Sunday, 27 July 2014

Subnetting

IP Address: 
Internet Protocol address is a 32 bits address for a host in a TCP/IP network.


IP address Class: 
             Class A: 0.0.0.0 -------------- 127.255.255.255
             Class B: 128.0.0.0 -------------- 191.255.255.255
             Class C: 192.0.0.0 -------------- 223.255.255.255
             Class D: 224.0.0.0 -------------- 239.255.255.255
             Class E: 240.0.0.0 -------------- 255.255.255.255

Priority Bits: 
               Class A: 0
               Class B: 10
               Class C: 110
               Class D: 1110
               Class E: 1111 

Network & Host Part: 
               Class A:              N            H            H            H 
               Class B:              N            N            H            H 
               Class C:              N            N            N            H

Usage of Class:
              Class A:
              Class B:              Used on LAN/MAN/WAN Communication. 
              Class C:    
              Class D:              Used on Multicast Communication.
              Class E:              Used on Research & Development.
  
Network & Host Bits:
Bits
Class A
Class B
Class C
Total Network Bits
8
16
24
Total Host Bits
24
16
8

Network ID:
In case of Network ID, all the host bits are set to zero’s (0’s).
             Example: 192.168.1.10
             192.168.1. XXXX XXXX         (X = 0) 
             192.168.1. 0000 0000
             192.168.1.0
So NID of the IP address 192.168.1.10 is 192.168.1.0

Broadcast ID: 
In case of Network ID, all the host bits are set to one’s (1’s)
             Example: 192.168.1.10
             192.168.1. XXXX XXXX         (X = 1)
             192.168.1. 1111 1111
             192.168.1.255
So NID of the IP address 192.168.1.10 is 192.168.1.255 

Subnet Mask:
Subnet mask is a 32 bits value which is used to differentiate the host & network portion of an IP address. In case of Subnet Mask, Network is represented by 1 & Host is represented by O. 
Default Subnet Mask: 
               Class A: 255.0.0.0
               Class B: 255.255.0.0
               Class C: 255.255.255.0

Private IP Address:
              Class A: 10.0.0.0 – 10.255.255.255
              Class B: 172.16.0.0 – 172.31.255.255
              Class C: 192.168.0.0 – 192.168.255.255

Reserve IP Address:
             0.0.0.0 - 0.255.255.255 = Self Identification.
             10.0.0.0 – 10.255.255.255 = Class A Private IP Addres.
             127.0.0.0 – 127.255.255.255 = Loopback Address
             169.254.0.0 – 169.254.255.255 = APIPA Range used Microsoft OS
             172.16.0.0 – 172.31.255.255 = Class B Private IP Addres
             192.168.0.0 – 192.168.255.255 = Class C Private IP Addres
             224.0.0.0 – 239.255.255.255 = Multicast Communication
             240.0.0.0 – 255.255.255.255 = Research & Development
             255.255.255.255 = Limited Broadcast Address.

Subnetting: 
The Process of dividing a large network into equal smaller parts is known as Subnetting. In subnetting some of host bits will be converted to network bits. 
  • Reduce the wastage of IP address.
  • Allow us to manage the network efficiently.
  • Reduce the network threats. 
Formula:  
  • (2h-2)≥No of host/network.
  • (2n-2) ≥ No of sunetwork. 
Subnetting for Class C:
Example: 192.168.1.10; divide the given network in such a way where each subnetwork will have minimum of 30 hosts & also find out the Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address. 

Solution: From the above question, host is given. So we will use the formula (2h-2)≥No of host/network. 
Step1: Find out the value of “h”, where “h” represent the Host bits.
                 (2h-2)≥No of host/network
                 (2h-2)≥30
                 (25-2)≥30
                 (32-2) ≥30
                 30≥30
        From the above calculation, h = 5. 
Note: As we know, in subnetting, some of the host bits will be converted to network bits. So we can say that -
                              In class C: n+h=8 
                              In class B: n+h=16 
                              In class A: n+h=24 
Step2: Find out the value of “n”, where “n” represents the Network bits. So given network is 192.168.1.10, which is a class C network. So we will use
                           n+h=8
                           n+5=8
                           n=3 
Step3: Find the total number of subnetwork:
                          (2n-2) ≥ No of sunetwork
                          (23 – 2) ≥ No of sunetwork
                          (8-2) ≥ No of sunetwork
                          6≥ No of sunetwork
           Total no of subnetwork will be 8.
           Total number of valid subnetwork will be 6. 
Step4: Find out the Total Network Bits (TNB):
           TNB = Default Network Bits + n
                  = 24 + 3
                  = 27 
Step5: Find out the customize Subnet Mask (CSM):
       CSM =          8                    8                8                   3
                      1111 1111   1111 1111    1111 1111    111 00000 
                          255              255             255                224
      CSM = 255.255.255.224 
Point to Remember:
        1           2           3          4           5           6          7           8 
      128       192       224       240       248       252       254       255 
Step6: Finding the increment:
Increment = 256 – Change value on the CSM.
                = 256 – 224
                = 32 
Step7: Writing the Range of subnet:
        192.168.1.0 – - - - - - - 192.168.1.31
        192.168.1.32 – - - - - - - 192.168.1.63
        192.168.1.64 – - - - - - - 192.168.1.95
        192.168.1.96 – - - - - - - 192.168.1.127
        192.168.1.128 – - - - - - - 192.168.1.159
        192.168.1.160 – - - - - - - 192.168.1.191
        192.168.1.192 – - - - - - - 192.168.1.223
        192.168.1.224 – - - - - - - 192.168.1.255
192.168.1.10 is the IP address which is belongs to Subnet (192.168.1.0 --- 192.168.1.31). So
         Network ID = 192.168.1.0
         Broadcast ID = 192.168.1.31
         First Valid IP address = 192.168.1.1
         Last Valid IP Address = 192.168.1.30 
Note: 
(192.168.1.0 – - - - - - - 192.168.1.31) is a subnetwork which is known as Subnet Zero. Cisco IOS prior to 12.0, the IP Subnet Zero is restricted (i.e. Disable). IOS 12.0 to all new IOS, the IP Subnet Zero is enabling by default. 

Sample Network with Subnetted IP Address on PC:
Task to Do: 
Perform the Subnetting based on the following requirements & Find out the following: Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address: 
  • 200.200.200.200; Host = 75
  • 221.195.156.156; Host = 45
  • 193.151.200.200; Host = 125
  • 205.205.103.31; Host = 20
  • 219.215.215.213; Host = 32
Subnetting for Class B: 
Example: 172.16.3.10; divide the given network in such a way where each subnetwork will have minimum of 300 hosts & also find out the Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address. 

Solution: From the above question, host is given. So we will use the formula
           (2h-2)≥No of host/network. 
Step1: Find out the value of “h”, where “h” represent the Host bits.
                 (2h-2)≥No of host/network
                 (2h-2)≥300
                 (29-2)≥300
                 (512-2) ≥300
                 510≥300
         From the above calculation, h = 9. 
Step2: Find out the value of “n”, where “n” represents the Network bits
So given network is 172.16.3.10, which is a class B network. So we will use
                  n+h=16
                  n+9=16
                  n=7 
Step3: Find the total number of subnetwork:
                 (2n-2) ≥ No of sunetwork
                 (27 – 2) ≥ No of sunetwork
                 (128-2) ≥ No of sunetwork
                 126≥ No of sunetwork
          Total no of subnetwork will be 128.
          Total number of valid subnetwork will be 126 
Step4: Find out the Total Network Bits (TNB):
          TNB = Default Network Bits + n
                 = 16 + 7
                 = 23 
Step5: Find out the customize Subnet Mask (CSM):
           CSM =          8                 8                  7                 0
                        1111 1111   1111 1111    1111 1110    0000 0000 
                             255             255              254                0
           CSM = 255.255.254.0 
Step6: Finding the increment:
Increment = 256 – Change value on the CSM.
                = 256 – 254
                = 2
Step7: Writing the Range of subnet:
               172.16.0.0 – - - - - - - 172.16.1.255
               172.16.2.0 – - - - - - - 172.16.3.255
               172.16.4.0 – - - - - - - 172.16.5.255
               -----------------------------------------
               -----------------------------------------
               172.16.254.0 – - - - - - - 172.16.255.255
172.16.3.10 is the IP address which is belongs to subnet (172.16.2.0 --- 172.16.3.255). So
               Network ID = 172.16.2.0
               Broadcast ID = 172.16.3.255
               First Valid IP Add = 172.16.2.1
               Last Valid IP Add = 172.16.3.254
Task to Do: 
Perform the Subnetting based on the following requirements & Find out the following: Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address: 
  • 151.163.20.3; Host = 500
  • 191.164.12.134; Host = 750
  • 142.158.26.30; Host = 128
  • 158.156.29.32; Host = 817
  • 183.169.176.168; Host = 150 
Subnetting for Class A: 
Example: 17.16.3.10; divide the given network in such a way where each subnetwork will have minimum of 1000 hosts & also find out the Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address. 

Solution: From the above question, host is given. So we will use the formula
              (2h-2)≥No of host/network. 
Step1: Find out the value of “h”, where “h” represent the Host bits.
              (2h-2)≥No of host/network
              (2h-2)≥1000
              (210-2)≥1000
              (1024-2) ≥1000
               1022≥1000
          From the above calculation, h = 10. 
Step2: Find out the value of “n”, where “n” represents the Network bits. So given network is 17.16.3.10, which is a class A network. So we will use
                      n+h=24
                      n+10=24
                      n=14 
Step3: Find the total number of subnetwork:
             (2n-2) ≥ No of sunetwork
             (214 – 2) ≥ No of sunetwork
             (16384-2) ≥ No of sunetwork
              16382≥ No of sunetwork
        Total no of subnetwork will be 16384.
        Total number of valid subnetwork will be 16382. 
Step4: Find out the Total Network Bits (TNB):
        TNB = Default Network Bits + n
               = 8 + 14
               = 22 
Step5: Find out the customize Subnet Mask (CSM):
       CSM =          8                 8                 6                 0
                    1111 1111   1111 1111    1111 1100   0000 0000 
                         255              255              252              0
       CSM = 255.255.252.0 
Step6: Finding the increment:
           Increment = 256 – Change value on the CSM.
                           = 256 – 252
                           = 4 
Step7: Writing the Range of subnet:
            17.0.0.0 – - - - - - - 17.0.3.255
            17.0.4.0 – - - - - - - 17.0.7.255
            ----------------------------------
            ----------------------------------
           17.1.0.0 – - - - - - - 17.1.3.255
           17.1.4.0 – - - - - - - 17.1.7.255
           -----------------------------------
           -----------------------------------
          17.16.0.0 – - - - - - - 17.16.3.255
          17.16.4.0 – - - - - - - 17.16.7.255
17.16.3.10 is the IP address which is belongs to subnet (17.16.0.0---17.16.3.255). So
          Network ID = 17.16.2.0
          Broadcast ID = 17.16.3.255
          First Valid IP Add = 17.16.0.1
          Last Valid IP Add = 17.16.3.254

Task to Do: 
Perform the Subnetting based on the following requirements & Find out the following: Network ID, Broadcast ID, and First Valid IP Add & Last Valid IP of the given IP address: 
  • 10.1.15.10; Host = 600
  • 115.100.15.100; Host = 1000
  • 111.125.136.124; Host = 455
  • 56.125.24.29; Host = 799
  • 76.75.82.86; Host = 1500
CIDR (Classless Inter Domain Routing): 
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and routing Internet Protocol packets. 

CIDR was developed in the 1990s as a standard scheme for routing network traffic across the Internet. Before CIDR technology was developed, Internet routers managed network traffic based on the class of IP addresses. In this system, the value of an IP address determines its Subnetwork for the purposes of routing. 

CIDR Notation: 
CIDR specifies an IP address range using a combination of an IP address and its associated network mask. IDR notation uses the following format –
                         XXX.XXX.XXX.XXX/n
Where n is the number of (leftmost) '1' bits in the mask. For example, 192.168.12.0/23. 

Example: 192.168.1.100/28; Find out the NID, BID, FVIP, LVIP, Total No of Subnets & Total no of host per subnet. 

Solution: Here in this question Total Network Bits is given, which is 28. 
Step1: Finding the Customized Subnet Mask from the Total Network Bits (TNB):

                 8                         8                          8                         4
               255                      255                      255                      240 
Step2: Finding the value of “n”:
            TNB = Default Network Bits + n
            28   = 24 + n
                n = 4
Step3: Find the value of ‘h”: 
So given network is 192.168.1.100, which is a class C network. So we will use
                              n+h=8
                              h+4=8
                                  h=4 
Step4: Finding the increment:
           Increment = 256 – Change value on the CSM.
                           = 256 – 240
                           = 16 
Step5: Writing the Range:
                 192.168.1.0 – - - - - - - 192.168.1.15
                 192.168.1.16 – - - - - - - 192.168.1.31
                 192.168.1.32 – - - - - - - 192.168.1.47
                 192.168.1.48 – - - - - - - 192.168.1.63
                 192.168.1.64 – - - - - - - 192.168.1.79
                 192.168.1.80 – - - - - - - 192.168.1.95
                 192.168.1.96 – - - - - - - 192.168.1.111
                 ---------------------------------------------
                 ---------------------------------------------
                 192.168.1.240 – - - - - - - 192.168.1.255
192.168.1.100 is the IP address which is belongs to subnet (192.168.1.96 – 192.168.1.111). So
                        Network ID = 192.168.1.96
                        Broadcast ID = 192.168.1.111
                        First Valid IP Add = 192.168.1.97
                        Last Valid IP Add = 192.168.1.110
Finding the Total number of Subnets:
                       (2n-2) ≥ No of sunetwork
                       (24 – 2) ≥ No of sunetwork
                       (16-2) ≥ No of sunetwork
                              14≥ No of sunetwork
                Total no of subnetwork will be 16.
                Total number of valid subnetwork will be 14.
Finding the Total number of host per subnets:
                      (2h-2) ≥ No of host/sunetwork
                      (24 – 2) ≥ No of host/sunetwork
                      (16-2) ≥ No of host/sunetwork
                            14≥ No of host/sunetwork
               Total number of Host/Subnetwork is 14
Task to do: 
Find the NID, BID, FVIP, LVIP, and Total No of Subnets & Total no of host per subnet based on the following: 
  • 195.168.1.15/25
  • 174.16.100.100/24
  • 115.10.10.152/16
  • 142.158.158.120/23
  • 182.85.168.200/22
  • 199.199.199.100/30

No comments:

Post a Comment