Test2Review Flashcards
What are the 2 types of network media transmission & examples of each?
Guided - copper, fiber optics.
Unguided - radio waves, wireless
Frequency (with waves) definition, an measurement unit
Frequency = number of oscillations/second. Unit = Hertz.
Coaxial cable composition.
Composed of 2 conductors - inner (insulated) one for data transmission, and outer braided metal shield to protect the data.
2 types of coax cable connectors.
BNC & F-connector.
2 types of twisted-pair cabling.
Unshielded Twisted Pair (UTP) & Shielded Twisted Pair (STP). UTP has 4 pairs of insulated copper wires and has some resistance to EMI. STP also has 4 pairs of insulated copper wires and each pair is wrapped in foil, and all 4 pairs are wrapped in wire mesh. STP is very resistant to EMI.
Category of UTP & STP.
UTP = cat 6. STP = cat 7.
What is RJ-45?
Used with ethernet. 8-pin connector.
What is RJ-11?
Used on most home telephone networks. 4-pin connector.
What is DB-9, and is it sync or async?
9-pin connector. Used to connect the serial port on a computer to a networking device. Asynchronous serial communication.
What is USB & (sync/async)?
Universal serial bus. Synchronous communication.
USB 2.0 & 3.0 data rate.
USB 2.0 is up to 480 mbps. USB 3.0 up to 5 gbps.
What is fiber optic cabling?
Uses light from an LED or laser to transmit info through a glass fiber.
2 categories of fiber optic cable.
Multimode fiber (MMF) & Single-mode fiber (SMF).
MMF core size & usage.
Core size = 62.5 microns. Usage = router -> switch, switch -> switch, server -> switch
SMF core size & usage.
Core size = 10 microns. Usage = routers -> switches, switches -> switches.
Fiber optic vs copper (benefits of both)
Copper: cheaper, easy to install, inexpensive tools.
Fiber optic: higher bandwidth, longer distances, immune to EMI, better security, does not corrode.
What is the ethernet standard? (IEEE….)
IEEE 802.3
CSMA/CD definition.
Carrier Sense Multiple Access/Collision Detection
What is carrier sense?
Listen to the wire and verify that it is not busy. If it is busy, keep listening until it’s free.
What is multiple access?
All devices have access to the wire at the same time.
What is collision detection?
If 2 devices transmit at the same time, a collision occurs. Back off & wait a random time, then try again.
What is needed in ethernet frame for ARP & DHCP?
MAC address.
How many bits in MAC address?
48
What is MAC broadcast address?
All 48 bits are 1’s. FF:FF:FF:FF:FF:FF
What is a HUB?
Takes every incoming bit on a port & repeats it on every other port.
HUB OSI layer & topology.
Layer 1. Physically a star topology but logically a bus.
What is a bridge?
Joins 2 or more LAN segments. Analyze source MAC addresses in frames entering the bridge & populate and internal MAC address table based on those addresses. Make intelligent forwarding decisions based on the destination MAC address in the frame.
Why switch replace bridge?
Bridge makes forwarding decisions in software. Switch makes forwarding decisions in hardware using application-specific integrated circuits (ASIC). This reduces cost, has more features, and better performance.
OSI layer of switches.
Layer 2.
What are collision & broadcast domains?
Collision - set of all devices whose transmissions can cause collision of frames. Broadcast - set of all devices that receive a frame if one of them indicates a broadcast address in its transmitted frame.
of collision & broadcast domains in HUB.
1 collision, 1 broadcast
of collision & broadcast domains in bridge.
2 collision, 1 broadcast
of collision & broadcast domains in switches
4 collision, 1 broadcast
of collision & broadcast domains in routers
8 collision, 2 broadcast.
What is a multilayer switch?
Combine features of layer 2 switches & layer 3 routers. Can make decisions based on both MAC & IP addresses.
of collision & broadcast domains in multilayer switch?
4 collision, 4 broadcast.
VPN definition.
VPN = virtual private network. Allows secure communication via a tunnel network over an untrusted network.
What is a Firewall?
Network security appliance. Guards entrance to your network. Protects from malicious internet traffic. Can be software or hardware.
What is DNS?
Domain Name System. Takes a domain name like google.com and resolves it to an IP address.
How DNS service is established.
PC requests the IP address for a website. DNS server responds with the IP address. Packet is sent to the desired web server.
