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What Is A VPN?

December 24th 2011 20:22

Encryption of packets requires extensive resources, corporate environments use, dedicate hardware devices to provide power to handle IPSec encryption. Juniper's SSG is one of the widely used security devices in the market.

People who have used a VPN service to access blocked websites in their offices or school campuses, might just know that a VPN is simply a way to anonymously surf the internet. But a VPN has much more to it, infact it has come up as the most secure way to connect with each other on the Internet, no matter where your location is.

VPN stands for Virtual Private Network. It is simply a virtual connection over the Internet between two sites. As we all know that the Internet is a network of networks where millions of nodes are interconnected all talking to each other using different type of circuits. In order to transfer data to another remote workstation through the Internet, you can imagine how many routes the packets have to take before reaching the destination.

Therefore anybody in the intermediate network can sniff the packet and extract all the critical data out of it. Therefore there should be some way of protecting the data. We use the 'https' service for accessing confidential data on the internet, but how about encrypting the data at much lower levels of the OSI layer to allow communication between many nodes just like we do in a local area network.

This is what a VPN does! It basically encrypts the IP packet using the IPSec suite of protocols, which provides a mechanism of authentication and encryption of IP packets on the Network layer of the OSI layer model along with other encryption mechanism on top of it. These mechanism are the Secure Socket Layer (SSL) and Transport Layer Security (TLS) at the Presentation layer; the same mechanism is used for encryption of the Https service.

This full proof security of VPN allows you to connect with different nodes on the Interent just like you do locally, it is infact considered a type of WAN where different offices are now connecting there branches over cheap and high speed DSL connections using VPN. However a dedicated circuit is till established over several of the WAN technologies as they provide what is called as a Service Level Agreement (SLA) to deliver a guaranteed bandwidth and uptime, which is not available with a DSL connection.

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Types Of RFID Tags

October 25th 2011 05:13

Passive RFID Tag

Recently I had chance to work in a RFID project, which allowed me to post some basic stuff about RFID here in my blog too. RFID is a promising technology, which has its origin dating back to 1945.

Radio frequency spectrum is quite an old phenomenon which was already applied in conventional radio years back. But no one knew what wonders we can achieve with this spectrum.

RFID stands for Radio Frequency Identification, it consists of two main components, namely an Interrogator and the Transponder. The Interrogator is actually a scanning device just like barcode scanner, which can scan the different RF tags from a particular distance.

The Interrogator consists of an RF transceiver which, sends and receives data on free ISM band. The Interrogator is typically connected to a computer database where real time updates are made to a database.

The RFID tags called the transponder are of two types:

1. Active Tags

Active tags are really promising for the reason that they can be scanned from a large distance which can be more than 100 meters. That is why they have been popular in applications like toll charging on free ways and highways. But its draw back is that it requires a battery to remain active, however it allows us to send and receive data without communication being initiated from the Interrogator.

2. Passive Tag

Passive tags are the more widely used ones mainly because they are extremely compact and that they are comparatively cheaper than active tags. This allows them to be suitable in inventory management systems, where they can be effectively placed on hundreds of items, for Asset tracking. Passive Tags work when an Interrogator initiates communication my sending an RF signal which hits the tag and makes it active to send back the data it has stored . It has a typical range of upto 5 meters.

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Types Of Routing Protocols

August 26th 2011 13:32

Cisco Branch Router (Courtesy Cisco)

In the last post we focused on IPv6, which is the next generation of Internet Protocol. In this post lets head back to some of the more basic concepts of IPv4 which is routing.

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