Redundancy support for network address translation (NAT)
AssigneeFoundry Networks, Inc.
InventorSridhar J. Devarapalli
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Abstract
Stateful failover redundancy support is provided for network address translation (NAT). A master NAT device is backed-up with at least one back-up NAT device. Existing sessions are synchronized between the two NAT devices, such as via a dedicated link between them. In the event of a failover where the master NAT device is unable to perform its NAT functions, ownership of Internet protocol (IP) addresses is transferred from the master NAT device to the back-up NAT device. The back-up NAT device, which is now owner of the IP addresses, assumes the NAT functionality associated with these IP addresses and continues the existing sessions, as well as processing new sessions.
Claims32
A method in a first network device, the method comprising:
- associating to said first network device a base address corresponding to a first pool of first addresses that are not owned by said first network device;
- while said first network device does not said own said first pool of first addresses, performing network address translation (NAT), by said first network device, for a second pool of second addresses;
- detecting, by said first network device, a failure of a second network device;
- and
- asserting ownership, by said first network device, of a plurality of said first addresses of said first pool corresponding to said base address, in response to detection by said first network device of said failure.
An article of manufacture, comprising:
- a storage medium having instructions stored thereon and executable by a first network device to:
- associate to said first network device a base address corresponding to a first pool of first addresses not owned by said first network device;
- while said first network device does not said own said first pool of first addresses, perform network address translation (NAT), by said first network device, for a second pool of second addresses;
- detect, by said first network device, a failure of a second network device;
- and
- assert ownership, by said first network device, of a plurality of said first addresses of said first pool corresponding to said base address, in response to detection by said first network device of said failure.
An apparatus, comprising:
- a first network device adapted to be associated to a base address corresponding to a first pool of first addresses that are not owned by said first network device,
- said first network device being further adapted to perform, while said first network device does not said own said first pool of first addresses, network address translation (NAT) for a second pool of second addresses, and
- said first network device further being adapted to detect a failure of a second network device and assert ownership of a plurality of said first addresses of said first pool corresponding to said base address, in response to detection of said failure.
An apparatus, comprising:
- a device adapted to own a base address corresponding to a first pool of first addresses, said first pool of first addresses being associated to but not owned by another device,
- said device further being adapted to perform network address translation (NAT) for said first pool of first addresses, wherein ownership of said first pool of first addresses changes from said device to said another device if there is a failure of said device,
- wherein if there is said failure of said device, with respect to any individual one of said first addresses:
- said ownership, of a plurality of said first addresses of said first pool corresponding to said base address, changes from said device to said another device.
Dependencies are inferred from the claim text.