In summary, LANs and WLANs are used for connecting devices within a limited geographical area, while WANs, MANs, and CANs are used for connecting devices over a larger geographical area. PANs are used for connecting personal devices within a very short range.
1.6 Describe TCP vs. UDP (connection-oriented vs. connectionless), FTP, SFTP, TFTP, HTTP, HTTPS, DHCP, DNS, ICMP, NTP
TCP vs. UDP: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both transport layer protocols in the TCP/IP suite. The main differences between them lie in their connection-oriented versus connectionless nature and the reliability of data delivery.
TCP is a connection-oriented protocol. It establishes a reliable and ordered communication channel between two endpoints. It guarantees that data is delivered without errors and in the same order as it was sent. TCP achieves this by using acknowledgments, retransmission of lost packets, and flow control mechanisms. It is commonly used for applications that require error-free and ordered data delivery, such as web browsing, file transfer, and email.
UDP, on the other hand, is a connectionless protocol. It does not establish a dedicated connection before sending data. UDP is considered unreliable because it does not guarantee the delivery or order of packets. It is a lightweight protocol that provides a best-effort delivery mechanism. UDP is commonly used for applications that prioritize speed and efficiency over reliability, such as real-time streaming, video conferencing, and online gaming.
FTP (File Transfer Protocol): FTP is a network protocol used for transferring files between a client and a server on a network. It operates on the application layer of the TCP/IP model. FTP provides a set of commands and responses to facilitate file transfers. It supports authentication and various file operations like uploading, downloading, renaming, and deleting files. FTP can work in either active mode (where the client initiates the data connection) or passive mode (where the server initiates the data connection).
SFTP (SSH File Transfer Protocol): SFTP is a secure file transfer protocol that runs over SSH (Secure Shell) protocol. It provides secure file access, transfer, and management functionalities. SFTP encrypts the data during transmission, offering better security compared to traditional FTP. SFTP is commonly used when data confidentiality and integrity are essential.
TFTP (Trivial File Transfer Protocol): TFTP is a simple file transfer protocol used for transferring files between a client and a server. It operates on the transport layer of the TCP/IP model. TFTP is a connectionless protocol and lacks many features of FTP. It is primarily used for lightweight tasks like firmware upgrades or transferring boot files in network devices.
HTTP (Hypertext Transfer Protocol): HTTP is an application layer protocol used for transmitting hypertext documents on the World Wide Web. It follows a client-server model, where a web browser acts as the client and requests web pages or resources from web servers. HTTP is a stateless protocol, meaning each request-response cycle is independent of previous ones. It uses TCP as the underlying transport protocol and typically operates on port 80.
HTTPS (HTTP Secure): HTTPS is the secure version of HTTP. It adds a layer of security by encrypting the data exchanged between the client and the server using SSL/TLS protocols. HTTPS uses port 443 instead of port 80 for communication. It is widely used for secure online transactions, such as e-commerce, online banking, and sensitive data transfers.
DHCP (Dynamic Host Configuration Protocol): DHCP is a network management protocol used to dynamically assign IP addresses and network configuration parameters to devices on a network. It allows devices to obtain IP addresses automatically, eliminating the need for manual configuration. DHCP operates on the application layer and uses a client-server model. It simplifies network administration and enables efficient IP address management in large networks.
DNS (Domain Name System): DNS is a distributed system that translates human-readable domain names (e.g., www.certexamscom) into IP addresses that computers can understand. It acts as a phone book of the Internet, mapping domain names to their corresponding IP addresses. DNS operates on the application layer and uses a hierarchical and decentralized architecture. It is crucial for browsing the web, sending emails, and other network services that
2. Addressing and Subnet Formats
2.1 Compare and contrast private addresses and public addresses. Address classes, NAT concepts
Private addresses and public addresses are two types of IP addresses used in computer networks. Here's a comparison between them:
Private Addresses:
Private addresses are used within private networks, such as home or office networks, and are not routable over the internet.
They are defined by specific address ranges reserved for private use, as defined by the Internet Assigned Numbers Authority (IANA).
The most commonly used private address ranges are:
Class A: 10.0.0.0 to 10.255.255.255
Class B: 172.16.0.0 to 172.31.255.255
Class C: 192.168.0.0 to 192.168.255.255
Private addresses are used for internal communication within a private network and are not directly accessible from the internet.
Private addressing allows multiple organizations to use the same address ranges without conflict, as long as they are separate networks.
Public Addresses:
Public addresses are globally unique and routable addresses assigned by an Internet Service Provider (ISP).
They are used for devices or services that need to be accessible from the internet.
Public addresses allow devices to communicate with each other across the internet.
Public addresses are limited, and ISPs manage their allocation to organizations and individuals.
Examples of public addresses are 203.0.113.0 or 2001:db8:0:1234:0:567:8:1 (IPv6).
NAT (Network Address Translation) Concepts:
NAT is a technique used to convert private addresses into public addresses and vice versa.
It enables multiple devices with private addresses to share a single public IP address when accessing the internet.
NAT is commonly implemented in home routers or firewalls to provide internet connectivity to devices on a private network.
Outgoing traffic from private addresses is translated to the public address of the NAT device.
Incoming traffic from the internet to the public address is translated and forwarded to the appropriate private address.
NAT helps conserve public IP addresses as multiple private addresses can be translated to a single public address.
It also provides a level of security by hiding the internal IP addresses from the outside world.
In summary, private addresses are used within private networks and are not directly accessible from the internet, while public addresses are globally unique and routable addresses used for devices or services accessible from the internet. NAT allows private addresses to be translated into public addresses and vice versa, enabling private networks to access the internet using a limited number of public addresses.
