Sarath Pillai's picture

Difference Between Segments, Packets and Frames

Segments, Packets & Frames

The terms “Segment”, “Packet”, “Datagram”, “Frames” etc are so much used and reused in different books and articles to convey different meanings, that it has now become totally confusing. Especially after the introduction of different layered architecture of network communication.


A good way to look at this is and clear the confusion, is to call them as “PDU (Protocol Data Unit)”. Irrespective of whether you are talking about network layer, transport layer or physical layer, the term PDU is generic and applies to all.


Sarath Pillai's picture

How is TCP & UDP Checksum Calculated?

TCP & UDP Checksum

When you send and receive data over the wire, there are possibilities where the data can get corrupted, altered, or modified(it can be accidental, purposely done with evil intention). Whatever may be the case, there needs to be a method where the receiver can verify and figure out easily if the data is altered or corrupted.


Generally what happens is this..The sender calculates a short checksum value(very small in size) which represents the message/data that is being sent. The value calculated is either sent along with the message, or through other methods. Once the data is received, the receiver also calculates the checksum. If both the values(of the sender and the receiver) tallies, then the data is uncorrupted/unaltered.

Sarath Pillai's picture

How Does UDP Work ?

IETF(Internet Engineering Task Force) is a community of engineers and computer scientists, who work towards bringing different new internet technologies, standards and specifications. A RFC is a document that is published by IETF.


It is generally written formally for peer review. Mostly it discusses different protocol methods and its complete details and features. It mostly works as a standard document for engineers to implement, give feedback, submit a new protocol related information and its concepts(sort of proposal as well - Hence the name “Request for Comments”).  Why am I discussing about IETF and RFCs here?.


Satish Tiwary's picture

Backup and Restore router configuration file using TFTP server with Packet Tracer -Cisco CCNA

This tutorial is all about Backup and Restore router configuration file using TFTP server with Packet Tracer.If you are a network admin or you are preparing for a network admin,you may face a critical problem like your router configuration get messed or you want to take complete backup of your router configuration before doing some major changes in it so that if something bad happens you can restore it back to previous mode.And if you are able to restore it back to previous mode where it was working well,it will save you from a disaster.Here in this lab i have created a scenario using cisco packet tracer in which i am going to show you how to take backup of router configuration file using TFTP SERVER and Restore back when needed.

Here you can clearly see

Sarath Pillai's picture

What is a Jumbo Frame in Ethernet

Ethernet Jumbo Frames

Ethernet is one of the core technology that enables most of our communications and data transfer that we do over the internet possible.  Its an inexpensive technology for high performance networking.

When your application (no matter what..can be a web browser, a download client etc etc) initiates a connection to a remote server, the application’s job is to transfer the data/request it wants to send to the network protocol stack.

The job of the protocol stack is to break that data down to smaller chunks and wrap it with required information, to send it through the wire. This information wrapped around the data chunks enables the data to be received by the correct receiver, and reassemble the data chunk in the correct order.

Sarath Pillai's picture

Find Network Traffic and Bandwidth usage per Process in Linux

Network Traffic Per Process in Linux

Being a system administrator, there are times when we need to check which process is taking high network bandwidth on a machine. This is not that easy to do without any standard tool designed only for that purpose. In this article we will be looking at one such tool. But before looking at that tool we will try to fetch details with other methods.


I request my readers to share any other command line techniques/tools that can be used to achieve this.


Sarath Pillai's picture

What is Anycast and How it works

Anycast and its working

If you try to access from US the request will be routed to the Linode London data center. If you try to access from Asia, again the request will be routed to the same Linode London Data Center. Take one more case, and try to access from Europe (Ireland) the request will be again routed to Linode London.


The bottom line is, You will be routed to Linode London, no matter from where you access.


There are two primary problems associated with this architecture. They are mentioned below.


Satish Tiwary's picture

How to configure a Router to work as a DHCP Server.

DHCP server configuration in router

As we know ip addresses can be assigned to a end device in two way.

  • Static
  • Dynamic

In static way network admin or system admin or user manually assigned ip address on the device, but if the number of devices are much more and you dont want to take the headache for assigning the ip addresses, then it become so teasing and time taking to manually assign ip address to every device. To solve this problem, Dynamic way of ip assigning is used.


DHCP is a protocol that is heavily used to assign IP addresses automatically over LAN networks. If you are interested in understanding how DHCP works, then refer the below blog post.


Sarath Pillai's picture

How Does Traceroute Work and Example's of using traceroute command

How does traceroute work

If you are working as a network administrator, system administrator, or in any system operations team, then you might have already heard about the tool named TRACEROUTE. Its a very handy tool available in most of the operating systems by default.


Network administrators and system administrators use this tool most commonly in their day to day activities. Its basically a network diagnostic tool that is very handy. There are three main primary objectives of traceroute tool. These objectives fulfilled by tracroute gives an insight to your network problem.


  1. The entire path that a packet travels through

Satish Tiwary's picture

RIP and EIGRP Configuration on same network

After static routing configuration, and dynamice routing configuration we are going to introduce Hybrid Routing Configuration here now. We will use RIP and EIGRP together and merge them to get the benefits of Distance vector and Link State. So when you use both RIP and EIGRP together then the most accurate metrics to determine the best path to destination automatically get changed with change in network topology.This type of routing is allowed for rapid convergence but consume less memory and lesser processing power.


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