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Unit 1 :computer:, image, image, :keyboard:, image, image, https…
Unit 1 :computer:
LO1
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Output Devices: send data from a computer system to a user, or another computer system. E.g. monitor
Input Devices: send data into a computer system. Often used by people to interact with computers. E.g. a mouse
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Membrane: a "membrane" covers the surface under all keys, which detects which key(s) have been pressed.
Communication device: a hardware device capable of transmitting an analog or digital signal over a communication wire, or wirelessly.
Modem: a hardware device that connects a computer or router to a broadband network. A modem takes the digital signals from a computer system and converts them into analogue for sending. Once received, it then converts these signals back into digital signals.
Network Interface Card (NIC) responsible for sending packets of data across a network.
- It's connected to the motherboard
- allows connection to a network via Wi-Fi or Ethernet cable.
- each has a globally unique address- the MAC address- (48bits)
Router: A device which connects networks together across the Internet.
- It manages data packets by determining the shortest path to their destination network.
- Algorithms are used to determine the quickest journey time.
- They maintain a table of neighborhood networks which can be shared.
- Home routers connect to their ISP, which manages the transmission of packets.
- Larger organisations manage the transmission of packets themselves.
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LO2
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Diagnostic Tools:
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Event Log Viewer:
- Use: To capture and display system events and error.
- How it works:
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UDP:
- Protocol type: Connectionless.
- Reliability: Doesn't guarantee packet delivery.
- Error-checking: Uses checksums for basic error detection.
- Overhead: Minimal header overhead, making it lightweight.(Not many directions).
- Ordering: Doesn't guarantee ordered delivery of packets.
- Port Numbers: Utilises port numbers for addressing and data differentiation.
- Uses: for streaming services(where data has to be sent quickly rather than making sure it's perfect.)
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SNMP(Simple Network Management Protocol)
- Purpose: Designed for network monitoring and management.
- Components: SNMP has two primary components:
- agents (reside on network devices)
- the management system (monitors and controls agents).
- Uses:
- Monitor Device Performance: SNMP provides real-time data on the performance of network devices. *This includes metrics like bandwidth usage, error rates, and uptime.
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- Health Check & Diagnostics: Through SNMP, administrators can quickly gauge the health and operational status of network devices, identifying potential issues or bottlenecks.
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- Configuration Management: Beyond passive monitoring, SNMP allows remote configuration of network devices. Administrators can make changes to a device's settings or even reboot it remotely.
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- Receive Alerts: When certain predefined conditions or thresholds are reached, SNMP agents send "traps" to the management system, alerting administrators to potential issues in real time.
- Benefits of Using SNMP:
- Scalability: SNMP can be used to manage small home networks or large enterprise networks with thousands of devices.
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- Interoperability: Given its standardized nature, SNMP offers interoperability among various hardware and software vendors. Devices from different manufacturers can be managed using a single SNMP management system.
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- Proactive Management: With the trap functionality, SNMP allows for proactive network management. Instead of waiting for issues to become noticeable, administrators are alerted at the first sign of trouble.
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- Resource Efficiency: SNMP provides a centralized way of managing multiple devices. This reduces the need for manual checks and onsite visits, saving time and resources.
IP: a set of rules that dictate how data should be sent and received over the internet. It provides an addressing system and facilitates the routing of data packets between devices across diverse networks.
- Key features & concepts:
- IP Addressing: A unique string of numbers separated by periods that identifies each device connected to a network. (IPv4 or IPv6)
- Datagrams: Packets of data sent across IP networks. They contain source and destination addresses and data.
- Routing: The process of moving a packet of data from its source to its destination. Routers read the destination IP address and forward the packet to its final destination.
- Fragmentation: When a datagram is too large for a network to transmit, it's broken into smaller pieces. These pieces are reassembled at the destination.
- Time-to-Live (TTL): A limit on the lifespan of a data packet. It ensures that undeliverable packets are discarded, preventing infinite looping in the network.
- Benefits:
- Flexibility: Can work with virtually any underlying network technology.
- Scalability: Supports vast networks like the internet, as well as small local networks.
- Interoperability: Allows devices of different types and manufacturers to communicate.
- Challenges:
- Address Exhaustion: Especially with IPv4, due to limited number of addresses.
- Security Concerns: IP alone does not offer encryption or authentication.
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TCP (Transmission Control Protocol): Ensures data delivery and correct ordering. Used in tandem with IP in the TCP/IP protocol suite.
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UDP (User Datagram Protocol): Connectionless and does not guarantee delivery. Faster than TCP but less reliable.
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ICMP (Internet Control Message Protocol): Used by network devices to send error messages and operational information.
LO3
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Topologies-A Network' topology is the arrangement, or pattern in which all nodes on a network are connected together.
- A Star Topology connects all devices through a central device.
- Insecure
- If there's a problem with the server, it won't work
- Slower
- Cheaper
- A Full Mesh network connects every device to every other device.
-More cabling
-More expensive(to set up & maintain)
-Robust & secure
- (Token)Ring network connects devices after one another.
-Easy to set up
-Might break
- Bus network nodes are connected to one ethernet cable.
-Easy and cheap to set up
Virtualisation
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Server:
- Benefits:
- Cost Savings: Reduces the initial capital outlay and long-term maintenance costs.
- Resource Utilisation: Increases the use of existing physical resources.
- Business Continuity: Facilitates faster disaster recovery and better backup procedures.
- Energy Savings: Less physical hardware means reduced electricity consumption.
- Drawbacks:
- Complexity: Management can become more complicated.
- Security: If one virtual machine is compromised, others on the same physical server are at risk.
- Performance: Virtual machines share resources, which may result in performance issues.
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