 price of a certain commodity, whether it's a tangible service or an intangible artifact is very important in business community. We shall now look at the pricing schemes which possibly could be adopted or are already widely in use for different CDN networks and the kind of resultant business model which comes into play with the adoption of certain pricing scheme. The basic content provider and CDN into play in a business model actually is on an assumption. The assumption is that CDN is going to provide some economic benefits to content provider because the content provider could very much host her own network but why is it banking on CDN? Number one, speeding up the performance in terms of end-to-end service time. The economies of scale by aggregating the users in multiple profiles and servicing every user at a certain server, data center or even a customer site. The pure finance terms, the marginal cost is actually the resultant cost which is incurred in providing certain service per customer is expected to reduce than what a content provider would incur. In addition, the content provider expects higher availability during certain anomalous situations like flash crowds or loss attacks. Now the concern is how could we measure the value and how much price could we tag to that particular service? As we know it is beyond stating anything further that the pricing policies significantly impact the margin of CDN that it is going to get out of the content provider and the surplus that is the resultant profit that CDN that the content provider is there to earn. This means there would be some kind of tricky issues that have to be resolved by the content provider and CDN that includes the impact of the nature of traffic whether it is Poisson or it is very much deterministic or if it is bursty. How much profits could be afforded both for content provider and CDN? Then could we look at some kind of discount policy like we get sales in our peak season like Ramazan and New Year etc. Then if there is a certain change in the market inflation or anything unexpected like the dollar rate, so the overages in current pricing mechanism have to be rethought. It is a tricky issue. Then the competition within the CDN market because sometimes CDNs have to enter into the market so the prices that they quote are so artificial and so unsustainable for others to maintain. Let us look at very basic form of pricing schemes. The pricing schemes are based on as simple as the aggregate usage. Aggregate usage is in terms of the megabytes or we call volume for instance 50 terabytes per month. If that is an agreement between the content provider and CDN then the CDN can charge the content provider per gigabyte delivered. It could be as low as at the MB level but it is normally amortized at the gigabyte level. Similarly, some discounts could be offered from the CDN to the content provider that if you consume anything around 50 terabytes we are going to charge you half a dollar per terabyte but if you go beyond 100 terabytes if you are a very good customer of us we might provide you a considerable subsidy and on the other side just to keep the content provider in check some excess usage could have penalties as well. Another form of pricing is the percentile based pricing. The content provider consumption is as low as in the bandwidth consumption so the CDN periodically samples bandwidth usage using well-known tools like MRTG etc the content provider consumption of the bandwidth is measured and then to to make it more fair 95th percentile of usage and correspondingly the content provider is charged per megabits per second. So far so good we are not incorporating any QoS issues but the problem becomes complicated because in reality the content provider is providing services to certain users who have an expectation in terms of quality of service so the congestion pricing in networks actually means that there has to be some kind of price tag associated with how much does it cost to have congestion in the network for the content delivery network. So congestion pricing focuses on interaction between how much money the content provider is going to offer against certain QoS and this QoS is of course going to demand certain limits on the congestion. So the congestion cost is going to be for the content delivery network and the capacity cost are going to be the for content delivery network. Now the user or the content provider is interested in maximizing the QoS at minimum price but for the content delivery network when the capacity is fixed when it cannot be increased indefinitely and the QoS requirements from the content provider become stringent and stringent so it means now price is now going to be the factor that could possibly manipulate interaction or the business power gain between the content provider and the content delivery network. We are so far on the book by Raj Kumar by Content Delivery Networks.