Granted Patent B1

US 8,059,658 · App. 12/060,111 · Granted Nov 15, 2011

Assignee: Extreme Networks, Inc.

Abstract

Claims (59)

1. A method, comprising:

receiving a host route to be added as an entry to a forwarding database, wherein the forwarding database comprises a hardware implemented table having a first storage area provisioned to store host routes and a second storage area provisioned to store subnet routes;

checking the first storage area to determine if space is available for the host route to be added;

adding the host route to the first storage area of the hardware implemented table when space is determined to be available for the host route; and

when space is determined to not be available in the first storage area of the hardware implemented table:

expanding the first storage area of the hardware implemented table to include space from the second storage area that is provisioned to store the subnet routes but is unused space for storing the subnet routes when expanding the first storage area, and

adding the host route to an expanded space in the expanded first storage area of the first hardware implemented table.

2. The method of claim 1 , further comprising:

receiving a subnet route to be added as an entry to the second storage area of the hardware implemented table;

checking the second storage area to determine if space is available for the subnet route to be added;

adding the subnet route to the second storage area of the hardware implemented table when space is determined to be available in the second storage area; and

when space is determined to not be available in the second storage area:

contracting the expanded first storage area of the hardware implemented table to expand the second storage area, and

adding the subnet route to the expanded second storage area.

3. The method of claim 2 , wherein expansion of the second storage area is limited to a predefined threshold corresponding to an amount of space originally provisioned to the second storage area to store subnet routes prior to the second storage area being contracted to expand the first storage area.

4. The method of claim 1 , wherein the first storage area comprises a longest prefix match (LPM) hardware table and wherein the second storage area comprises a host hardware table.

5. The method of claim 1 , wherein the space allocated to the second storage area is user-provisioned.

6. The method of claim 1 , wherein the host route is one of an Internet Protocol version 4 (IPv4) or an IPv6 unicast host route.

7. The method of claim 2 , wherein the subnet route is one of an IPv4 subnet route or an IPv6 subnet route.

8. The method of claim 4 , further comprising bumping an IPv4 unicast host route from the host hardware table to accommodate an IPv6 host or an IPv4 multicast host seeking entry into the host hardware table.

9. A packet forwarding device, comprising:

a hardware module having a hardware implemented forwarding database table including a first storage area provisioned to store host routes and a second storage area provisioned to store subnet routes, the first storage area to expand to include space from the second storage area that is provisioned to store the subnet routes but is unused space for storing the subnet routes when expanding the first storage area, the expanded space of the first storage area to accommodate a host route when no space is available in the first storage area of the hardware module.

10. The packet forwarding device of claim 9 , wherein the expanded first storage area to contract and the second storage area to expand to accommodate a subnet route when no space is available in the second storage area.

11. The packet forwarding device of claim 9 , wherein the second storage area is user provisioned.

12. The packet forwarding device of claim 9 , wherein the host route is one of an Internet Protocol version 4 (IPv4) or an IPv6 unicast host route.

13. The packet forwarding device of claim 10 , wherein the subnet route is one of an IPv4 subnet route or an IPv6 subnet route.

14. A method, comprising:

receiving a subnet route to be added as an entry to a forwarding database, wherein the forwarding database comprises a hardware implemented table having a first storage area provisioned to store host routes and a second storage area provisioned to store subnet routes;

checking the second storage area to determine if space is available for the subnet route to be added;

adding the subnet route to the second storage area of the hardware implemented table when space is determined to be available for the subnet route; and

when space is determined to not be available in the second storage area of the hardware implemented table:

expanding the second storage area of the hardware implemented table to include space from the first storage area that is provisioned to store the host routes and is space originally provisioned to the second storage area to store subnet routes prior to the second storage area being contracted to expand the first storage area, and

adding the subnet route to an expanded space in the expanded second storage area of the hardware implemented table.

15. The method of claim 14 , further comprising:

receiving a host route to be added as an entry to the first storage area of the hardware implemented table;

checking the first storage area to determine if space is available for the host route to be added;

adding the host route to the first storage area of the hardware implemented table when space is determined to be available in the first storage area; and

when space is determined to not be available in the first storage area:

contracting the expanded second storage area of the hardware implemented table with space from the second storage area that is provisioned to store the subnet routes but is unused space for storing the subnet routes when expanding the first storage area, and

adding the host route to the expanded first storage area.

16. A non-transitory computer readable storage medium having instructions stored thereon that, when executed by an electronic device, cause the electronic device to perform a method comprising:

receiving a host route to be added as an entry to a forwarding database, wherein the forwarding database comprises a hardware implemented table having a first storage area provisioned to store host routes and a second storage area provisioned to store subnet routes;

checking the first storage area to determine if space is available for the host route to be added;

adding the host route to the first storage area of the hardware implemented table when space is determined to be available for the host route; and

when space is determined to not be available in the first storage area of the hardware implemented table:

expanding the first storage area of the hardware implemented table to include space from the second storage area that is provisioned to store the subnet routes but is unused space for storing the subnet routes when expanding the first storage area, and

adding the host route to an expanded space in the expanded first storage area of the hardware implemented table.

17. The non-transitory computer-readable storage medium of claim 16 , wherein the method further comprises:

receiving a subnet route to be added as an entry to the second storage area of the hardware implemented table;

checking the second storage area to determine if space is available for the subnet route to be added;

adding the subnet route to the second storage area of the hardware implemented table when space is determined to be available in the second storage area; and

when space is determined to not be available in the second storage area:

contracting the expanded first storage area of the hardware implemented table to expand the second storage area, and

adding the subnet route to the expanded second storage area.

18. The non-transitory computer-readable storage medium of claim 16 , wherein the second storage area is a longest prefix match (LPM) table and wherein the first storage area is a host hardware table.

19. The non-transitory computer-readable storage medium of claim 16 , wherein the host route is one of an Internet Protocol version 4 (IPv4) or an IPv6 unicast host route.

20. The non-transitory computer-readable storage medium of claim 17 , wherein the subnet route is one of an IPv4 subnet route or an IPv6 subnet route.

21. The non-transitory computer-readable storage medium of claim 18 , wherein the method further comprises:

bumping an IPv4 unicast host from the host hardware table to accommodate an IPv6 host or an IPv4 multicast host seeking entry into the host hardware table.

Assignments (10)

Continuity (2)