A subnet is an individually identifiable part of a particular Internet Protocol network. Subnetting is achieved by dividing the computer networks into groups of computers that manifest a distinct, selected IP address routing prefix. Subnetting is important when dealing with many connections of computers in large networks. These large connections create administration and network load that becomes a major problem. Computers send unicast and broadcast communication traffic in any given network hence the larger the network, the more constant the traffic becomes.
Subnetting ensures that there is control of network traffic such that unauthorized access to private information is avoided. The security of any information is maintained especially in circumstances when dealing with sensitive information. In situations when network equipment or protocols in use are not compatible, subnetting ensures their well matching. The same network cannot be used for two unrelated networking protocols. They are often used in different subnets and a router is used to connect them. The router transmits network traffic between two unlike networks while a network switch transmits traffic in similar networks. An organization’s network may be arranged in a hierarchy that partitions its address space.
The global routing prefix “is the high-order bits of an IP address used to identify the subnet or a specific type of address” (Hagen 38). Classless Interdomain Routing (CIDR) notation expresses the routing prefix used in subnetted IPv4 addresses. The notation affixes the first address of a network, prefix length, written as several bits with a slash. An example is 191.164.1.0/21 denotes the prefix of the IPv4 network beginning from the address given, having 21 bits assigned to the network number, and the rest of the bits are designated for addressing the host.
A subnet mast gives the specific bits of the IPv4 address that fit in the network ID. It is the prefix bit mask denoted in four numbers separated by dots. The prefix distinguishes the subnet that an interface is a part of, and routers use it for forwarding since all hosts in a subnet are reachable via one routing hop. All subnet hosts are attached to the same link.
Subnetting makes it possible for the network to be segmented notwithstanding the physical arrangement of the network. Physical subnets can be partitioned into many several subnets by putting together different host computers to utilize different routers.
Even though subnetting plays an important role in increasing the performance of a network, it amplifies the routing complexity. This is attributed to the representation of every locally connected subnet by a dissimilar entry within the routing tables of every router that has been connected.
All the computers and devices that are involved in the operation of a network, for example, the internet or intranet, possess a logical address, which is exclusive to every appliance. They are often distinguished to be constituted dynamically or statically which refers to the address from a network server or an administrator respectively. The purpose of a network address is to recognize the host and position it on the system of connections. This is essential in enabling ease of communication flow from one device to the other. The commonly used addressing system is Internet Protocol version 4 (IPv4). The recent version, IPv6, is still being fully configured. The IPv4 address is composed of 32 bits that are often written in a distinguishable form made up of four octets split by dots, referred to as dot-decimal notation. On the other hand, an IPv6 address is made up of 128 bits.
Class A, Class B, and class C are the main means of classifying IP addresses in IPv4. Class D is used for multicasting operations while Class E is mainly used in circumstances that require privacy. The distinguishable feature between the different classes is the number of networks and host octets present. Every network octet serves the purpose of categorizing which network host is on. This implies that having more octets yields more networks and vice versa. Every class has a varied range that the foremost octet can be allocated. This distinguishes the network class that any IP fits into (“How to Subnet a Network” para. 7)
To smooth the progress of routing a packet of data traversing the many networks, the IP address is sub-divided into twin components: a network prefix and a host identifier. A network prefix is a certain number of bits that commences from the left-most bit. It is used to identify the network where the host or other network crossing point is situated. It is sometimes called the network identifier. Host identifier is the remainder of the low-order bits that are used to identify the host on the network. It indicates a specific device in the neighboring network (Kozierok 247).
The form of a network identifier may be similar to that of the address. In IPv4, it is referred to as the subnet mask.
Every IP address is noted in a decimal form, for example, 192.162.3.1, conversely, the computers in the binary format essentially use every IP address.
The procedure for carrying out IPv4 subnetting entails the division of the network and the subnet component of an address from the low-order bits of the host identifier. This action is done by a bitwise AND process that incorporates the IP address and the subnet prefix or the bitmask. After this process, a network address is formed while the host identifier remains. The subnet masks in IPv4 are composed of 32 bits that are arranged in a series of ones trailed by a block of zeros. The host identifier forms the final block of zeros that distinguishes it from the rest.
The process of subnetting takes place by designating bits beginning from the host portion and making them into groups together with the network portion. This action portions the network into smaller subnets.
To enable the identification of particular address functionality in using the Internet Protocol version 4, special formats of addresses are used. IPv4 uses the end address in a network for broadcast transmission to every host situated within the link.
The IP version four can support only 4,294,967,296 distinct IP addresses. This number is small compared to version 6 that can support 2ˆ128 unique addresses. The main reason for subnetting IP version 4 is to increase its effectiveness in using its small space, but such a limitation of space does not apply to IP version 6. In subnetting the IPv6, CIDR notation is used that is developed for IPv4 as well. It is a way of specifying the size of the network in addition to the actual network number. IPv6 subnets are at least 64 bits wide. Subnetting in IPv4 results in network complexity, but this is not a problem in IPv6 as the servers have a different interface ID, hence they can all exist in the same subnet (Malone & Murphy 27).
Subnetting plays a vital role in assigning networks for diverse administrative, technological reasons, for example, routing or security.
Works Cited
Hagen, Silvia. IPv6 essentials. California: O’Relly Media, 2006. Print.
“How to Subnet a Network.” Learning Networking. 2007. Web.
Kozierok, Charles. The TCP/IP guide: a comprehensive, illustrated internet protocols reference. San Francisco: William Pollock, 2005. Print.
Malone, D., & Murphy, N. IPv6 network administration.California: O’Relly Media, 2005. Print.