Ch-1: Intro to Networking Flashcards
OSI
Open System Interconnection
Networking Models:
- Set of rules that everybody should follow
- Every company has their own N/w model.
Ex: 1. IBM - Systems N/w architecture (SNA).
2. Digital equipment coorporation (DECnet)
What does having vendor neutral protocol help with?
- it reduces complexity
Con: increases competition
Which org created OSI model?
International Org for Standardization (ISO)
How many layers does OSI model have?
- Physical layer
- Data link layer
- Network layer
- Transport layer
- Session layer
- Presentation layer
- Application layer
Physical layer?
- Medium in which actual bit transmission (0s & 1s) takes place (wireless or wired medium).
- Controls the rate at which the bits are sent (Bit Rate Control).
Ex: 1 Gbps , 10 Gbps…
1 Gbps- in 1 sec , you send 10^9 bits.
Data link layer:
- Uses MAC addresses (Switching happens here)
- Negotiation of speed
- Duplex negotiation
- full duplex
- half duplex
What are the types of duplex negotiation?
- full duplex (able to speak as well as hear) - 2-way communication
Ex: phone - half duplex 1-way communication
Ex: walkie talkie
Network layer:
- takes care of Routing packets by discovering the best path across physical networks
- uses IP address to find the best path
What is an end point?
Where data is originated or terminated.
Ex: PC, tablet, server, cellphone, etc.)
What are networking devices? Give examples.
Data will flow through them (does not terminate)
- Switch
- Router
Transport layer:
- Flow control (TCP/UDP)
- provides error recovery
Session layer:
Creates communication channels or sessions for data transfer.
Presentation layer:
- takes care of Encryption (encoding)
- prepares the data for application layer.
- compression of data
Application layer:
- This layer interacts with users.
- software is built on this (web browsers)
Protocol Data Unit (PDU)?
Header + Data
TCP/IP networking model:
- has only 5 layers
Application, presentation and Session layers are combined to a single layer (Application layer)
In TCP/IP models what are PDUs of layers named as?
Layer 1- Physical layer- Bits
Layer 2- Data link layer- frames
Layer 3- Network layer- Packets
Layer 4- Transport layer- Segments
Layer 7- Application layer- Data
What is Routing?
Routing is the process of path selection in a network or across multiple networks.
What is the role of a network engineer?
Designing & implementing
new network solutions and improving the efficiency of current networks.
What is networking?
Practice of transporting and exchanging data between devices
