API supporting server and key based networking

1. A computer implemented method for implementing an application programming interface for allowing communication between servers in a direct-connect topology, the method comprising:

receiving one of a key and a server address from a service running on a server; and

returning a set of link indices to the service, each link index in the set of link indices identifying a candidate next hop to a destination defined by the received key or server address,

and wherein a portion of a key encodes an address of a home server responsible for the key, responsibility for the key being alterable to a different server, and the key further encodes fail-over information for computing an address of at least one alternative server responsible for the key for use when the home server is unreachable, the fail-over information being encoded such that all keys from the unavailable home server are mapped to at least two different servers.

2. A method according to claim 1 , wherein the set of link indices comprises a vector of link indices.

3. A method according to claim 1 , further comprising:

receiving one of a key and a server address from a service running on a server; and

returning a set of hop counts to the service, each hop count corresponding to a link index in the set of link indices and comprising a minimum number of hops between servers in the direct-connect topology to reach the destination starting with the candidate next hop specified by the link index.

4. A method according to claim 1 , wherein the key further encodes fail-over information for computing an address of at least one alternative server responsible for the key for use when the home server is unreachable.

5. A method according to claim 4 , further comprising:

receiving a key from a service running on a server; and

returning at least one address of a reachable server responsible for the key.

6. A method according to claim 5 , wherein returning at least one address of a reachable server responsible for the key comprises returning an ordered list of addresses of k servers responsible for the key, where k is an integer.

7. A method according to claim 1 , wherein the key further encodes replication information which identifies an ordered list of server addresses for use in replication.

8. A method according to claim 7 , further comprising:

receiving a key from a service running on a server; and

returning an ordered list of k server addresses, where k is an integer.

9. A method according to claim 1 , further comprising:

receiving, from a service running on a server, data identifying a set of outbound links for use in transmitting a packet from the server to a destination server;

placing one of the packet and a descriptor for the packet in a queue associated with each of the outbound links in the set of outbound links; and

once the packet is committed for transmission over one of the set of outbound links, removing the packet or descriptor from the queues associated with each of the other outbound links in the set of outbound links.

10. A method according to claim 9 , further comprising:

providing data on failures of at least one of links and servers within at least a portion of the direct-connect topology to a service running on a server.

11. A system adapted to instantiate an application programming interface (API) configured to expose a programming interface for allowing communication between servers in a direct-connect topology the system comprising:

a processor; and

a memory communicatively coupled to the processor, the memory having stored therein computer-executable instructions implementing the API and which, when executed, cause the processor to:

returning a set of link indices to a service running on a server in response to receiving one of a key and a server address from the service, each link index in the set of link indices identifying a candidate next hop to a destination defined by the received key or server address,

and wherein the key encodes an address of a home server responsible for that key and information for generating an ordered list of alternative server addresses, responsibility for the key being alterable to a different server, and the key further encodes fail-over information for computing an address of at least one alternative server responsible for the key for use when the home server is unreachable, the fail-over information being encoded such that all keys from the unavailable home server are mapped to at least two different servers.

12. A system according to claim 11 , wherein the ordered list of alternative server addresses comprises alternative home servers for use if the home server is unreachable.

13. A system according to claim 11 , the memory further having stored therein computer-executable instructions which, when executed, cause the processor, in response to receiving from a service running on a server, data identifying a set of outbound links for use in transmitting a packet from the server to a destination server, to:

place one of the packet and a descriptor for the packet in a queue associated with each of the outbound links in the set of outbound links; and

once the packet is committed for transmission over one of the set of outbound links, removing the packet or descriptor from the queues associated with each of the other outbound links in the set of outbound links.

14. A computer storage medium, the computer storage medium being hardware and having computer-readable instructions that when executed by a processor cause the processor to perform actions implementing an application programming interface for allowing communication between servers in a direct-connect topology, the actions comprising:

receiving one of a key and a server address from a service running on a server; and

returning a set of link indices to the service, each link index in the set of link indices identifying a candidate next hop to a destination defined by the received key or server address,

and wherein a portion of a key encodes an address of a home server responsible for the key, responsibility for the key being alterable to a different server, and the key further encodes fail-over information for computing an address of at least one alternative server responsible for the key for use when the home server is unreachable, the fail-over information being encoded such that all keys from the unavailable home server are mapped to at least two different servers.

15. A computer storage medium according to claim 14 , wherein the set of link indices comprises a vector of link indices.

16. A computer storage medium according to claim 14 , the actions further comprising:

receiving one of a key and a server address from a service running on a server; and

returning a set of hop counts to the service, each hop count corresponding to a link index in the set of link indices and comprising a minimum number of hops between servers in the direct-connect topology to reach the destination starting with the candidate next hop specified by the link index.

17. A computer storage medium according to claim 14 , the actions further comprising:

receiving a key from a service running on a server; and

returning at least one address of a reachable server responsible for the key.

18. A computer storage medium according to claim 17 , wherein returning at least one address of a reachable server responsible for the key comprises returning an ordered list of addresses of k servers responsible for the key, where k is an integer.

19. A computer storage medium according to claim 14 , wherein the key further encodes replication information which identifies an ordered list of server addresses for use in replication.