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.
An IP address has two fields, a network prefix and a host identifier.[1]
The network prefix is identified using CIDR notation.[2]
In IPv4, the network prefix may also be identified using a 32-bit subnet mask in dotted-decimal notation.[3]
A network is divided into two or more subnetworks by dividing the host identifier field into separate subnet number and smaller host identifier fields.[4]
All hosts on a subnetwork have the same network prefix.[5]
Traffic between subnets is exchanged through a router.[6]
The first address on any given IPv4 network or subnet is reserved for the network itself.[7]
The last address on any given IPv4 network or subnet is reserved for broadcast.[8]
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.[9]
The number of subnetworks created by subnetting can be calculated as 2n, where n is the number of bits used for subnetting.[10]
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.[11]
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.[12]
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.[13]
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.[14]
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.[15]
CIDR notation
A compact specification of an Internet Protocol address and its associated routing prefix.[16]
provider-independent address space
A block of IP addresses assigned by a regional Internet registry (RIR) directly to an end-user organization.[17]
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.[18]
subnet
A logically visible subdivision of an IP network.[19]
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.[20]
subnetting
The practice of dividing a network into two or more networks.[21]
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.[22]
An IP address has two fields, a network prefix and a host identifier.
The network prefix is identified using _____.
The network prefix is identified using CIDR notation.
In IPv4, in addition to using CIDR notation, the network prefix may be identified using _____.
In IPv4, in addition to using CIDR notation, the network prefix may be identified using a 32-bit subnet mask in dotted-decimal notation.
A network is divided into two or more subnetworks by dividing _____.
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 _____.
All hosts on a subnetwork have the same network prefix.
Traffic between subnets is exchanged through a _____.
Traffic between subnets is exchanged through a router.
The first address on any given network or subnet is reserved for _____.
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 _____.
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 _____.
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 _____.
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 _____.
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 _____.
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 _____.
Classless Inter-Domain Routing is based on variable-length subnet masking (VLSM).
The benefits of supernetting are _____.
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.