SYSTEM FOR PROTECTION AGAINST DDOS ATTACKS
A method is presented that enables a server to make use of client or third party resources. The client request data contains data about the network location of the client. The server may store this location data of each client. Before or after execution of the request, the server determines if the server is in or close to an overload situation. If the server is not in an overload situation, no further changes are needed. If the server is in or close to an overload situation, the server selects a new location in the network from the database with all client locations. The server allocates a new instance of the server function at a resource provider on (or close to) this new location. The server may select one or more clients from the database. The selected clients are transparently redirected to the offloaded server function. Subsequent requests from clients are handled by the offloaded server function. The offloaded server function employs the same functionality and thus may decide to offload a server function to another network location.
1 . A method for handling server overload, comprising:
providing a part or all of the functionality of a server application by a server function; said server function comprising one or more offloadable server functions that provide a part or all of the functionality of the server application, and which may be loaded on other resources;
providing resource providers able to provide resources for hosting said offloadable server functions;
detecting a server load by a load detection function constructed to determine if the server function is in or close to an overload situation; and
redirect detected client requests to the offloaded server function on a selected resource in response to a load detection function detecting an overload situation.
2 . The method according to claim 1 , wherein the server further comprises a resource provider lookup function to select a resource from said resource providers.
3 . The method according to claim 1 , wherein the selection is provided by a client request advertisement indicating a selectable resource.
4 . The method according to claim 1 wherein the offloaded server function is executable on a resource provider and wherein the offloaded server function in turn comprises offloadable server functions that provide a part or all of the functionality of the server application, and which may be loaded on other resources in another network location.
5 . The method according to claim 1 , further comprising;
retrieving addresses of communication devices that are close to attack sources at the upstream;
transmitting the offloaded server function to a resource provider in a defense position at the upstream.
6 . The method according to claim 5 , wherein the resource provider lookup function comprises an attack source determining function able to extract the address of a communication device to be chosen as an upstream defense position from the candidates of upstream communication device close to the attack sources retrieved by the resource provider lookup function.
7 . The method according to claim 1 , wherein the resource providers comprise at least one of physical and virtual resources.
8 . The method according to claim 1 , wherein the physical resources comprise at least one of CPU load, and communication bandwidth.
9 . The method according to claim 1 , wherein the non-physical resources comprise at least one of a number of database reads per time unit, a number of database writes per time unit, a number of requests per time unit, and a number of simultaneous sessions.
10 . The method according to claim 1 , the information processing system comprising system control means, interface means and client application means, the method comprising next steps when the system is overloaded or threatens to be overloaded:
it is detected whether the system control means, the interface means or the relevant client application means are or are threatened to be overloaded;
it is detected whether the requested access will load the system control means, the interface means or the relevant client application means;
if the requested access is not deemed to contribute to the overload of the relevant system means, the requested access is judged to be admissible and/or if the requested access is deemed to load the relevant system means, the requested access is judged to be not-admissible.
11 . The method according to claim 1 , several clients requesting for access to the information processing system and service level indicators being assigned to those clients, the method comprising that if the kind of requested access is deemed to contribute to the system overload, the requested access of clients having a relative high service level indicator is given preference or priority over clients having a relative low service level indicator.
12 . The method according to claim 1 , the requested access, deemed to contribute to the system overload, is judged to be admissible for clients having a relative high service level indicator and/or not-admissible for clients having a relative low service level indicator.
13 . A system for handling an access request to an information processing system, comprising processing means and memory means, whereby the apparatus is communicatively connected to the information processing system, whereby the apparatus is further connected to a network for transmitting the access request, characterised by that the apparatus is adapted to perform the steps of claim 1 .
14 . A non-transitory computer-readable medium having a computer program embodied thereon for handling an access request to an information processing system, the computer program including instructions that cause a processor to perform the method of claim 1 .