This is an improved (version 2) spreadsheet model of the NetForecast web performance analysis formula described in "Understanding Web Performance" by Peter Sevcik and John Bartlett. The article appears in two forms:
Business Communications
Review, October 2001, original version.
NetForecast Report 5055 (on our web site), expanded version.
This model and formula differ from the published version by improving
how packet loss effects performance. The new formula specifies a TCP retransmission
time that has an average effective value of 1.25 seconds on many TCP implementations.
As a result, the packet loss term (L) in this example is reduced in order
to match the results of the typical case in Table 2 of both documents.
Below is a link to an Excel spreadsheet that implements this formula for calculating response time across a network. A full description of this formula and its application can be found in an article we published in Business Communications Review (BCR) in October 2001, and also in NetForecast Report 5055. Please read the following license agreement before downloading the file, and indicate your acceptance of these terms by clicking the link. The download will immediately start.
License Agreement
Recipients of this model agree to the following conditions:
NetForecast does not warrant this model or software. This model was developed using our best judgment based upon our analysis and measurements performed by third parties and by us.
User agrees to reference NetForecast as the source in any presentation of results derived by the model. User agrees to not turn this model into a commercial product or part of a commercial product.
User agrees to send
an email message to Peter (
)
as a verification of receiving the model and accepting these terms