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Wednesday, 31 July 2019

What is Router

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Router is an internetworking device and used to connect two and more different network. Router works on network layer (Layer 3) in OSI model. Router forwards data packets between computer networks. Router decide best and easy route for forwarding the data packets. A data packet be forwarding from one router to another router through the networks and makes an internetwork, until they reached destination.

Router reads only data packets because router works on Network Layer, Network Layer receives data in the form of packets. Router have own Operating System that allows the router to move data packets.
Router create a table that's called routing table. By the help of routing table the router send data packets one router to another router. Router control broadcast traffic in Network, router restrict broadcast to the LAN network. Router acts as the default gateway.

Cisco, Juniper, 3com and HP, Nortel are the most popular companies in routers.

Access Router:

Access routers are used by the small organization and home office. They routers are easily located at computer stores.

Distribution Router:

Distribution routers are used by the ISP and they are also known as ISP router. Distribution routers are responsible for enforcing of service across a wide area network.

Core Routers:

Core routers are used by global ISP’s and they are also known as backbone router. They router optimized for high bandwidth.

Sunday, 28 July 2019

Layer 4 Switch

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Layer 4 Switches:

Layer 4 of the OSI Model coordinates communications between systems. Layer 4 (The Transport Layer) switches are capable of identifying which application protocols (HTTP, SNTP, FTP, and so forth) are included with each packet, and they use this information to hand off the packet to the appropriate higher-layer software. Layer 4 switches make packet-forwarding decisions based not only on the MAC address and IP address, but also on the application to which a packet belongs.

Because Layer 4 devices enable you to establish priorities for network traffic based on application, you can assign a high priority to packets belonging to vital in-house applications, such as e-mail and video conferencing, with different forwarding rules for low-priority packets such as generic HTTP-based Internet traffic. Layer 4 switches also provide an effective wire-speed security shield for your network because any company-or industry-specific protocols can be confined to only authorize switched ports or users. This security feature is often reinforced with traffic filtering and forwarding features.

Speed vs. Capability:

As the layers increase in switches, so does the CPU power and processing time (latency) of the switch. The trade-off for more control and capabilities in a higher layer switch is less speed and increased power consumption. Lower layer switches are faster and use less processing power. Choosing a switch that matches your network needs creates maximum networking efficiency

Saturday, 27 July 2019

Layer 3 switch

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Layer 3 switch:

Layer 3 switch also known as multilayer switches and it works on Network Layer in OSI Model. These switches act as a router because it has making routing decision. Layer 3 switch require advanced technology and they are expensive. Layer 3 switches use in large LAN networks. These switches totally based on IP address and stored in the header of IP datagram. Routers use microprocessors to make forwarding decision in software but switch performs only hardware-based packet switching.

Advantages of layer 3 Switches:

  • Layer 3 Switches act as a router because it has IP routing table.
  • Layer 3 switches have fast hardware-based packet forwarding.
  • It’s gives high-performance packet switching and high-speed scalability. 
  • Layer 3 switches Uses low latency and lower per-port cost and manage flow accounting and gives quality of service.

Disadvantages of layer 3 Switches:

  • Layer 3 switches are more expensive than traditional switches.
  • Configuring and VLANs also require additional effort.
  • Layer 3 switch no use for home network or small network.

How to Layer 3 Switches Works:

Layer 3 switch works like a layer 2 switch. Layer 2 switch works on Data Link Layer and it uses MAC address for sending data but layer 3 switch works on Network Layer and it uses IP address for sending data. Layer 3 switches maintain an IP table. When IP address not match in IP table they broadcast a message in the network and update the table.

What is Network switch

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Network switch:

Networking Switch that’s connects network segments or network devices. Network Switches also called Switching Hub and Switching Bridge and Mac Bridge. The first Network Switch was introduced by Kalpana in 1990. Switch works on Data Link Layer (Layer 2) in OSI model. But some advanced switches work on Physical Layer (layer 3). That switches called multilayer switches. Switches receives a data from any device connect to it and then transmits the data only to that device for which the data was. Switch receive data on own port in the form of frame and transmit this data. Switch is intelligent device from Hub. The Switch has a separate collision domain for each port. Switches maintain a table that’s called forwarding table or Mac address table. Switch stored all computer mac address and connected ports in the table. 

Types of switches and switching:

Store and Forward 
Cut through
Fragment free
Adaptive switching


The switches use buffer and store the data in buffer and start to checks error, when data with comes error, the data does not forwarding. Store-and-Forward switch working some slow because that’s switch checks errors and storing the data in buffer. The data send by these switches is very reliable. 


This type switches reads only frames header address before forwarding. The switch not checks errors. 

Fragment switch:

The switch performs both attempts Store-and-Forward and Cut-Through. This switch checks fragments for first 64 bytes, because first 64 bytes show all errors.

Adaptive Switching:

An adaptive switch is normally operated in Cut-Through mode but if a port's errors, the switch automatically reconfigure the port and run in Store and Forward mode. This optimizes the switch's performance by providing higher speed Cut-Through switching if error rates are low but higher through put Store-and-Forward switching when error rates are high.

Working of networking switch:

When we sending data from one computer to another computer. The switch checks destination computer Mac address and port and send data directly. The switch checks the errors in the data, when data comes with errors, switch does not forward the data. Switch provides High Speed data exchange and full duplex communication and Low Latency. Switch provides point to point communication.

What is the HUB

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An HUB is networking device and we can say network hardware. HUB is used to connecting multiple computer or devices together. HUB has provides multiple input and output ports. HUB is also called Network Hub, Ethernet Hub, Active hub and Repeaters. HUB works on physical layer in OSI model. HUB connected devices share same amount of bandwidth and same collision domain. More nodes leads to transmit or slow performance. HUB no need to configuration. HUBs are available into minimum four ports and up to 24 ports.

Types of HUB:-

Passive Hub
Active Hub
Intelligent Hub

Passive Hub:-

Passive Hub used for just creating connection between computers and other devices. Passive hubs not amplify or regenerate any signals. Passive hubs take all the packets and broadcast them all ports. Passive hubs have RJ-45 port and 10base-2 port. In more advanced passive hubs have AUI (Attachment Unit Interface) port.

Active Hub:-

These types of hub amplify or regenerate the data information and signals. It’s Also known as multiport repeater. Active hubs retime and resynchronize certain packets when they are being transmitted. An active hub provides best performance. Active hubs are expensive.

Intelligent Hub:-

Intelligent Hub can both tasks active and passive. It also works like bridging and routing. That’s hub increase the speed and effectiveness in the network. This types of hub providing network statistics to remote management console. Intelligent hub gives alerts on problems in collisions.