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Host to Host (Computer to Computer)
Usually computers communicate through internet
Logical Addressing
or IP address in TCP/IP protocol suite IPv4 and IPv6
IPv4 addresses are unique
The address space of IPv4 isor , , ,
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Dotted-decimal notation
Base 256 : IP Addresses
, ,
concept of classes
,
is divided into five classes:
, , , , an
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Finding the classes in binary and
otte - ec ma notat on
Netid
Hostid
Netid and Hostid concept does not apply to clases D and E
,
most of addresses were wasted and were notin use
Block in Class B is also too large
Block of Class C is robabl too small for many organizations
Class D: multicast ---- The internet authorities wron lpredicted a need for 268, 435, 456 groups. This never happened
Class E: were reserved for future use -----only few were used
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,
in blocks
The addresses in a block must be contiguous
e num er o a resses n a oc mus e
a power of 2 (1,2,4,8 ,)
e rs a ress mus e even y v s e y
the number of addresses
The above figure shows a block of addresses,
in both binary and dotted-decimal notation,
granted to a small business that needs 16
addresses
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We can see that the restrictions are applied to thisblock The addresses are contiguous
The number of addresses is a power of 2 (16 = 24)
and the first address is divisible by 16
The first address, when converted to a decimal number, is, , , , , ,
,
addresses can be defined as:
. . .
in which x.y.z.t defines one of the addresses
and the /n defines the mask
The address and the /n notation
completely define the whole block
the first address
the last address
and the number of addresses
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- .
The binary representation of the given. . .
11001101 00010000 00100101 00100111
11001101 00010000 00100101 00100000
or
205.16.37.32.
- .
The binary representation of the given
. . .
11001101 00010000 00100101 00100111
11001101 00010000 00100101 00101111
or
205.16.37.47
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- .
23228= 16
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The first address can be found b ANDinthe given addresses with the mask. ANDinghere is done bit by bit. The result of ANDing
otherwise.
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The last address can be found by ORing the givenaddresses with the complement of the mask. ORing
here is done bit by bit. The result of ORing 2 bits is 0if both bits are 0s; the result is 1 otherwise. Thecomplement of a number is found by changing each1 to 0 and each 0 to 1
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The last address can be found by ORing the givenaddresses with the complement of the mask. ORinghere is done bit by bit. The result of ORing 2 bits is 0if both bits are 0s; the result is 1 otherwise. Thecomplement of a number is found by changing each1 to 0 and each 0 to 1
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complementing the mask, interpreting it as a
decimal number, and adding 1 to it
Network Address
Three level Hierarchy: Subnetting
block of addresses starting with
. . . .
subnets of 32, 16 and 16 addresses.
mask and each subnet must also have
.
Suppose mask for first, second and third
,
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Network AddressThree level Hierarchy: Subnetting
Then n1=27
n3 = 28
s means a we ave e mas s
27,28,28 with the organization mask
e ng
Network Address ContdThree level Hierarchy: Subnetting
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Network Address ContdThree level Hierarchy: Subnetting
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An ISP is granted a block of addresses starting with190.100.0.0/16 (65,536 addresses). The ISP needs todistribute these addresses to three groups ofcustomers as follows:a) The first group has 64 customers; each needs 256
addresses.
b) The second group has 128 customers; each needs 128addresses.
c) The third group has 128 customers; each needs 64addresses.
Design the subblocks and find out how manyaddresses are still available after these allocations.
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Address allocation and distribution
y an
addresses internally
and one address or small set of addresses
externally
Addresses for private networks reserved by internet authorities
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100,000 dialup Customers
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Network la er at the source router and destination
, ,
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colon notation:
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Position of IPv4 in TCP/IP protocol suite
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Transition strategies from IPv4 to
v
A station must run IPv4 and IPv6 simultaneously until all
the Internet uses IPv6.
be decided by DNS.
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Two computers using IPv6 want to communicate
And the packet must pass through a region that
uses IPv4.
The sender wants to use IPv6 but receiver doesnot understand IPV6
In this case, tunneling will not work. Therefore
IPv4 header.
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Simplified forwarding module in classless address
Configuration for Example
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Configuration for Example
out ng ta e or router
Hierarchical routing with ISPs
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