-223
•Maximum networks: 2,097,152
•Maximum nodes per network: 254
NOTE: Class D 224 – 239 – Used for multicast
Class E 240 – 255 – Used for research purposes
Chapter 3 - Page 12
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
ADDRESSING GUIDELINES
•Network ID cannot be 127
–127 is reserved for loop-back diagnostics
–Ping 127.0.0.1 to test protocol installation
•Network ID cannot be all 1s or all 0s
–All 1s indicates “Broadcast”
–All 0s indicates “Any Address”
•Host IDs cannot be all 1s or all 0s
–All 1s indicates “Network Broadcast”
–All 0s indicates “The network only…”
•Private IP address (Private Internets)
–Used for internal IP addressing
–Will never be used on internet
– 10.0.0.0 – 10.255.255.255
– 172.16.0.0 – 172.31.255.255
–192.168.0.0 – 192.168.255.255
•Class D Multicast
–224 – 239
•Class E Experimental or Scientific purposes
–240 - 247
Chapter 3 - Page 13
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
IP ADDRESSING EXERCISE
IP Address
Class
Network ID
Host ID
10.226.30.8
100.100.3.2
150.50.5.145
201.2.10.25
168.16.30.98
126.63.120.135
ETHERNET INTERFACE SETUP
207.201.1.0
P2R1
P2R3
P2R2
e0
s1
s0
e0
s1
s0
e0
s1
s0
P1R1
P1R3
P1R2
e0
s1
s0
e0
s1
s0
e0
s1
s0
207.201.2.0
207.201.3.0
Chapter 3 - Page 14
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
•Divide a large network into smaller logical networks connected together by routers
•Uses bits from the host (node) portion of the address to create a subnet address
•Benefits of subnetting:
–Reduced network traffic
–Optimized network performance
–Facilitate spanning of large geographical distances
SUBNETTING A NETWORK
Chapter 3 - Page 15
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
SUBNET MASKS
•Distinguishes the network address from the host address
–1’s represent the positions in the IP address that refer to the network or subnet address
–0’s represent the positions in the IP address that refer to the host address
–When coming from host end, remember to jump over one for subnet mask
255 . 255 . 0 . 0
11111111 11111111 00000000 00000000
Network
Mask
Host
Mask
Chapter 3 - Page 16
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
DEFAULT SUBNET MASKS
•Networks that have not been divided into subnets will use the default network maskfor that class of address
–Class A255.0.0.0
(binary)11111111.00000000.00000000.00000000
–Class B255.255.0.0
(binary)11111111.11111111.00000000.00000000
–Class C255.255.255.0
(binary)11111111. 11111111. 11111111.00000000
DEFAULT SUBNET MASKS
# of Subnets = 2N – 2
# of Hosts/subnetwork = 2H – 2
N=number of bits used for subnetting
H = number of bits used for the host address
Chapter 3 - Page 17
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
CUSTOM SUBNET MASKS
•Maximum number of subnets
2 (number of masked bits) – 224 = (16) – 2 = 14
•Maximum number of hosts
2 (number of unmasked bits) –2212 (4096) – 2 = 4094
255 . 255 . 240 . 0
11111111 11111111 11110000 00000000
Network
Mask
Host
Mask
Subnet
Mask
Chapter 3 - Page 18
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
HOW TO IMPLEMENT SUBNETTING
•An IP address can be given a subnet address by reducing the number bits designatedas the host portion of the address
255 . 255 . 240 . 0
11111111 11111111 11110000 00000000
Network
Mask
Host
Mask
Subnet
Mask
Subnet Mask
150 . 19 . 16 . 15
Subnet
Address
10010110 00010011 00010000 00000001
Network Address Host Address
Class B Network Address
HOW TO IMPLEMENT SUBNETTING
•Determine the number of required Network Ids
–One for each subnet
–One for each Wide Area Network connection
150.50.0.0
255.255.0.0
Chapter 3 - Page 19
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
NETWORK ADDRESSING
•Determine the number of required host Ids per subnet
–One for each TCP/IP host
–One for each router interface
150.50.0.0
255.255.0.0
NETWORK ADDRESSING
•One subnet mask for your entire network
•A unique subnet ID for each physical segment
•A range of host IDs for each subnet
Subnet A
Host
Host
Host
Host
Subnet C
Subnet B
Network 150.19.0.0
Subnet Mask 255.255.0.0
Chapter 3 - Page 20
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
IMPLEMENTING SUBNETTING
The subnet mask will determine how many bits are used to create new subnetworks and
how many bits are available for use as Host Ids
•Requirements Analysis
–Determine number of subnets required
–Determine number of hosts on largest subnet
•Compute Subnet Mask
•Determine Subnet Ranges
•Determine Assignable Host Addresses
Subnet A
150.19.96.0
Host
Host
Host
Subnet C
150.19.64.0
Subnet B
150.19.32.0
Network 150.19.0.0
Subnet Mask 255.255.224.0
150.19.64.16
150.19.96.6
Host
150.19.96.5
150.19.64.125
SUBNET PROCEDURES
Chapter 3 - Page 21
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
SUBNET REQUIREMENTS ANALYSIS
• How many subnets are required?
• How many hosts per subnet?
14 PC’s
12 PC’s
10 VAC’s
2 Main-frames
•Add 2 subnet and host fields. These are for the reserved addresses (all 0s and all 1s)
–5 + 2 = 7 Subnet
–15 + 2 = 17 Hosts
•Round Subnet and Host up to next power of 2
–128 64 32 16 8 4 2
–Subnets = 7 rounded up to 23 (8) –2 = 6 subnets
–Hosts = 23 rounded up to 25 (32) – 2 = 30 Subnets
COMPUTE SUBNET MASKS
Chapter 3 - Page 22
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
COMPUTE SUBNET MASK
•23 – the 3 represents the number subnet bits which are masked and are indicated with1’s
•25 – the 5 represents the number of host bits which are not masked and are indicatedwith 0’s
•The appropriate Subnet Mask is:
128 64 32 16 8 4 2 1
1 1 1 0 0 0 0 0 = 224
23
25
Net ID
Host ID
DETERMINE SUBNETS
Determine the range of available subnets
Chapter 3 - Page 23
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
SUBNET EXAMPLE – CLASS C
•Valid hosts in subnet 255.255.255.224
Mask = 111 0 0000
Chapter 3 - Page 24
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
SUBNET REQUIREMENTS ANALYSIS
58 PC’s, 2 Servers
34 PC’s, 1 Server
• How many subnets are required?
•How many hosts per subnet?
Chapter 3 - Page 25
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
SUBNET PROCEDURES
•Requirements Analysis
–Determine number of subnets required: ______________
–Determine number of hosts on largest subnet: ______________
•Compute Subnet Mask: ________________________
–Subnet multiple: ______________
–Hosts/subnet: _______________
•Subnet Net IDs Host Address Range
_______________ ___________________________
_______________ ___________________________
_______________ ___________________________
_______________ ___________________________
SUBNETTING A NETWORK ADDRESS
150 . 50 . 1 . 0
P2R1
P2R3
P2R2
e0
s1
s0
e0
s1
s0
e0
s1
s0
P1R1
P1R3
P1R2
e0
s1
s0
e0
s1
s0
e0
s1
s0
Assigned by Pod 2
Assigned by Pod 1
150.50.1.2
200.20.2.0
100.10.1.0
150.50.1.3
Chapter 3 - Page 26
Infogem Institute of Technology CCNA Course
IP Addressing & Subnetting
Lab – Page 158Review QuestionsPage 160
Homework: - Written Lab
- Review3-10 & 13-20