Networking & Storage Flashcards
Computer Network
Collection of computers and network devices that use communication channels for communication and resource sharing.
Network Topology
How different computers and network devices are arranged physically.
Point-to-point topology
Direct communication between two devices.
Line Topology
Data is passed between nodes in a sequential order.
Ring Topology
Connection of devices through other intermediate devices so there is no direct communication.
Mesh Topology
No specific arrangement.
Star Topology
Uses one intermediate device that connects all the other devices.
Fully Connected Topology
All devices are connected directly to each other.
Tree Topology
Devices are connected in a hierarchical way to achieve different access levels.
Bus Topology
All the devices are connected to one base line.
OSI Model
Method of how computers communicate with each other over a network. This method contains a stake of protocols to support the duties of each layer’s task.
The OSI Model in the order of the sender transmitting Data
Application layer
Presentation layer
Session layer
Transport layer
Network layer
Data Link layer
Physical layer
The OSI Model in the order of the Receiver receiving data
Physical layer
Data Link layer
Network layer
Transport layer
Session layer
Presentation layer
Application layer
Application layer
Works with web applications and handles the data so it is converted to a format that can be humanly readable.
Presentation layer
- Translation
- Data compression
- Encryption
Session Layer
- Authentication
- Authorization
- Manages the session
Transport Layer
- Handles segments
- Flow control
- Error handling
Protocols in the Transport Layer
- TCP (Transmission Control Protocol)
- UDP (User Datagram Protocol)
TCP
Connection oriented protocol where a direct communication pathway is created.
Process of TCP
- Sender requests the establishment of communication pathway from Receiver.
- Receiver sends an notification of agreement.
- Sender sends the data.
Advantages of TCP
- High security
- High reliability
Disadvantage of TCP
- Slower
UDP
Connectionless oriented protocol.
Advantages of UDP
Faster due to the lack of proper pathway establishment.
Disadvantages of UDP
- Less secure
- Less reliable
Network Layer
- IP Addressing
- Path determination
- Routing
What are the additions to the segment in the Network Layer and what does it become?
- Source IP Address
- Destination IP Address
(Becomes a packet)
Protocol of the Network Layer
Internet Protocol
Data Link Layer
- Handles frames
- Responsible for sending the data to the actual physical device
- Handles Errors
What are the additions to the packet at the Data Link Layer and what does it become?
- Source MAC Address
- Destination MAC Address
(Becomes a frame)
How does the Data Link Layer handle errors?
Back Tracking
What happens to the frames when their physical location changes?
There source MAC and destination MAC changes according to each location.
Protocol used in the Data Link Layer
Physical addressing
Physical layer
Converts digital data into electrical or optical signals.
Primary memory characteristics
- Volatile
- Temporarily stores data and instructions that the CPU requires
- Fast Access
Examples of Primary Memory
- RAM
- Cache Memory
- Registers
Secondary Memory Characteristics
- Non-volatile
- Long-term storage for files, applications and operating systems.
- Long-term access
Examples of secondary memory
- HDD
- SSD
- Optical disc
- USB
Hard Disk Drives Characteristics
- Magnetic
- Consists of spinning platters coated with magnetic material
Advantage of HDD
Cheaper
Disadvantages of HDD
- Slower
- Creates large amounts of heat
Solid State Drive Characteristics
- Flash Memory
- No moving parts
Advantages of SSD
- Faster access
- Better durability
Disadvantages of SSD
- Expensive
- Generates less heat
Optical Disk Characteristics
- Uses optical technology - pits and lands that represent binary
Advantage of OD
Inexpensive long-term storage
Disadvantage of OD
Slower Access
USB Advantage
Small and portable
USB Disadvantage
Limited storage capacity
Registers
Are the smallest and fastest memory unit within the CPU
Function of Registers
Provides the CPU with direct access to critical data and instructions.
Data Registers
Used to temporarily store information that needs to be processed.
Address registers
Temporarily stores memory addresses.
Control Registers
Temporarily stores instructions and control signals generated by the CPU.
General purpose register
Can be used to temporarily store any type of data.
Pointer registers
Points towards the memory address where the data is processed.
Index registers
Stores index calculations and addressing.
Segment registers
Stores different segments of processing
- instructions
- data
- return addresses
Flag registers
Sends and receives data using user instructions.
DMA
Direct Memory Access
Function of DMA
Allows peripheral devices to directly access the internal storage without the CPU.
DMA Controller Process
- CPU delegates authority to DMA
- Peripheral devices access the memory through the DMA
Lossy File Compression
A type of compression which reduces bits by removing unnecessary or less important information.
Lossless Data Compression
Is a type of compression that reduces bits by identifying and eliminatingstatistical redundancy.
SAN
Storage Area Network
Function of SAN
Is a specialized, high-speed network that attaches servers and storage devices.
Characteristics of SAN
- Eliminates the traditional dedicated connection between a server and storage.
- Eliminates any restriction to the amount of data that a server can access.
Benefits of SAN
- Storage is independent of applications and accessible through multiple data paths for better reliability, availability, and serviceability.
- Higher application performance
- Data transfer and vaulting to remote sites
- Simplified centralized management
