Transit Switches in a Network of Logical Switches

• US 20110085559A1
• Filed: 10/08/2009
• Published: 04/14/2011
• Est. Priority Date: 10/08/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Chung, Daniel Ji Yong Park, Gnanasekaran, Sathish Kumar, Kollu, Badrinath
• Granted Patent: US 8,599,864 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 45/583 Stackable routers
• CPC Class Codes: H04L 45/586 of virtual routers
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A Layer 2 network switch is partitionable into a plurality of switch fabrics. The single-chassis switch is partitionable into a plurality of logical switches, each associated with one of the virtual fabrics. The logical switches behave as complete and self-contained switches. A logical switch fabric can span multiple single-chassis switch chassis. Logical switches are connected by inter-switch links that can be either dedicated single-chassis links or logical links. An extended inter-switch link can be used to transport traffic for one or more logical inter-switch links. Physical ports of the chassis are assigned to logical switches and are managed by the logical switch. Legacy switches that are not partitionable into logical switches can serve as transit switches between two logical switches.

Claims

1. A method of connecting logical switches in a network, comprising:

partitioning a first switch into a first plurality of logical switches;

partitioning a second switch into a second plurality of logical switches; and

creating a first inter-switch link between a first logical switch of the first plurality of logical switches and a third switch, wherein the third switch is not partitionable into logical switches.

2. The method of claim 1, further comprising:

creating a second inter-switch link between a second logical switch of the second plurality of logical switches and the third switch; and

creating a logical inter-switch link between a third logical switch of the first plurality of logical switches and a fourth logical switch of the second plurality of logical switches,

routing traffic for the logical inter-switch link over the first inter-switch link and the second inter-switch link.

3. The method of claim 2,

wherein the first logical switch, the second logical switch, and the third switch are assigned to a first switch fabric, and

wherein the third logical switch and the fourth logical switch are assigned to a second switch fabric, different from the first switch fabric.

4. The method of claim 3, wherein no other logical switch of the first plurality of logical switches is assigned to the first switch fabric or the second switch fabric.

5. The method of claim 2, wherein the logical inter-switch link is transparent to the third switch.

6. The method of claim 2, wherein routing comprises:

encapsulating frames transmitted across the logical inter-switch link, identifying the first logical switch as a source switch and the second logical switch as a destination switch; and

routing frames across the first inter-switch link and the second inter-switch link based on the source switch and the destination switch.

7. The method of claim 6, wherein encapsulating comprises:

inserting an inter-fabric routing header specifying a virtual fabric identifier associated with the third logical switch and the fourth logical switch; and

inserting an encapsulation extended header specifying the first logical switch as a source switch and the second logical switch as a destination switch.

8. The method of claim 1, further comprising:

assigning the first logical switch and the third switch to a first switch fabric,

wherein no other logical switch of the first switch is assigned to the first switch fabric.

9. The method of claim 8, further comprising:

assigning a second logical switch of the second plurality of logical switches to the first switch fabric,

wherein no other logical switch of the second switch is assigned to the first switch fabric.

10. A network of switches, comprising:

a first network switch and a second network switch, each comprising a plurality of logical switches;

a transit network switch,

a logical inter-switch link defined between a third logical switch of the plurality of logical switches of the first network switch and a fourth logical switch of the plurality of logical switches of the second network switch;

a first extended inter-switch link, connected between a first logical switch of the plurality of logical switches of the first network switch and the transit network switch, configured to provide transport of data for the logical inter-switch link between the first network switch and the transit network switch; and

a second extended inter-switch link, connected between a second logical switch of a plurality of logical switches of the second network switch and the transit network switch, configured to provide transport of data for the logical inter-switch link between the second network switch and the transit network switch.

11. The network of switches of claim 10, wherein the transit network switch is a legacy network switch, not partitionable into a plurality of logical switches.

12. The network of switches of claim 10, wherein the first network switch and the second network switch each further comprise:

a processor;

a storage medium, coupled to the processor, on which is stored software, which when executed by the processor causes the processor to perform actions comprising;

establishing an inter-switch link between a base logical switch and another network switch,

establishing a logical inter-switch link between a logical switch of the plurality of logical switches of the first network switch and a logical switch of the plurality of logical switches of the second network switch; and

generating routing data for routing traffic for the logical inter-switch link across the inter-switch link.

13. The network of switches of claim 12, wherein routing traffic for the logical inter-switch link across the inter-switch link comprises:

encapsulating frames transmitted across the logical inter-switch link, identifying the base logical switch of the first network switch as a source logical switch and the base logical switch of the second network switch as a destination logical switch; and

routing frames across the first inter-switch link based on the source switch and the destination switch.

14. The network of switches of claim 12, wherein encapsulating frames comprises:

inserting an inter-fabric routing header specifying a virtual fabric identifier associated with the source logical switch and the destination logical switch; and

inserting an encapsulation extended header specifying the source logical switch and the destination logical switch.

15. A computer readable medium on which is stored software for managing a network switch, the software for instructing a processor of the network switch to perform actions comprising:

partitioning a first switch into a first plurality of logical switches;

partitioning a second switch into a second plurality of logical switches; and

creating a first inter-switch link between a first logical switch of the first plurality of logical switches and a third switch, wherein the third switch is not partitionable into logical switches.

16. The computer readable medium of claim 15, the software for instructing a processor of the network switch to perform actions further comprising:

creating a logical inter-switch link between a third logical switch of the first plurality of logical switches and a fourth logical switch of the second plurality of logical switches,

generating routing data for routing traffic for the logical inter-switch link over the first inter-switch link and a second inter-switch link created between the third switch and a second logical switch of the second plurality of logical switches.

17. The computer readable medium of claim 16, wherein the logical inter-switch link is transparent to the third switch.

18. The computer readable medium of claim 16, wherein routing comprises:

encapsulating frames transmitted across the logical inter-switch link, identifying the first logical switch as a source switch and the second logical switch as a destination switch; and

routing frames across the first inter-switch link and the second inter-switch link based on the source switch and the destination switch.

19. The computer readable medium of claim 18, wherein encapsulating comprises:

inserting an inter-fabric routing header specifying a virtual fabric identifier associated with the third logical switch and the fourth logical switch; and

inserting an encapsulation extended header specifying the first logical switch as a source switch and the second logical switch as a destination switch.

20. The computer readable medium of claim 15, the software for instructing a processor of the network switch to perform actions further comprising:

assigning each of the first plurality of logical switches to a different virtual fabric of a plurality of virtual fabrics; and

assigning the third switch to the same virtual fabric as the first logical switch.