Chapter 5 – IP Addressing

IP Address Fundamentals Each host is assigned a unique IP address for each network connection (NIC) An IP address is a 32-bit address, written as four octets (bytes) separated by periods Example: This notation is called dotted decimal notation Each address has an associated subnet mask tha divides the address into its network and host components The network portion identifies where the host is located and host portion identifies device

IP Address Coordination IP Address assignments must be carefully coordinated Internet Network Information Center (InterNIC) is responsible for coordinating IP addresses To get an address, you may contact : –InterNIC Registration Services –C/o Network Solutions, Inc. –505 Huntmar Park Drive –Herndon, VA

IP Address Classes Five address classes are supported (A-E) Only Classes A, B, and C are assigned to the general user community Class D is reserved for multicasting Class E is reserved for experimental purposes

Class A IP Address Leading octet starts with 0 Subnet mask of Network range Number of networks: 126 Number of hosts per network: 16,777,214 All Class A addresses have been allocated

Class B IP Address Leading octet starts with 10 Subnet mask of Network range: – Number of networks: 16,384 Number of hosts per network: 65,534 Class B addresses are hard to obtain Mercer has a Class B (owned by Peachnet) that is sublet to Mercer, Macon State, and UGA

Class C IP Address Leading octet starts with 110 Subnet Mask of Network range: – Number of networks: 2,097,152 Number of hosts per network: 254

Class D IP Address Leading octet starts with 1110 Network range: 224 – 239

IP Classes Note that the first octet tells you what class the IP address is in A: B: C: 192 – 223 D: 224 – 239

Special IP Addressing Network FieldHost FieldDestination All ZeroesHost IDHost on this net All ones Local broadcast Network IDAll onesDirected broadcast 127AnythingLoopback

Use Windows Calculator to Convert Between Dec and Bin Open Windows calculator from the Accessories program group Under View, select Scientific Select Dec option Enter a decimal number Select Bin option to convert to binary

Concept of Subnetting Through subnetting, you can improve network efficiency Keeps local traffic local by keeping systems that need to share information together on their own subnet Makes job of setting up and managing routers easier Makes good use of assigned addresses

Subnetting Example Assume you have been assigned a Class B address of Default subnet mask is You have the potential for 65,534 host all on the same physical network What to do if you want some subnets in your network? See Handout with Table: Class B Subnetting