IP SubnettingStructure of IP addressesReserved IP addressesSlide 4Network maskTwo Virtual LANsTwo interconnected LANsThe ADDing techniqueSubnetting a class C networkSlide 10Slide 11Question 1Slide 13IP Subnetting(Week 4, Wednesday 1/31/2007)© Abdou Illia, Spring 20072Structure of IP addressesNetwork Part (n)Local Part (h)Class A nnnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh 10.0.0.1 – 126.255.255.255Class B nnnnnnnn.nnnnnnnn.hhhhhhhh.hhhhhhhh 128.0.0.1 – 191.255.255.255Class C nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh 192.0.0.1 – 223.255.255.255Sgmt. part Host part3Reserved IP addressesClass RangeA 10.0.0.0 – 10.255.255.255B 172.16.0.0 – 172.31.255.255C 192.168.0.0 – 192.168.255.255IP addresses reserved for private use.Address Use255.255.255.255Example: 10.255.255.255Local broadcast to LAN computersBroadcast to network 10.0.0.0/8127.0.0.1 Loopback address (for self addressing)0.0.0.0 Prohibited169.254.x.x Automatic Private IP Addressing Special IP addresses.4Structure of IP addressesThe division between Network part, Segment part, and Host part is determined by a computer or a router by using a network mask. Network PartSegmentPartHostPart5Network maskA 32 bit number, just like an IP address, where all bits in the Network Part and the Segment Part are set to 1, and all bits in the Host Part are set to 0. Example:11111111 11111111 11111111 00000000 (or 255.255.255.0 in decimal notation)Computers use Network mask, along with the IP address, to determine whether or not a destination IP address is on the same logical network.6Two Virtual LANs192.168.1.1255.255.255.0192.168.1.2255.255.255.0192.168.1.3255.255.255.0192.168.2.1255.255.255.0192.168.2.2255.255.255.0192.168.2.3255.255.255.0Switch7Two interconnected LANs8The ADDing techniqueAre the following three Class C IP addresses from the same network? 192.168.1.1, 192.168.1.50 and 192.168.2.1IP: 11000000 10101000 00000001 00000001 192.168.1.1Mask: 11111111 11111111 11111111 00000000 255.255.255.0Network: 11000000 10101000 00000001 00000000 192.168.1.0/24IP: 11000000 10101000 00000001 00110010 192.168.1.50Mask: 11111111 11111111 11111111 00000000 255.255.255.0Network: 11000000 10101000 00000001 00000000 192.168.1.0/24IP: 11000000 10101000 00000010 00000001 192.168.2.1Mask: 11111111 11111111 11111111 00000000 255.255.255.0Network: 11000000 10101000 00000010 00000000 192.168.2.0/241286432168421Network 1: 192.168.1.0/24, i.e network starting at 192.168.1.0 with network mask 255.255.255.0.Network 2: 192.168.2.0/24, i.e network starting at 192.168.2.0 with network mask 255.255.255.0.9Subnetting a class C networkSuppose the 192.168.1.0/24 networkYou want to divide that network into two segmentsYou can decide to use the first bit of the fourth octet as dividing point between your network segments. So, your network mask would be: 11111111 11111111 11111111 10000000 And you will have about 27 = 128 hosts in each segment.1286432168421Segment 1: 192.168.1.0 to 192.168.1.127 Segment 2: 192.168.1.128 to 192.168.1.255How to determine the two segments using the ADDing technique?10Subnetting a class C networkIP: 11000000 10101000 00000001 00000001 192.168.1.1Mask: 11111111 11111111 11111111 10000000 255.255.255.128Network: 11000000 10101000 00000001 00000000 192.168.1.0/25. . . . . .. . . . . .. . . . . .. . . . . .IP: 11000000 10101000 00000001 01111111 192.168.1.127Mask: 11111111 11111111 11111111 10000000 255.255.255.128Network: 11000000 10101000 00000001 00000000 192.168.1.0/251286432168421Segment 1: 192.168.1.0 to 192.168.1.12711Subnetting a class C networkIP: 11000000 10101000 00000001 10000000 192.168.1.128Mask: 11111111 11111111 11111111 10000000 255.255.255.128Network: 11000000 10101000 00000001 10000000 192.168.1.128/25. . . . . .. . . . . .. . . . . .. . . . . .IP: 11000000 10101000 00000001 11111110 192.168.1.254Mask: 11111111 11111111 11111111 10000000 255.255.255.128Network: 11000000 10101000 00000001 10000000 192.168.1.128/251286432168421Segment 2: 192.168.1.128 to 192.168.1.25512Question 1Network A is IP network 192.168.1.x/24 (i.e a Class C network with a default 24-bit mask). Using the IP Subnet Calculator, determine the maximum number of hosts (computers) in each of the Network A’s subnets assuming that there are two subnets. You answer: ________.Using the IP Subnet Calculator, determine the maximum number of subnets for a Class B network assuming that the four first bits of the third octet in each IP address are used as subnet bits. Your answer: _____. What is the maximum number of computers for each subnet? Your answer: