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The advantages of CIDR over the classful IP ADDRESSING are:

1. CIDR can be USED to effectively manage the available IP address SPACE.
2. CIDR can reduce the number of routing table entries.

The advantages of CIDR over the classful IP addressing are:

In CIDR notation, an IP address is represented as A.B.C.D /n, where "/n" is CALLED the IP PREFIX or network prefix. The IP prefix identifies the number of significant bits USED to identify a network. For example, 192.9.205.22 /18 MEANS, the first 18 bits are used to represent the network and the remaining 14 bits are used to identify hosts.

In CIDR notation, an IP address is represented as A.B.C.D /n, where "/n" is called the IP prefix or network prefix. The IP prefix identifies the number of significant bits used to identify a network. For example, 192.9.205.22 /18 means, the first 18 bits are used to represent the network and the remaining 14 bits are used to identify hosts.

In CIDR IP addressing, the FIRST 'n' bits of an IP address are assigned to identify the NETWORK and the remaining bits are USED to identify the host, where the value of 'n' MAY be between 1 to 31. The value of 'n' depends on the number of HOSTS in the network.

In CIDR IP addressing, the first 'n' bits of an IP address are assigned to identify the network and the remaining bits are used to identify the host, where the value of 'n' may be between 1 to 31. The value of 'n' depends on the number of hosts in the network.

The DIFFERENCE between classful IP addressing and classless IP addressing is in selecting the number of bits USED for the network ID PORTION of an IP ADDRESS. In classful IP addressing, the network ID portion can take only the predefined number of bits 8, 16, or 24. In classless addressing, any number of bits can be assigned to the network ID.

The difference between classful IP addressing and classless IP addressing is in selecting the number of bits used for the network ID portion of an IP address. In classful IP addressing, the network ID portion can take only the predefined number of bits 8, 16, or 24. In classless addressing, any number of bits can be assigned to the network ID.

RFCS 1517, 1518, and 1519 DISCUSSES about CIDR.

RFCs 1517, 1518, and 1519 discusses about CIDR.

Classless Inter Domain Routing (CIDR) is a method for assigning IP addresses without using the standard IP address classes like CLASS A, Class B or Class C. In CIDR, depending on the NUMBER of hosts PRESENT in a NETWORK, IP addresses are assigned.

Classless Inter Domain Routing (CIDR) is a method for assigning IP addresses without using the standard IP address classes like Class A, Class B or Class C. In CIDR, depending on the number of hosts present in a network, IP addresses are assigned.

The possible solutions to the limitation of IPv4 addressing are:

1. IP VERSION 6 (IPv6) or IP next generation (IPng). This is the LATEST version of IP. This solves a LOT of problems in IPv4. This DOCUMENT doesn't discuss about IPv6.
2. Classless INTER Domain Routing (CIDR).

The possible solutions to the limitation of IPv4 addressing are:

If a network has slightly more number of hosts than a particular class, then it needs either two IP addresses of that class or the next class of IP address. For example, LET use say a network has 300 hosts, this network needs either a single class B IP address or two class C IP addresses. If class B address is allocated to this network, as the number of hosts that can be defined in a class B network is (2^16 - 2), a large number of host IP addresses are wasted. If two class C IP addresses are allocated, as the number of networks that can be defined using a class C address is only (2^21), the number of available class C networks will quickly exhaust. Because of the above two REASONS, a lot of IP addresses are wasted and also the available IP address space is rapidly REDUCED.

If a network has slightly more number of hosts than a particular class, then it needs either two IP addresses of that class or the next class of IP address. For example, let use say a network has 300 hosts, this network needs either a single class B IP address or two class C IP addresses. If class B address is allocated to this network, as the number of hosts that can be defined in a class B network is (2^16 - 2), a large number of host IP addresses are wasted. If two class C IP addresses are allocated, as the number of networks that can be defined using a class C address is only (2^21), the number of available class C networks will quickly exhaust. Because of the above two reasons, a lot of IP addresses are wasted and also the available IP address space is rapidly reduced.

The limitations of IPv4 address CLASSES are:

1. A large number of IP addresses are wasted because of using IP address classes.
2. The ROUTING TABLES will become large. A separate routing table entry is needed for each network resulting in a large number of routing table entries.

The limitations of IPv4 address classes are:

RFC 1918, published in 1996, describe the reservation of PRIVATE IP address. . Private networks are segments of IP address space reserved by IANA for use within an organization. These addresses can be used by anyone WITHOUT being officially assigned by a registry or an ISP. The three most popular blocks AMONG RFC1918 addresses are 192.168/16, 10/8 and 172.16/12. That is 10.0.0.0 – 10.255.25.255, 172.16.0.0 – 172.31.255.255 and 192.168.0.0. – 192.168.255.255 The addresses in these blocks are called "private IP addresses" in the Internet VERNACULAR.

RFC 1918, published in 1996, describe the reservation of Private IP address. . Private networks are segments of IP address space reserved by IANA for use within an organization. These addresses can be used by anyone without being officially assigned by a registry or an ISP. The three most popular blocks among RFC1918 addresses are 192.168/16, 10/8 and 172.16/12. That is 10.0.0.0 – 10.255.25.255, 172.16.0.0 – 172.31.255.255 and 192.168.0.0. – 192.168.255.255 The addresses in these blocks are called "private IP addresses" in the Internet vernacular.

APIPA stands for Automatic Private IP Addressing. When you configure your computer to obtain IP Address automatically and a DHCP server cannot be contacted, then the computer will automatically assign an IP address from a specific range (169.254.0.1 to 169.254.255.254). Then this network will be isolated from all networks. Because it has no a default GATEWAY and any other CONFIGURATION parameters.

APIPA stands for Automatic Private IP Addressing. When you configure your computer to obtain IP Address automatically and a DHCP server cannot be contacted, then the computer will automatically assign an IP address from a specific range (169.254.0.1 to 169.254.255.254). Then this network will be isolated from all networks. Because it has no a default gateway and any other configuration parameters.

A SUBNET is a portion of a NETWORK that is logically ISOLATED from other PARTS of the network. Usually it’s divided by a router.

A subnet is a portion of a network that is logically isolated from other parts of the network. Usually it’s divided by a router.

No. NEVER. A work station computer can BROWS the Internet only if it has a DEFAULT GATEWAY.

No. Never. A work station computer can brows the Internet only if it has a default gateway.

In general, a gateway is a device on a network that acts as an entrance to another network. In more technical terms, a gateway is a routing device that knows how to PASS traffic between different subnets and networks. A computer will know some routes (a route is the address of each NODE a packet must go through on the INTERNET to reach a specific destination), but not the routes to every address on the Internet. It won't even know all the routes on the nearest subnets. A gateway will not have this INFORMATION either, but will at least know the addresses of other gateways it can hand the traffic off to. Your default gateway is on the same subnet as your computer, and is the gateway your computer relies on when it doesn't know how to route traffic.

If you don’t have a gateway your network communication have no PROBLEM. But you cannot communicate with other networks. That means your packet will not reach other networks.

In general, a gateway is a device on a network that acts as an entrance to another network. In more technical terms, a gateway is a routing device that knows how to pass traffic between different subnets and networks. A computer will know some routes (a route is the address of each node a packet must go through on the Internet to reach a specific destination), but not the routes to every address on the Internet. It won't even know all the routes on the nearest subnets. A gateway will not have this information either, but will at least know the addresses of other gateways it can hand the traffic off to. Your default gateway is on the same subnet as your computer, and is the gateway your computer relies on when it doesn't know how to route traffic.

If you don’t have a gateway your network communication have no problem. But you cannot communicate with other networks. That means your packet will not reach other networks.

A MASK used to determine what subnet an IP address belongs to. An IP address has two COMPONENTS, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) REPRESENT the Class B network address, and the second two numbers (017.009) identify a particular host on this network.

A mask used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network.