A traffic management system comprising: a first interface to an external network for receiving requests from clients and providing files in response to said requests; a second interface to an internal network for issuing requests to servers and receiving files in response to said requests, and for effecting load balancing between the servers; and a processing device for: monitoring response times of the servers when responding to requests from the clients, wherein for each request the response time is the time taken between the server receiving the request and starting to serve a file in response; for each response time, determining a first value based on whether it is greater or less than a threshold value, and inserting said first value into a FIFO buffer; summing the values in said FIFO buffer to determine a second value, and determining a service level based on a comparison between said second value and a second threshold value; switching the traffic management system from a first operational mode in which no measures are taken to a second operational mode in which a measure is taken for at least some requests when: the traffic management system is operating in the first operational mode and the second value is greater than the second threshold value; switching the traffic management system from the second operational mode to the first operational mode when: the traffic management system is operating in the second operational mode and the second value is lower than a third threshold value, wherein the third threshold value is lower than the second threshold value; and processing the requests received from the clients based on the operational mode of the traffic management system, wherein in the second operational mode the measure taken reduces the time taken for a server to provide a response to a request. a first interface to an external network for receiving requests from clients and providing files in response to said requests; a second interface to an internal network for issuing requests to servers and receiving files in response to said requests, and for effecting load balancing between the servers; and a processing device for: monitoring response times of the servers when responding to requests from the clients, wherein for each request the response time is the time taken between the server receiving the request and starting to serve a file in response; for each response time, determining a first value based on whether it is greater or less than a threshold value, and inserting said first value into a FIFO buffer; summing the values in said FIFO buffer to determine a second value, and determining a service level based on a comparison between said second value and a second threshold value; switching the traffic management system from a first operational mode in which no measures are taken to a second operational mode in which a measure is taken for at least some requests when: the traffic management system is operating in the first operational mode and the second value is greater than the second threshold value; switching the traffic management system from the second operational mode to the first operational mode when: the traffic management system is operating in the second operational mode and the second value is lower than a third threshold value, wherein the third threshold value is lower than the second threshold value; and processing the requests received from the clients based on the operational mode of the traffic management system, wherein in the second operational mode the measure taken reduces the time taken for a server to provide a response to a request. monitoring response times of the servers when responding to requests from the clients, wherein for each request the response time is the time taken between the server receiving the request and starting to serve a file in response; for each response time, determining a first value based on whether it is greater or less than a threshold value, and inserting said first value into a FIFO buffer; summing the values in said FIFO buffer to determine a second value, and determining a service level based on a comparison between said second value and a second threshold value; switching the traffic management system from a first operational mode in which no measures are taken to a second operational mode in which a measure is taken for at least some requests when: the traffic management system is operating in the first operational mode and the second value is greater than the second threshold value; switching the traffic management system from the second operational mode to the first operational mode when: the traffic management system is operating in the second operational mode and the second value is lower than a third threshold value, wherein the third threshold value is lower than the second threshold value; and processing the requests received from the clients based on the operational mode of the traffic management system, wherein in the second operational mode the measure taken reduces the time taken for a server to provide a response to a request.