Returning domain identifications without reconfiguration

• US 8,085,687 B2
• Filed: 02/28/2008
• Issued: 12/27/2011
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sasso, Christian, Kasat, Siddharth, Desai, Ronak
• Primary Examiner(s): Banks Harold, Marsha D
• Assistant Examiner(s): HASSAN, SAAD K
• Application Number:
  US12/039,455
• Publication Number:
  US 20090219928A1
• Time in Patent Office: 1,398 Days
• Field of Search: 370/254, 370/255, 370/389, 370/399
• US Class Current: 370/254
• CPC Class Codes: H04L 12/4035 in which slots of a TDMA packet structure are assigned based on a contention resolution carried out at a master unit TDM/TDMA multiplex systems per se H04J3/1694; hybrid switching systems H04L12/64
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2101/645 Fibre channel identifiers
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]

Abstract

In one embodiment, a technique for returning Domain IDs to a Fibre Channel fabric without a full build fabric (BF) phase is provided. A switch in the fabric may send a principal switch a message requesting the return of one or more Domain IDs assigned to that device. The principal switch may update the list of fabric Domain IDs to remove the Domain IDs identified in the message and send the updated list to devices in the fabric.

Claims

1. A method, comprising:

determining a set of one or more domain identifiers assigned to a switch in a network fabric when the switch joined the network fabric, wherein each of the set of one or more domain identifiers uniquely identifies the switch relative to other switches in the network fabric;

composing a message to de-assign the set of one or more domain identifiers from the switch in the network fabric, wherein the message is composed according to a predefined format of a request domain identifier (RDI) message configured to request one or more domain identifiers to be assigned to the switch, the predefined format specifying a valid range of domain identifiers, the message specifying the set of one or more domain identifiers, wherein the set of one or more domain identifiers is within the valid range, and wherein the message further specifies a trigger value outside of the valid range, wherein the RDI message is characterized by absence of the trigger value, and wherein presence of the trigger value in the message indicates that the message is a reverse request domain identifier (RRDI) message configured to request the set of one or more domain identifiers to be de-assigned from the switch;

sending the message to a principal switch of the fabric requesting de-assignment of the set of one or more domain identifiers from the switch in the network fabric without a build fabric phase, such as to render the set of one or more domain identifiers available for reassignment to other switches in the network fabric, wherein the build fabric phase comprises reconfiguring one or more switches in the network fabric by flooding the network fabric with build fabric frames;

receiving, from the principal switch, a response to the message;

upon determining, based on the response indicating that the message contains an invalid domain identifier, that the principal switch does not support return of domain identifiers without a build fabric phase, initiating a build fabric phase to effect removal of the domain identifiers; and

upon determining, based on at least one of the response acknowledging the message and the response including an updated list of fabric identifiers reflecting removal of the domain identifiers, that the principal switch supports return of domain identifiers without a build fabric phase, updating a local list of fabric identifiers to effect removal of the domain identifiers without any build fabric phrase.

2. The method of claim 1, wherein the network fabric is part of a virtual storage area network (VSAN), and wherein the determined domain identifiers comprise one or more virtual identifiers.

3. The method of claim 1, wherein the fabric comprises a Fibre Channel fabric.

4. A method, comprising:

receiving a message requesting return of a set of one or more domain identifiers assigned to a switch in a Fibre Channel fabric when the switch joined the Fibre Channel fabric, wherein each of the domain identifiers uniquely identifies the switch relative to other switches in the Fibre Channel fabric, wherein the message is composed according to a predefined format of a request domain identifier (RDI) message configured to requesting one or more domain identifiers to be assigned to the switch, the predefined format specifying a valid range of domain identifiers, the message specifying the set of one or more domain identifiers, the set of one or more domain identifiers being within the valid range, wherein the message further specifies a trigger value comprising a domain identifier outside of the valid range, wherein the RDI message is characterized by absence of the trigger value, and wherein presence of the trigger value in the message indicates that the message is a reverse request domain identifier (RRDI) message configured to request the set of one or more domain identifiers to be de-assigned from the switch;

updating a list of fabric identifiers to remove the one or more domain identifiers; and

sending a response containing the updated list of fabric identifiers to one or more switches in the Fibre Channel fabric, wherein at least one of the switches is configured to;

receive the response;

upon determining, based on the response indicating that the message contains an invalid domain identifier, that return of domain identifiers without a build fabric phase is not supported, initiate a build fabric phase to effect removal of the domain identifiers, wherein the build fabric phase comprises reconfiguring one or more switches in the Fibre Channel fabric by flooding the Fibre Channel fabric with build fabric frames; and

upon determining, based on the response containing the updated list of fabric identifiers, that the return of domain identifiers without a build fabric phase is supported, update a local list of fabric identifiers to effect removal of the domain identifiers without any build fabric phrase.

5. The method of claim 4, further comprising:

sending a response message to a switch that sent the message requesting return of the set of one or more domain identifiers.

6. An apparatus, comprising:

an interface for connecting the apparatus to a Fibre Channel fabric;

logic for sending a message to a principal switch of the Fibre Channel fabric requesting return of a set of domain identifiers as available for reassignment to other switches in the network fabric and without a build fabric phase, wherein the build fabric phase comprises reconfiguring one or more switches in the Fibre Channel fabric by flooding the network fabric with build fabric frames, and wherein the set of domain identifiers is previously assigned to a switch in the Fibre Channel fabric, wherein each of the domain identifiers uniquely identifies the switch relative to other switches in the Fibre Channel fabric, wherein the message is composed according to a predefined format of a request domain identifier (RDI) message configured to request one or more domain identifiers to be assigned, the predefined format specifying a valid range of domain identifiers, the message specifying the set of domain identifiers, the set of domain identifiers being within the valid range, wherein the message further specifies a trigger value comprising a domain identifier outside of the valid range, wherein the RDI message is characterized by absence of the trigger value, and wherein presence of the trigger value in the message indicates that the message is a reverse request domain identifier (RRDI) message configured the set of domain identifiers to be de-assigned from the switch;

logic for receiving, from the principal switch, a response to the message;

logic for, upon determining, based on the response indicating that the message contains an invalid domain identifier, that the principal switch does not support return of domain identifiers without a build fabric phase, initiating a build fabric phase to effect removal of the domain identifiers; and

logic for, upon determining, based on at least one of the response acknowledging the message and the response including an updated list of fabric identifiers reflecting removal of the domain identifiers, that the principal switch supports return of domain identifiers without a build fabric phase, updating a local list of fabric identifiers to effect removal of the domain identifiers without any build fabric phrase.

7. The apparatus of claim 6, wherein:

the fabric is part of a virtual storage area network (VSAN); and

the determined domain identifiers comprise one or more virtual identifiers.

8. The apparatus of claim 6, wherein:

the apparatus is capable of acting as a principal switch in the fabric; and

the apparatus further comprises logic for, when the apparatus is acting as a principal switch, receiving a message requesting return of one or more domain identifiers assigned to a switch in the fabric, updating a list of fabric identifiers to remove the one or more domain identifiers, and sending the updated list of fabric identifiers to one or more switches in the fabric.

9. The apparatus of claim 8, further comprising:

logic for, when the apparatus is acting as a principal switch, sending a response message to a switch that sent the message requesting return of the one or more domain identifiers.

10. An apparatus, comprising:

an interface for connecting the apparatus to a network fabric;

means for sending a message to a principal switch of the fabric requesting return of a set of domain identifiers as available for reassignment to other switches in the network fabric and without a build fabric phase, wherein the build fabric phase comprises reconfiguring one or more switches in the network fabric by flooding the network fabric with build fabric frames, and wherein the set of domain identifiers is previously assigned to a switch in the network fabric, wherein each of the domain identifiers uniquely identifies the switch relative to other switches in the network fabric, wherein the message is composed according to a predefined format of a request domain identifier (RDI) message configured to request one or more domain identifiers to be assigned to the switch, the predefined format specifying a valid range of domain identifiers, the message specifying the set of domain identifiers, the set of domain identifiers being within the valid range, wherein the message further specifies a trigger value outside of the valid range, wherein the RDI message is characterized by absence of the trigger value, and wherein presence of the trigger value in the message indicates that the message is a reverse request domain identifier (RRDI) message configured to request the set of domain identifiers to be de-assigned from the switch;

means for receiving, from the principal switch, a response to the message;

means for, upon determining, based on the response indicating that the message contains an invalid domain identifier, that the principal switch does not support return of domain identifiers without a build fabric phase, initiating a build fabric phase to effect removal of the domain identifiers; and

means for, upon determining, based on at least one of the response acknowledging the message and the response including an updated list of fabric identifiers reflecting removal of the domain identifiers, that the principal switch supports return of domain identifiers without a build fabric phase, updating a local list of fabric identifiers to effect removal of the domain identifiers without any build fabric phrase.

11. The apparatus of claim 10, further comprising:

means for, when the apparatus is acting as a principal switch in the fabric, receiving a message requesting return of one or more domain identifiers assigned to a switch in the fabric, updating a list of fabric identifiers to remove the one or more domain identifiers, and sending the updated list of fabric identifiers to one or more switches in the fabric.