CLASSLESS INTER-DOMAIN ROUTING {CIDR} & SUBNETTING PHILLIP LAFLEUR NATHAN GRAMMES JONATHAN BENNETT

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE STEP 1: CONNECT A BUNCH OF COMPUTERS STEP 2: DEVELOP ADDRESS SYSTEM Internet Protocol (IP) Address

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE BIT CONVERTER

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE Octet 32 Bits

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE STEP 1: CONNECT A BUNCH OF COMPUTERS STEP 2: DEVELOP ADDRESS SYSTEM Internet Protocol (IP) Address STEP 3: ASSIGN IP ADDRESSES ?

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE The CLASSFUL NETWORK (ABRIDGED) A B C 17 MILLION 65 THOUSAND 254 Assigned based on 3 classes,, representing available hosts What if you only need 3,000? C C C C C C Cluttered routing table. B Waste 62,000+ addresses!

The CLASSFUL NETWORK (ABRIDGED) 1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE

CLASSFUL NETWORK ADDRESSING ARCHITECTURE

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE Available IP’s exhausted after 254 assignments of Class B. PROBLEM

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE INTERNET ENGINEERING TASK FORCE

HOST NUMBER SUBNET NETWORK PREFIX HOST NUMBER IP ADDRESS 1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) SUBNETTING Let’s just divide our network into MANAGABLE bits.

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) SUBNETTING Let’s just divide our network into MANAGABLE bits Designates network prefix 255 = Entire Octet (0 – 254) or (in binary) Leading 1s and trailing 0s

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) SUBNETTING Network prefix and host suffix can be found with binary operation AND AND IP Address Subnet Mask Network Prefix Host Number 1 AND 0 = 00 AND 0 = 01 AND 1 = 1

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) CIDR+SUBNETTING CIDR represents the notation in which subnetting is represented. IP / INITIAL BITS /

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) / – Hosts

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) / – Hosts

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) / – Hosts

1993 CLASSLESS INTER-DOMAIN ROUTING AND SUBNETTING The SOLUTION (UNABRIDGED) IMPLICATIONS / / / / 16

1981 CLASSFUL NETWORK ADDRESSING ARCHITECTURE IP ‘division’ via subnetting allows for specific distribution of IPs AWESOME