Lecture 2 Flashcards
What is a network?
Any thing reticulated or decussated, at equal distances, with interstices between the intersections.
What is the G(V,E) notation?
A graph is made up of vertices & edges. Vertices are all the dots and edges are which dots connect to which.
What does a router do?
Handle packets from different networks.
Routes traffic between two different networks.
What are the three different communication modes?
Simplex - One way only
Half Duplex - Two ways, one at a time
Duplex - Two ways both at the same time.
What is the difference between symmetric and asymmetric communication?
Symmetric: Send and receive using the same communication media.
Asymmetric: Send and receive using different communication medias.
Name the four different communication methods. Unicast…
Unicast: 1-to-1
Broadcast: 1-to-all
Multicast: 1-to-many
Anycast: 1-to-any
Name three different types of area networks.
Local Area Network (LAN): Devices often within the same building.
Metropolitan Area Network (MAN): Devices often within the same city.
Wide Area Network (WAN): Networks extending over large / multiple geographical regions.
BAN, PAN, Internet and Interplanetary Internet
I say CSMA, you say? (Two things)
CSMA/CD: Carrier Sense Multiple Access / Collision Detection. Send, if a collission is detected wait random time and then send again.
CSMA/CA: Carrier Sense Multiple Access / Collision Avoidance.
What is the truncated binary exponential backoff?
After a collision is detected by, each station waits for a random time between [0, 1] slot before attempting to retransmit again.
Each collision is expands this window to increase the chances of a collision.
What is the maximum amount of tries in the binary exponential backoff?
10.
What is a VLAN?
A Virtual LAN (VLAN) is a group of devices on one or more LANs that are configured to communicate as if they were attached to the same wire.
Physically they may be on the same device, but logically they are different and cannot talk to each other.
What is ARP used for?
Converting IP Addresses to MAC Addresses, allows for Layer 2 communication.
Which type of hardware is controlled by IEEE802.11?
Wireless Adapters.
What is the bus topology?
Multiple nodes are connected via a main shared-half duplex link.
What are the pros of bus topology?
Simple connection and extension of computers and other devices.
Cheap as chips.
What are the cons of bus topology?
Single point of failure
Bigger networks would not work well as high probs of packet crashing ya’ll.
What is ring topology?
All nodes have exactly two other nodes connected to each other, to form a circle.
What are the pros of ring topology?
Better performance than bus topology
No central host
Relatively simple to add new hosts
What are the cons of ring topology?
Faulty host can break the ring
Increasing communication delay as a function of number of hosts
Higher complexity in configuring new hosts
What is the star topology?
All hosts connected to a central node. I.E. a switch.
What are the pros of a star topology?
No disruptions to the network when adding/removing devices.
Easy to install and simple wiring.
Simple fault detection and component replacements.
What are the cons of a star topology?
Central node (hub) is the single point of failure.
More expensive than linear bus topologies - costs more cable than bus topology.
What is mesh topology?
All nodes directly connected to all other nodes.
What is the fat tree concept?
For every downlink there’s an uplink.
I.E. if two servers connect to a switch, that switch should have two uplinks to the next intermediary device.
