Basics about CIDR and VLSM

CIDR

Classless Inter-Domain Routing (CIDR) known as subnet mask or can be used as super netting where, all the IP address and its associated routing prefix is presented. It is noted as “/” such as /0, /10 etc/. It is an appropriate method of designating a subnet mask. It improves the efficiency of the address distribution which was followed in older class based IP address system. It is based on variable length subnet masking (VLSM). 

The earlier classfull address were as below

Class A: over 16 million host identifiers.

Class B: 65535 hosts

Class C: 254 host identifiers.

CIDR Block

A CIDR block is nothing a group of IP addresses that share the same prefix and contain the same number of bits. Super netting occurs when multiple CIDR blocks are connected together to structure a larger network. A prefix’s length determines the size of a CIDR block.

Subnet Mask and their CIDR value

255.0.0.0 : /8

255.128.0.0: /9

255.192.0.0: /10

255.224.0.0: /11

255.240.0.0: /12

255.248.0.0: /13

255.252.0.0: /14

255.254.0.0: /15

255.255.0.0: /16

Similarly, it will continue up to 255.255.255.252 having the CIDR value /30.

For example

If one Class A IP address have default subnet mask is 255.0.0.0, this means the first byte of the subnet mask is all ones (1s). As mentioned below, having CIDR value /8:

11111111.0.0.0 

VLSM

VLSM enables network administrators to divide IP address in to hierarchy of subnets of different sizes. 

For example

If an IP address is 127.10.50.34 and with a subnet mask 255.0.0.0 (8 network bits) then it will be noted as 127.10.50.34/8

There are many sub netting concepts that we can cover later. 

If you have any suggestions, please feel free to post below.

-DR

Basics of KVM Switch

KVM Switch

KVM is a hardware device in computer world and is stands for Keyboard, Video (monitor) and Mouse. It allows to use multiple computers or systems or servers in one keyboard, video, and mouse to control and switch between them. The KVM is also called as Console.

Normally this is used where there lots of servers available such as data centre or large infrastructure, WAN environment. The KVM switch then allows data center personnel to connect to any server in the rack.

A KVM allows for switching with the correct signals every time through the use of signal emulation technology. 

As per study high performance KVM solutions offer maximum security, flexibility and reliability for your network. From a single screen, keyboard and mouse, you can access all your computers no matter where they are located whether in another room or building. You can switch promptly between applications and carry out several functions in quick sequence with no delay. Traditional switching configurations range from 2 to 64 possible computers attached to a single device. 

There are two types of KVM available such as local remote KVM and KVM over IP.

Local remote KVM device allows users to control computer equipment up to approximate 1,000 feet away from the user consoles (keyboard, monitor and mouse). It includes standard cat5 cables and usb cables for connectivity.

KVM over IP delivers better content faster for a range of applications, including broadcasting and control rooms. It uses a dedicated micro-controller and specialized video capture hardware to capture the video, keyboard, and mouse signals. The it compresses and converts them into packets, and sends them over an Ethernet link to a remote console application.

Below are advantages to consider using KVM.

• Multiple computer or server control in a network.
• Not required to invest in extra computer equipment and that helps save money.
• It helps to keep your space less use.
• Some KVM switches support USB peripherals, for example, eliminating the need for separate USB hub.
• Remotely access and control computers and servers.
• Gain network flexibility.

So, a KVM switch is to reduce the pain, complexity, vulnerability and cost of IT environments.

-DR

TCP IP Data Encapsulation

TCP IP Data Encapsulation

Data Encapsulation is a process in which, some additional information (such as header or tailor) is added in to the data while travelling from one host to another host over the network through the OSI layer.

It is about creating and wrapping user’s data with the control information layer by layer. 

To communicate information, each layer uses Protocol Data Units (PDUs) that holds the control information attached to the data at each layer of the model.

The data encapsulation works at transmitting host like;

• User information is converted in to data for transmission on the network.
• Data is converted to segments and a reliable connection is made.
• Segments are converted to TCP packet or UDP datagrams. A logical address is added at header.
• Then the converted segment are sent to network layer where they are converted to frames for transmission on the local network.
• Frames are converted to bits then and sent to receiver address.

De-encapsulation

This is the reverse of encapsulation process. The additional information is removed at receiver end from physical layer to application layer. The physical layer receives the bits data, de-encapsulates them in to frames and then sends them to upper layer.

The benefits of encapsulation

The prime benefit of encapsulation is security in transmission. Further it enhances maintenance, increases usability. 

-DR