TOP 10 you need to know about MEACHINE LEARNING (ML) | Interview Ready

Network layer

1] Internetworking & devices: Repeaters, Hubs, Bridges, Switches, Router, Gateway

In computer networking, there are several devices that are used to connect different network segments together. These devices are called internetworking devices, and they include repeaters, hubs, bridges, switches, routers, and gateways.

Repeaters: A repeater is a simple device that is used to regenerate a signal. It receives a signal from one network segment and repeats it on another network segment, allowing the signal to travel further distances without degrading.

Hubs: A hub is a device that is used to connect multiple network segments together. It receives data packets from one network segment and broadcasts them to all other network segments that are connected to it. Hubs are considered a legacy technology and are rarely used today.

Bridges: A bridge is a device that is used to connect two or more network segments together. It operates at the data link layer of the OSI model and can filter and forward data packets based on their MAC addresses. Bridges are used to divide a large network into smaller segments to improve performance.

Switches: A switch is a device that is used to connect multiple network segments together. It operates at the data link layer of the OSI model and can filter and forward data packets based on their MAC addresses. Switches are more advanced than hubs and provide better performance and security.

Routers: A router is a device that is used to connect multiple networks together. It operates at the network layer of the OSI model and can forward data packets based on their IP addresses. Routers are used to connect local networks to the Internet and to divide a large network into smaller subnets.

Gateways: A gateway is a device that is used to connect different types of networks together. It translates data packets from one network type to another, allowing devices on different networks to communicate with each other. For example, a gateway can be used to connect a local network to the Internet, which uses a different network protocol.

2] Addressing : IP addressing, subnetting

IP addressing is a method used to assign unique numerical identifiers, known as IP addresses, to devices connected to a computer network. An IP address is a 32-bit or 128-bit binary number that is used to identify a device on the network.

In IPv4, the most common IP addressing scheme, addresses are divided into four octets, each consisting of 8 bits. These octets are separated by dots and represented in decimal form. For example, 192.168.1.1 is an IPv4 address.

Subnetting is a technique used to divide a larger network into smaller subnetworks, called subnets. Subnetting enables network administrators to create a more efficient and secure network by segmenting traffic and limiting the impact of network issues. It also helps to conserve IP address space.

Subnetting involves borrowing bits from the host portion of an IP address to create a subnet mask, which determines the size of the subnets. The subnet mask is a 32-bit binary number that consists of a string of contiguous 1s followed by a string of contiguous 0s. The 1s represent the network portion of the address, while the 0s represent the host portion.

3] Routing : techniques, static vs. dynamic routing

Routing is the process of selecting the path that network traffic takes from one network node to another. There are two main techniques for routing: static and dynamic routing.

Static routing is a technique in which the network administrator manually configures the routes that traffic will take between nodes. This method is simple and requires little overhead, as the routes do not change unless the administrator manually updates them. Static routing is often used in small networks where there is little network traffic, and the network topology does not change frequently.

Dynamic routing, on the other hand, is a technique in which routing protocols are used to automatically update the routing tables of network devices as changes occur in the network topology. Dynamic routing protocols, such as OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol), allow routers to communicate with each other and exchange information about the network topology. This allows the routers to adapt to changes in the network, such as the addition or removal of a network link, and to automatically calculate the best path for network traffic.

Dynamic routing is more complex than static routing and requires more overhead, as routers must constantly exchange information with each other. However, dynamic routing provides a number of benefits over static routing, including better network scalability, faster network convergence in the event of a failure, and more efficient use of network resources.

4] PROTOCOLS (ARP, IP, ICMP, IPV6)

ARP (Address Resolution Protocol) is a protocol used to map a network address (such as an IP address) to a physical address (such as a MAC address) in a local network.

IP (Internet Protocol) is a protocol used for communicating data across a network. It provides a logical address for devices on a network, called an IP address, and specifies how data should be packetized, addressed, transmitted, routed, and received.

ICMP (Internet Control Message Protocol) is a protocol used by network devices, like routers, to send error messages and operational information indicating whether a requested service is available, unreachable, or inoperable.

IPv6 (Internet Protocol version 6) is a newer version of the Internet Protocol that is designed to replace IPv4, which is currently the most widely used version. IPv6 provides a larger address space and more efficient routing capabilities than IPv4, which is becoming increasingly important as the number of internet-connected devices grows.

Transport layer:

5] UDP

UDP stands for User Datagram Protocol. It is a transport layer protocol used in computer networking that operates on top of the Internet Protocol (IP). Unlike TCP, which provides reliable data delivery and error checking, UDP provides a connectionless and unreliable datagram delivery service.

UDP is often used for applications that need low-latency, such as online gaming or real-time streaming. This is because UDP doesn't have the overhead of connection setup and error checking that TCP has, which can introduce additional delays.

However, because UDP doesn't provide any reliability or error correction, packets can be lost or arrive out of order. Applications that use UDP must handle this themselves, either by implementing their own error correction or by simply accepting that some data may be lost or received out of order.

Overall, UDP is a useful protocol for certain types of applications, but it's important to understand its limitations and use cases.

6] TCP

TCP stands for Transmission Control Protocol. It is a protocol used for reliable data transmission over a network. TCP is one of the core protocols in the Internet protocol suite and is responsible for establishing and maintaining connections between devices, ensuring that data is delivered in order and without errors or loss.

TCP operates at the transport layer of the OSI model, and provides a reliable, connection-oriented service for sending and receiving data packets. When two devices establish a TCP connection, they exchange control messages to negotiate the parameters of the connection, such as the maximum segment size and window size.

TCP also uses a flow control mechanism to ensure that data is transmitted at a rate that the receiver can handle. This is accomplished through the use of windowing, where the receiver sends back an acknowledgment message indicating how much data it can receive at a given time.