20CS271 CHS RECORD (1)-39-72

Hardware Devices Used in Network

Hub

• Connects multiple computer networking devices together.

• Acts as a repeater, amplifying signals over long distances.

• Simplest network connecting device, connecting LAN components with identical protocols.

• Configurable for both digital and analog data formats.

• Digital data: sent as packets.

• Analog data: sent in signal form.

• Does not perform packet filtering or addressing; sends data packets to all connected devices.

• Operates at the Physical layer of the OSI model.

• Types: Simple hub and multiple port hub.

Switch

• More intelligent than hubs; improves network efficiency.

• Maintains limited routing information about nodes in the internal network.

• Allows connections to systems like hubs or routers.

• Reads hardware addresses of incoming packets to direct them correctly.

• Offers virtual circuit capability, enhancing network security and efficiency.

• Works at the Data Link layer or Network layer of the OSI model.

• Multilayer switches can operate at both layers, fulfilling router functions as well.

• Flood guards prevent DDoS attacks; implement switch port security by disabling unused ports.

Router

• Transmits packets to their destinations by determining paths through interconnected devices.

• Intelligent; stores information about connected networks.

• Configurable for packet-filtering firewalls using access control lists (ACLs).

• Translates LAN framing to WAN framing with CSU/DSU, known as border routers.

• Divides internal networks into sub-networks, establishing communication through routing tables.

• Supports both static and dynamic routing.

• Operates at the Network layer of the OSI model.

Bridge

• Connects two or more hosts or network segments.

• Stores and forwards frames between different segments based on MAC addresses.

• Can connect two physical LANs into a larger logical LAN.

• Operates at the Physical and Data Link layers of the OSI model.

• Bridges filter frames for addresses; typically less functional than switches.

Gateway

• Operates at the Transport and Session layers of the OSI model.

• Connects two or more autonomous networks using different routing algorithms.

• Provides translation between networking technologies.

Modem

• Modulates and demodulates signals to transmit digital data over analog telephone lines.

• Converts digital signals for transmission and vice versa.

• Works on the Physical and Data Link layers.

Repeater

• Amplifies and retransmits signals to extend their reach over longer distances.

• Operates on the Physical layer.

Access Point (AP)

• Commonly a wireless device, but serves as a bridge or router.

• Creates a wireless LAN (WLAN) using a transceiver.

• Provides connections between WLANs and wired Ethernet LANs.

• May require multiple access points for full network coverage.

• Can be configured as fat (manual configuration) or thin (remote management).

UTP and Optical Fibers in Networking

UTP (Unshielded Twisted Pair) Cable

• 100 ohm copper cable consisting of 2 to 1800 unshielded twisted pairs surrounded by an outer jacket.

• Vulnerable to electrical interference, but twists improve EMI immunity.

• Categories of UTP cables based on applications and performance.

• Solid Conductor: Single solid wire; stable for longer transmission and higher data rates.

• Stranded Conductor: Used mainly for patch cables; flexible but less suited for long runs.

Applications of UTP

• Used primarily for LANs including voice, data, audio systems, and building automation.

Optical Fiber

• Technology for data transmission using light pulses through glass or plastic fibers.

• Less susceptible to electromagnetic interference; higher bandwidth than copper.

• Types: Single-mode for long distances; multimode for shorter distances.

• Fiber types based on refractive index: Step index, graded index.

Testing the Connectivity Using Tester Tool

Importance of Network Testing Tools

• Periodically tests network performance to ensure efficient resource sharing.

• Helps detect network attacks and gauge end-user experience.

Types of Testing Tools

• Ping: Tests device availability; sends ICMP echo messages to verify activity.

• SNMP Ping: Tests if SNMP is enabled and retrieves device info.

• Proxy Ping: Pings through a router to get device status.

Service and Process Testing

• Checks the availability of services like DNS, IMAP, etc.

Workflow Automations

• Automate routine testing tasks, such as restarting servers or logging issues.

Installation of Network Drivers

Windows Installation Steps:

• Insert the adapter.

• Open Device Manager and update driver software.

• Browse to the driver location and install.

Linux Installation Steps:

• Use ifconfig to check network interfaces.

• Uncompress and unpack drivers, then load them.

Firewall and Its Types

Definition

A firewall is a device that monitors network traffic, providing a filtering mechanism based on defined rules to enhance security.

Types of Firewalls

• Software Firewalls:

  • Installed on individual devices (e.g., personal computers).

  • Resource-intensive as they consume device processing power.

  • Provides a customizable security layer for each individual device.

• Hardware Firewalls:

  • Standalone devices dedicated to protect multiple systems on a network.

  • Often placed between a router and the network.

  • Offers a unified approach to network security without burdening individual devices.

• Packet-Filtering Firewalls:

  • Inspects incoming and outgoing packets against rules defined in access control lists (ACLs).

  • Can block or allow traffic based on IP addresses, ports, and protocols.

  • Provides inline security, acting on packets as they flow through the network.

• Proxy Firewalls:

  • Acts as an intermediary between the client and the internet.

  • Masks client identities and prevents direct connections, enhancing privacy.

  • Can also cache data for improved performance and reduce latency.

Cyber Threats and Backup Tools

Definition of Cyber Threats

Cyber threats refer to attacks against digital devices aiming at disruption, theft, or espionage. Cybersecurity is key for data integrity and corporate security.

Common Cyber Threat Types

• Malware:

  • Malicious software designed to harm, exploit, or otherwise compromise devices and data.

  • Includes viruses, worms, Trojans, ransomware, and spyware.

• Phishing:

  • A tactic used to deceive individuals into providing sensitive information by masquerading as a trustworthy entity.

  • Often occurs through emails or fake websites that resemble legitimate sources.

• Man in the Middle (MitM):

  • An attack where the attacker secretly intercepts and relays messages between two parties who believe they are communicating directly with each other.

  • Can lead to data theft or impersonation.

• Ransomware:

  • Malicious software that encrypts files on a victim’s computer and demands a ransom for the decryption key.

  • Usually spreads through phishing emails or by exploiting system vulnerabilities.

• DDoS Attacks:

  • Distributed Denial of Service attacks flood a targeted website or service with excessive traffic, causing disruptions or outages.

  • Often involves networks of compromised computers (botnets).

• Data Breaches:

  • Unauthorized access to confidential data, often resulting in the exposure of sensitive information.

  • Can occur through hacking, human error, or inadequate security practices.

Backup and Recovery

• The process of creating data copies for recovery after loss.

• Regular backups minimize data loss risks and facilitate recovery from various failures.