IP Addressing and Subnetting - Expert Network Consultant

1 1111111010101001000111110010111001010111 0010110001110100110111101000110100000101 0010110010100101010110011111110101010001 0111010011010100110010100101010101010101 0001100100101010010110001101011000110101 1010100001011001010100110100101001010011 0000101110100111000011010010101000110110 01IP AddressingandSubnettingWorkbookVersion Name:IP Address ClassesClass A1 127( Network 127 is reserved for loopback and internal testing)Leading bit B128 191 Leading bit C192 223 Leading bit D224 239(Reserved for multicast)Class E240 255(Reserved for experimental, used for research)Private Address SpaceClass to to to Subnet MasksClass . Host . Host . HostNetwork . Network .

2 Host . HostNetwork . Network . Network . HostInside CoverProduced by: Robb County Career & Technology CenterCisco Networking AcademyFrederick County Public SchoolsFrederick, Maryland, USAS pecial Thanks to Melvin Baker and Jim Dorschfor taking the time to check this workbook for errors,and to everyone who has sent in suggestions to improve the included in the series:IP Addressing and Subnetting WorkbooksACLs - Access Lists WorkbooksVLSM Variable-Length Subnet Mask IWorkbooksBinary To Decimal Conversion1286432168421 Answers Scratch Area10010010 14601110111 1191111111111000101111101100001001110000 0010011000101111000111100000011101100000 1110001101110101010011011111111100000100 0000101010100111110000000111110110111000 0001281621466432164211191 Decimal To Binary Conversion1286432168421 = 255 Scratch Area_____ 238_____ 34_____ 123_____ 50_____ 255_____ 200_____ 10_____ 138_____ 1_____ 13_____ 250_____ 107_____ 224_____ 114_____ 192_____ 172_____ 100_____ 119_____ 57_____ 98_____ 179_____ 2238-128110-6446-3214-86-42-20 1110111034-322-20 001

3 0001 0 Use all 8 bits for each problem2 Address Class Identification & Host IdentificationCircle the Network portionof these the host portion ofthese AddressesUsing the IP address and subnet mask shown write out the Network . 10 . 0 . 010 . 10 . 48 . 0 Host AddressesUsing the IP address and subnet mask shown write out the host . 0 . 18 . 20 . 0 . 0 . 806 Default Subnet MasksWrite the correct default subnet mask for each of the following . 255 . 0 . 0255 . 0 . 0 . 07 ANDING WithDefault subnet masksEvery IP address must be accompanied by a subnet mask. By now you should be able to lookat an IP address and tell what class it is. Unfortunately your computer doesn t think that your computer to determine the Network and subnet portion of an IP address it must AND the IP address with the subnet Subnet Masks:Class Equations:1 AND 1 = 11 AND 0 = 00 AND 1 = 00 AND 0 = 0 Sample:What you Address:192.

4 100 . 10 . 33 What you can figure out in your Class: CNetwork Portion:192 . 100 . 10 . 33 Host Portion:192 . 100 . 10 . 33In order for you computer to get the same information it must AND the IP address withthe subnet mask in binary. ANDING with the default subnet mask allows your computer to figure out the networkportion of the 1 0 0 0 0 0 0 . 0 1 1 0 0 1 0 0 . 0 0 0 0 1 0 1 0 . 0 0 1 0 0 0 0 11 1 1 1 1 1 1 1 . 0 1 1 1 1 1 1 1 . 1 1 1 1 1 1 1 1 . 0 0 0 0 0 0 0 01 1 0 0 0 0 0 0 . 0 1 1 0 0 1 0 0 . 0 0 0 0 1 0 1 0 . 0 0 0 0 0 0 0 0(255 . 255 . 255 . 0)(192 . 100 . 10 . 33)(192 . 100 . 10 . 0)NetworkHost IP Address:Default Subnet Mask:AND:8 ANDING WithCustom subnet masksWhen you take a single Network such as and divide it into five smaller networks( , , , , ) the outsideworld still sees the Network as , but the internal computers and routers see fivesmaller subnetworks.

5 Each independent of the other. This can only be accomplished by usinga custom subnet mask. A custom subnet mask borrows bits from the host portion of theaddress to create a subnetwork address between the Network and host portions of an IPaddress. In this example each range has 14 usable addresses in it. The computer must stillAND the IP address against the custom subnet mask to see what the Network portion is andwhich subnetwork it belongs Address:192 . 100 . 10 . 0 Custom Subnet to to to (Range in the sample below) to to to to to to to to to to to to to the next set of problems you will determine the necessary information to determine thecorrect subnet mask for a variety of IP 1 0 0 0 0 0 0.

6 0 1 1 0 0 1 0 0 . 0 0 0 0 1 0 1 0 . 0 0 1 0 0 0 0 11 1 1 1 1 1 1 1 . 0 1 1 1 1 1 1 1 . 1 1 1 1 1 1 1 1 . 1 1 1 1 0 0 0 01 1 0 0 0 0 0 0 . 0 1 1 0 0 1 0 0 . 0 0 0 0 1 0 1 0 . 0 0 1 0 0 0 0 0(255 . 255 . 255 . 240)(192 . 100 . 10 . 33)(192 . 100 . 10 . 32)Four bits borrowed from the hostportion of the address for thecustom subnet ANDING process of the four borrowed bitsshows which range of IP addresses thisparticular address will fall Address:Custom Subnet Mask:AND:9 How to determine the number of subnets and thenumber of hosts per subnetTwo formulas can provide this basic information:Number of subnets = 2 (Second subnet formula: Number of subnets = 2 - 2)Number of hosts per subnet = 2 - 2 Both formulas calculate the number of hosts or subnets based on the number of binary bitsused.

7 For example if you borrow three bits from the host portion of the address use thenumber of subnets formula to determine the total number of subnets gained by borrowing thethree bits. This would be 2 or 2 x 2 x 2 = 8 subnetsTo determine the number of hosts per subnet you would take the number of binary bits used inthe host portion and apply this to the number of hosts per subnet formula If five bits are in thehost portion of the address this would be 2 or 2 x 2 x 2 x 2 x 2 = 32 dealing with the number of hosts per subnet you have to subtract two addresses fromthe range. The first address in every range is the subnet number. The last address in everyrange is the broadcast address. These two addresses cannot be assigned to any device inthe Network which is why you have to subtract two addresses to find the number of usableaddresses in each example if two bits are borrowed for the Network portion of the address you can easilydetermine the number of subnets and hosts per subnets using the two 195.

8 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 The number of subnetscreated by borrowing 2bits is 2 or 2 x 2 = number of hosts created byleaving 6 bits is 2 - 2 or2 x 2 x 2 x 2 x 2 x 2 = 64 - 2 = 62usable hosts per about that second subnet formula:Number of subnets = 2 - 2In some instances the first and last subnet range of addresses are reserved. This is similar tothe first and last host addresses in each range of first range of addresses is the zero subnet. The subnet number for the zero subnet isalso the subnet number for the classful subnet last range of addresses is the broadcast subnet.

9 The broadcast address for the lastsubnet in the broadcast subnet is the same as the classful broadcast 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 0 195. 223 . 50 . 0 0 0 0 0 0 0 (Invalid range)(Invalid range)totototo(0)(1)(2)(3)Class C Address unsubnetted:195. 223 . 50 . 0195. 223 . 50 . 0195. 223 . 50 . 0195. 223 . 50 . 0195. 223 . 50 . to C Address subnetted (2 bits borrowed):Notice that the subnet andbroadcast addresses the 2 - 2 formula and don t use thezero and broadcast ranges routing is usedRIP version 1 is usedThe no ip subnet zero command isconfigured on your routerUse the 2 formula and use the zero andbroadcast ranges routing or VLSM is usedRIP version 2, EIGRP, or OSPF is usedThe ip subnet zero command isconfigured on your router (default setting)No other clues are givenWhen to use which formula to determine the number of subnetsssThe primary reason the the zero and broadcast subnets were not used had to do pirmarily withthe broadcast addresses.

10 If you send a broadcast to are you sending it to all 255addresses in the classful C address or just the 62 usable addresses in the broadcast range?The CCNA and CCENT certification exams may have questions which will require you todetermine which formula to use, and whehter or not you can use the first and last subnets. Usethe chart below to help line for the CCNA exams; if a question does not give you any clues as to whether or notto allow these two subnets, assume you can use workbook has you use the number of subnets = 2 Subnet MasksProblem 1 Number of needed subnetsNumber of needed usable hostsNetwork AddressAddress classDefault subnet maskCustom subnet maskTotal number of subnetsTotal number of host addressesNumber of usable addressesNumber of bits.