Second is the actual hardware. This is the modem. Again if you are going with a cable modem then the modem and/or router can be installed by the local cable company. You must determine if your computer is equipped with a CAT5 (thick phone cord) or USB port. Either can be used but the USB connection will drain resources from your computer that the CAT5 will not.

In some cases your computer may have one or both of these connections built in. If this is the case then a modem and router will not need to be installed. You can just plug the appropriate cable into your computer and the hardware is set up.

In most cases you will have software that also needs to be installed. This can be application software and/or drivers that will be given to you on a CD from either the cable company or from the hardware you purchased.

You can also choose to go wireless. In this case you will need to purchase a wireless router and card (unless your computer comes with a wireless card). The instructions will explain how to set this up and when and how to install the software for your computer.

The last thing to do is have Windows connect to the Internet. Follow the following steps to achieve this:

1. Click the Windows orb
2. Click Control Panel
3. Select Network and Internet
4. Choose Network and Sharing Center
5. Setup a connection or network
6. Select Connect to the Internet
7. The Connect to the Internet Wizard will appear and you just follow the instructions.

In all cases you will find that connecting to the Internet and acquiring your email is a simple process. Just follow the directions given and you will be on your way in a short amount of time. If you have any problems with the instructions Windows help will usually have enough information to get you through the installation process. If not, then there is technical support through your cable provider, hardware manufacturer, or your computer manufacturer.

Asynchronous Transfer Mode (ATM) is a connection-oriented Data Link Layer (OSI Reference Model Layer 2), circuit-switched, cell relay protocol that runs over Synchronous Optical Network (SONET) Physical Layer (OSI Reference Model Layer 1) links. ATM encodes data traffic into small uniform (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells.

Origins of Asynchronous Transfer Mode (ATM)

During development of the standards for the Asynchronous Transfer Mode (ATM), in the mid 1980s, the goals were to create a unified networking strategy that could act as an all-round transport system for real-time video and audio as well as image, text and email. A “Jack-of-all-trades” transport system if you will.

The two groups primarily responsible for the development of the ATM standards were the International Telecommunications Union [ITU 2004] and the ATM Forum [ATM 2004].

Main Implementations of ATM

The majority of implementations and uses that ATM has fulfilled have been primary concerned with telephony and IP networks.

Unlike Ethernet and the Internet Protocol (IP) which are packet-switched based network technologies, that use packets of variable size referred to as frames, ATM is a circuit-switched cell relay protocol that uses cells of identical and never varying size. Consistent predictability is the underlying ethos here.

Benefits of Using Small Fixed Size Cells

The major benefits of using small data cells were to reduce jitter in multiplexing data streams as well as overcoming problems associated with end-to-end-round-trip delays and delay variance particularly when carrying voice traffic.

The reason this is important is inherently due to the nature of operation of the compression/decompression (codec) algorithms used in the conversion of a digitalized data stream back into an analogue audio signal, which is very much a “real-time” process.

To be able to do an “acceptable” job the codec needs the data items (the digitized voice data) presented to it in an evenly spaced (in time) stream hence the term “real-time streaming”. The nature of time as we humans perceive it is an analogue continuum (that is to say time is a linear progression).

If the transport protocol is unable to present the data as and when the codec expects it, the codec, has no choice but to assume silence or make a “best guess”. Either way is unacceptable where voice is concerned as the conversation rapidly becomes untenable and the message does not get through.

If the data arrives late then the time sequence relating to that part of the data-stream will have passed and the codec will simply drop it. Once again, this is unacceptable for IP telephony. Remember that time is analogue by nature and once a “time window” elapses, the “lost” time becomes unrecoverable.

Queue Delay and Jitter

Asynchronous Transfer Mode (ATM) carries data from a multitude of sources and variable sizes including voice, audio and many other variable sized files. When combined with standard queuing strategies, maximum queuing delays were common.

Because ATM was designed to implement a low-jitter network interface this situation is intolerable whenever voice and video communications are to take place. The answer was to use small-fixed size cells (packet) to overcome the effects of queue delay.

With small fixed-sized cells, ATM is able to transport both large datagrams while still maintaining short/minimal queuing delays.

Asynchronous Transfer Mode (ATM) Cell Structure

ATM breaks all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each one. The 5-byte header is essential for later reassembly.

The reason for the header being 5-bytes in length is that 10% of the payload of every cell is considered to be more than enough to dedicate to routing information.

ATM multiplexed these 53-byte cells instead of packets and in so doing reduced the worst-case queuing jitter by a factor of almost 30, removing the need for echo cancellers.

ATM defines two different cell formats the Network-Network Interface (NNI) and the User-Network Interface (UNI). Most ATM links use the UNI cell format.

Asynchronous Transfer Mode (ATM) Adaption Layers (AAL)

ATM Adaptation Layers (AAL) are the rules for segmenting and reassembling packets and streams into cells. It is the AALs that provide the support for the various services delivered by ATM.

Currently there are five different AALs and which one is in use for each cell is not included in the cell. Instead, it is negotiated by or configured at the endpoints on a per-virtual-connection basis.

• AAL1 - Constant Bit Rate (CBR) Services, Circuit Emulation
• AAL2 - Variable Bit Rate (VBR) Services
• AAL3 - Variable Bit Rate (VBR) Services
• AAL4 - Variable Bit Rate (VBR) Services
• AAL5 - Data Transport

Asynchronous Transfer Mode (ATM) Connectivity

Being a connection-oriented channel-based technology means that ATM needs to establish a “logical” connection between the two endpoints prior to commencement of data exchange.

Virtual Circuits (VC)

By including an 8-bit or 12-bit Virtual Path Identifier (VPI) and a 16-bit Virtual Channel Identifier (VCI) pair in the ATM frame's header each Virtual Circuit (VC) is uniquely identifiable. Virtual Circuits (VC) are admirably suited to multiplexing scenarios.

Virtual Channel

An ATM Virtual Channel represents the basic means of communication between two end-points. Cells are given a unique identifier called the Virtual Channel Identifier (VCI) which is placed into the ATM cells' header. All ATM cells containing identical VCIs are transported in the same Virtual Channel.

Virtual Path (VP)

A Virtual Path (VP) denotes the transport of ATM cells belonging to virtual channels which share a common identifier called a Virtual Path Identifier (VPI) which is included in the header of every ATM frame. In other words a Virtual Path (VP) is a bunch of Virtual Channels (VC) connecting the same end-points, and have a common traffic allocation.

Virtual Path Idetifier (VPI)

The Virtual Path Idetifier's (VPI) length varies depending on the interface it is sent on (inside the nework or on the edge of the network.

Asynchronous Transfer Mode (ATM) Traffic Contracts

When an ATM circuit is set up each switch is informed of the traffic class of the connection. These ATM contracts constitute part of ATM's Quality of Service (QoS) mechanisms. There are four basic types of contracts:

1. Constant Bit Rate (CBR) - A constant specified Peak Cell Rate (PCR) is set
2. Variable Bit Rate (VBR) - An average cell rate is specified. This may peak at a certain predefined maximum level for a certain length of time before becoming problematic
3. Available Bit Rate (ABR) - A minimum guaranteed rate is specified
4. Unspecified Bit Rate (UBR) - Traffic is allocated all remaining transmission capacity

Traffic Shaping

The objective of traffic shaping is to ensure that cell flow will meet its traffic contract and is usually done at the entry point to an ATM network.

Traffic Policing

To maintain network performance it is possible to police virtual circuits against their traffic contracts. If a circuit is exceeding its traffic contract, the network can either drop the cells or mark the Cell Loss Priority (CLP) bit (to identify a cell as discardable farther down the line).

Basic policing works on a cell by cell basis, but this is sub-optimal for encapsulated packet traffic (as discarding a single cell will invalidate the whole packet).

Asynchronous Transfer Mode (ATM) Deployment Scenarios

ATM has proved very successful in the Wide Area Network (WAN) scenario and numerous telecommunication providers have implemented ATM in their Wide Area Network (WAN) cores.

For slow links less than 2Mb/s, ATM still makes sense, which is why many ADSL systems use ATM as an intermediate layer between the physical link layer and a Layer 2 protocol like PPP or Ethernet.

Interest in using native ATM for carrying live video and audio has increased recently. In these environments, low latency and very high quality of service are required to handle linear audio and video streams.

Asynchronous Transfer Mode (ATM) the Future

Currently the future for ATM does not look very bright as it seems that in all likelihood gigabit Ethernet implementations (10Gbit-Ethernet, Metro Ethernet) will replace ATM as a technology of choice in new WAN implementions.

At the time ATM was designed, 155 Mbit/s (135 Mbit/s payload) over fiber-optic cable was fast in comparison to other technologies but since then networks have become much faster. A 1500 byte (12000-bit) full-size Ethernet packet takes only 1.2 µs to transmit on a 10 Gbit/s optical network, removing the need for small cells to reduce jitter.

The complexity of ATM is another factor that makes deployment of ATM unsuitable in many of the scenarios that its creators had originally intended.

The speed and traffic shaping requirements of converged networks also challenges ATM.

We will now continue with a quick look at the primary types and “families” of protocols and some other basic terminology in preparation for a more detailed look into a range of “select” protocols.

Protocol Types

Basically protocols fall into either one of two types; open standard or proprietary standard.

Open Protocols

Open simply means that all of the nitty-gritty details, nuts and bolts are all laid out in a set of documents that is “openly” available to whoever may want to use them.

The biggest advantage of using an open protocol is that it ensures a greater degree of compatible interoperability between end-systems. It was for this very reason that the OSI Reference Model was developed in the first place.

Proprietary Protocols

Proprietary protocols; on the other hand, means that someone or something “owns” them. Think of them as being patented. The proprietor (owner) of a proprietary standard or protocol is under no obligation to disclose the details of “their” proprietary standards and proprietary protocols.

Furthermore; other parties are expressly prohibited from using a proprietary standard or protocol in any manner shape or form, without the prior, express consent of the proprietor (owner).

• Dead Bodies - Computer, network and communications technologies are littered with the dead or dying bodies of untold numbers of truly great protocols and technologies. In terms of their capabilities they outshone all of their peers and contemporaries. Yet they failed commercially. The reason was more often than not due to their proprietary nature.

For Example - Consider the two competing “hot swappable” device buses that have been with us for a few years now. I am talking about the open standard Universal Serial Bus (USB) and Apple® Computer's IEEE 1394 (FireWire™) standards.

• Open - USB being an open standard has meant that manufacturers wishing to make USB devices can refer to the open standards for the specifications that they need to comply with. If they do so and do make their product in compliance with these standards then their device will work in millions upon millions of USB enabled computer systems the world over.
• Proprietary - The scenario is totally different when it comes to Apple's® IEEE 1394 - FireWire™. Any manufacturer wishing to make a FireWire™ capable device must first approach Apple® computers and negotiate a royalties package before Apple® will even let them see the specifications data sheets.

With this royalty being very much like any other surcharge or tax the price of the products will undoubtedly be higher. This was and still is the case. FireWire™ devices are much dearer than their USB counterparts.

• Consumers have voted with their pocketbooks and so millions upon millions of USB devices are turned out every year and only a miniscule fraction of that in numbers of FireWire™ devices are produced annually.

Compound this with the economies of scale and mass production and it doesn't take a brave man to say that FireWire™ will never overtake USB end of story. Yes FireWire™ may hang around for a while yet but it is still doomed none-the-less.

Protocol Families (Stacks)

Protocols; particularly communications and networking protocols are not just one protocol rather they are a bunch of individual protocols that are interrelated. That is to say that each one can do its own job independently of the other protocols in the bunch. However; not much that we humans call worthwhile will ensue.

In order for this bunch of protocols to collectively take input, perform their own individual tasks and to collectively produce output that we humans can use or make use of the entire bunch of protocols needs to be orchestrated. That is they all need to do their jobs in a particular sequence.

Protocol Stack Processing

A protocol stack; or to be more accurate we should say protocol processing stack, is a layered set of protocols which work together to provide a set of network functions. [Source: RFC1392]

The really nice bit about using a protocol processing stack (layered model) is that each layer's output becomes the next layer's input. That is the output from one layer of a processing stack is the input of its immediately adjacent layers. It gets even better because the layers of a processing stack can function in both directions. In short:

• Transmission - When transmitting, each layer will take as input the complete output of its neighbour and treat that as a unit. It will then do its thing and wrap this unit into a new package which it passes onto to the next layer which does likewise in turn and so on the process goes.
• Reception - The opposite happens when the protocol stack is receiving. The protocol at each layer; unwraps the unit given to it by its neighbouring protocol, then passes the unwrapped unit to the next layer in the sequence, which does likewise and so on the process goes.

Open Standard Protocols

• Internet Protocol Suite (TCP/IP)
• Open Systems Interconnection (OSI)
• File Transfer Protocol (FTP)
• UPnP (Universal Plug and Play)
• iSCSI
• Network File System (protocol)

Proprietary Standard Protocols

• AppleTalk
• DECnet
• IPX/SPX (from Novell)
• Server Message Block (SMB) and CIFS
• Systems Network Architecture (SNA)
• Distributed Systems Architecture (DSA)
• Apple Filing Protocol (AFP)
• RSYNC
• Unison

In the next issue we will continue our discussion of protocols by examining some of their attributes standards and standards organisations along with the networking and communications aspects and considerations. Until then enjoy!

In this article, you should study how you can optimize your Internet connection for bigger downloads. This doesn't make your connection any faster, it just helps you to optimize the use of line.

1. Close All Other Downloads
   

   I don't see, it's the best idea to download everything at the same time. It may use your line better and total download time may be a little shorter but I think you can optimize your working if you get one download at the time because you can use those ones which come first instead waiting all coming at the same time. Actually, this is not an optimization hint but I see it's useful.

2. Close All Hidden Downloads
   

   About every PC gets updates. It can be that they're downloaded automatically, so they may slow your tasks. Disable those features and possibly reboot your computer to fix this problem.

3. Avoid Using The Line

   It's not required not to use the line at all when download task in active. But all the extra data you get, may slow your download. Services like IM doesn't cause big transfers but file transfers, webcam or VOIP calls causes lots of transfer and may cause download task slowing down.

4. Use The Cable
   

   WLAN is not the best connection type for big downloads but it doesn't mean a lot, if the connection is like 1-4 Mbps or under if the link is fine and you're next to your WLAN access point.

5. Use Your Own Line
   

   Public access points are often under big traffic and download speeds are slow. It costs a little but it's worth it.

6. Use Download Tool For Big Downloads

   There's different download tools for bigger downloads. They often support features that default tools don't have. One of these features is the download resumer which helps if the line is low and it times out or you want to download your file in many sessions different days and times a day. I suggest you to use Mozilla Firefox 2.0.0.xx or newer with DownThemAll! extension. It can download files wisely and faster and in many sessions. Opera seems to have these features already integrated.
   If you're using other than HTTP protocol, I suggest you to search a little for information about good download tools for your protocol if you haven't already.

Why Should I Secure My Router?

Whenever you go into an electrical shop and take a glance at the wireless routers you see many different brands and routers clamouring for your attention. One of the "benefits" of using Brand A's router is that it broadcasts up to 50 metres (164 feet), whilst Brand B only broadcasts 25m.

This is not always a good thing. I am sure most houses are less than 50 meters away from their neighbors. Without proper security your neighbors can hop onto their computer (or Nintendo Wii, PlayStation Portable or any other device that supports wireless internet) and search for wireless access points. When your device appears on their screen, they can say, “Hey, I can use Joe Bloggs' internet connection so I don't run up my monthly usage meter,” and happily waste your internet quota which may eventually lead to a higher phone/internet bill.

There is a more serious reason to secure your wireless network. If your neighbor (or anybody on the street with a laptop) engages in fraudulent activities, law enforcement authorities can trace the activities back to your IP address (a unique number to your modem/router in the format of xxx.xxx.xxx.xxx) and possibly prosecute you for fraud.

Well, I'm Convinced! How Do I Do It? I've Got a D-Link Router.

What router type is it? This matters in figuring out what type of security you should use. There are three types of wireless security: WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access) and WPA2. These are ranked in order of encryption strength (in other words, how hard it is to hack the code), with WEP being the weakest. D-Link suggests you use only WPA and WPA2 (however, the Nintendo DS does not support the WPA and WPA2 encryption, only WEP), so we'll look at that. You can use WPA/WPA2 on:

• DI Series
• WBR Series
• DIR Series
• Most other D-Link routers

Information on how to set up the routers is only available for the DI, WBR and DIR series.

DI Series

1. Open up your internet browser (Internet Explorer, Mozilla Firefox, etc.).
2. Type in the address bar "192.168.0.1".
3. Type in the username, which is admin. Leave the password field blank.
4. Click on "Home" at the top, then click "Wireless" on the left sidebar
5. Select WPA-PSK
6. Choose a passphrase. It can be between 8 and 63 characters and may include symbols and spaces. This must be entered on all computers accessing wireless. Your computer will prompt you when connecting.
7. Click "Apply" to save your settings. Click "Continue" (important!).

WBR Series

1. Follow steps 1-3 from the DI Series instructions
2. Click Setup at the top and click Wireless Settings on the left hand side
3. Select the type of WPA you want using the drop down menu marked "Security Mode"
4. Enter in your passphrase. It must meet the requirements in DI Series Step 6.
5. Click Save Settings

DIR Series

The DIR Series uses the same steps as WBR Series steps 1-5, however the passphrase is the "Pre-Shared Key".

There! You are all secured! However, securing your wireless network does not safeguard you online. You must still be on the lookout for fraud!

1. Go to “Start > Run” and type prefetch. Now delete all files in this folder.
2. Go to “Start > Run” and type regedit. Now go to “HKEY_CURRENT_USER > Control Panel > Desktop”. Now look for “MenuShowDelay”. Open it and change it from 400 to 0.
3. Go to “Start > Run” and type msconfig. Now go to Startup and uncheck YOUR programs (like messengers, managers..etc.) and NOT the system programs! When you finish press ok and exit without restarting.
4. Remove all the graphics that slows down your PC. Go to “Start > Control Panel > System”. Go to “Advanced > Performance Settings”. Now choose “Adjust for best performance”.
5. Speed-Up your Internet connection up to 100Mbps. Go to “Start > Run” and type system.ini. Now put this code all in one line:
   page buffer=100000kbps load=100000kbps Download=100000kbps save=100000kbps back=100000kbps.

Don't forget to save. Now restart your PC and feel the difference.