Multi-homing using controlled route leakage at a backup service provider
In one embodiment, a network node of a secondary network receives a message from a multi-homed network. The message includes a block of network addresses allocated to the multi-homed network. It is determined that a primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses. Advertisements of the multi-homed network's allocated block of network addresses are suppressed, after a determination that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses. It may be later be determined that the multi-homed network has lost network connectivity via the primary network. Advertisements of the multi-homed network's allocated block of network addresses are unsuppressed, after a determination that the multi-homed network has lost network connectivity via the primary network.
1. A method comprising:
receiving, by a network node of a secondary network, a message from a multi-homed network, the message including a block of network addresses allocated to the multi-homed network;
determining that a primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses;
suppressing advertisements of the multi-homed network's allocated block of network addresses, after determining that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses;
determining that the multi-homed network has lost network connectivity via the primary network; and
unsuppressing the advertisements of the multi-homed network's allocated block of network addresses, after determining that the multi-homed network has lost network connectivity via the primary network.
2. The method of claim 1 , wherein the suppressing further comprises:
preventing advertisements of the multi-homed network's allocated block of network addresses from being advertised into a backbone network coupled to both the secondary network and the primary network.
3. The method of claim 1 , wherein the determining that the multi-homed network has lost network connectivity via the primary network further comprises:
determining that the multi-homed network has lost network connectivity via the primary network to a backbone network coupled to both the secondary network and the primary network; and
wherein the unsuppressing further comprises:
unsuppressing the advertisements of the multi-homed network's allocated block of network addresses from being advertised into the backbone network.
4. The method of claim 1 , wherein the suppressing further comprises:
preventing advertisements of the multi-homed network's allocated block of network addresses from being advertised outside the secondary network.
5. The method of claim 4 , wherein the suppressing further comprises:
associating a no_export community attribute with the multi-homed network's allocated block of network addresses.
6. The method of claim 5 , wherein the unsuppressing further comprises:
removing the no_export community attribute from association with the multi-homed network's allocated block of network addresses.
7. The method of claim 1 , wherein the suppressing further comprises:
preventing advertisements of the multi-homed network's allocated block of network addresses from being advertised from the network node of the secondary network.
8. The method of claim 7 , wherein the suppressing further comprises:
associating a no_advertise community attribute with the multi-homed network's allocated block of network addresses.
9. The method of claim 8 , wherein the unsuppressing further comprises:
removing the no_advertise community attribute from association with the multi-homed network's allocated block of network addresses.
10. The method of claim 1 , wherein the determining that the multi-homed network has lost network connectivity via the primary network further comprises:
receiving a message indicating that the multi-homed network has lost network connectivity with the primary network.
11. The method of claim 1 , wherein the determining that the multi-homed network has lost network connectivity via the primary network further comprises:
receiving a message indicating that the aggregated route advertised by the primary network is no longer reachable.
12. The method of claim 1 , wherein the determining that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses further comprises:
searching a border gateway protocol (BGP) table for the aggregated route.
13. The method of claim 1 , wherein the determining that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses further comprises:
receiving, by the network node of the secondary network, a message containing the aggregated route.
14. An apparatus comprising:
a processor;
a network interface configured to receive a message from a multi-homed network, the message including a block of network addresses allocated to the multi-homed network; and
a memory configured to store instructions that are executable by the processor, the instructions, when executed by the processor, to
determine that a primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses,
suppress advertisements of the multi-homed network's allocated block of network addresses, after determination that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses,
determine that the multi-homed network has lost network connectivity via the primary network, and
unsuppress the advertisements of the multi-homed network's allocated block of network addresses, after determination that the multi-homed network has lost network connectivity via the primary network.
15. The apparatus of claim 14 , wherein the instructions to suppress comprise instructions to prevent advertisements of the multi-homed network's allocated block of network addresses from being advertised into a backbone network coupled to the primary network.
16. The apparatus of claim 14 , wherein the instructions to determine that the multi-homed network has lost network connectivity via the primary network comprise instructions to determine that the multi-homed network has lost network connectivity via the primary network to a backbone network coupled to the primary network, and the instructions to unsuppress comprise instructions to unsuppress the advertisements of the multi-homed network's allocated block of network addresses from being advertised into the backbone network.
17. The apparatus of claim 14 , wherein the wherein the instructions to suppress further comprises instructions to prevent advertisements of the multi-homed network's allocated block of network addresses from being advertised outside of a secondary network that includes the apparatus.
18. The apparatus of claim 14 , wherein the instructions to suppress further comprises instructions to prevent advertisements of the multi-homed network's allocated block of network addresses from being advertised from the apparatus.
19. The apparatus of claim 14 , wherein the memory is configured to store a border gateway protocol (BGP) table and the instructions to determine that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses further comprise instructions to search the BGP table for the aggregated route.
20. An apparatus comprising:
a network interface configured to receive a message from a multi-homed network, the message including a block of network addresses allocated to the multi-homed network;
means for determining that a primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses;
means for suppressing advertisements of the multi-homed network's allocated block of network addresses, after determining that the primary network has advertised an aggregated route including the multi-homed network's allocated block of network addresses;
means for determining that the multi-homed network has lost network connectivity via the primary network; and
means for unsuppressing the advertisements of the multi-homed network's allocated block of network addresses, after determining that the multi-homed network has lost network connectivity via the primary network.