What Does It All Mean?
The problem when dealing with computers in general, especially when talking about networking, is that every other word seems to be an acronym. If you don't know what these acronyms mean understanding a conversation with a computer nerd can be quite tricky. In general you don't actually need to know the full ins and outs of these terms but a general understanding of what each means and does is essential if you want to set up your home network or troubleshoot problems.
TCP / IP
TCP / IP stands for Transmission Control Protocol / Internet Protocol. TCP / IP is the main protocol used in networking today to transmit data from one host to another. TCP / IP is actually a group of protocols that applications can use to send data and is based on a reference model called the OSI model. The reason this group of protocols is called TCP / IP is because these are the two protocols used most.
The way TCP / IP works is that an application chooses which protocol it needs to use from the upper layer. This protocol manipulates the data in some way and then passes it down to a protocol in the next layer down. Each protocol and layer will perform specific tasks on the data to be sent which can include splitting the data up into packets, adding address information to the packets and making sure that any received packets make up the entirety of the data being sent. The bottom layer puts or collects the data on or off the transmission media like an ADSL connection or an Ethernet LAN.
When data is received off of the transmission media it enters at the bottom of the stack, works it's way up the stack finally being delivered to the correct application which the data is intended for.
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Sample of a typical TCP / IP Protocol stack(Note : Applications access the top layer, data flows down the layers |
DNS
DNS stands for Domain Name System. The Domain Name System is the system used on the Internet and most computer networks to resolve computer names to IP Addresses. In basic terms the easiest way of describing the Domain Name System is a dynamic address book for hosts.
Because computers communicate with each other using a numbered IP Addressing scheme computer operators need a way to be able to remember the addresses of the hosts that they access on a regular basis. Because it would be quite difficult to remember lots of different IP Addresses and us humans find it easier to remember names a hierarchical naming system was created which could map a specific name (e.g. www.SmithIT.co.uk) to it's IP Address (e.g. 212.227.124.7).
More can be read about this service here.
DHCP
DHCP stands for Dynamic Host Configuration Protocol. The Dynamic Host Configuration Protocol is a service which issues IP Addresses to hosts that are set up to Obtain an IP Address automatically. DHCP servers can be either software based and come with Operating Systems like Windows 2003 Server or as stand alone applications or they can come hardware based where they are written into firmware, for example in routers.
DHCP servers are used as an easy way to make sure all of your hosts have valid IP Addresses for the subnet (local group of computers) that they are connected to. The computers usually request an IP Address when they boot up for all of it's network connections set to Obtain an address automatically. The DHCP server will then issue IP Addresses out of a pool of addresses which it knows it has not already issued.
This means that you should not need to worry about two hosts having the same IP Address and you do not need to remember which IP Addresses you have already set when setting up new computers as you do in a manually set IP Address configuration. Also you can easily move computers between subnets and the address will be reset according to the subnet it is put on.
For more on DHCP read here.
HTTP, HTML, ASP & PHP
HTTP stands for HyperText Transfer Protocol and is the protocol used to display web pages. When you type a WWW address into your web browser the protocol the browser uses for the transfer of the web page data is HTTP.
HTML stands for HyperText Markup Language and is the basic language that is used to write web pages. It is an easy way to define the structure, layout and formatting of your web pages. If viewing this page with Internet Explorer you can view the HTML code for it by right clicking on the grey area to the side of the page and selecting View Source. This will open a notepad page with the HTML code.
ASP stands for Active Server Pages and PHP stands for Hypertext PreProcessor. They are both programming languages which, although capable of much more, are for creating more dynamic, interactive web sites. You program scripts in these languages which you can use to run processes at the server or locally on the browser to access databases and generally create a more dynamic experience.
FTP
FTP stands for File Transfer Protocol and is the main protocol used for efficiently uploading and downloading large sized or a large number of files over the internet. For example this web site is being hosted on a hosting company's server somewhere miles away from where I live. When editing web pages I edit them locally and when finished I upload the completed files to my web space on the hosting companies server using a program which utilizes the FTP protocol.
POP3, SMTP & IMAP
POP3 stands for Post Office Protocol 3, SMTP stands for Simple Mail Transfer Protocol and IMAP stands for Internet Message Access Protocol. These protocols are all used as a way of transferring mail over the Internet. A mail client like Microsoft Outlook would use these protocols to send and collect mail to and from your mail server.
POP3 is a protocol which can be used for collecting mail from your mail server. When using the POP3 protocol any mail that you collect from your mail server is deleted from the server at the time of collection. This is OK if you only collect your mail from one computer and will not need to access any of your mail through a web mail facility offered by your E-mail suppliers after you have already collected them.
IMAP is another protocol which can be used for collecting mail from your mail server. The main differences between POP3 and IMAP is that when IMAP collects mail from the server it does not delete the mail off of the server, usually clients only actually download the header of the message to save local space and clients stay connected to the mail server all the time the mail client is open. This method allows mail that has already viewed locally to be viewed later through a web mail facility. However, as the clients only usually download the header when connected if you later open your client when not connected to the Internet any pictures or content sent in the message will not be viewable. This default setting can usually be switched off on most mail clients.
SMTP is the service which is used to send mail to your mail servers when sending out an E-mail to somebody.
