S3 - Host to Host Communication

Question 1

Network Characteristics (7)

Answer 1

Topology
Speed
Cost
Security
Availability
Scalability
Reliability

Question 2

OSI Reference Model (5)

Answer 2

OSI - Open Systems Interconnect
Standard of ISO
General Purpose Framework that characterises and standardised how computers communicate over the network
7 layers
Each layer servers the layer above it and is served by the layer below it

Question 3

7 OSI Layers (7)

Answer 3

7. Application
8. Presentation
9. Session
10. Transport
11. Network
12. Data Link
13. Physical

Question 4

OSI Benefits (4)

Answer 4

Engineers can just focus on their layers
App developers can just focus on upper layer (top 3 layers
Open standard mean multi-vendor interoperability
Troubleshooting is easier as you can analyser problem logically layer by layer

Question 5

OSI Acronyms (1)

Answer 5

Please do not throw sausage Pizza Away

Question 6

TCP/IP Suite (5)

Answer 6

Developed in 1960s by US DoD
Protocol stack which consists of multiple protocols
Main stack used today
TCP/IP not conceptual like OSI
Does not use all OSI layers

Question 7

TCP/IP Layers (4)

Answer 7

Application
Transport
Internet
Network Access

Question 8

Host communication Terminology (5)

Answer 8

Protocol Data Unit (PDU) - Whole Stack
Application - Data
Transport - Segment
Internet - Packet
Network Access - Frame

Question 9

Application Layer (4)

Answer 9

Network Services to Application
Doesn’t provide services to other layers
Establishes availability of communication partners
Establishes agreement for error recovery and control of data integrity

Question 10

Presentation Layer (2)

Answer 10

Ensure Data sent by application layer is readable by the application layer of another system
Translate among multiple Data formats (encoding schemes)

Question 11

Session Layer (4)

Answer 11

Establishes, manages and terminates sessions between two hosts
Synchronises dialog of presentations layers and manages data exchange
Example: Web Servers have multiple user communication going on at any one time
Offers Efficient data transfer (CoS) and exception reporting

Question 12

Transport Layer (3)

Answer 12

Whether TCP or UDP is used
Defines services to segment, transfer and reassemble data
Breaks down larger files to smaller segments

Question 13

Network Layer (4)

Answer 13

Most important info is source and destination IP
Routers operate at Layer 3
Provides connectivity and path selection for 2 hosts
Manages connectivity by providing logical addressing

Question 14

Data Link Layer (5)

Answer 14

Most important info is source and destination layer 2 address
Example MAC Address for Ethernet
Switches Operate at Layer 2
Defines how data is formatted for transmission and how access to physical media is controlled
Includes error correction and detection

Question 15

Physical Layer (4)

Answer 15

Literal Physical components (cables)
Enables bit transmission
Specifications for activating, maintaining and deactivating
Example: voltage levels, physical data rate, maximum transmission