Customers may report varying levels of service because some data are cached and some are not. Purchasing and installing cache servers quickly enough to deal with dynamic Web traffic flows may not be practical. One final option is simply adding enough capacity to deal with the traffic. However, this solution may not be cost efficient or easily scalable for the following reasons. Traffic surges may be temporary, possibly caused by content that has unexpectedly become hot news.
Additional bandwidth is expensive.
High operational costs mean lower profit margins. The procurement time for high-bandwidth circuits can be measured in months. Bandwidth upgrades are not always in useful increments. For example, the cost of ordering multiple T1s equals the cost of ordering a DS-3 in some cases. Using either an offline utility or online dynamic methods, you can determine which paths can provide the highest capacity with the lowest congestion required to meet the customers' performance requirements.