You can modify Fibre Channel protocol-related timer values for the switch by configuring the following timeout values (TOVs):
Distributed services TOV (D_S_TOV)—The valid range is from 5,000 to 10,000 milliseconds. The default is 5,000 milliseconds.
Error detect TOV (E_D_TOV)—The valid range is from 1,000 to 10,000 milliseconds. The default is 2,000 milliseconds. This value is matched with the other end during port initialization.
Resource allocation TOV (R_A_TOV)—The valid range is from 5,000 to 10,000 milliseconds. The default is 10,000 milliseconds. This value is matched with the other end during port initialization.
Note
The fabric stability TOV (F_S_TOV) constant cannot be configured.
You can modify Fibre Channel protocol related timer values for the switch.
Caution
The D_S_TOV, E_D_TOV, and R_A_ TOV values cannot be globally changed unless all VSANs in the switch are suspended.
Note
If a VSAN is not specified when you change the timer value, the changed value is applied to all VSANs in the switch.
You can configure Fibre Channel timers across all VSANs.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
fctimer R_A_TOVtimeout
Example:
switch(config)# fctimer R_A_TOV 800
Configures the R_A_TOV timeout value for all VSANs. The unit is milliseconds.
This type of configuration is not permitted unless all VSANs are suspended.
Timer Configuration Per-VSAN
You can also issue the fctimer for a specified VSAN to configure different TOV values for VSANs with special links such as Fibre Channel. You can configure different E_D_TOV, R_A_TOV, and D_S_TOV values for individual VSANs. Active VSANs are suspended and activated when their timer values are changed.
Note
This configuration must be propagated to all switches in the fabric. Be sure to configure the same value in all switches in the fabric.
You can configure per-VSAN Fibre Channel timers.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
fctimer D_S_TOVtimeoutvsanvsan-id
Example:
switch(config#)# fctimer D_S_TOV 900 vsan 15
Configures the D_S_TOV timeout value (in milliseconds) for the specified VSAN. Suspends the VSAN temporarily. You have the option to end this command, if required.
EXAMPLES
This example shows how to configure the timer value for VSAN 2:
switch(config#)# fctimer D_S_TOV 6000 vsan 2
Warning: The vsan will be temporarily suspended when updating the timer value This
configuration would impact whole fabric. Do you want to continue? (y/n) y
Since this configuration is not propagated to other switches, please configure the same
value in all the switches
fctimer Distribution
You can enable per-VSAN fctimer fabric distribution for all Cisco SAN switches in the fabric. When you perform fctimer configurations, and distribution is enabled, that configuration is distributed to all the switches in the fabric.
You automatically acquire a fabric-wide lock when you enter the first configuration command after you enabled distribution in a switch. The fctimer application uses the effective and pending database model to store or commit the commands based on your configuration.
For additional information, refer to Using Cisco Fabric Services in the System Management Configuration Guide for your device.
Enabling or Disabling fctimer Distribution
You can enable or disable fctimer fabric distribution.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
fctimer distribute
Example:
switch(config)# fctimer distribute
Enables fctimer configuration distribution to all switches in the fabric. Acquires a fabric lock and stores all future configuration changes in the pending database.
Step 3
nofctimer distribute
Example:
switch(config)# no fctimer distribute
Disables (default) fctimer configuration distribution to all switches in the fabric.
Committing fctimer Changes
When you commit the fctimer configuration changes, the effective database is overwritten by the configuration changes in the pending database and all the switches in the fabric receive the same configuration. When you commit the fctimer configuration changes without implementing the session feature, the fctimer configurations are distributed to all the switches in the physical fabric.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
fctimer commit
Example:
switch(config)# fctimer commit
Distributes the fctimer configuration changes to all switches in the fabric and releases the lock. Overwrites the effective database with the changes made to the pending database.
Discarding fctimer Changes
After making the configuration changes, you can choose to discard the changes by discarding the changes instead of committing them. In either case, the lock is released.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
fctimer abort
Example:
switch(config)# fctimer abort
Discards the fctimer configuration changes in the pending database and releases the fabric lock.
Overriding the Fabric Lock
If you have performed a fctimer fabric task 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.
The changes are 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 fctimer session, use the clear fctimer session command.
switch# clear fctimer session
Fabric Database Merge Guidelines
When merging two fabrics, follow these guidelines:
Be aware of the following merge conditions:
The merge protocol is not implemented for distribution of the fctimer values. You must manually merge the fctimer values when a fabric is merged.
The per-VSAN fctimer configuration is distributed in the physical fabric.
The fctimer configuration is only applied to those switches containing the VSAN with a modified fctimer value.
The global fctimer values are not distributed.
Do not configure global timer values when distribution is enabled.
Note
The number of pending fctimer configuration operations cannot be more than 15. After 15 operations, you must commit or abort the pending configurations before performing any more operations.
For additional information, refer to CFS Merge Support in the System Management Configuration Guide for your device.
Verifying Configured fctimer Values
Use the show fctimer
command to display the configured fctimer values. The following example displays the configured global TOVs:
switch# show fctimer
F_S_TOV D_S_TOV E_D_TOV R_A_TOV
----------------------------------------
5000 ms 5000 ms 2000 ms 10000 ms
Note
The F_S_TOV constant, though not configured, is displayed in the output of the show fctimer command.
The following example displays the configured TOV for VSAN 10:
switch# show fctimer vsan 10
vsan no. F_S_TOV D_S_TOV E_D_TOV R_A_TOV
-------------------------------------------------
10 5000 ms 5000 ms 3000 ms 10000 ms
World Wide Names
The world wide name (WWN) in the switch is equivalent to the Ethernet MAC address. As with the MAC address, you must uniquely associate the WWN to a single device. The principal switch selection and the allocation of domain IDs rely on the WWN.
Cisco SAN switches support three network address authority (NAA) address formats. (see the following table).
Table 1 Standardized NAA WWN Formats
NAA Address
NAA Type
WWN Format
IEEE 48-bit address
Type 1 = 0001b
000 0000 0000b
48-bit MAC address
IEEE extended
Type 2 = 0010b
Locally assigned
48-bit MAC address
IEEE registered
Type 5 = 0101b
IEEE company ID: 24 bits
VSID: 36 bits
Caution
Changes to the world-wide names should be made by an administrator or individual who is completely familiar with switch operations.
Use the show wwn commands to display the status of the WWN configuration. This example shows how to display the status of all WWNs:
switch# show wwn status
Type Configured Available Resvd. Alarm State
---- ---------- -------------- ------ -----------
1 64 48 ( 75%) 16 NONE
2,5 524288 442368 ( 84%) 73728 NONE
This example shows how to display the information for block ID 51:
switch# show wwn status block-id 51
WWNs in this block: 21:00:ac:16:5e:52:00:03 to 21:ff:ac:16:5e:52:00:03
Num. of WWNs:: Configured: 256 Allocated: 0 Available: 256
Block Allocation Status: FREE
This example shows how to display the WWN for a specific switch:
switch# show wwn switch
Switch WWN is 20:00:ac:16:5e:52:00:00
Link Initialization WWN Usage
Exchange Link Protocol (ELP) and Exchange Fabric Protocol (EFP) use WWNs during link initialization. ELPs and EFPs both use the VSAN WWN by default during link initialization. However, the ELP usage changes based on the peer switch’s usage:
If the peer switch ELP uses the switch WWN, then the local switch also uses the switch WWN.
If the peer switch ELP uses the VSAN WWN, then the local switch also uses the VSAN WWN.
Configuring a Secondary MAC Address
You can allocate secondary MAC addresses.
Procedure
Command or Action
Purpose
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Enters global configuration mode.
Step 2
wwn secondary-macwwn-idrangevalue
Example:
switch(config)# wwn secondary-mac 33:e8:00:05:30:00:16:df range 55
Configures the secondary MAC address. This command cannot be undone.
EXAMPLES
This example shows how to configure the secondary MAC
address:
switch(config)# wwn secondary-mac 00:99:55:77:55:55 range 64
This command CANNOT be undone.
Please enter the BASE MAC ADDRESS again: 00:99:55:77:55:55
Please enter the mac address RANGE again: 64
From now on WWN allocation would be based on new MACs. Are you sure? (yes/no) no
You entered: no. Secondary MAC NOT programmed
FC ID Allocation for HBAs
Fibre Channel standards require a unique FC ID to be allocated to an N port attached to an F port in any switch. To conserve the number of FC IDs used,
Cisco SAN switches use a special allocation scheme.
Some HBAs do not discover targets that have FC IDs with the same domain and area. The switch software maintains a list of tested company IDs that do not exhibit this behavior. These HBAs are allocated with single FC IDs. If the HBA can discover targets within the same domain and area, a full area is allocated.
To allow further scalability for switches with numerous ports, the switch software maintains a list of HBAs that can discover targets within the same domain and area. Each HBA is identified by its company ID (also known as Organizational Unique Identifier, or OUI) used in the pWWN during a fabric log in. A full area is allocated to the N ports with company IDs that are listed and for the others, a single FC ID is allocated. Regardless of the type (whole area or single) of FC ID allocated, the FC ID entries remain persistent.
All
Cisco SAN switches contain a default list of company IDs that require area allocation. Using the company ID reduces the number of configured persistent FC ID entries. You can configure or modify these entries using the CLI.
Caution
Persistent entries take precedence over company ID configuration. If the HBA fails to discover a target, verify that the HBA and the target are connected to the same switch and have the same area in their FC IDs, then perform the following procedure:
Shut down the port connected to the HBA.
Clear the persistent FC ID entry.
Get the company ID from the port WWN.
Add the company ID to the list that requires area allocation.
Bring up the port.
The list of company IDs have the following characteristics:
A persistent FC ID configuration always takes precedence over the list of company IDs. Even if the company ID is configured to receive an area, the persistent FC ID configuration results in the allocation of a single FC ID.
New company IDs added to subsequent releases are automatically added to existing company IDs.
The list of company IDs is saved as part of the running and saved configuration.
The list of company IDs is used only when the fcinterop FC ID allocation scheme is in auto mode. By default, the interop FC ID allocation is set to auto, unless changed.
Tip
We recommend that you set the fcinterop FC ID allocation scheme to auto and use the company ID list and persistent FC ID configuration to manipulate the FC ID device allocation.
Use the fcinterop FCID allocation auto command to change the FC ID allocation and the show running-config command to view the currently allocated mode.
When you enter a write erase, the list inherits the default list of company IDs shipped with a relevant release.
Verifying the Company ID Configuration
You can view the configured company IDs by entering the show fcid-allocation area command. Default entries are listed first and the user-added entries are listed next. Entries are listed even if they were part of the default list and you later removed them.
This example shows how to display the list of default and configured company IDs:
switch# show fcid-allocation area
FCID area allocation company id info:
00:50:2E <--------------- Default entry
00:50:8B
00:60:B0
00:A0:B8
00:E0:69
00:30:AE + <------------- User-added entry
00:32:23 +
00:E0:8B * <------------- Explicitly deleted entry (from the original default list)
Total company ids: 7
+ - Additional user configured company ids.
* - Explicitly deleted company ids from default list.
You can implicitly derive the default entries shipped with a specific release by combining the list of Company IDs displayed without any identification with the list of deleted entries.
You can also view or obtain the company IDs in a specific WWN by entering the show fcid-allocation company-id-from-wwn command. Some WWN formats do not support company IDs. In these cases, you many need to configure the FC ID persistent entry.
This example shows how to display the company ID for the specified WWN:
switch# show fcid-allocation company-id-from-wwn 20:00:00:05:30:00:21:60
Extracted Company ID: 0x000530
Switch Interoperability
Interoperability enables the products of multiple vendors to interwork with each other. Fibre Channel standards guide vendors towards common external Fibre Channel interfaces.
Not all vendors follow the standards in the same way, which results in the need for interoperability modes. This section briefly explains the basic concepts of these modes.
Each vendor has a regular mode and an equivalent interoperability mode, which specifically turns off advanced or proprietary features and provides the product with a standards-compliant implementation.
Note
For more information on configuring interoperability for
Cisco Nexus devices, see the
Cisco MDS 9000 Family Switch-to-Switch Interoperability Configuration Guide.
The following table lists the changes in switch
operation when you enable interoperability mode. These changes are specific to
Cisco Nexus devices while in interop mode.
Table 2 Changes in Switch Operation When
Interoperability Is Enabled
Switch Feature
Changes if Interoperability Is Enabled
Domain IDs
Some vendors cannot use the full range of
239 domains within a fabric.
Domain IDs are restricted to the range 97
to 127, to accommodate McData’s nominal restriction to this same range. Domain
IDs can either be static or preferred, which operate as follows:
Static: Cisco switches accept only one
domain ID; if a switch does not get that domain ID it isolates itself from the
fabric.
Preferred: If the switch does not get
its requested domain ID, it accepts any assigned domain ID.
Timers
All Fibre Channel timers must be the same
on all switches as these values are exchanged by E ports when establishing an
ISL. The timers are F_S_TOV, D_S_TOV, E_D_TOV, and R_A_TOV.
F_S_TOV
Verify that the Fabric Stability Time Out
Value timers match exactly.
D_S_TOV
Verify that the Distributed Services Time
Out Value timers match exactly.
E_D_TOV
Verify that the Error Detect Time Out Value
timers match exactly.
R_A_TOV
Verify that the Resource Allocation Time
Out Value timers match exactly.
Trunking
Trunking is not supported between two
different vendor’s switches. This feature may be disabled per port or per
switch.
Default zone
The default zone operation of permit (all
nodes can see all other nodes) or deny (all nodes are isolated when not
explicitly placed in a zone) may change.
Zoning attributes
Zones may be limited to the pWWN and other
proprietary zoning methods (physical port number) may be eliminated.
Note
On a Brocade switch, use the
cfgsave command to save
fabric-wide zoning configuration. This command does not have any effect on
Cisco SAN
switches if they are part of the same fabric. You must explicitly save the
configuration on each
Cisco SAN
switch.
Zone propagation
Some vendors do not pass the full zone
configuration to other switches, only the active zone set gets passed.
Verify that the active zone set or zone
configuration has correctly propagated to the other switches in the fabric.
VSAN
Interop mode only affects the specified
VSAN.
Note
Interop modes cannot be enabled on
FICON-enabled VSANs.
TE ports and SAN port channels
TE ports and SAN port channels cannot be
used to connect Cisco switches to non-Cisco SAN switches. Only E ports can be
used to connect to non-Cisco SAN switches. TE ports and SAN port channels can
still be used to connect a Cisco switch to other Cisco SAN switches even when
in interop mode.
FSPF
The routing of frames within the fabric is
not changed by the introduction of interop mode. The switch continues to use
src-id, dst-id, and ox-id to load balance across multiple ISL links.
Domain reconfiguration disruptive
This is a switch-wide impacting event.
Brocade and McData require the entire switch to be placed in offline mode
and/or rebooted when changing domain IDs.
Domain reconfiguration nondisruptive
This event is limited to the affected VSAN.
Cisco SAN
switches have the capability to restart only the domain manager process for the
affected VSAN and not the entire switch.
Name server
Verify that all vendors have the correct
values in their respective name server database.
Configuring Interop Mode 1
You can interop mode1 in Cisco SAN switches disruptively or nondisruptively.
Note
Brocade’s msplmgmtdeactivate command must explicitly be run prior to connecting from a Brocade switch to either Cisco SAN switches or to McData switches. This command uses Brocade proprietary frames to exchange platform information, which Cisco SAN switches or McData switches do not recognize. Rejecting these frames causes the common E ports to become isolated.
Procedure
Command or Action
Purpose
Step 1
Place the VSAN of the E ports that connect to the OEM switch in interoperability mode.
switch# configuration terminal
switch(config)# vsan database
switch(config-vsan-db)# vsan 1 interop 1
switch(config-vsan-db)# exit
Step 2
Assign a domain ID in the range of 97 (0x61) through 127 (0x7F).
Note
This is an limitation imposed by the McData switches.
In Cisco SAN switches, the default is to request an ID from the principal switch. If the preferred option is used, Cisco SAN switches request a specific ID, but still join the fabric if the principal switch assigns a different ID. If the static option is used, the Cisco SAN switches do not join the fabric unless the principal switch agrees and assigns the requested ID.
Note
When changing the domain ID, the FC IDs assigned to N ports also change.
Step 3
Change the Fibre Channel timers (if they have been changed from the system defaults).
Note
The Cisco SAN switches, Brocade, and McData FC Error Detect (ED_TOV) and Resource Allocation (RA_TOV) timers default to the same values. They can be changed if needed. The RA_TOV default is 10 seconds, and the ED_TOV default is 2 seconds. Per the FC-SW2 standard, these values must be the same on each switch within the fabric.
switch(config)# fctimer e_d_tov ?
<1000-100000> E_D_TOV in milliseconds(1000-100000)
switch(config)# fctimer r_a_tov ?
<5000-100000> R_A_TOV in milliseconds(5000-100000)
Step 4
When making changes to the domain, you may or may not need to restart the Domain Manager function for the altered VSAN.
Force a fabric reconfiguration with the disruptive option.