Internet Protocol: - Communication between hosts takes place only when they can be recognized on the network. In a single collision domain [where each packet sent by each host on one host is heard by other hosts] the host can communicate directly via the MAC address. The MAC address is a factory-coded 48-bit hardware address, or it can be uniquely Identify the host. However, if the host wants to communicate with the remote host, that is, not in the same segment or logically not connected, some addressing methods are needed to specifically identify the remote host. Provides a logical address for all hosts connected to the Internet, which is called an Internet Protocol address.
The network layer is responsible for transferring data from one host to another. It provides a way to assign logical addresses to hosts and uniquely identify them using the same method. The network layer takes the data units from the transport layer and switches them to a smaller unit called a packet.
The network layer defines the data path and the packet should follow the destination. The router works on this layer and provides a mechanism to route data to its destination. Most Internet uses a suite of protocols called the Internet Protocol Suite, also known as the TCP/IP suite. The kit is a combination of protocols that contain many different protocols for different purposes and needs. Since the two main protocols in this suite are TCP [Transmission Control Protocol] and IP [Internet Protocol], they are often referred to as the TCP/IP protocol suite. The protocol suite has its own reference model, which is tracked over the Internet. This protocol model contains fewer layers than the OSI model.
Internet Protocol Version 4 [IPv4]
The Internet Protocol is one of the main protocols in the TCP/IP suite of protocols. The protocol works in the network layer of the OSI model and the Internet layer of the TCP/IP model. Therefore, the protocol is responsible for identifying hosts based on their logical addresses and routing data between them through the underlying network.
IP provides a mechanism for uniquely identifying hosts through IP schemes. IP uses best-effort delivery, ie it does not guarantee that the packet will be delivered to the target host, but it will try to reach its destination. Internet Protocol version 4 uses a 32-bit logical address.
The Internet Protocol, which is an Layer 3 Protocol [OSI], acquires data segments from Layer 4 [Transport] and divides them into packets. The IP packet encapsulates the data unit received from the upper layer and is added to its own header information.
The package data is called IP Payload. The IP header contains all the necessary information to transmit the packet at the other end.
The IP header contains a number of related information, including the version number, which in this context is 4. Other details are as follows:
from
• Version: Version number. The Internet protocol used [for example, IPv4].
from
• International humanitarian law: the length of the Internet title; the length of the entire IP header.
from
• DSCP: Differentiated service code point; this is the type of service.
from
• ECN: Explicit congestion notification; it contains information about the congestion seen in the route.
from
• Total length: The length of the entire IP packet [including the IP header and IP payload].
from
• Identification: If an IP packet is fragmented during transmission, all fragments contain the same identification number. Identify the original IP packets to which they belong.
from
• Flag: According to the requirements of network resources, if the IP data packet is too large to be processed, then these flags will have problems. Tell them if they can be dispersed. In this 3-digit flag, the MSB is always set to ' 0'.
from
• Fragment Offset: This offset indicates the exact location of the fragment in the original IP packet.
from
• Time to live: To avoid looping through the network, each packet is sent with some TTL value setting, which tells the network how many routers [hops] this packet can span. At each hop, its value is decremented by one, and when the value reaches zero, the packet is discarded.
from
• Protocol: Tells the network layer on the target host which protocol the packet belongs to, ie the next level of protocol. For example, ICMP has a protocol number of 1, TCP is 6, and UDP is 17.
from
• Header Checksum: This field is used to retain the checksum value of the header and is then used to check if the packet is received without error.
from
• Source Address: The 32-bit address of the sender [or source] of the packet.
from
• Destination Address: The 32-bit address of the receiver [or destination] of the packet.
from
• Option: This is an optional field that is used if the value of IHL is greater than 5. These options may include values for options such as security, record path, timestamp, and so on.
The Internet Protocol hierarchy contains several types of IP that can be used effectively in a variety of situations depending on the host requirements of each network. Broadly speaking, IPv4 systems are divided into five types of IP addresses. All five classes are identified by the first octet of the IP.
The Internet Corporation for Assigned Names and Numbers is responsible for assigning IP.
The first octet mentioned here is the leftmost one. The octet number is as follows, depicting the dotted decimal notation of IP:
You can export the number of networks and the number of hosts per class by the following formula:
When computing the host #39; IP, 2 IP is released because they cannot be assigned to the host, ie the first IP of the network is the network number and the last IP is reserved for the broadcast IP.
Class A address
The first bit of the first octet is always set to 0 [zero]. Therefore, the first octet ranges from 1 to 127, ie
Class A addresses only include IPs from 1.xxx to 126.xxx. The IP range 127.xxx is reserved for the loopback IP address.
The default subnet mask for Class A IP addresses is 255.0.0.0, which means that Class A addressing can have 126 networks [27-2] and 16777214 hosts [224-2].
Therefore, the class A IP address format is: 0NNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH
Class B address
The IP address belonging to class B sets the first two bits of the first octet to 10, that is,
Class B IP ranges from 128.0.xx to 191.255.xx The default subnet mask for class B is 255.255.xx
Class B has 16384 [214] network addresses and 65534 [216-2] host addresses.
The class B IP format is: 10NNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH
Class C address
The first 3 bits of the first octet of the class C IP address are set to 110, namely:
Class C IP ranges from 192.0.0.x to 223.255.255.x. The default subnet mask for class C is 255.255.255.x.
Class C gives the 2097152 [221] network address and the 254 [28-2] host address.
The C class IP address format is: 110NNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH
Class D address
The first four bits of the first octet in the class D IP address are set to 1110, giving the following range:
The IP range of class D ranges from 224.0.0.0 to 239.255.255.255. Class D is reserved for multicast. In multicast data, the data is not specific to a particular host, which is why it is not necessary to extract the host address from the IP address, and Class D does not have any subnet mask.
Class E address
This IP class is for experimental purposes only for research or development. The IP address range in this class is 240.0.0.0 to 255.255.255.254. Like the D class, this class is not equipped with any subnet mask.
Each IP class is equipped with its own default subnet mask, which binds the IP class to a host with a prefixed number of networks and a prefix number per network. Classful IP does not provide any flexibility, that is, each network has a smaller number of hosts or each IP class has more networks.
CIDR or classless inter-domain routing provides the flexibility to borrow bits of an IP host and use them as a network in a network, called a subnet. By using subnetting, you can use a single Class A IP address to create smaller subnets, providing better network management capabilities.
Class A subnet
In class A, only the first octet is used as the network identifier, and the remaining three octets are used to allocate to the host [ie, 16,777,214 hosts per network]. To create more subnets in class A, you can borrow bits from the host section and change the subnet mask accordingly.
For example, if you borrow an MSB [most significant bit] from the host bit of the second octet and add it to the network address, two subnets [21 = 2] and [223-2] are created for each subnet. ]8388606 host.
Change the subnet mask accordingly to reflect the subnetting. The following lists all possible combinations of Class A subnets:
In the case of subnetting, the first and last IP of each subnet are used for subnet number and subnet broadcast IP, respectively. Since these two IP addresses cannot be assigned to the host, subnets cannot be implemented using network bits with more than 30 bits, and the network bits provide fewer than two hosts per subnet.
Class B subnet
By default, a classful network is used, with 14 bits used as network bits, providing [214] 16384 networks and [216-2] 65534 hosts. Class B IP addresses can be subnetted in the same way as Class A addresses by borrowing from host bits. All possible combinations of Class B subnetting are given below:
Class C subnet
Class C IP addresses are usually assigned to a very small network because it can only have 254 hosts in the network. The following lists all possible combinations of subnet Class B IP addresses:
Internet service providers may face the need to allocate different sizes of IP subnets based on customer requirements. One customer may ask for a Class C subnet for three IP addresses, while another customer may request 10 IP addresses. For ISPs, it is not feasible to divide the IP address into fixed-size subnets. Instead, you may want to subnet the subnets in this way, thus minimizing the waste of IP addresses.
For example, an administrator has a network of 192.168.1.0/24. The suffix / 24 [pronounced "slash 24"] indicates the number of bits...
Orignal From: Internet Protocol Version 4
No comments:
Post a Comment