System and method for resolving network layer anycast addresses to network layer unicast addresses

• US 7,725,596 B2
• Filed: 04/26/2001
• Issued: 05/25/2010
• Est. Priority Date: 04/28/2000
• Status: Expired due to Fees

• Current Assignee: Online Video Networks, Inc.
• Original Assignee: ADARA Networks, Inc.
• Inventors: Garcia-Luna-Aceves, Jose J., Smith, Bradley R.
• Primary Examiner(s): Chankong; Dohm
• Application Number:
  US09/844,759
• Publication Number:
  US 20020016860A1
• Time in Patent Office: 3,316 Days
• Field of Search: 709/203, 709/227, 709/228, 709/229, 709/238, 709/240, 709/242, 709/245
• US Class Current: 709/238
• CPC Class Codes: G06F 12/1483 using an access-table, e.g. matrix or list
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/45 Network directories; Name-to-address mapping
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

An information object repository is configured to resolve a network layer anycast address to a network layer unicast address in response to a request for an information object at the network layer anycast address. The information object repository may be further configured to resolve the network layer anycast address by transmitting a request for the network layer unicast address and awaiting a response thereto, and, in some cases, to return a failure message to a source of the request for the information object if the response to the request for the network layer unicast address is not received within a timeout period. Preferably, the request for the network layer unicast address is a single IP packet that includes the network layer anycast address. Similarly, the request for the network layer unicast address is preferably a single IP packet that includes the network layer unicast address. The response to the request for the network layer unicast address may be returned by a host having the network layer unicast address, or another network node configured to do so.

Claims

1. A method, comprising:

receiving a first request for an information object at an anycast address of a network, wherein the request is received at an information object repository selected according to specified performance metrics by executing a Web Information Locator by Distance (WILD) communication protocol that runs on top of a Transmission Control Protocol (TCP) to map an address of a client to one or more addresses of Web caches or a content server that has a best type-of-service distance to the address of the client and to one or more addresses of redirecting Web routers that have the best type-of-service distance to the address of the client wherein the WILD protocol comprises a WILD update message for communicating mappings of client address ranges to neighboring Web routers, wherein the WILD update message comprises a basic routing update, a list of type-of-service distances from the Web caches to destinations, and a list of type-of-service distances from the redirecting Web routers to the destinations;

resolving the anycast address to a corresponding unicast network address for the information object, wherein the resolving includes transmitting a second request for the corresponding unicast network address in response to the first request, awaiting an anycast resolution response to the second request for a predetermined time, and returning a failure message if the response to the second request is not received within the predetermined time, wherein the second request is a single Internet Protocol (IP) packet having the anycast network address;

instructing the information object repository to obtain a copy of the information object at the corresponding unicast network address; and

returning the corresponding unicast network address, if the anycast resolution response in response to the second request is received within the predetermined time, the anycast resolution response is a single IP packet having the corresponding unicast network address.

2. The method of claim 1 further comprising returning the unicast network address for the information object.

3. The method of claim 1 wherein the performance metrics comprise one or more of:

reliability of a path from the selected information object repository, available bandwidth in said path, average delay from the selected information object repository to a source of the request, average processing delay at the selected information object repository, and loads on the selected information object repository.

11. The method of claim 1 wherein the first request is received at the information object repository selected without regard as to whether the information object is actually stored at the information object repository.

4. An information object repository comprising a Web router configured to resolve a network layer anycast address of a network to a network layer unicast address in response to a first request for an information object at the network layer anycast address, wherein resolving the network layer anycast address includes transmitting a second request to the anycast address in response to the first request, to obtain a copy of the information object at the network layer unicast address, and to receive an anycast resolution response in response to the second request to resolve the network layer anycast address, wherein the information object repository is selected according to specified performance metrics by the Web router executing a Web Information Locator by Distance (WILD) communication protocol to communicate with neighboring Web routers that runs on top of a Transmission Control Protocol (TCP) to map an address of a client to one or more addresses of Web caches or a content server that has a best type-of-service distance to the address of the client and to one or more addresses of redirecting Web routers that have the best type-of-service distance to the address of the client, wherein the Web router comprises storage means for storing a WILD update message for communicating mappings of client address ranges to the neighboring routers, wherein the WILD update message comprises a basic routing update, a list of type-of-service distances from the Web caches to destinations, and a list of type-of-service distances from the redirecting Web routers to the destinations, wherein the second request to resolve is a single Internet Protocol (IP) packet that includes the network layer anycast address, wherein the anycast resolution response is a single Internet Protocol (IP) packet that includes the network layer unicast address.

5. The information object repository of claim 4 being further configured to resolve the network layer anycast address by transmitting the second request for the network layer unicast address and awaiting the response thereto.

6. The information object repository of claim 5 being further configured to return a failure message to a source of the request for the information object if the response to the request for the network layer unicast address is not received within a timeout period.

7. A network, comprising:

at least one client configured to transmit a first request for an information object using a network layer anycast address;

an information object repository configured to receive the request for the information object, to resolve the network layer anycast address into a network layer unicast address that includes transmitting a second request to the network layer anycast address for the network layer unicast address in response to the first request, to obtain a copy of the information object at the network layer unicast address, and to receive an anycast resolution response in response to the second request to resolve the network layer anycast address; and

a Web router, wherein the information object repository is selected according to specified performance metrics by the Web router executing a Web Information Locator by Distance (WILD) communication protocol to communicate with neighboring Web routers that runs on top of a Transmission Control Protocol (TCP) to map an address of a client to one or more addresses of Web caches or a content server that has a best type-of-service distance to the address of the client and to one or more addresses of redirecting Web routers that have the best type-of-service distance to the address of the client, wherein the Web router comprises storage means for storing a WILD update message for communicating mappings of client address ranges to the neighboring routers, wherein the WILD update message comprises a basic routing update, a list of type-of-service distances from the Web caches to destinations, and a list of type-of-service distances from the redirecting Web routers to the destinations, wherein the second request is a single IP packet that includes the network layer anycast address, wherein the anycast resolution response is a single IP packet that includes the network layer unicast address.

8. The network of claim 7 wherein the information object repository is further configured to resolve the network layer anycast address by transmitting the second request for the network layer unicast address and awaiting the anycast resolution response thereto.

9. The network of claim 8 wherein the information object repository is further configured to return a failure message to the client if the anycast resolution response to the second request for the network layer unicast address is not received within a timeout period.

10. The network of claim 8 wherein the anycast resolution response to the second request for the network layer unicast address is returned by a host having the network layer unicast address.

12. The network of claim 7 wherein the single IP packet comprising the second request for the network layer unicast address and the single IP packet comprising the anycast resolution response to the second request for the network layer unicast address further comprise an IP header and a UDP header.