Method for automatically allocating address prefixes
As routers ( 15 ) are added to an existing network ( 41 ), links serviced by such routers that lack a pre-existing corresponding address prefix may occur. The router ( 15 ) can contact a prefix server ( 14 ) and engage in a process to automatically receive a new address prefix from the prefix server ( 14 ) to use with such links. In one embodiment, the prefix server ( 14 ) can automatically assign such address prefixes to form or maintain an aggregation of routes to facilitate the efficient operation of routers within the network and overall network growth.
1. A method comprising:
providing a prefix server having a plurality of address prefixes for use within at least a portion of a communications network;
receiving over the communications network and at the prefix server a communication from a router;
in response to the communication from the router, using the prefix server to assign at least a single address prefix from the plurality of address prefixes; and
sending over the communications network a communication to the router containing at least a single address prefix causing the router to advertise at least the single address sent by the prefix server for use by endpoints attached to the router.
2. The method of claim 1 wherein using the prefix server to assign at least a single address prefix from the plurality of address prefixes for subsequent use with and by the router includes selecting at least a particular address prefix based at least in part upon a topological location of the router within the communications network.
3. The method of claim 2 wherein selecting at least a particular address prefix based at least in part upon a topological location of the router within the communications network includes inferentially determining the topological location of the router within the communications network.
4. The method of claim 2 wherein selecting at least a particular address prefix based at least in part upon a topological location of the router within the communications network includes accessing explicit information regarding the topological of the router.
5. The method of claim 3 wherein inferentially determining the topological location of the router within the communications network includes accessing information regarding previous assignments of address prefixes within the communications network.
6. The method of claim 1 wherein receiving over the communications network and at the prefix server a communication from a router includes receiving over the communications network and at the prefix server a communication comprising a request for at least one prefix assignment from the router.
7. The method of claim 1 wherein using the prefix server to assign at least a single address prefix from the plurality of address prefixes for subsequent use with and by the router includes using the prefix server to assign at least a single address prefix from the plurality of address prefixes for subsequent use with and by the router as a function at least in part of a routing aggregation that includes a route that passes through the router.
8. The method of claim 7 wherein using the prefix server to assign at least a single address prefix from the plurality of address prefixes for subsequent use with and by the router as a function at least in part of a routing aggregation that includes a route that passes through the router further includes using the prefix server to assign at least a single address prefix from the plurality of address prefixes for subsequent use with and by the router as a function at least in part of a routing aggregation that includes a route that passes through the router and at least one other route that passes through to another router.
9. The method of claim 1 and further comprising using, the router, at least the single address prefix.
10. The method of claim 1 wherein the step of sending over the communications network a communication to the router containing at least a single address prefix causing the router to advertise at least the single address prefix sent by the prefix server for use by endpoints attached to the router, comprises the step of sending over the communications network a communication to the router containing at least a single address prefix causing the router to advertise at least the single address prefix sent by the prefix server for simultaneous use by multiple endpoints attached to the router.
11. A method for operating a prefix server, the method comprising the steps of:
receiving a communication from a communication unit;
retrieving from the communication an address that corresponds to the communication unit;
determining that the communication unit requires at least one additional address prefix;
determining a topology position of the communication unit within a communications network as a function, at least in part, of the address;
selecting at least one additional address prefix as a function, at least in part, of the topology position; and
sending a communication to the communication unit, the communication containing at least a single address prefix which causes the communication unit to advertise at least the single address prefix for use by endpoints attached to the communication unit.
12. The method of claim 11 and further comprising assigning the at least one additional address prefix to the communication unit.
13. The method of claim 11 wherein receiving a communication from a communication unit includes receiving a request for at least one address prefix from a router.
14. The method of claim 11 wherein determining a topology position of the communication unit within a communications network as a function, at least in part, of the address includes determining a topology position of the communication unit within a communications network as a function, at least in part, of the address, previously retrieved addresses, and previously assigned address prefixes as assigned within the communications network.
15. The method of claim 11 wherein selecting at least one additional address prefix as a function, at least in part, of the topology position includes selecting at least one additional address prefix that will aggregate a route that passes through to the communication unit with at least one other a route that passes through to another communication unit with respect to topology of the communications network.
16. The method of claim 11 wherein selecting at least one additional address prefix as a function, at least in part, of the topology position includes selecting at least one additional address prefix to balance, at least in part:
facilitating both aggregation of a route that passes through to the communication unit with at least one other a route that passes through to another communication unit with respect to topology of the communications network;
against:
potential future needs to select other address prefixes to also facilitate aggregation of other routes with respect to topology of the communications network.
17. The method of claim 11 wherein the step of sending a communication to the communication unit, the communication containing at least a singe address prefix which causes the communication unit to advertise at least the single address prefix for use by endpoints attached to the communication unit comprises the step of sending a communication to the communication unit, the communication containing at least a single address prefix which causes the communication unit to advertise at least the single address prefix for simultaneous use by multiple endpoints attached to the communication unit.
18. A method comprising:
providing a prefix server having a plurality of address prefixes for use within at least a portion of a communications network;
automatically maintaining a record of assigned address prefixes and topological locations within the communications network to which the address prefixes have been assigned;
automatically determining that at least one new address prefix from the plurality of address prefixes should be assigned for use by a specific communications unit within the at least a portion of a communications network;
automatically selecting the at least one new address prefix as a function, at least in part, of:
facilitating topological aggregation of a route that passes through to the specific communications unit via the new address prefix; and
ensuring, when possible, that the new address prefix is at least not sequentially adjacent to another address prefix that is already assigned.
19. The method of claim 18 wherein ensuring, when possible, that the new address prefix is at least not sequentially adjacent to another address prefix that is already assigned includes ensuring that the new address prefix is selected so as to maximize a minimum of a set of absolute values of numerical differences between the new address prefix and all known prefixes that have already been assigned.