Download IP Address - Department of Computer Engineering

Subnet Design and IP Addressing
Asst. Prof. Chaiporn Jaikaeo, Ph.D.
[email protected]
http://www.cpe.ku.ac.th/~cpj
Computer Engineering Department
Kasetsart University, Bangkok, Thailand
Adapted from the notes by Lami Kaya and lecture slides from Anan Phonphoem
© 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
© The McGraw-Hill Companies, Inc.
Outline


IP Address
CIDR
2
Internet Addresses




Internet protocol must hide physical network
details
Application doesn’t care about physical
Need address to communicate without knowing
underlying network of each other
Address should be



Unique
Uniform addressing scheme
Independent to physical networks
3
Internet Model Revisited
router
sender
router
receiver
Application
Application
Transport
Transport
Network
Network
Network
Network
Data Link
D.L.
D.L.
D.L.
D.L.
Data Link
Physical
P.L.
P.L.
P.L.
P.L.
Physical
Transmission medium
4
Network Layer Revisited
Data
1.1 5.7
1.1
1.1, 1.2, 6.1, 5.7, ... are logical addresses
1.2
Network 1
R1
6.1
6.6
Network 6
6.3
R3
R2
5.2
Router
3.3
Network 5
5.7
Network 3
3.8
IP Addressing Scheme




Unique 32-bit binary number (4 bytes)
Assigned to each network interface
Used for identify host and communicate
Two-level hierarchical address



prefix (network ID) – assigned globally
suffix (Node/host ID) – assigned locally
Address must be coordinated globally
Network ID
Host ID
Prefix
Suffix
6
Internet Classes

Traditional addressing scheme
Classful Addressing
7
IP Address Class
8
IP Address Class
B
25%
A
50%
C
12.5%
D
E
9
No. of Network / Host
10
IP address in decimal notation
0
x
0
x
27 2 6
0
0
1
0
x
x
x
x
25
24
23
22
8+
1
x
1
x
21 20
2 + 1 = 11
11
Example: IP address practice
#1
10011110 01101100 00100000 00010010 158.108.32.18
#2
00001100 00011001 00000001 00010111 12.25.1.23
11001001 01111101#310001001 11010101 201.125.137.213
12
Class ranges of Internet Address
13
IP address in decimal notation
www.ku.ac.th
14
Class A example
15
Class C example
16
Network Address
17
Sample internet
Network and
Host addresses
18
A Network with Two Levels of
Hierarchy
19
A Network with Three Levels of
Hierarchy

"Subnetting" the given network
20
Addresses with and without
Subnetting
21
Subnet Masks
22
Example: Subnet Mask

Find the network ID of each of the following
hosts with specified subnet masks:




IP:
IP:
IP:
IP:
192.168.5.3
172.130.10.20
192.168.10.5
158.108.228.178
Mask: 255.255.255.0
Mask: 255.255.255.0
Mask: 255.255.255.128
Mask: 255.255.240.0
23
Default (Classful) Mask
Class
In Binary
A
11111111 00000000
00000000 00000000
B
11111111 11111111
C
11111111 111111111 11111111 00000000
00000000 00000000
"CIDR"
notation
In DottedDecimal
Using
Slash
255.0.0.0
/8
255.255.0.0
/16
255.255.255.0
/24
24
Outline


IP Address
CIDR
25
Classless Inter-Domain Routing


CIDR - Classless Inter-Domain Routing
Introduced in 1993 to replace classful
network design in the Internet



To slow the growth of routing tables on routers
To help slow the rapid exhaustion of IPv4
addresses
No longer restrict network addresses as one
or more 8-bit groups
26
CIDR Notation

Specifies mask with prefix size


More convenient than binary representation
Example:


NetID: 158.108.0.0 Subnet Mask: 255.255.0.0
CIDR notation: 158.108.0.0/16
27
CIDR Host Address
28
Example: CIDR Notation

Convert mask to corresponding prefix size




255.0.0.0
255.192.0.0
255.255.255.252
Convert prefix size to corresponding mask





/8
/12
/16
/20
/28
29
Example: CIDR Notation

Find the network ID of each of the following
hosts with specified prefix size:


IP: 192.168.5.3/24
IP: 172.130.10.20/18
30
Special IP Addresses

Network Address


Directed Broadcast Address




Broadcast to local network
all 1; e.g. 255.255.255.255
This computer Address


Broadcast to a specified network
all hosts = 1; e.g. 158.108.255.255/16
Limited Broadcast Address


all hosts = 0; e.g. 158.108.0.0/16
all 0; e.g. 0.0.0.0
Loopback Address

127.0.0.0/8  127.x.x.x
31
Loopback Addresses

Allow programmers to test the program logic
quickly


During loopback testing no packets ever
leave a computer


without needing two computers and without
sending packets across a network
the IP software forwards packets from one
application to another
The loopback address never appears in a
packet traveling across a network
32
Loopback Addresses
โปรเซส
โปรเซส A
Process
A
A
TCP/UDP
/
Process B
Outgoing packet from
Loopback to Process
127.0.0.1
IP
Loopback Interface
Data Link
Incoming packet
to Loopback Interface
Physical
Other Addresses
33
Directed Broadcast Address



Ending with 255
Use for sending to all nodes in class range
Class A broadcast:


Class B broadcast:


10.255.255.255
158.108.255.255
Class C broadcast:

202.100.15.255
34
Special IP Address
35
Example: Subnet Design

You are given an IP address block


You want to divide this block into subnets




12.6.8.0/24
Subnet A to serve 28 hosts
Subnet B to serve 40 hosts
Subnet C to serve 70 hosts
List the designed subnets with the following
information

(1) subnet ID, (2) mask, (3) first usable address,
(4) last usable address, (5) directed broadcast address
36
Example: Subnet Design

Design subnetting scheme
Original
/24 block
(256 addrs)
Subnet C
(70 hosts)
/25 block
(128 addrs)
Subnet A
(28 hosts)
/26 block
(64 addrs)
Subnet B
(40 hosts)
/26 block
(64 addrs)
37
Example: Subnet Design

Create summary table
Subnet SubNet ID
Subnet Mask
First Host IP
Last Host IP
Broadcast Addr
C
12.6.8.0
255.255.255.128
12.6.8.1
12.6.8.126
12.6.8.127
A
12.6.8.128
255.255.255.192
12.6.8.129
12.6.8.190
12.6.8.191
B
12.6.8.192
255.255.255.192
12.6.8.193
12.6.8.254
12.6.8.255
38