TCP IP ETHERNET IP ADDRESSING

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TCP IP ETHERNET IP ADDRESSING Powered By Docstoc
					TCP/IP/ETHERNET, IP
   ADDRESSING
   Nilay Saha, DGM(C)
                IP Addressing
•   32 bit unique address for each active host.
•   Hierarchical: Network part plus Host part.
•   Length of each part is variable.
•   Address scheme:
      * 32- bit word divided into 4 groups of 8-
      bit octets.
      * Each octet is converted into decimal.
            IP Addressing
Example:
32-bit binary IP address:
  10111100101100111101110011001000
Place dots after each octet:
  10111100.10110011.11011100.11001000
Convert each octet into decimal:
  140.179.220.200 dotted decimal format.
Finding the classes in binary and dotted-decimal notation
 IP Addressing: Address Classes

• Different network sizes in terms of the no.
  of hosts.
• 5- address classes.
  Class   Starts With   Net ID             Host ID           #Net        #Host
  A       0             7-bit              24-bit            126         16,777,214

  B       10            14-bit             16-bit            16,384      65,534

  C       110           21-bit             8-bit             2,097,152   254

  D       1110          28-bit             IP Multicast Address

  E       11110         Reserved for future use




                                                                                  Back
       Example

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

Solution
a. The first bit is 0. This is a class A address.
b. The first 2 bits are 1; the third bit is 0. This is a class C
    address.
c. The first byte is 14; the class is A.
d. The first byte is 252; the class is E.
      IP Address: Subnet Mask
• The network & host parts of IP address separated by
  the subnet mask.
• Subnet mask is 32-bit binary number (eg
  11111111.11111111.11111111.00000000
  or 255.255.255.0 in dotted decimal format).
• 1’s in subnet mask represent network bits in ip
  address.
• 0’s in subnet mask represent host bits in ip address.
• Network address: Set host bits in ip address to zero.
• Broadcast address: Set host bits in ip address to 1.
Default masks for classful addressing
         Private IP Networks

• Used for making internal networks behind a
  router performing NAT or proxy server.
• Internet does not forward packets with these
  addresses.
• Unique within the organization, but not
  globally. Not routed in public domain.
Addresses for private networks
          IP Address : Subnet
• To derive two or more smaller networks from a
  single large network by including suitable number
  of higher order host bits in the network part.

• Advantages:
  a) Preservation of address space.
  b) Control network traffic.
  c) Security.
  d) Different physical media.
                                                Expl
         IP Addressing: Supernetting
• Classful system wastes address space.
• Supernetting done to circumvent the crisis.
• Several networks combined to form a
  supernetwork.
e.g. 4 class C addresses for 4 networks:
     192.60.128.0 (11000000.00111100.10000000.00000000) Class C Subnet Address
     192.60.129.0 (11000000.00111100.10000001.00000000) Class C Subnet Address
     192.60.130.0 (11000000.00111100.10000010.00000000) Class C Subnet Address
     192.60.131.0 (11000000.00111100.10000011.00000000) Class C Subnet Address
---------------------------------------------------------------------------------------------------------------------
     192.60.128.0 (11000000.00111100.10000000.00000000) Supernetted address
     255.255.252.0(11111111.11111111.11111100.00000000) Subnet Mask
     192.60.131.255 (11000000.00111100.10000011.11111111) Broadcast Address.
IP Addressing: CIDR Advantages
•   Efficient routing.
•   Decrease in routing table size.
•   Less memory to store.
•   Less loss probability during periodic updates.
•   Simplified design – easy troubleshooting.
Thank You !

				
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posted:11/4/2011
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