15361 ipv4 addresses

8/2/2019 15361 Ipv4 Addresses

1/30

Topics

What is an IP address ?

Types of IP addressing

Classes of IP address Networks & subnetworks

IP addresses and routing


2/30

What is an IP address?

IP (Internet Protocol) address device used by routers, to select best path

from source to destination, across networksand internetworks

network layer address, consisting ofNETWORK portion, and HOST portion

logical address,assigned in software by

network administrator part of a hierarchical numbering scheme -

unique, for reliable routing may be assigned to a host pc, or router port


3/30

Types of IP address

Static address

Dynamic address


4/30

Types of IP address

Static IP address

manually input by network administrator

manageable for small networks

requires careful checks to avoid duplication


5/30

Types of IP address

Dynamic IP address

examples - BOOTP, DHCP

assigned by server when host boots derived automatically from a range of

addresses

duration of lease negotiated, then address

released back to server


6/30

IPv4 ADDRESSES

1) An IPv4 address is 32 bits long.2) The IPv4 addresses are unique and universal.

Address SpaceAn address space is the total number of addresses

used by the protocol. If a protocol uses N bits to define

an address, the address space ispower(2,N) becauseeach bit can have two different values (0 or 1)

and N bits can have power(2,N) values.


7/30

Class A IP address

1st octet = network address, octets 2-4 =host address

1st bits of 1st octet set to 0

up to (2^24- 2) host addresses


8/30

The address space of IPv4 is power(2,32)or

4,294,967,296.


9/30

Binary Notation (Octet Notation)

01110101 10010101 00011101 00000010

Dotted-Decimal Notation

117.149.29.2


10/30

Example 19.1

Change the following IPv4 addresses from

binary notation to dotted-decimal notation.

a. 10000001 00001011 00001011 11101111

b. 11000001 10000011 00011011 11111111


11/30

We replace each group of 8 bits with its

equivalent decimal number (see Appendix B)

and add

dots for separation.

a. 129.11.11.239

b. 193.131.27.255


12/30


13/30

Solution

We replace each decimal number with its

binary equivalent (see Appendix B).

a. 01101111 00111000 00101101 01001110

b. 11011101 00100010 00000111 01010010


14/30


15/30

Classful Addressing

In classful addressing, the address space is

divided into five classes:

A, B, C, D, and E.

In classful addressing, a large part of theavailable addresses were wasted.


16/30

17

Addressing IPV4

Courtesy - From Fig. 19.10 Page 479, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

Network ID, Host ID

Class A 128 blocks (First Byte), 16,777,216 hosts

Class B 16,384 blocks (First & Second Byte), 65536 hosts

Class C 2,097,152 blocks (First, Second, Third byte), 256 hosts

Class D 1 block, Multicasting


17/30

18

Finding the Class

Courtesy - From Fig. 19.12 Page 480, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill


18/30

19

Netid and Hostid

Courtesy - From Fig. 19.13 Page 481, Data Communications and Networks, 3rd edition,Forouzan, McGrawHill


19/30

Example 19.4

Find the class of each address.

a. 00000001 00001011 00001011 11101111 b. 11000001 10000011 00011011 11111111

c. 14.23.120.8

d. 252.5.15.111


20/30

Solution

a. The first bit is O. This is a class A address.

b. The first 2 bits are 1; the third bit is O. Thisis a class C address.

c. The first byte is 14 (between 0 and 127); the

class is A.

d. The first byte is 252 (between 240 and 255);

the class is E.


21/30


22/30

November 29, 2004 Prof. Paul Lin 23

Masks

Courtesy - From Table 19.1 Page 489, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

Class In BinaryIn Dotted-

Decimal Using Slash

A 11111111 00000000 00000000 00000000 255.0.0.0 /8

B 11111111 11111111 00000000 00000000 255.255.0.0 /16

C 11111111 111111111 11111111 00000000 255.255.255.0 /24


23/30

Explain the Net id and Host id,mask of the

following IP addresses:(a)114.34.2.8

(b)19.20.21.5 (c)220.34.6.8?


24/30

So now it is clear that the subnet mask for theaddress 114.34.2.8 is 255.0.0.0The subnet mask for the address 19.20.21.5 is255.0.0.0

The subnet mask for the address 220.34.6.8 is255.255.255.0

So it is clear 114 is the network id and 34.2.8 is

the host address19 is the network id 20.21.5 is the host id220.34.6 is the network id and 8 is the host id


25/30


26/30

Mask

A better way to define a block of addresses is

to select any address in the block and the

mask. As we discussed before, a mask is a 32-

bit number in which the n leftmost bits

are Is and the 32 - n rightmost bits are Os.


27/30


28/30

Example 19.6

A block of addresses is granted to a small

organization. We know that one of the

addresses is

205.16.37.39/28. What is the first address in

the block?


29/30

Solution

The binary representation of the given

address is 11001101 00010000 00100101

00100 I 11. If we

set 32 - 28 rightmost bits to 0, we get

11001101 000100000100101 0010000 or

205.16.37.32.


30/30

Solution The binary representation of the given address is 11001101

000100000010010100100111. If we

set 32 - 28 rightmost bits to 1, we get 11001101 00010000

001001010010 1111 or 205.16.37.47. This is actually the block shown in Figure 19.3.

Number of Addresses The number of addresses in the blockis the difference between

the last and first address. It can easily be found using the

formula 232- n. The number of addresses in the block can be found by

using the formula 232- n

15361 ipv4 addresses

Documents