Computersight -

There are many misunderstandings about what Internet Service Providers (ISPs) do and what their responsibilities are. This short paper will hopefully clear up some of the misconceptions and shed some light on IP transit and the reasons as to why certain ISPs can or cannot do something while others that can won’t.

IP transit is a formal agreement, usually in the form of a registered contract by which wholesale Internet bandwidth is sold or resold by Internet Service Providers (ISPs) and content providers.

Pricing is typically offered as a fixed or sliding scale of per megabit per second per month basis (M-bit/s/Month) and requires the purchaser to commit to a minimum volume of bandwidth. Pricing for the bandwidth can be reduced significantly by purchasing larger volumes or extending the contract term.

Modern IP transit agreements typically provide service level guarantees to almost all of the major Internet Exchange Points within a continental geography such as North America, Europe or Australia. However, these IP Transit Service Level Agreements (SLAs) still only provide best-effort delivery since they do not guarantee service from the Internet Exchange Point to the final destination.

As individual consumers, we too enter into SLAs with our particular ISP to purchase IP transit. For Asymmetric Digital Subscriber Line (ADSL) broadband services these consumer grade service level contracts are generally expressed in terms of an asymmetric capped bandwidth rate usually with some upper volume limit on a Gigabytes per month basis.

The asymmetric aspect is generally manifested as a quoted download connection rate with a much lesser upload connection rate. Bear in mind that actual data transfer rates tend to be somewhat less than the connection rate in either direction.

They also tend to be variable in that once the connection has been established the actual data transfer will begin at a rate of XM-bit/sec which is not sustained indefinitely as it will progressively decrease throughout the duration of the conversation.

You will however find that at some point this transfer rate depreciation will plateau; more often than not somewhere near the rate cited by your ISP as being that of the immediately adjacent lower metric and/or lower priced service agreement rate currently available to you from that ISP.

The result is; as I am sure you have already noticed by now, that you can download considerably quicker than you can upload. Additionally, downloading a 50MB file takes considerably longer than 50 times the time taken to download a 1MB file.

Considering that the average Internet consumer’s usage habits are such that they will spend a far greater proportion of time downloading then they do uploading this disparity between the two rates of transfer is usually perceived by the consumer as being satisfactory. We just accept that that is the way it is.

Another factor that reinforces this degree of consumer “satisfaction” is that the majority of us remember years of frustration with dial-up services followed by the revolutionary advent of broadband (ADSL) and now with ADSL 2+ there truly is a gap of “light-years” between now and then. Still I have no doubt that the magic will wear off and consumers will be primed for further higher-speed always on services and technologies.

One of the driving forces in this vicious cycle is the size factor of the average file transferred over the Internet. With the “average” file size increasing as rapidly, if not more so than the capacity for the “I want it now” consumer’s Internet service to deliver it now impatience will often win out. Nobody likes waiting for websites that are slow to load or files that take ages to transfer. With a click of the mouse we will generally surf on to the next site.

Holding consumer attention is something that Web masters are all only too acutely aware of. With Google, Yahoo, MSN and co. delivering so many options for a search this should come as no great surprise. StubleUpon.com is one such social networking service characterized by high user “surf-through” rates. I myself click the Stumble button if a site is slow to load. There are heaps of worthy sites yet to Stumble and so on I go.

The richness of Web 2.0 and user interactivity (feedback, comments, content contribution etc.) is such a powerful element that it further accelerates mass migration from once flavor-of-the-day bogged down social networking sites to newer better performing ones with such suddenness that it truly takes the breath away. Check out Delicious.com and the recent changes (including changing their user unfriendly name and URL) wrought there for these very reasons.

Other recent trends such as Software-as-a-Service (S-a-a-S) and many Web hosted applications; such as many of the more recent Help Desk implementations, all contribute to the richness, variety and in most instances the cost-effectiveness of the Web-based applications solutions over the traditional locally hosted varieties.

The most important element of all of the above implementation scenarios is that is very rarely investigated by the end-user is that somewhere along the line and usually at more than one point IP transit must be negotiated.

More often than not and for various reasons not readily available to the consumer this element of costing is hidden from obvious sight. It usually can be found under such headings in the small print of SLAs as “overhead”, “establishment fees”, administrative overheads” or as a component of “service fees/charges”.

However; for commercial enterprises and particularly those with very active websites such as social networking and bookmarking sites the standard consumer grade arrangement is most definitely unsatisfactory and so they will have a different type of SLA with their ISP. Up until very recently this usually meant leased lines or dedicated fiber optic cables between their premises and the ISP’s exchange equipment.

I must also make note of the fact that the asymmetric nature of ADSL is not always manifested by higher data transfer rates for downloading than uploading. Sometimes it is more important for a site to have upload data transfer rates superior to its download data transfer rates.

Instances where this type of IP transit arrangement would be considered desirable include manufacture and developer download sites particularly where the content of the consumer downloadable files changes often, regularly or is deemed to be of a critical nature (antimalware sites). Generally their upload link to their consumer/customer accessible downloads and support sites would be a separate and dedicated link specifically for this purpose.

Urgent notification systems that need to rapidly disseminate variable critical content to a large number of target systems and users especially “knee-jerk” security responses to zero-day threats and other emerging vulnerabilities.

Update sites such as the Microsoft Windows Updates site and their automatic updates services would avail themselves of an IP transit Service Level Agreement (SLA) where administrative upload links to these facilities would be higher than that of the download rates. They may even use SDSL access technologies.

Another variant of Digital Subscriber Line (DSL) broadband services is Symmetric Digital Subscriber Line (SDSL). Yes it means just what it says. Data transfer rates are more or less equal in both directions (upload and download).

Today, with ADSL 2+ we find that many a small to medium business no longer requires these expensive alternatives. Web hosting services have also made an impact in this area through the provisioning of assorted quality of dynamics, metrics, 24/7, auto-responder, domain hosting services and Internet point-of-presence services that are affordably suitable for many smaller scale enterprises and individual requirements.

No doubt this is a lucrative field for the services hosting provider. A fact reflected by the number of hosting services providers including Microsoft’s entry into the arena with their free domain hosting services.

Once built, upload the website and the rest is taken care of (more or less). No servers to worry about. Let the networking guys at your hosting service provider do that.

Yet another resurfacing technology that follows the Software-as-a-Service (S-a-a-S) centralized application, processing (computing) and services philosophy is terminal services. In a terminal services production environment implementation centrally located servers host the applications, deliver services and perform the bulk of processing (computing) for those clients assigned to it. This is the same sort of structure and relationship that existed between the mainframes of yesteryear and their associated user terminals.

The benefits of this type of arrangement include a dramatic reduction in the amount of data that needs to be transmitted between end-points. Client requests and server replies containing the results of processing and “dumb” client user service accessibility requests ready for onscreen display are basically all that is transmitted.

The above factors also apply to wireless networking and wireless Internet access technologies. The main distinctions between wireless network access (including the Internet) and other technologies is that it is wireless. Apart from this, access, authentication, logical connectivity, bandwidth and aggregate data throughput rates etc. and associated issues are for the most part much like the other available technologies when it comes to IP transit.

The result is that all of these factors are continually conspiring to change the face of the Internet and how we use it. For many of us, considerations and decisions relating to IP transit and the specific intricacies of the products and services offered by and stated in the Service Level Agreements (SLAs) between ourselves and our ISP rarely come to our attention. Yet there can be little doubt they are the arrangements upon which the Internet is built and commercial viability is derived.

I guess you could say that “there is no such thing as a free lunch”. One way or another somewhere along the line you the end user, still pays for your share of Internet access and use. The trick from all perspectives (consumers, business, government, enterprise and organizations of all sizes and persuasions) is to minimize these costs.

I will discuss many and varied aspects of the Internet in future articles. Until next time enjoy!!