Packet Transmissions : Unicast, Broadcast, Multicast and Anycast

Unicast, ( refers the left diagram ) is a type of packet transmission sent from a source to another destination. In unicast, there is only one sender and one receiver. Most of the application today is Unicast, example HTTP, SMTP, FTP etc. which employ the TCP transport protocol.

Broadcast transmission, (  refers the diagram below ) is a communication method where a piece of packet/information is sent from a source to all other destinations within the given address range. Broadcasting normally happen on Layer-2 using ARP ( Address Resolution Protocol )

Multicast, ( refers the diagram right below ) is a transmission technology that delivered the sender’s packet or information to a specific groups of recipients. Most common low level protocol to use multicasting addressing is UDP. Unlike broadcast transmission, the recipients only receive the packets if they have previously choose to receive by joining using IGMP. The multicasting is useful when a group of recipients are to receive the same packets from a specific sender over the network at the same time ( refers the diagram below ), it would contribute a significant bandwidth savings and optimizations ( refers the diagram below ). The common usage of the multicasting is IP-television.

Multicast (top) compared with unicast broadcasting (bottom). Orange circles represent endpoints, and green circles represent routing points.

Anycast, ( refers the left diagram ) is another type of transmission that may not commonly discussed. Anycast transmission is mostly used in the routing purposes where the packets are transmits to the destinations via the “best” routing topology. BGP is one of the anycast transmission where the destination IP address/range is received by the source/sender’s router via difference routes but the will be only one route to be chosen for the packet transmission.

**Pictures source from Wikipedia

Chronological of Microsoft Windows

Microsoft Windows is a series of Operating Systems produced by Microsoft. The first release of Windows was a replacement to the MS-DOS with the enhancement of Graphical User Interface(GUI) on the November 1985 namely Windows 1.0.

I believe most of the reader here has never use it before, I was started with PC-DOS, then followed by MS-DOS6 and ‘jumped’ into Windows 3.0 at about 10-15 years ago. Windows 3.0 was introduced on May 1990 and followed by Windows 3.1 on August 1992 which was much more popular at that time.

 

On the August 1995, Windows introduced a much more ‘today-look-a-like” windows i.e. Windows 95.

Again, Microsoft created another legend which attracted many users i.e. Windows 98 on June 1998 and Windows 98SE on May 1999. Windows 98SE was actually a much more stable version.

Followed by Windows ME, Windows 2000 Professional and Windows 2000 Server as replacement of Windows NT.

A most popular version of Windows i.e. Windows XP which I am still using it ( never believe any other craps that introduced later i.e. Vista which is too ‘secure’ and troublesome for me ) :P

Read more at Wikipedia : List of Microsoft Windows Versions.

What does DNS registration contact means?

The Registrant is the licensee of the domain name - this is the individual or company who has the right to use, sell or destroy a domain name.

The Administrative Contact is the licensee's appointed agent for the functions above and any other purpose. In the case that the Registrant is a company the Administrative Contact should be an
employee, director, manager of the company. This person has full authority for all changes in our system so care should be taken in selecting the appropriate person to nominate for this role.

The Technical Contact is the person responsible for maintaining the DNS nameservers associated with the domain name. This enables that contact to make updates if necessary if, for example, the
name of the DNS nameserver changes.

The Billing Contact is the primary point of contact responsible for paying for the domain name's license renewals.

In the case of a company, the company itself would normally be the Registrant. An officer or possibly a trusted employee of the company would be the Administrative Contact.

The Technical Contact would normally be the ISP or webhosting provider (maybe us if you use these services).

In the case of an individual domain name owner, you may be listed as three of the four contacts or conceivably even four of the four contacts. It isn't so important if you're in control of your own domain name but now you can probably see why so many contacts could be required.