Structured Cabling, ISO OSI Flashcards
Structured Cabling uses _____ to offer long term support of networks
High Performance Components
Why do we use standardized tech
Cause IT is always changing
Advantages of Structured Cabling Systems
Performance of LANs, Telecommunications, Data Systems will work predictably
Components of Structured Cabling Systems (Distributions)
Campus Distribution, Building Distribution, Floor Distribution, Telecommunications Outlet
Campus Distribution
Backbone cabling infrastructure connecting buildings on a large campus, typically using cables such as fiber optic or wireless
Building Distribution
Cabling infrastructure connecting campus distribution to floor distribution cabling
Floor Distribution
Cabling infrastructure that connects building distribution cabling to individual workstations or devices. Typically horizontal cabling running from IDF to telecommunications outlet.
Telecommunications Outlet
Endpoint of the structured cabling system providing connectivity to a specific device. Located in a wall or floor box. May include different jacks.
ISO 11801 Standard 3 Layer Model (Layers)
Horizontal Cabling, Building Backbone Cabling, Campus Backbone Cabling
Horizontal Cabling
Provides telecommunications services between floor distribution and Telecommunications outlet (Mostly copper cable)
Building Backbone Cabling
Provides telecommunications services between floors on a building. Connects building distribution to floor distributions
Campus Backbone Cabling
Connects building, connects two or more Building distributions (Almost always fiber optic)
Hardware used in cabling methods
Fibre Cables, Copper Cables, Wall sockets, cables, patch panels, patch cords, Standing Rack.
Notation for Communications Cabinet
“U” known as rack unit, equivalent to 445mm. 42U Rack will accept 42 one unit U patch.
Channel limit
100m for category 5,6,7 based cabling systems. Link should be limited to 90m.
Difference between the 2 allows patch cords to connect equipment at patch panel and devices from Telecommunications Outlet.
Communications Cabinets
used to house termination of backbone and horizontal cabling subsystems + electronics. Housed in Telecommunications Room.
Telecommunications Room
Void of direct sunlight, toilets, emergency escapes, areas prone to flooding, and areas containing fire extinguishers.
Communications Cabinets must avoid
force majure, unsecurity, vibration, dust, humidity
Communications cabinets should have
proper earthing, ventilation, lighting, security, fire protection, raised floors and documentation.
Idea of common standards in layered protocols
To develop a core of approaches amongst all vendors and provide reasonable point of departure.
Modern networks designer around ______. and what does it achieve?
layered protocols. Achieves logical decomposition, standard interfaces, and symmetry in functions.
Purpose of layered model is so layers can offer certain services to higher layers.
ISO OSI principles:
Layers created when different level of abstraction is needed
Each layer has a well defined function
Function of each layer should be chosen with international standards in mind
Layer boundaries chosen to minimize info flow between layers
Enough layers so functions do not need to be thrown into one layer out of necessity.
Line Coding
Process of converting digital data into a digital signal to transmit over communication channel.
Assigns a specific pattern of voltage to each bit of data, which helps receiver distinguish between bits.
How should we encode data
Efficiently and error-free, with as little transactions as possible.
Manchester Coding ideal
Subnet Layers
Physical, Data Link, Network
Physical Layer
Responsible for transmitting raw bitstream over physical medium, and establishing connections between devices.
Data Link Layer
If receiving -> Construct frame
If sending -> send frame via bitstream
Contains error handling and lets transmitter know buffer space
Network Layer
Routing occurring to deliver the frame to some destination. Contains either static or dynamic routes
Static Routes
Series of addresses that define a destination
Dynamic Routes
Network is aware of the networks that are connected together
Transport Layer
Split data from session layer up and pass it to network layer. Establish host to host connection.
Session Layer
User’s interface to network. Establish connection with other machines. Manages dialogue.
Session
Connection between users
Presentation Layer
Functions such as Data compression, cryptography, Data diddling, salami attack (small unnoticable attacks), Piggy-backing (using users passwords), DoS.
Data diddling
Modifying data prior to entry in stream
Encryption/Decryption
Reversible encoding scheme based around a private key known to transmitter and receiver.
Either Transposition Cypher or Substitution Cypher
Transposition Cypher
keys of letters reorganised but not necessarily disguised
Substitution Cypher
Substitute one letter with another letter or group of letters
OSI RM Security Services
Authentication
Access Control
Non-Repudiation
Integrity
Data confidentiality
Audit framework
Key Management
Non Repudiation
Prevents users from wrongly denying a specific action.
Includes Proof of origin and Proof of delivery
IEEE
Develop standards for networks. (IEEE Lan Standards Committee)
TCP/IP Main Objective
Interconnect multiple networks running in heterogeneous systems
Internet Protocol Suite
Part of TCP/IP. Created by DARPA
All protocols used by TCP IP are…
described as a protocol suite and standardized under auspices of the ISOC
ISOC
Internet Society, ISOC contains a board of trustees, along with other boards (research, engineering…)
