Data Comms Flashcards
What are the seven Omi layers?
Application
Presentation
Session
Transport
Network
Data link
Physical
What is the physical layer
The electrical and physical specifications for devices
What is the data link layer
The transfer of data between a network entities
What is the network layer?
Responsible for IP handling
What is the transport layer?
Assembled data packets into their correct sequence
What is attenuation?
The Gradual weakening of a signal as it passes through a wire or other medium
What are the advantages of UTP STP and fiber optics?
UTP
- cheap
- easy to install
STP
- less susceptible to emi
- less susceptible to crosstalk
- greater bandwidth
- reduced emissions
Fiber optics
- not susceptible to emi
- not susceptible to cross talk
- even greater bandwidth
What are the physical topologies?
Bus: a single cable supports an entire network segment. Inexpensive
Star: each node is connected to a central device. Inexpensive, easy wire ring, expandable.
Ring: all nodes are connected to each other, forming a circle. Equal access to data.
Mesh: each node is connected to every other node. Provides redundancy, reliable, greater bandwidth.
What’s all the internet working devices and how do they work?
Repeaters: regenerate signal, physical layer
Bridges: connects two or more data segments, data link layer
Routers: sends packets to their appropriate destinations, Network layer
Gateways: translates between protocols and data, application to transport layer.
An example of a private IP
- 13
What parameters can a firewall check
Packet source and destination
Protocol
Port number
