Basics of Computer Networking

Open system: 
A system which is connected to the network and is ready for communication. 

Closed system: 
A system which is not connected to the network and can’t be communicated with. Computer Network: 
An interconnection of multiple devices, also known as hosts, that are connected using multiple paths for the purpose of sending/receiving data or media. Computer networks can also include multiple devices/mediums which help in the communication between two different devices; these are known as Network devices and include things such as routers, switches, hubs, and bridges. 

Network Topology: 
The layout arrangement of the different devices in a network. Common examples include: Bus, Star, Mesh, Ring, and Daisy chain. 

The 7 layers are:-

1. physical layer
2. Data link layer
3. Network layer
4. Transport layer
5. Session layer
6. Presentation layer
7. Application layer

Protocol: 
A protocol is the set of rules or algorithms which define the way how two entities can communicate across the network and there exists different protocol defined at each layer of the OSI model. Few of such protocols are TCP, IP, UDP, ARP, DHCP, FTP and so on. UNIQUE IDENTIFIERS OF NETWORK
Host name:
Each device in the network is associated with a unique device name known as Hostname. 
Type “hostname” in the command prompt(Administrator Mode) and press ‘Enter’, this displays the hostname of your machine. 

import calendar
from datetime import datetime
d=datetime.now()
print(d)
print(d.date())
print(d.date().month)