EPAM Systems Interview Questions and Answers

The OSI model has 7 layers that define how data is transmitted over a network.

• Layer 1: Physical - deals with the physical connection of devices

• Layer 2: Data Link - responsible for error-free transfer of data between devices

• Layer 3: Network - handles routing of data between different networks

• Layer 4: Transport - ensures reliable delivery of data between applications

• Layer 5: Session - establishes and manages connections between applications

• Layer 6: Presentation - translates dat...read more

Networks are a collection of interconnected devices that communicate with each other to share resources and information.

• Networks can be wired or wireless

• They can be local (LAN) or wide area (WAN)

• They use protocols such as TCP/IP to facilitate communication

• Examples include the internet, corporate networks, and home networks

Yes, there are seven layers in the OSI model.

• The seven layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

• Each layer has a specific function and communicates with the layers above and below it.

• The OSI model is used to standardize communication between different computer systems.

• Examples of protocols that operate at each layer include Ethernet at the Data Link layer and HTTP at the Application layer.

A dangling pointer is a pointer that points to a memory location that has been deallocated or freed.

• Dangling pointers can lead to crashes or unpredictable behavior in a program.

• They can occur when a pointer is not updated after the memory it points to is freed.

• Example: accessing a dangling pointer after freeing the memory it points to can result in a segmentation fault.

A router is a networking device that forwards data packets between computer networks, while a switch is a networking device that connects devices within a network.

• Router operates at the network layer of the OSI model

• Switch operates at the data link layer of the OSI model

• Router connects multiple networks together

• Switch connects devices within the same network

• Router uses IP addresses to route traffic

• Switch uses MAC addresses to forward data within a network

MAC address is a unique identifier assigned to network interfaces for communications on a network.

• MAC address stands for Media Access Control address

• It is a 12-digit hexadecimal number (e.g. 00:1A:2B:3C:4D:5E)

• Used to identify devices on a network at the data link layer of the OSI model

DHCP stands for Dynamic Host Configuration Protocol, used to automatically assign IP addresses to devices on a network.

• Automatically assigns IP addresses to devices on a network

• Helps in managing and organizing IP addresses efficiently

• Reduces the need for manual configuration

• Prevents IP address conflicts

• Example: When a device connects to a network, DHCP assigns it an IP address from a pool of available addresses

REST APIs are a set of rules and conventions for building and interacting with web services using HTTP methods.

• REST stands for Representational State Transfer

• Uses standard HTTP methods like GET, POST, PUT, DELETE

• Data is transferred in JSON or XML format

• Stateless communication between client and server

• Example: Twitter API allows developers to access and interact with Twitter data