Network Capacity Sizing Worksheet

Use the Network Capacity Sizing worksheet to estimate the size of the network required to support your web site. Choose between an estimated network size of 100 Mbps Ethernet, 100 Mbps switched Ethernet, or 1Gbps Ethernet. Please see Chapter 9 for a complete description of the data and calculations in the worksheet. Also, see Chapter 10, Case Study: Preparing to Test, for an example using this worksheet. The worksheet calculates in seconds, so please use the "per second" data from the Capacity Sizing worksheet.

Input Data

	Input Data	Source of Data	Your Data
1.	Average page size (bytes)	Web application architect
2.	Maximum page size (bytes)	Web application architect
3.	Requests per second	Capacity Sizing worksheet, line 14
4.	User arrival rate per second	Capacity Sizing worksheet, line 11
5.	Average bytes of application data transferred per request (i.e., from database)	Web application architect
6.	Percentage of requests requiring data transfer	Web application architect/marketing
7.	HTTP session size (only if shared session is used)	Web application architect
8.	Size of applets	Web application architect
9.	Percentage of user requests requiring applet download	Web application architect/marketing

Calculating Network Requirements

	Network Data	Equation	Total
10.	Outbound HTML / static elements	Average page size * Requests/sec Line 1 * Line 3
11.	Inbound HTTP requests (estimate)	20% * Outbound data 20% * Line 10
12.	Application data transfer	Average bytes/request * Requests/sec * % requests requiring data Line 5 * Line 3 * Line 6
13.	HTTP session data transfer	HTTP session size * Requests/sec Line 7 * Line 3
14.	Applet transfer	Applet size * User arrival rate/sec * % requests using applet Line 8 * Line 4 * Line 9
	Total

Network Sizing

Network Speed (Bits)	Estimated Bytes Supported (Planning)	Equation	Yes/No
100Mbps Ethernet	5MBps	5MBps > Total?
100Mbps switched Ethernet	8MBps	8MBps > Total?
1Gbps Ethernet	50MBps	50MBps > Total?
The Minimum Network Requirement is _______.