E-mail Internet Applications

SMTP - SMTP is an abbreviation for Simple Mail Transfer Protocol, it is an internet standard for the sending of electronic mails(E-mails) across IP networks. Websites that provide this kind of services would be for example: hotmail.com, gmail.com, yahoo.com. These servers use SMTP to send and receive mail messages on behalf of the users.

POP3 - POP3 is an abbreviation for Post Office Protocol, version 3. It is an application layer internet standard protocol allowing the user to retrieve download mail from a remote server using a TCP/IP connection, it deletes all mails from the server after the user disconnects from it.

IMAP4 - IMAP4 is an abbreviation for Internet Message Access Protocol. It has the same functions as POP3, but it can also support both on-line and off-line modes of operation, it also allows the function of storing mail in the server, however, it requires a better CPU and larger hard disk space because of the potential amount of information that is going to be stored.

Differences between CANs, MANs, and WANs

 Network Sizes - Campus Area Networks(CANs) have the smallest network size that can only be in a common area, such as Ngee Ann Polytechnic, people outside that area cannot access these networks, Metropolitan Area Networks(MANs), however, has a moderately large network size that can span across the geographical boundary of a country. Lastly, Wide Area Networks(WANs) have the largest network size that can span international borders.

Distance Capabilities - CANs can be used to transfer data within the common area, while MANs can be used to transfer data within a city or distances of 30 miles or less, and WANs can be used to transfer data worldwide.

Transmission Rate - CANs usually has the lowest transmission rate, followed by MANs, then WANs

Price - CANs has the cheapest set-up costs because of its lack of capabilities to cover great distances, followed by MANs which can cover decent distances, then WANs as it requires high speed connections due to the great distances covered globally.

CAN

MAN

WAN

 

 

Various types of Protocols, Internet Domain, IPv4 and IPv6

DNS - DNS is an abbreviation for Domain Name Server, which is the hierarchical naming system for converting IP addresses of various computer devices or services on the World Wide Web(WWW) into friendly and meaningful names that can be easily remembered by the people on the internet. One example would be www.google.com, Google redirects connections and gives different types of addresses to various people living in different parts of the world, since the IP address varies, for my case, it would be 173.194.38.145. Because we are unable to remember so many long strings of numbers just to go to website, DNS converts them to names that are easy to remember, just like how you save contacts in your phone, because you cannot possibly remember all the phone numbers of your friends or family.

The various top-level domains can be seen below, sub-domains and the host can be seen below:

HTTP - HTTP is an abbreviation for Hypertext Transfer(Transport) Protocol. It acts as a request and response protocol. When the client computer submits a HTTP request to the server, the server appropriately responses to the request and provide the correct resources to the client. For example, when trying to view a picture on a website, your computer will send this request to the respective website, and the client controlling the website will respond by displaying the picture that you are trying to view. Sometimes you may come across cases where a website doesnt appear as, for example: http://www.google.com. Rather, https://www.google.com. The extra s behind the HTTP stands for secure, which adds security capabilities and ensures secure communication between the client and servers.

FTP - FTP is an abbreviation for File Transfer Protocol. It is a network protocol that is used solely for transferring files for one host to the other, usually through the internet.

Internet Domain - Internet Domain, also known as Domain Name, is a string used to identify different websites and servers on the internet, based on using friendly names. For example, a complete domain name for a website would be www.google.com. com is the Top-Level Domain, while www.google is the Sub-Domain of com. In other words, in the internet, devices such as computers and servers are given these names to be identified easily by other users.

  

IPv4 and IPv6 - IPv4 uses 32 bits, which can support up to 4,294,967,296 IP addresses simultaenously, because of the vast growing number of people using the internet, IPv6 uses 128 bits to resolve the issue of the lack of space which can support up to about 340,282,366,920,938,463,463,374,607,431,770,000,000 IP addresses.

Singnet's Internet Topology

Singnet's Ethernet line uses the point-to-point topology. There are two types of point-to-point topology: Permanent(dedicated) or switched. In this case, Singnet is using the dedicated type of point-to-point topology. As you can see from the diagram below, Singnet forms a permanent circuit or a connection channel which is called ConnectPlus E-Line between them and the customer, there, internet access is provided and data is transmitted through this channel, and it provides services internationally too. While for customers inside the geographical boundary of Singapore, a network called Local MetroEthernet Network, also known as, Metropolitan Area Network(MAN), is used to transfer data in the same region.

Singnet belongs to the Tier 1 topology because it provides services beyond international borders.