Fast acceptance of diameter peer failover

1. A method performed by a network node, the method comprising:

receiving a connection request from a peer network node including a peer identifier;

determining that the received peer identifier matches an identifier of an existing peer;

sending a verification message to the existing peer;

setting a timer;

when a response to the verification message is received before the timer expires:

cancelling the timer; and

rejecting the received connection request;

when the timer expires:

closing a connection to the existing peer; and

accepting a new connection to a new peer.

2. The method of claim 1 , wherein a connection between the network node and the peer network node is a persistent connection.

3. The method of claim 1 , wherein a connection between the network node and the peer network node uses the DIAMETER protocol.

4. The method of claim 3 , wherein the verification message is a DIAMETER watchdog message.

5. The method of claim 1 , wherein the peer network node includes redundant elements including a primary element and a backup element and wherein the primary and backup elements use the same peer identifier.

6. The method of claim 5 , wherein the network node receives the connection request from the peer network node when a primary element fails and the backup element replaces the primary element.

7. The method of claim 1 , wherein closing the connection to the existing peer includes removing the connection from a peer table.

8. The method of claim 1 , wherein rejecting the received connection request includes closing a connection associated with the received connection request.

9. The method of claim 1 , wherein the network node and the peer network node implement DIAMETER.

10. A method performed by a network node, the method comprising:

receiving a first connection request from a peer network node including a first peer identifier;

determining that the first received peer identifier matches an identifier of an existing peer;

sending a first verification message to the existing peer;

setting a first timer; and

after the first timer expires, closing a connection to the existing peer and accepting a new connection from a new peer.

11. The method of claim 10 , further comprising:

receiving a second connection request from a peer network node including a second peer identifier;

determining that the second received peer identifier matches an identifier of an existing peer;

sending a second verification message to the existing peer;

setting a second timer;

receiving a second response to the second verification message before the timer expires;

cancelling the second timer; and

rejecting the second received connection request.

12. A tangible and non-transitory machine-readable storage medium encoded with instructions for execution by a network node, the tangible and non-transitory machine-readable storage medium comprising:

instructions for receiving a connection request from a peer network node including a peer identifier;

instructions for determining that the received peer identifier matches an identifier of an existing peer;

instructions for sending a verification message to the existing peer;

instructions for setting a timer;

instructions for when a response to the verification message is received before the timer expires:

cancelling the timer; and

rejecting the received connection request;

instructions for when the timer expires:

closing a connection to the existing peer; and

accepting a new connection from a new peer.

13. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein the connection between the network node and the peer node is a persistent connection.

14. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein a connection between the network node and the peer network node uses the DIAMETER protocol.

15. The tangible and non-transitory machine-readable storage medium of claim 14 , wherein the verification message is a DIAMETER watchdog message.

16. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein the peer network node includes redundant elements including a primary element and a backup element and wherein the primary and backup elements use the same peer identifier.

17. The tangible and non-transitory machine-readable storage medium of claim 16 , wherein the network node receives the connection request from the peer network node when a primary element fails and the backup element replaces the primary element.

18. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein instructions for closing the connection to the existing peer includes instructions for removing the connection from a peer table.

19. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein instructions for rejecting the received connection request includes instructions for closing a connection associated with the received connection request.

20. The tangible and non-transitory machine-readable storage medium of claim 12 , wherein the network node and the other network node is one of a policy and charging rules node (PCRN), serving gateway (SGW), and packet data network gateway (PGW).