This document discusses different types of traffic and related issues:

• How is traffic calculated?
• How do I change the traffic limit?
• Throttle policy

Calculating Traffic

Traffic is the amount of data transferred to and from your site or home directory. Depending on the service, you can run up different types of traffic, as suggested in the following table:

The traffic is reset once a month regardless of your billing period. The current day is not included in the amount of traffic you have run up.

How Do I Change the Traffic Limit?

The use of traffic cannot be physically restricted. This means nothing happens if you exceed your traffic limit: your web-sites, mailboxes and virtual ftp accounts will continue to work. Each gigabyte beyond the limit, however, will be charged at the overlimit rate. Per-gigabyte charges are usually higher, so it is wise to set your transfer limit to the level you are expecting to have. To change your plan default, do the following:

1. In the info/control area, click the edit icon for Total traffic.
2. On the page, enter the HTTP monthly traffic you expect to run up.

Throttle Policy

You can throttle the use of traffic in your account by delaying or refusing requests to your sites.

To enable the Throttle module, do the following:

1. On the control panel home page, click Web Options. Select the domain if you have more than one.
2. Scroll the page to find the Throttle Policy option and turn it on:

   

3. Agree to charges, if any.
4. Select the type of policy anc click Submit:

   

5. Complete the wizard.
6. At the top of the Web Service page, click the Apply link.

The eight throttling policies are:

• Concurrent - impose a limit on the number of concurrent requests at any one time. The period specifies how long data is accumulated before the counters are reset.
• Document - excluding requests for HTML page elements such as images and style sheets, impose a limit on the number of requests per period. When this limit is exceeded, all further requests are refused, until the elapsed time exceeds the period length, at which point the elapsed time and the counters are reset. Note that the requests (hits) column of the throttle status display does not include the requests for page elements.
• Idle - impose a mimimum idle time between requests. When the miminum is not reached, the request incurs a calculated delay penalty or is refused. First, whenever the elapsed time exceeds the period length, then the counters are reset. Second, if the idle time between requests exceeds the minimum, then the the request proceeds without delay. Otherwise the request is delayed between one and ThrottleMaxDelay seconds. If the delay would exceed ThrottleMaxDelay, then the request is refused entirely to avoid occupying servers unnecessarily. The delay is computed as the policy minimum less the idle time between requests.
• Original - impose a limit on the volume (kbytes sent) per period, which when exceeded the request incurs a counter-based delay penalty or is refused. First, whenever the elapsed time exceeds the period length, then the volume and elapsed time are halved. Second, if the volume is below the limit, then the delay counter is decreased by one second if it is not yet zero. Otherwise, when the limit is exeeded, the delay counter is increased by one second. The delay can be between zero and ThrottleMaxDelay seconds, after which the request will be refused to avoid occupying servers unnecessarily.
• Random - randomly accept a percentage (limit) of the requests. If the percentage is zero (0), then every request is refused; if the percentage is 100, then all requests are accepted. The period specifies how long data is accumulated before the counters are reset.
• Request - impose a limit on the number of requests per period. When this limit is exceeded all further requests are refused until the elapsed time exceeds the period length, at which point the elapsed time and counters are reset.
• Speed - impose a limit on the volume (kbytes sent) per period, which when exceeded the request incurs a calculated delay penalty or is refused. First, whenever the elapsed time exceeds the period length, then the limit (allowance) is deducted from the volume, which cannot be a negative result; also the period length is deducted from the elapse time. Second, if the volume is below the limit, in which case the request proceeds without delay. Otherwise the request is delayed between one and ThrottleMaxDelay seconds. If the delay would exceed ThrottleMaxDelay, you refuse the request entirely to avoid occupying servers unnecessarily. The delay is computed as one plus the integer result of the volume times 10 divided by the limit.
• Volume - impose a limit on the volume (kbytes sent) per period. When this limit is exceeded all further requests are refused, until the end of the period at which point the elapsed time and counters are reset.

You can also set throttle policy to None which imposes no restrictions on a request and used as a place holder to allow monitoring. The limit currently serves no purpose. The period specifies how long data is accumulated before the counters are reset. Remember to apply the changes you have made. Press Apply in the Web Service -> Server Configuration row.