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Name Server Proxy

The name server functionality maintains a database containing the attributes for all hosts and storage devices in each VSAN. Name servers allow a database entry to be modified by a device that originally registered the information.

The proxy feature is useful when you want to modify (update or delete) the contents of a database entry that was previously registered by a different device.

About Registering Name Server Proxies

All name server registration requests come from the same port whose parameter is registered or changed. If it does not, then the request is rejected.

This authorization enables WWNs to register specific parameters for another node.

About Rejecting Duplicate pWWN

You can prevent a malicious or accidental login when using another device’s pWWN by enabling the reject-duplicate-pwwn option. If you disable this option, these pWWNs are allowed to log in to the fabric and replace the first device in the name server database.

You can prevent a malicious or accidental login when using another device’s pWWN. These pWWNs are allowed to log in to the fabric and replace the first device in the name server database.

About Name Server Database Entries

The name server stores name entries for all hosts in the FCNS database. The name server permits an Nx port to register attributes during a PLOGI (to the name server) to obtain attributes of other hosts. These attributes are deregistered when the Nx port logs out either explicitly or implicitly.

In a multiswitch fabric configuration, the name server instances running on each switch shares information in a distributed database. One instance of the name server process runs on each switch.

FDMI

Cisco MDS 9000 Family switches provide support for the Fabric-Device Management Interface (FDMI) functionality, as described in the FC-GS-4 standard. FDMI enables management of devices such as Fibre Channel host bus adapters (HBAs) through in-band communications. This addition complements the existing Fibre Channel name server and management server functions.

Using the FDMI functionality, the NX-OS software can extract the following management information about attached HBAs and host operating systems without installing proprietary host agents:

• Manufacturer, model, and serial number
• Node name and node symbolic name
• Hardware, driver, and firmware versions
• Host operating system (OS) name and version number

All FDMI entries are stored in persistent storage and are retrieved when the FDMI process is started.

RSCN

The Registered State Change Notification (RSCN) is a Fibre Channel service that informs hosts about changes in the fabric. Hosts can receive this information by registering with the fabric controller (through SCR). These notifications provide a timely indication of one or more of the following events:

• Disks joining or leaving the fabric.
• A name server registration change.
• A new zone enforcement.
• IP address change.
• Any other similar event that affects the operation of the host.

Apart from sending these events to registered hosts, a switch RSCN (SW-RSCN) is sent to all reachable switches in the fabric.

Note The switch sends an RSCN to notify registered nodes that a change has occurred. It is up to the nodes to query the name server again to obtain the new information. The details of the changed information are not delivered by the switch in the RSCN sent to the nodes.

About the multi-pid Option

If the RSCN multi-pid option is enabled, then RSCNs generated to the registered Nx ports may contain more than one affected port IDs. In this case, zoning rules are applied before putting the multiple affected port IDs together in a single RSCN. By enabling this option, you can reduce the number of RSCNs. For example, suppose you have two disks (D1, D2) and a host (H) connected to switch 1. Host H is registered to receive RSCNs. D1, D2, and H belong to the same zone. If disks D1 and D2 are online at the same time, then one of the following applies:

• The multi-pid option is disabled on switch 1— Two RSCNs are generated to host H, one for the disk D1 and another for disk D2.
• The multi-pid option is enabled on switch 1— A single RSCN is generated to host H, and the RSCN payload lists the affected port IDs (in this case, both D1 and D2).

Some Nx ports might not support multi-pid RSCN payloads. If this situation occurs, disable the RSCN multi-pid option.

RSCN Timer Configuration Distribution Using CFS

Because the timeout value for each switch is configured manually, a misconfiguration occurs when different switches time out at different times. This means different N ports in a network can receive RSCNs at different times. Cisco Fabric Services (CFS) alleviates this situation by automatically distributing configuration information to all switches in a fabric. This also reduces the number of SW-RSCNs.

RSCN supports two modes, distributed and nondistributed. In distributed mode, RSCN uses CFS to distribute configuration to all switches in the fabric. In nondistributed mode, only the configuration commands on the local switch are affected.

Note All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed.

The RSCN timer is registered with CFS during initialization and switchover. For high availability, if the RSCN timer distribution crashes and restarts or a switchover occurs, it resumes normal functionality from the state prior to the crash or switchover.

Note Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the default value. Failure to do so will disable the links across your VSANs and other devices.

Compatibility across various Cisco MDS NX-OS releases during an upgrade or downgrade is supported by conf-check provided by CFS. If you attempt to downgrade from Cisco MDS SAN-OS Release 3.0, you are prompted with a conf-check warning. You are required to disable RSCN timer distribution support before you downgrade.

By default, the RSCN timer distribution capability is disabled and is therefore compatible when upgrading from any Cisco MDS SAN-OS release earlier than Release 3.0.

RSCN Timer Configuration Distribution

Because the timeout value for each switch is configured manually, a misconfiguration occurs when different switches time out at different times. This means different Nports in a network can receive RSCNs at different times. Cisco Fabric Services (CFS) infrastructure alleviates this situation by automatically distributing the RSCN timer configuration information to all switches in a fabric. This action also reduces the number of SW-RSCNs. Refer to the Cisco MDS 9000 Family NX-OS System Management Configuration Guide .

RSCN supports two modes, distributed and nondistributed. In distributed mode, RSCN uses CFS to distribute configuration to all switches in the fabric. In nondistributed mode, only the configuration commands on the local switch are affected.

Note All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed.

Note Only the RSCN timer configuration is distributed.

The RSCN timer is registered with CFS during initialization and switchover. For high availability, if the RSCN timer distribution crashes and restarts or a switchover occurs, it resumes normal functionality from the state prior to the crash or switchover.

Note You can determine the compatibility when downgrading to an earlier Cisco MDS NX-OS release using show incompatibility system command. You must disable RSCN timer distribution support before downgrading to an earlier release.

Note By default, the RSCN timer distribution capability is disabled and is compatible when upgrading from any Cisco MDS SAN-OS release earlier than 3.0.

Note For CFS distribution to operate correctly for the RSCN timer configuration, all switches in the fabric must be running Cisco SAN-OS Release 3.0(1) or later, or Cisco NX-OS 4.1(1b).

Locking the Fabric

The first action that modifies the database creates the pending database and locks the feature in the VSAN. Once you lock the fabric, the following situations apply:

• No other user can make any configuration changes to this feature.
• A copy of the configuration database becomes the pending database along with the first active change.

Registering Name Server Proxies

To register the name server proxy, follow these steps:

To register the name server proxy, follow these steps:

Step 1 Expand a fabric, expand a VSAN, and then select Advanced.

You see the VSAN advanced configuration in the Information pane.

Step 2 Click the NS Proxies tab.

You see the existing name server proxy for the selected VSAN.

Step 3 Double-click the PortName field to register a new name server proxy.

Step 4 Click Apply Changes to save these changes, or click Undo Changes to cancel any unsaved changes.

Rejecting Duplicate pWWNs

To reject duplicate pWWNs, follow these steps:

Configuring the multi-pid Option

To configure the multi-pid option, follow these steps:

To configure the multi-pid option, follow these steps:

Step 1 Expand a fabric, expand a VSAN, and then select Advanced.

You see the VSAN advanced configuration in the Information pane.

Step 2 Click the RSCN Multi-PID tab.

Step 3 Check the Enable check box.

Step 4 Click Apply Changes to save these changes, or click Undo Changes to cancel any unsaved changes.

Suppressing Domain Format SW-RSCNs

A domain format SW-RSCN is sent whenever the local switch name or the local switch management IP address changes. This SW-RSCN is sent to all other domains and switches over the ISLs. The remote switches can issue GMAL and GIELN commands to the switch that initiated the domain format SW-RSCN to determine what changed. Domain format SW-RSCNs can cause problems with some non-Cisco MDS switches (refer to the Cisco MDS 9000 Family Switch-to-Switch Interoperability Configuration Guide ).

Detailed Steps

To suppress the transmission of these SW RSCNs over an ISL, follow these steps:

Note You cannot suppress transmission of port address or area address format RSCNs.

Clearing RSCN Statistics

You can clear the counters and later view the counters for a different set of events. For example, you can keep track of how many RSCNs or SW-RSCNs are generated on a particular event (such as ONLINE or OFFLINE events). You can use these statistics to monitor responses for each event in the VSAN.

Use the clear rscn statistics command to clear the RSCN statistics for the specified VSAN.

After clearing the RSCN statistics, you can view the cleared counters by issuing the show rscn command.

Configuring the RSCN Timer with CFS

To configure the RSCN timer with CFS, follow these steps:

Step 1 Expand a fabric, expand a VSAN, and then select Advanced in the Logical Domains pane.

Step 2 Click the RSCN Event tab.

You see the VSAN advanced configuration in the Information pane.

Step 3 Double-click the TimeOut value to change the value (in milliseconds) for the selected VSAN.

Step 4 Click Apply Changes to save these changes, or click Undo Changes to cancel any unsaved changes.

Configuring the RSCN Timer

RSCN maintains a per-VSAN event list queue, where the RSCN events are queued as they are generated. When the first RSCN event is queued, a per VSAN timer starts. Upon time-out, all the events are dequeued and coalesced RSCNs are sent to registered users. The default timer values minimize the number of coalesced RSCNs sent to registered users. Some deployments require smaller event timer values to track changes in the fabric.

Note The RSCN timer value must be the same on all switches in the VSAN. See the “RSCN Timer Configuration Distribution Using CFS” section.

Note Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the default value. Failure to do so will disable the links across your VSANs and other devices.

To configure the RSCN timer, follow these steps:

Enabling RSCN Timer Configuration Distribution

To enable RSCN timer configuration distribution, follow these steps:

Committing the RSCN Timer Configuration Changes

If you commit the changes made to the active database, the configuration is committed to all the switches in the fabric. On a successful commit, the configuration change is applied throughout the fabric and the lock is released.

To commit RSCN timer configuration changes, follow these steps:

Discarding the RSCN Timer Configuration Changes

If you discard (abort) the changes made to the pending database, the configuration database remains unaffected and the lock is released.

To discard RSCN timer configuration changes, follow these steps:

Clearing a Locked Session

If you have changed the RSCN timer configuration and have forgotten to release the lock by either committing or discarding the changes, an administrator can release the lock from any switch in the fabric. If the administrator performs this task, your changes to the pending database are discarded and the fabric lock is released.

Tip The pending database is only available in the volatile directory and are subject to being discarded if the switch is restarted.

To use administrative privileges and release a locked DPVM session, use the clear rscn session vsan command in EXEC mode.

Displaying FLOGI Details

To view the FLOGI database details, use the show flogi database command. See Examples 23-1 to 23-4 .

Example 23-1 Displays Details on the FLOGI Database

Example 23-2 Displays the FLOGI Database by Interface

Example 23-3 Displays the FLOGI Database by VSAN

Example 23-4 Displays the FLOGI Database by FC ID

For more information, see the “Default Company ID List” section and refer to the “Loop Monitoring” section in the Cisco MDS 9000 Family Troubleshooting Guide .

To verify that a storage device is in the fabric login (FLOGI) table, follow these steps:

Step 1 Expand Switches, expand Interfaces, and then select FC Physical.

You see the interface configuration in the Information pane.

Step 2 Click the FLOGI tab.

You see all end devices that are logged into the fabric.

Viewing Name Server Database Entries

To view the name server database using Device Manager, follow these steps:

Step 1 Select FC > Name Server.

You see the Name Server dialog box.

The General tab is the default tab; you see the name server database.

Step 2 Click the Statistics tab.

You see the name server statistics.

Step 3 Click Close to close the dialog box.

Displaying Name Server Database Entries

Use the show fcns command to display the name server database and statistical information for a specified VSAN or for all VSANs (see Examples 23-5 to 23-8 ).

Example 23-5 Displays the Name Server Database

Example 23-6 Displays the Name Server Database for the Specified VSAN

Example 23-7 Displays the Name Server Database Details

Example 23-8 Displays the Name Server Statistics

Displaying FDMI

Use the show fdmi command to display the FDMI database information (see Examples 23-9 to 23-11 ).

Example 23-9 Displays All HBA Management Servers

Example 23-10 Displays HBA Details for a Specified VSAN

Example 23-11 Displays Details for the Specified HBA Entry

To display the FDMI database information using Device Manager, choose FC > Advanced > FDMI. You see the FDMI dialog box.

Displaying RSCN Information

Use the show rscn command to display RSCN information (see Examples 23-12 and 23-13 ).

Example 23-12 Displays Register Device Information

Note The SCR table is not configurable. It is populated when hosts send SCR frames with RSCN information. If hosts do not receive RSCN information, then the show rscn scr-table command will not return entries.

Example 23-13 Displays RSCN Counter Information

To display RSCN information, follow these steps:

Step 1 Expand a fabric, expand a VSAN, and then select Advanced.

You see the VSAN advanced configuration in the Information pane.

Step 2 Click the RSCN Reg tab or the RSCN Statistics tab.

Displaying RSCN Configuration Distribution Information

Use the show cfs application name rscn command to display the registration status for RSCN configuration distribution.

Use the show rscn session status vsan command to display session status information for RSCN configuration distribution.

Note A merge failure results when the RSCN timer values are different on the merging fabrics.

Use the show rscn pending command to display the set of configuration commands that would take effect when you commit the configuration.

Note The pending database includes both existing and modified configuration.

Use the show rscn pending-diff command to display the difference between pending and active configurations. The following example shows the time-out value for VSAN 10 was changed from 2000 milliseconds (default) to 300 milliseconds.

FC Interfaces FLOGI

FDMI HBAs

FDMI Ports

FDMI Versions

RSCN Nx Registrations

RSCN Multi-PID Support

RSCN Event

RSCN Statistics

Name Server General

Name Server Advanced

Name Server Proxy

Name Server Statistics

Related Document

Standards

RFCs

MIBs