Internet Protocol Analysis/Subnetting

This lesson continues the Internet layer and looks at subnetworks, Classless Inter-Domain Routing (CIDR), subnetting, and supernetworks. Activities include IPv4 subnetting, and using the Cisco Subnet Game.

Readings

 * 1)  Subnetwork
 * 2)  IPv4 subnetting reference
 * 3)  CIDR notation
 * 4)  Classless Inter-Domain Routing
 * 5)  Supernetwork

Multimedia

 * 1) YouTube: Subnetting, Cisco CCNA, Binary Numbers - Part 1
 * 2) YouTube: Subnetting, Cisco CCNA, Binary Numbers - Part 2
 * 3) YouTube: Subnetting, Cisco CCNA, Binary Numbers - Part 3
 * 4) YouTube: Subnetting, Cisco CCNA, Binary Numbers - Part 4
 * 5) YouTube: Subnetting Cisco CCNA - Part 1 The Magic Number
 * 6) YouTube: Subnetting Cisco CCNA - Part 2 The Magic Number
 * 7) YouTube: Subnetting Cisco CCNA - Part 3 The Magic Number
 * 8) YouTube: Subnetting Cisco CCNA - Part 4 The Magic Number
 * 9) YouTube: Subnetting Cisco CCNA - Part 5 The Magic Number
 * 10) YouTube: Subnetting Cisco CCNA - Part 6 The Magic Number

Activities

 * 1) Review Cisco: IP Addressing and Subnetting for New Users.
 * 2) Review Understanding TCP/IP addressing and subnetting basics.
 * 3) Experiment with an online subnet calculator such as Online IP Subnet Calculator.
 * 4) Generate practice subnetting questions using this Subnet Calculator.
 * 5) Review EasySubnetting.com subnetting resources.
 * 6) Play the Cisco: Subnet Troubleshooting Game.
 * 7) Consider situations in which a packet analyzer might be used to troubleshoot subnetting and routing traffic.

Lesson Summary

 * An IP address has two fields, a network prefix and a host identifier.
 * The network prefix is identified using CIDR notation.
 * In IPv4, the network prefix may also be identified using a 32-bit subnet mask in dotted-decimal notation.
 * A network is divided into two or more subnetworks by dividing the host identifier field into separate subnet number and smaller host identifier fields.
 * All hosts on a subnetwork have the same network prefix.
 * Traffic between subnets is exchanged through a router.
 * The first address on any given IPv4 network or subnet is reserved for the network itself.
 * The last address on any given IPv4 network or subnet is reserved for broadcast.
 * The separation of the network prefix/subnet number from the host identifier is performed by a bitwise AND operation between the IP address and the (sub)network mask.
 * The number of subnetworks created by subnetting can be calculated as 2n, where n is the number of bits used for subnetting.
 * The number of available hosts on each subnet can be calculated as 2n -2 ,where n is the number of bits available for the host identifier.
 * The goal of Classless Inter-Domain Routing was to slow the growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses.
 * Classless Inter-Domain Routing is based on variable-length subnet masking (VLSM), which allows a network to be divided into variously sized subnets, providing the opportunity to size a network more appropriately for local needs.
 * The benefits of supernetting are conservation of address space and efficiencies gained in routers in terms of memory storage of route information and processing overhead when matching routes.

Key Terms

 * bitwise AND
 * A binary operation that takes two representations of equal length and performs the logical AND operation on each pair of corresponding bits. The result in each position is 1 if the first bit is 1 and the second bit is 1; otherwise, the result is 0.


 * CIDR notation
 * A compact specification of an Internet Protocol address and its associated routing prefix.


 * provider-independent address space
 * A block of IP addresses assigned by a regional Internet registry (RIR) directly to an end-user organization.


 * routing table
 * A data table stored in a router or a networked computer that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes.


 * subnet
 * A logically visible subdivision of an IP network.


 * subnet mask
 * A bitmask that encodes the (sub)network prefix length in dotted-decimal notation, starting with a number of 1 bits equal to the prefix length, ending with 0 bits, and encoded in four-part dotted-decimal format.


 * subnetting
 * The practice of dividing a network into two or more networks.


 * supernet
 * An Internet Protocol (IP) network that is formed from the combination of two or more networks (or subnets) with a common Classless Inter-Domain Routing (CIDR) prefix.

Assessments

 * /Lesson Flashcards/
 * /Terms Flashcards/
 * /Quiz/