Method and system for network port addressing

1. A method for routing Fibre Channel frames, comprising:

(a) receiving a frame at a port of a switch element;

(b) determining if the frame is to be routed using extended area routing;

(c) if extended area routing is not to be used for routing the frame, routing the frame using a standard destination identifier (D_ID) field in a header of the frame; and

(d) if extended area routing is to be used for routing the frame, identifying a source for obtaining extension bits for expanding an area identification field (Area_ID) in the header, expanding the Area_ID field using the extension bits from the identified source to create an extended Area_ID field, and routing the frame using the extended Area_ID field.

2. The method of claim 1 , wherein the identified source is a domain identifier field (Domain_ID).

3. The method of claim 1 , wherein the identified source is a port identifier field (Port_ID).

4. The method of claim 1 , wherein extended area routing is used if there are more than 256 ports that have to be addressed by a switch that receives the frame.

5. The method of claim 1 , wherein the Area_ID field is extended by using 2 extension bits.

6. The method of claim 5 , wherein the extended Area_ID field allows a switch that receives the frame to address 1024 devices.

7. A Fibre Channel switch element, comprising:

a port for receiving a frame; and

routing logic for:

(a) determining if the frame is to be routed using extended area routing;

(b) if extended area routing is not to be used for routing the frame, routing the frame using a standard destination identifier (D_ID) field in a header of the frame; and

(c) if extended area routing is to be used for routing the frame, identifying a source for obtaining extension bits for expanding an area identification field (Area_ID) in the header, expanding the Area_ID field using the extension bits from the identified source to create an extended Area_ID field, and routing the frame using the extended Area_ID field.

8. The Fibre Channel switch element of claim 7 , wherein the identified source is a domain identifier field (Domain_ID).

9. The Fibre Channel switch element of claim 7 , wherein the identified source is a port identifier field (Port_ID).

10. The Fibre Channel switch element of claim 7 , wherein extended area routing is used if there are more than 256 ports that have to be addressed by the switch element.

11. The Fibre Channel switch element of claim 7 , wherein the Area_ID field is extended by using 2 extension bits.

12. The Fibre Channel switch element of claim 7 , wherein the extended Area_ID field allows the switch to address 1024 devices.

13. A method for routing Fibre Channel frames, comprising:

(a) receiving a frame at a port of a Fibre Channel switch element;

(b) determining if extended area routing is used based on the switch element addressing a certain number of ports;

(c) if extended area routing is not to be used for routing the frame, routing the frame using a standard destination identifier (D_ID) field in a header of the frame; and

(d) if extended area routing is to be used for routing the frame, determining if extension bits from a domain identifier field (Domain_ID) in the header or a port identifier field (Port_ID) in the header are used for expanding an area identification field (Area_ID) in the header, expanding the Area_ID field using the extension bits from the Domain_ID or from the Port_ID to create an extended Area_ID field, and routing the frame using the extended Area_ID field.

14. The method of claim 13 , wherein extended area routing is used if there are more than 256 ports that have to be addressed by the switch element.

15. The method of claim 13 , wherein the Area_ID field is extended by using 2 extension bits.

16. The method of claim 15 , wherein the extended Area_ID field allows the switch element to address 1024 devices.

17. The method of claim 13 , wherein when bits from the Port_ID field are used for extending the Area_ID field, then 2 bits from the Port_ID field are used as extension bits.

18. The method of claim 17 , wherein after using 2 bits as extension bits, remaining 6 bits of the Port_ID field are used as a virtual identifier (NPIV_ID) to assign more than one virtual address to a same port.

19. The method of claim 13 , wherein a routing logic module at the port of the Fibre Channel switch element determines if extended area routing is used for routing the frame.

20. The method of claim 13 , wherein when extended area routing and domain based routing is used to route the frame, then lower Domain_ID field bits are used to extend the Area_ID field.