Fast flooding based fast convergence architecture
Fast flooding based fast convergence to recover from a network failure. A router detects a network failure, and responsive to that failure, transmits a fast failure notification message to a set of one or more routers. The fast failure notification message includes information that identifies the network failure and also indicates that the fast failure notification message is to be flooded by the set of routers independently of convergence. The router updates a routing table to reflect the network failure. The transmission of the fast failure notification message is performed prior to completion of the routing table update to reflect the network failure.
1. A method in a router for initiating fast flooding based fast convergence to recover from a network failure, the method comprising the steps of:
detecting a network failure;
responsive to the detected network failure, transmitting a fast failure notification message to a set of one or more routers before or concurrently of convergence of the router;
performing the convergence of the router, wherein the fast failure notification message includes information that identifies the network failure and also indicates that the set of one or more routers floods the fast failure notification message before or concurrently of convergence of the set of one or more routers, wherein each of the set of one or more routers has registered to receive the fast failure notification message, wherein the convergence comprises updating a routing table to reflect the network failure and rerouting data packets using the updated routing table,
and wherein the fast failure notification message has a common message format different from Interior Gateway Protocol (IGP) Protocol Data Unit (PDU) message format used for a normal IGP flooding protocol.
2. The method of claim 1 , wherein the step of detecting the network failure is performed by one or more of: Layer-2 link-event monitoring and signaling, and Bidirectional Forwarding Detection (BFD).
3. The method of claim 1 , further comprising the step of initiating the normal flooding of a message that indicates the network failure after the step of updating the routing table to reflect the network failure.
4. The method of claim 1 , wherein the fast failure notification message includes a specific destination IP address or a specific destination MAC address that identifies it as a fast failure notification message.
5. A method in a router for participating in fast flooding based fast convergence to recover from a network failure, the method comprising the steps of:
receiving a fast failure notification message that includes information that identifies a network failure;
forwarding the fast failure notification message to a set of one or more routers before or concurrently of convergence of the router, wherein each of the set of one or more routers has registered to receive the fast failure notification message, wherein the set of one or more routers floods the fast failure notification message before or concurrently of convergence of the set of one or more routers wherein the convergence comprises updating a routing table to reflect the network failure and rerouting data packets using the updated routing table,
and wherein the fast failure notification message has a common message format different from Interior Gateway Protocol (IGP) Protocol Data Unit (PDU) message format protocol used for a normal IGP flooding protocol.
6. The method of claim 5 , wherein the fast failure notification message is identified through identification of a specific destination IP address or specific destination MAC address reserved for fast flooding based fast convergence.
7. The method of claim 5 , wherein the step of updating the routing table includes the step of forwarding the fast failure notification message to an IGP module of an application layer of the router to update the routing table.
8. The method of claim 7 , wherein prior to the step of updating the routing table, the IGP module foregoing an adjacency check to accept the fast failure notification message.
9. A router to initiate fast flooding based fast convergence to recover from a network failure, the router comprising:
a data transport layer including a Fast Failure Notification (FFN) module configured to, in response to a detected network failure, transmit a fast failure notification message to a set of one more routers before or concurrently of convergence of the router, wherein the fast failure notification message includes information that identifies the network failure and also indicates that the set of one or more routers floods the fast failure notification message before or concurrently of convergence of the set of one or more routers, wherein each of the set of one or more routers has registered to receive the fast failure notification message; and
an application layer including a routing protocol module configured to perform the convergence by updating a routing table and rerouting data packet using the updated routing table in response to the detected network failure;
wherein the fast failure notification message has a common message format different from Interior Gateway Protocol (IGP) Protocol Data Unit (PDU) message format used for a normal IGP flooding protocol.
10. The router of claim 9 , wherein the router is further configured to detect the network failure by one or more of: Layer-2 link-event monitoring and signaling, and Bidirectional Forwarding Detection (BFD).
11. The router of claim 9 , wherein the routing protocol module is further configured to initiate a normal flooding of a message that indicates the network failure after the routing protocol module updates the routing table.
12. The router of claim 9 , wherein the fast failure notification message includes a specific destination IP address or a specific destination MAC address that identifies it as a fast failure notification message.
13. A router to participate in fast flooding based fast convergence to recover from a network failure, the router comprising:
a data transport layer including a Fast Failure Notification (FFN) module configured to, in response to receipt of a fast failure notification message, perform the following:
transmit the fast failure notification message to a set of one more routers before or concurrently of convergence of the router, wherein the fast failure notification message includes information that identifies the network failure and also indicates that the set of one or more routers floods the fast failure notification message before or concurrently of convergence of the set of one or more routers, wherein each of the set of one or more routers has registered to receive the fast failure notification message, and
perform the convergence of the router by transmitting the fast failure notification message to a routing protocol module on an application layer of the router; and
the application layer including the routing protocol module configured to update a routing table and reroute data packets using the updated routing table in response to receipt of the fast failure notification message from the FFN module;
wherein the fast failure notification message has a common message format different from Interior Gateway Protocol (IGP) Protocol Data Unit (PDU) message format used for a normal IGP flooding protocol.
14. The router of claim 13 , wherein the data transport layer is further configured to identify the fast failure notification message through identification of a specific destination IP address or specific destination MAC address reserved for fast flooding based fast convergence.
15. The router of claim 13 , wherein the routing protocol module is further configured to forego an adjacency check on the fast failure notification message that is to be received from the FFN module.