8. What is a network?
- [[NIC]]
- [[MAC Address]]
- Modulation of Wavelengths
9. Most basic type of network
- [[RJ45]]
- [[UTP]] (Unshielded Twisted Pair) - e.g. shielding is not thick enough to protect from electric interference
- [[NIC]]
- [[MAC Address]]
- Modulation of Wavelengths
10. A bit of networking history
- [[10BASE5]] - also known as thick Ethernet or [[thicknet]]. Was a first commercially available [[Ethernet]].
- 10Mbit/s max shared bandwidth between max 100 station over max 500m.
- [[10BASE2]] - also known as [[thinnet]]. Cheaper and more convenient alternative to [[10BASE5]]
- **10Mbit/s** over thick coaxial cable over max 185m.
- [[Bus Network]] - single collision domain. All devices share same bandwith.
- [[UTP]] / [[STP ]]
- [[Fiber Cable]]
- [[Multi-mode Fiber]]
- [[Single-mode Fiber]]
11. Servers, Clients, Ports and Protocols
- [[Network]]
- [[Server]]
- Server provides service to a [[client]]
- Server needs to listen on specific port number, as it doesnt automatically switch from one to another
- [[Client]]
- [[Protocol]] - set of rules used for communication between devices. e.g. [[TCP IP]]
- [[Port Number]]
12. Practical Demonstration using Packet Tracer
- [[Ethernet Cable]]
- [[Straight Through Cable]] - connects computer to a [[network device]]. should have both ends wired in the same color. As such both ends in either [[T568B]] or [[T568A]]. Used to connect **2 different types of devices.**
- [[Crossover Ethernet cable]] - connects 2 computers or [[network device]]s directly to one another. should have one wiring standard on one end and another on another. So e.g. T568B on one side, T568A on another side. Crossover Cables are used to wire same type of devices.
- [[MAC]] - MAC Address stand for [[Media Access Control]]. It is a unique identifier for NICs within networks they operate. As such each [[NIC]] has their own MAC address, and devices on a network do not share the same MAC Address.
- [[DHCP]] - DHCP Stands for [[Dynamic Host Configuration Protocol]]. It allocated IP addresses automatically. And allows to computers to communicate between each other.
13. Networking Devices: Repeaters, Hubs, Switches and Routers
- [[Repeater]] - It simply amplifies the signal and repeats it .: e.g. because 10base5 was limited to only 500m, thus if you wanted to extend it you would need to use **repeater**.
- [[Hub]] - works at Layer 1. Sometimes called as multi-port-repeater. Same as [[repeater]], but with multiple RJ45 ports. It simply amplifies and repeats the signal from one port to multiple ports. It doesn't understand the frames it receives, nor any information. The problem is if you have too many repeats on one network, the more collisions you gonna have.
- Nowadays, the closest alternative to a hub is [[WiFi]], but just in the air.
- [[Wireless Access Point]]
- [[Bridge]] - learns MAC addresses in software.
- [[Switches]] - works at Layer 2. Uses hardware to route traffic. Learns MAC addresses by using HARDWARE ASICS (Application Specific Integrated Circuit). Smarter than hubs, able to read frames. Has mac address table. Thus, it learns from which port the information was received and from which port it was sent out, as such reducing the amount of collisions, and network downtimes.
- *Some switches nowadays have routing functionality, thus they are Layer 3 devices. They are able to route traffic from one VLAN to another. From one subnet to another subnet.
- [[WAN]]
- [[LAN]]
- [[Routers]] - work at Layer 3. They use [[IP Address]]es to route traffic from one network to another. Usually to route traffic from *LAN* to *WAN*. Some switches nowadays can also route traffic.
14. Networking Devices: Firewalls, IDS, IPS and WLC
- [[Firewall]] - allow to restrict access to a network. They use firewall rules to permit or deny traffic. You usually position it before the router or after the router.
- [[WLC]] (Wireless Lan Control) - to control WAPs (Wireless Access Points)
- [[IPS]] (Intrusion Prevention System) - sits within the traffic. And when there is attack it will block it.
- [[IDS]] (Intrusion Detection System) - sits outside the traffic. It will notify you.
Flashcards/Active Recall Q+A: #CCNA/DavidBombal/cards
What is [[RJ45 cable]]? #card
- Most common cable used to connect computers onto Ethernet-based LANs.
- Also called [[8P8C]] (8 pin 8 position) or [[UTP]] ([[Unshielded Twisted Pair]]) or [[STP]] ([[Shielded Twisted Pair]]), or simply [[Ethernet Cable]]
What is [[UTP]] & [[STP]]? #card
- UTP stands for Unshielded Twisted Pair. [[Cable]] which inside has 8 separate wires, which are then twisted in 4 pairs. At the end of these cables a connector can be places, known as [[RJ45]].
- UTP wires are not protected, thus better alternative is [[STP]] ([[Shielded Twisted pair]])
What is [[NIC]]? #card
- NIC stands for [[Network Interface Card]]. Sometimes also referred as [[network adapter]], [[LAN adapter]] or [[physical network interface]].
- NIC is a computer expansion card for connecting to a network using an [[Ethernet cable]] with an [[RJ45]] connector. But also might be in a form of dongle or USB.
What is [[MAC Address]]? #card
- MAC Address stand for [[Media Access Control]]. It is a unique identifier for NICs within networks they operate. As such each [[NIC]] has their own MAC address, and devices on a network do not share the same MAC Address.
What was [[10BASE5]] and [[10BASE2]], what were their limitation? #card
- [[10BASE5]] used big thick and stiff coaxial cable, which gave its name as [[thicknet]]. It also used [[Bus Topology]], which meant [[single collision domain]], all devices were connected to the same cable. Which made it difficult to troubleshoot individual devices. All devices shared the same bandwidth of 10Mbit/s.
- [[10BASE2]] used thin coaxial cable, as such was also called as [[thinnet]]. Although, it still used [[Bus Topology]] and shared bandwidth with all other devices on the same cable.
What is a [[Server]]? #card
- Server provides service to a [[client]].
What is a [[Protocol]]? #card
- Most common example of a protocol is [[TCP IP]] . TCP/IP. It is a set of rules used for communication between devices.
- Other examples of [[protocol]]s include, [[FTP]], [[SSH]], [[HTTP]], [[ARP]], [[ICMP]] etc.
What is [[Ethernet Cable]], [[Straight Through Cable]] and [[Crossover Ethernet Cable]]? #card
- Ethernet cable also known as [[LAN Cable]], [[Cat 5]]. Consists of 4 pairs of twisted pairs of copper wire terminated by an RJ45 connector.
- [[Straight Through Cable]] and [[Crossover Ethernet Cable]] are simply defined by how they are wired.
- [[Straight Through Cable]] connect computer to a network device. Should have both ends wired in the same color. As such both ends in either T568B or T568A. Used to connect **2 different types of devices.**
- [[Crossover Ethernet cable]] connects 2 computer, or 2 network devices directly together e.g. [[NIC]] to NIC. Should have one wiring standard on one end and another on another. So e.g. [[T568B]] on one side, [[T568A]] on another side. Crossover Cables are used to wire same type of devices.
What is [[DHCP]]? #card
- DHCP Stands for [[Dynamic Host Configuration Protocol]]. It allocated [[IP address]]es automatically.
- And allows to computers to communicate between each other.
What is [[Repeater]]? #card
- It simply amplifies the signal and repeats it .: e.g. because 10base5 was limited to only 500m, thus if you wanted to extend it you would need to use **repeater**.
What is a [[Hub]]? #card
- [[Hub]] - works at Layer 1. Sometimes called as multi-port-repeater. Same as [[repeater]], but with multiple RJ45 ports. It simply amplifies and repeats the signal from one port to multiple ports. It doesn't understand the frames it receives, nor any information. The problem is if you have too many repeats on one network, the more collisions you gonna have.
At what [[OSI Model]] does [[Hub]] operates? #card
- Layer 1
What is [[Bridge]] ? #card
- Something between a [[Switch]] and a [[Hub]]. It learns MAC addresses in software.
What is a [[Switch]], and at what OSI Model does it operate? #card
- Works at Layer 2. Uses hardware to route traffic. Learns MAC addresses by using HARDWARE ASICS (Application Specific Integrated Circuit). Smarter than hubs, able to read frames. Has mac address table. Thus, it learns from which port the information was received and from which port it was sent out, as such reducing the amount of collisions, and network downtimes.
- *Some switches nowadays have routing functionality, thus they are Layer 3 devices. They are able to route traffic from one VLAN to another. From one subnet to another subnet.
What is a [[Router]], and at what OSI Model does it operates? #card
- [[Routers]] - work at Layer 3. They use [[IP Address]]es to route traffic from one network to another. Usually to route traffic from LAN to WAN. Some switches nowadays can also route traffic.
What is [[Firewall]]? #card
- [[Firewall]] - allows to restrict access to the network. It can allow or deny access to either inbound or outband traffic. Firewall usually sits before the router, or after the router.
What is [[WLC]]? #card
- Centralised spot for all [[Wireless Access Point]]s.
- WLC stands for Wireless Lan Controller which acts a controller for multiples of WAP (Wireless Access Points).
What is [[IPS]] and [[IDS]]? #card
- Intrusion Prevention System - which sits within the traffic. And is able to block any attacks.
- Intrusion Detection System - sits outside the traffic. And simply notifies of an attack.