Networking Midterm Flashcards
Give the order of the OSI model (top to bottom)
What is the Application layer and give an example
Completes an identification of communication partners, provides resources, and synchronizes communications
Set of protocols and services to access resources
Example: http
What is the Presentation layer and give an example
Designed to identify the type of information being sent/received
Example: PDF
What is the Session layer and give an example
Establishes and teardown of a session
Determines if data is local or remote
Checkpoint so only the data sent after a network failure needs to be resent
Implements Class of Service
Example: FTP
What is the Transport layer and give an example
Responsible for mechanics of setup, teardown, and maintenance of a session
Encapsulate data into packet
Provides reliable or unreliable delivery of data
(Reliable requires a check after each data packet is sent, unreliable does not require a check after sending)
Example: TCP, UDP
What is the Network Layer and give an example
Connections between hosts on different networks
Defines local topology of a network
Find the logical path from source to destination
Relies on IP addresses (32 bit and 128 bit)
Routers operate on this layer (Network info updated to reflect state of network, Information stored in the routing table, used for traffic encryption)
Example: IPv4
What is the Data-Link Layer and give an example
Uses MAC addresses
Defines mechanics of physical communication
4 types of data type:
Unicast - One destination
Broadcast - Everyone on the broadcast domain
Multicast - Groups of destinations
Anycast - Data sent to receiver closest in network
Switches implemented on this layer
Ethernet and wifi for protocols
Communicate between nodes within a local layer
What is the Physical layer and give an example
Wiring
Hub acts as a physical connection
Booster will reproduce and boost the signal, increasing the maximum length
Example: Cat 5, Fibre Optic
What is Class of Service
Method of managing traffic in a network grouping similar types of traffic together and treating type as a class with its own level of service priority
Does not guarantee a level of service (bandwidth and delivery of time)
What is Quality of Service
Any technology that manages data traffic to reduce packet loss, latency, and jitter on the network.
Controls and manages network resources by setting priorities for specific types of data on the network
Often implemented on enterprise networks
Slows down/ makes traffic go faster
What is LAN
Close geographical area [Local area network]
Can be made up of many devices
What is WAN
Wide area network
Connects multiple LANs, often separated by distance
What is MAN
Metropolitan area network
A special type of WAN
What is DWAN
Defence Wide Area Network
Unclassified network, store up to protected A, process protected B
What is CSNI
Consolidated Secret Network Infrastructure
Canadian Secret Level II network
CAN-US network
What are the types of network topologies
Peer to peer
Ring
Star
Bus
Physical vs logical network topologies
Physical is geographical location of components
Logical is based on data flow
Explain peer-to-peer topology and give pros/cons
Dedicated link between two machines
Pro:
Fast
Simple
Cons:
Little flexibility
Difficult to expand
Explain ring topology and give pros/cons
Closed loop with connections between each node, data is passed through every node
Pro:
Fast
Simple
Cons:
Single medium
Limits participation
Explain star topology and give pros/cons
One central node branches out
Pro:
Lines not a SPOF
Troubleshooting
Flexible
Cons:
Central node is SPOF
Explain bus topology and give pros/cons
Each node is connected to a common medium
Pro:
Broadcasting is easy
Graceful degradation
Con:
Single backbone is SPOF
Collisions
What is a switch
Reads MAC addresses
Multiple devices can talk at once
What is a hub
Signal repeated everywhere, talks and everyone hears it
What is TCP/IP
Transmit Control Protocol / Internet Protocol
Networking protocols
Transport and network layers
What is contention
Multiple nodes putting data on the line at the same time cause collisions.
Use algorithm to avoid starvation [CSMA, CSMA/CD, CSMA/CA]
What is CSMA
Carrier Sense Multiple Access
MAC protocol which node verifies the absence of traffic before transmitting on a shared transmission medium
What is CSMA/CD
Carrier Sense Multiple Access / Collision Detect
Improves upon CSMA, terminates transmission as soon as a collision is detected thus shortening time require to retry
Used by Ethernet as a MAC protocol
What is CSMA/CA
Carrier Sense Multiple Access / Collision Avoidance
Improves upon CSMA, if the transmission medium is sensed busy before transmission, then transmission is deferred some random time
Peer-to-Peer Concept
Network where all machines carry the same application software
Simple sharing of data and devices (printer)
“Peers” share resources (processing power, disk storage), create more capability
Small to medium LANs
Advantages:
Less initial expense
No need for a dedicated server
Disadvantages:
Decentralized
Security, not same level as on client/server network
Client-server concept
Servers are highly capable specialized network machines that act to serve many users (servers have applications, data, etc.)
Clients need a small amount of software to access the server
Advantages:
Centralized
Flexible (put in new tech easily)
Accessibility (server can be accessed remotely and across multiple platforms)
Disadvantages:
Expense (large initial cost to set up server)
Maintenance (Large networks require staff to ensure efficient operation)
Network interface card, bridge, gateway (look these up) , network hardware in general
Repeaters and hubs
Same connection type, read packets inbound and transmit outbound to all devices connected to the hub/repeater
Repeaters used for extended distances
(still don’t see major difference between hubs?)
What arrays does CMS use
Raid 5 (strips data between disks, uses parity bits to be able to reconstruct data if one disk is lost)
Draw unshielded twisted pair
Draw shielded twisted pair
Recall the Ethernet naming convention
Physical mediums:
T - Twisted Pair
F - Fibre Optic
S - Short range fibre
L - Long range fibre
K - Copper backplane
C - Balanced copper cable
B - Two wavelengths over a single optical cable
S - short-range multi-mode optical cable
L - long-range single/multi-mode optical cable
E - extended range optical cable
Z - long-range single-mode cable at high wavelength
Frequencies:
BASE - Baseband, single signal on cable
BROAD - Broadband, can have multiple signals on same channel
PASS - Passband, Wireless comms
Lanes:
1 - serial
4 or 10 - copper wire
Encoding:
X - 4B/5B Block coding for fast ethernet or 8B/10B block coding for gigabit ethernet
R - 64B/66B block coding
Draw 10Base2 Thinnet (Cheapernet)
Jacket - protects cable from environment
Shield - surrounding the cable protects the data from noise
Insulator - Surrounded central core, prevent contact w/ shield
Core - Transports data
Draw Thicknet
Carries signals over long distances
Single vs. Multimode Fibre Optic Cable
Single mode - Longer range
???
MIMO
Antenna technology for wireless comms where multiple antennas are used by source and receiver. The antennas at each end of the comms circuit are combined to minimize errors and optimize data speed.
What is ISDN
Integrated Services Digital Network
Simultaneous voice and data
BRI
2X 64 kb/s B channels and 1X 16kb/s D channel
Meets needs of most individual users
PRI
23X B channels
1X D channel
PRI used for users with greater capacity requirements
