Difference between Hub, Switch and Router

Difference between Hub, Switch and Router

  03:33    Cloud Technet

---

HUB	SWITCH	ROUTER
Hub functionality plays in physical layer	Data link layer	Network layer
It is Dump device	Intelligent device	Hub and switch functionality
Always broadcast	Broadcast first time and then unicast	Can be configured to send  a broadcast
Single broadcast and single collision domain	Single broadcast and multiple collision domain	Multiple broadcast and multiple collision domain
Broadcast information to all devices in network	Forwarded data to destination based on MAC	Ability to share internet connection
Half duplex	Full duplex	Firewall device
Act as repeater	Maintain MAC table	Act as DHCP server, NAT box, Switch, DGW, VPN client and VPN server

Read More

Network Layers OSI Model 7

Network Layers OSI Model 7

  03:29    Cloud Technet

---

Layer 7: Application Layer

Defines interface to user processes for communication and data transfer in network

Provides standardized services such as virtual terminal, file and job transfer and operations

Layer 6: Presentation Layer

Masks the differences of data formats between dissimilar systems
Specifies architecture-independent data transfer format
Encodes and decodes data; Encrypts and decrypts data; Compresses and decompresses data

Layer 5: Session Layer

Manages user sessions and dialogues
Controls establishment and termination of logic links between users
Reports upper layer errors

Layer 4: Transport Layer

Manages end-to-end message delivery in network
Provides reliable and sequential packet delivery through error recovery and flow control Mechanisms Provides connectionless oriented packet delivery

Layer 3: Network Layer

Determines how data are transferred between network devices
Routes packets according to unique network device addresses
Provides flow and congestion control to prevent network resource depletion

Layer 2:Data Link Layer

Defines procedures for operating the communication links
Frames packets
Detects and corrects packets transmit errors

Layer 1:Physical Layer

Defines physical means of sending data over network devices
Interfaces between network medium and devices
Defines optical, electrical and mechanical characteristics

Read More

Types Of Networking ?

Types Of Networking ?

  03:20    Cloud Technet

---

local-area networks (LANs) : 

The computers are geographically close together (that is, in the same building).

wide-area networks (WANs) : 

The computers are farther apart and are connected by telephone lines or radio waves.

campus-area networks (CANs): 

The computers are within a limited geographic area, such as a campus or military base.

metropolitan-area networks MANs): 

A data network designed for a town or city.

home-area networks (HANs): 

A network contained within a user's home that connects a person's digital devices.

Read More

Media Access Control (MAC) Addresses and Address Resolution Protocol

Media Access Control (MAC) Addresses and Address Resolution Protocol

  11:07    Cloud Technet

---

An IP address alone cannot be used to deliver data from one LAN device to another. To send data between LAN devices, you must convert the IP address of the destination device to its MAC address. Each device on an Ethernet network has a unique MAC address, which is a 48-bit number assigned to each device by the manufacturer. The technique that associates the IP address with a MAC address is known as address resolution. Internet Protocol uses the Address Resolution Protocol (ARP) to resolve MAC addresses. If a device sends data to another station on the network and the destination MAC address is not yet recorded, ARP is used. An ARP request is broadcast onto the network. All stations (computers, for example) on the network receive and read the request. The destination IP address for the chosen station is included as part of the message so that only the station with this IP address responds to the ARP request. All other stations discard the request.

Read More

Internet Security and Firewalls

Internet Security and Firewalls

  11:05    Cloud Technet

---

When your LAN connects to the Internet through a router, an opportunity is created for outsiders to access or disrupt your network. A NAT router provides some protection because by the very nature of the process, the network behind the router is shielded from access by outsiders on the Internet. However, there are methods by which a determined hacker can possibly obtain information about your network or at the least can disrupt your Internet access. A greater degree of protection is provided by a firewall router.

Read More

What is a Firewall?

What is a Firewall?

  11:01    Cloud Technet

---

A firewall is a device that protects one network from another while allowing communication between the two. A firewall incorporates the functions of the NAT router, while adding features for dealing with a hacker intrusion or attack. Several known types of intrusion or attack can be recognized when they occur. When an incident is detected, the firewall can log details of the attempt, and it can optionally send e-mail to an administrator to report the incident. Using information from the log, the administrator can take action with the ISP of the hacker. In some types of intrusions, the firewall can fend off the hacker by discarding all further packets from the hacker’s IP address for a period of time.

Read More