# US 6,185,619 B2 · Method and apparatus for balancing the process load on network servers according to network and serve based policies > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,185,619 B2 - Document ID: US6185619B2 - Status: Granted - Kind: B2 - Application number: 08/965,848 - Filed: 1997-11-07 - Granted: 2001-02-06 - Earliest claimed: 1996-12-09 - Assignees: Genuity Inc.; GTE Service Corporation - Inventors: Rodney Lance Joffe; Barry A. Dykes; Jason Alan Brittain; Victor Joseph Oppleman; Brian Everett Pettingell; James Joseph Lippard; Ian Burke Vandeventer; Brett Dean Watson; Steven Michael Hotz; Nils Herbert Mc Carthy - Web page: https://patentgrep.com/patent/US6185619B2 ## CPC - G06F 9/505: {considering the load} - H04L 67/1001: for accessing one among a plurality of replicated servers - H04L 67/1008: based on parameters of servers, e.g. available memory or workload (monitoring of computer activity G06F11/30) - H04L 67/101: based on network conditions - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract According to the present invention, a method and system provides the ability to assign requests for data objects made by clients among multiple network servers. The invention provides a distributed computing system and methods to assign user requests to replicated servers contained by the distributed computing system in a manner that attempts to meet the goals of a particular routing policy. Policies may include minimizing the amount of time for the request to be completed. ## Claims ### Claim 1 A system for routing requests for data objects from a plurality of clients comprising: a plurality of content servers configured to serve said data objects; a director component for routing said requests for data objects, said director component further comprising: a server selection component configured to select a content server from said plurality of content servers based upon a policy; an identification component configured to identify a plurality of routes from a requesting client to said content server; a determination component configured to determine a time to traverse each of said plurality of routes; and a route selection component configured to: select a route from said requesting client to said content server having the shortest time to traverse; and identify one of a plurality of IP addresses associated with said content server that directs content to the requesting client, from the content server, along the selected route. ### Claim 2 (depends on 1) The system of claim 1 wherein said director component includes an answer component for answering a request for a data object with a response that redirects a request from one of said plurality of clients to said selected content server along said route. ### Claim 3 (depends on 2) The system of claim 2 wherein said answer component includes a redirection component that uses an HTTP redirect response. ### Claim 4 (depends on 1) The system of claim 1 wherein said determination component includes a measurement component that measures the time to traverse said route using an ICMP echo reply. ### Claim 5 (depends on 1) The system of claim 1 wherein said server selection component includes: a determination component configured to determine the number of open TCP connections for each content server in said plurality of content servers; and a selection component configured to select a content server having the least number of open TCP connections. ### Claim 6 (depends on 1) The system of claim 1 wherein said server selection component includes: a determination component configured to determine the amount of available free RAM for each content server in said plurality of content servers; and a selection component configured to select a content server having the largest amount of available free RAM. ### Claim 7 (depends on 1) The system of claim 1 wherein said server selection component includes: a determination component configured to determine the amount of available free SWAP for each content server in said plurality of content servers; and a selection component configured to select a content server having the largest amount of available free SWAP. ### Claim 8 (depends on 1) The system of claim 1 wherein said server selection component includes: a determination component configured to determine the amount of CPU idle time for each content server in said plurality of content servers; and a selection component capable of selecting the content server having the highest amount of CPU idle time. ### Claim 9 A method for routing requests for data objects from a plurality of clients comprising the steps of: receiving a request for a data object from one of said plurality of clients; providing a plurality of content servers capable of serving data objects, wherein each of said plurality of content servers are comprised of a plurality of IP addresses that each route data objects from said content servers along a different path; determining a best server from said plurality of content servers according to a policy; identifying a plurality of routes from said client to said best server; determining a time to traverse each of said plurality of routes; selecting one of said routes having the shortest time to traverse; and informing said client of one of said plurality of IP addresses associated with the best server that directs content to the client, from the best server, along said route. ### Claim 10 (depends on 9) The method of claim 9 wherein said informing a particular client further comprises: answering a request for a data object with a response that causes said particular client to redirect said request to said best server. ### Claim 11 (depends on 10) The method of claim 10 wherein said response that redirects uses an HTTP redirect response. ### Claim 12 (depends on 9) The method of claim 9 wherein determining said best server according to said policy further comprises selecting a least loaded content server from said plurality of content servers. ### Claim 13 (depends on 12) The method of claim 12 wherein determining said best server further comprises: determining the number of open TCP connections for each content server in said plurality of content servers; and selecting as the least loaded content server the content server having the least number of open TCP connections. ### Claim 14 (depends on 12) The method of claim 12 wherein determining a best server further comprises: determining the amount of available free RAM for each content server in said plurality of content servers; and selecting as the least loaded content server the content server having the largest amount of available free RAM. ### Claim 15 (depends on 12) The method of claim 12 wherein determining said best server further comprises: determining the amount of available free SWAP for each content server in said plurality of content servers; and selecting as the least loaded content server the content server having the largest amount of available free SWAP. ### Claim 16 (depends on 12) The method of claim 12 wherein determining said best server further comprises: determining the amount of CPU idle time for each content server in said plurality of content servers; and selecting as the least loaded content server the content server having the highest amount of CPU idle time. ### Claim 17 (depends on 9) The method of claim 9 wherein said time to traverse is determined by measuring the time associated with an ICMP echo reply made over said route. ### Claim 18 A method for routing information from a plurality of clients comprising the steps of: receiving a request for a data object from one of a plurality of clients; determining a best server from said plurality of content servers according to a policy associated with a packet networking environment; determining one of a plurality of routes from said requesting client to said best server, said route having the shortest time to traverse; and relaying said request back to said client, wherein said request is comprised of one of a plurality of IP addresses associated with said best server that directs content corresponding to the clients request to the client along said route. ### Claim 19 (depends on 18) The method of claim 18 wherein said relaying information from a particular client further comprises: forwarding said information to said best server using network layer protocols. ### Claim 20 (depends on 18) The method of claim 18 wherein determining a best server further comprises selecting a least loaded content server from said plurality of content servers. ### Claim 21 (depends on 18) The method of claim 18 wherein said determining a route further comprises: identifying a plurality of routes from said requesting client to said best server; determining a time to traverse each of said plurality of routes; and selecting one of said plurality of routes having the shortest time to traverse said route. ### Claim 22 (depends on 21) The method of claim 21 wherein said time to traverse is determined by an ICMP echo reply. ### Claim 23 (depends on 18) The method of claim 18 wherein determining a best server further comprises: determining the number of open TCP connections for each content server in said plurality of content servers; and selecting as the best server the content server having the least number of open TCP connections. ### Claim 24 (depends on 18) The method of claim 18 wherein determining a best server further comprises: determining the amount of available free RAM for each content server in said plurality of content servers; and selecting as the best server the content server having the largest amount of available free RAM. ### Claim 25 (depends on 18) The method of claim 18 wherein determining a best server further comprises: determining the amount of available free SWAP for each content server in said plurality of content servers; and selecting as the best server the content server having the largest amount of available free SWAP. ### Claim 26 (depends on 18) The method of claim 18 wherein determining a best server further comprises: determining the amount of CPU idle time for each content server in said plurality of content servers; and selecting as the best server the content server having the highest amount of CPU idle time. ### Claim 27 A system for routing requests for data objects from a plurality of clients comprising: plurality of content servers that serve said data objects, each of said plurality of content servers comprising a plurality of IP addresses; and a director component that identifies a least loaded server based upon a policy that: selects said least loaded server from one of said plurality of servers; selects one of a plurality of routes from a requesting client to said least loaded server, wherein said route has the shortest time to traverse; and identifies an IP address associated with the least loaded server that directs content to the client along said route. ### Claim 28 (depends on 27) The system of claim 27 wherein said director component further includes: a selection component capable of selecting a server from said plurality of servers based upon said policy; and an answer component capable of answering a request for a data object by indicating to one of said plurality of clients to redirect the request to said server selected by said selection component. ### Claim 29 A method of routing requests for data objects from a plurality of clients comprising the steps of: providing a plurality of content servers that serve said data objects; and routing said requests for data objects back to a requesting client for subsequent transmission to one of said plurality of servers, wherein each of said requests is comprised of one of a plurality of IP addresses associated with said content server that directs content corresponding to the client's request from said content server along a route having the shortest time to traverse.