Chapter: 11 Local Network Access ( Networking Terminology)

Overview of Networking

• Networking involves a group of connected computers or nodes through communication media and protocols.

• The size of networks can vary vastly, from small home networks of PCs to large multinational corporate networks.

Networking Terminology

• Client-Server Networks: A central concept in networking describes a relationship where a client requests services from a server.

  • A client (e.g., desktop computer) accesses resources provided by a server.

  • Switches provide connectivity between local clients and servers, while servers offer resources like files and printers to clients.

  • Clients can also send requests to servers across multiple networks, like accessing HTML documents from web servers.

• Peer-to-Peer Networks: In contrast to client-server models, P2P networks include computers that can act as both clients and servers.

  • Common in home office setups (SOHO), where a router connects to various local computers and the Internet.

  • File sharing services such as Server Message Block (SMB) and its variant, Common Internet File System (CIFS), are used for peer-to-peer connections.

  • Samba provides P2P networking on CentOS 7, allowing file sharing between systems like Windows 10 and CentOS.

Local Area Networks (LANs) and Wide Area Networks (WANs)

• Local Area Networks (LANs):

  • Typically confined to a specific geographic area such as a building or campus.

  • Can range from a few computers to hundreds, facilitating resource sharing and communication.

  • The standard networking protocols have led to widespread use of LANs in businesses and educational organizations.

• Wide Area Networks (WANs):

  • Connect multiple geographically separated LANs using various technologies (leased lines, satellite links, etc.).

  • WANs vary in complexity, from simple remote access systems to extensive networks interlinking multiple offices globally.

The Internet and Intranets

• The Internet: A global system of linked networks that provides data communication services.

  • It has transformed communication and enabled social media platforms to gain popularity.

• Intranets: Private networks using Internet-like applications that are restricted to specific organizations.

  • Serve as platforms for easy access to corporate information and web-based applications for employees.

Virtual Private Networks (VPN)

• VPNs utilize tunneling to secure data transfer over the Internet to a remote workplace server.

  • This method reduces costs associated with long-distance calls and uses encryption for data security.

Internet Protocol (IP) and Networking Protocols

• Internet Protocol (IP) is the primary networking protocol that enables data delivery between computers via unique IP addresses.

  • The rule set guiding computer communication is referred to as a protocol, which governs connection formats and message exchanges.

Internet Protocol Suite

• Consists of various protocols used in tandem for networking tasks.

  • Central to the suite are IP and the Transmission Control Protocol (TCP).

  • IP manages the delivery of data packets, while TCP organizes and reassembles these packets into files.

Layers of the Internet Protocol Suite

1. Network Layer: Links computers.

2. Internet Layer: Transfers IP packets across the network.

3. Transport Layer: Organizes packets with TCP.

4. Application Layer: Involves protocols for various data transfers (HTTP, FTP, SMTP, etc.).

Network Access and Addressing

• Network Access Layer: Specifies data transmission as signals over physical media using MAC addresses (48 bits, represented as 12-digit hexadecimal numbers).

  • MAC addresses identify physical devices on the network.

• IP Addressing:

  • IPv4 addresses consist of 32 bits, divided into four octets, whereas IPv6 offers 128 bits for more address possibilities.

  • Dynamic Host Configuration Protocol (DHCP) servers can dynamically assign IP addresses to devices.

Transport and Application Layers

• Transport Layer: Provides session management and delivery guarantees using protocols like TCP and UDP.

• Application Layer: Hosts numerous protocols, including:

  • HTTP: For web requests.

  • FTP: For file transfers.

  • POP3 and SMTP: For email handling.

Additional Network Models

• Alternative models, including the OSI model, have similarities to the Internet protocol suite but may differ in structure, notably with an additional link layer.