Cisco 7600 Series Cisco IOS Software Configuration Guide, 12.1E
Configuring the Switch Fabric Module
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Configuring the Switch Fabric Module

Table Of Contents

Configuring the Switch Fabric Module

Understanding How the Switch Fabric Module Works

Switch Fabric Module Overview

Switch Fabric Module Slots

Switch Fabric Redundancy

Forwarding Decisions for Layer 3-Switched Traffic

Switching Modes

Configuring the Switch Fabric Module

Configuring the Switching Mode

Configuring Fabric-Required Mode

Configuring an LCD Message

Monitoring the Switch Fabric Module

Displaying the Module Information

Displaying the Switch Fabric Module Redundancy Status

Displaying Fabric Channel Switching Modes

Displaying the Fabric Status

Displaying the Fabric Utilization

Displaying Fabric Errors


Configuring the Switch Fabric Module


This chapter describes how to configure the Switch Fabric Module (SFM) for the Catalyst 6500 series switches.


Note For complete syntax and usage information for the commands used in this chapter, refer to the Catalyst 6500 Series Switch Cisco IOS Command Reference publication.


This chapter consists of these sections:

Understanding How the Switch Fabric Module Works

Configuring the Switch Fabric Module

Monitoring the Switch Fabric Module

Understanding How the Switch Fabric Module Works

These sections describe how the Switch Fabric Module works:

Switch Fabric Module Overview

Switch Fabric Module Slots

Switch Fabric Redundancy

Forwarding Decisions for Layer 3-Switched Traffic

Switching Modes

Switch Fabric Module Overview


Note The Switch Fabric Module is supported only with Supervisor Engine 2.


The Switch Fabric Module creates a dedicated connection between fabric-enabled modules and provides uninterrupted transmission of frames between these modules. In addition to the direct connection between fabric-enabled modules provided by the Switch Fabric Module, fabric-enabled modules also have a direct connection to the 32-Gbps forwarding bus.

The Switch Fabric Module does not have a console. A two-line LCD display on the front panel shows fabric utilization, software revision, and basic system information.

Switch Fabric Module Slots

With a WS-C6513 chassis, install the Switch Fabric Modules in either slot 7 or 8.


Note In a WS-C6513 chassis, only slots 9 through 13 support dual-switch fabric interface switching modules (for example, WS-X6816-GBIC).


With all other chassis, install the Switch Fabric Modules in either slot 5 or 6.

Switch Fabric Redundancy

The Switch Fabric Module first installed functions as the primary module. For redundancy, you can install a redundant Switch Fabric Module. When two Switch Fabric Modules are installed at the same time, the module in the upper slot functions as the primary module, and the one in the lower slot functions as the backup. If you reset the module installed in the upper slot, the one in the lower slot becomes active.

No configuration is required for Switch Fabric Module redundancy. The module in the upper slot functions as the primary module and a redundant Switch Fabric Module in the lower slot automatically takes over if the primary module fails.

Forwarding Decisions for Layer 3-Switched Traffic

Either a PFC2 or a Distributed Feature Card (DFC) makes the forwarding decision for Layer 3-switched traffic as follows:

A PFC2 makes all forwarding decisions for each packet that enters the switch through a module without a DFC.

A DFC makes all forwarding decisions for each packet that enters the switch on a DFC-enabled module in these situations:

If the egress port is on the same module as the ingress port, the DFC forwards the packet locally (the packet never leaves the module).

If the egress port is on a different fabric-enabled module, the DFC sends the packet across the SFM to the egress module, which sends it out the egress port.

If the egress port is on a different nonfabric-enabled module, the DFC sends the packet across the SFM to the Supervisor Engine 2. The Supervisor Engine 2 fabric interface transfers the packet to the 32-Gbps switching bus where it is received by the egress module and is sent out the egress port.

Switching Modes

When you install a Switch Fabric Module, the traffic is forwarded to and from modules in one of the following modes:

Compact mode—The switch uses this mode for all traffic when only fabric-enabled modules are installed. In this mode, a compact version of the DBus header is forwarded over the switch fabric channel, which provides the best possible performance.

Truncated mode—The switch uses this mode for traffic between fabric-enabled modules when there are both fabric-enabled and nonfabric-enabled modules installed. In this mode, the switch sends a truncated version of the traffic (the first 64 bytes of the frame) over the switch fabric channel.

Bus mode—The switch uses this mode for traffic between nonfabric-enabled modules and for traffic between a nonfabric-enabled module and a fabric-enabled module. In this mode, all traffic passes between the local bus and the supervisor engine bus.

Table 37-1 shows the switch modes used with fabric-enabled and nonfabric-enabled modules installed.

Table 37-1 Switching Modes with Switch Fabric Module Installed

Modules
Switching Modes

Between fabric-enabled modules (when no nonfabric-enabled modules are installed)

Compact1

Between fabric-enabled modules (when nonfabric-enabled modules are also installed)

Truncated2

Between fabric-enabled and nonfabric-enabled modules

Bus

Between non-fabric-enabled modules

Bus

1 In show commands, displayed as dcef mode for fabric-enabled modules with DFC installed; displayed as fabric mode for other fabric-enabled modules.

2 Displayed as fabric mode in show commands.


Configuring the Switch Fabric Module

These section describe configuring the Switch Fabric Module:

Configuring the Switching Mode

Configuring Fabric-Required Mode

Configuring an LCD Message


Note With Release 12.1(11b)E and later releases, when you are in configuration mode you can enter EXEC mode-level commands by entering the do keyword before the EXEC mode-level command.


Configuring the Switching Mode


Note The commands in this section are supported only with Release 12.1(11b)E and later releases.


To configure the switching mode, perform this task:

Command
Purpose

Router(config)# [no] fabric switching-mode allow {bus-mode | {truncated [{threshold [number]}]}

Configures the switching mode.


When configuring the switching mode, note the following syntax information:

To allow use of nonfabric-enabled modules or to allow fabric-enabled modules to use bus mode, enter the fabric switching-mode allow bus-mode command.

To prevent use of nonfabric-enabled modules or to prevent fabric-enabled modules from using bus mode, enter the no fabric switching-mode allow bus-mode command.


Caution When you enter the no fabric switching-mode allow bus-mode command, power is removed from any nonfabric-enabled modules installed in the switch.

To allow fabric-enabled modules to use truncated mode, enter the fabric switching-mode allow truncated command.

To prevent fabric-enabled modules from using truncated mode, enter the no fabric switching-mode allow truncated command.

To configure how many fabric-enabled modules must be installed before they use truncated mode instead of bus mode, enter the fabric switching-mode allow truncated threshold number command.

To return to the default truncated-mode threshold, enter the no fabric switching-mode allow truncated threshold command.

Configuring Fabric-Required Mode


Note The commands in this section are supported only with Release 12.1(11b)E and later.


To configure fabric-required mode, which prevents all switching modules from operating unless there is a Switch Fabric Module installed, perform this task:

Command
Purpose

Router(config)# fabric required

Configures fabric-required mode, which prevents switching modules from operating without a switch-fabric module.

Router(config)# no fabric required

Clears fabric-required mode.



Caution If you enter the fabric required command on a switch that does not have a Switch Fabric Module installed, all modules except the supervisor engine turn off.

When configuring fabric-required mode, note the following syntax information:

If you boot the switch with fabric-required mode configured but without a Switch Fabric Module installed, only the supervisor engine receives power; no switching modules power up.

When the switch is operating with fabric-required mode configured and a Switch Fabric Module installed, if you remove the switch fabric module or if it fails, the switch removes power from all switching modules; only the supervisor engine remains active.

When the switch is operating with fabric-required mode configured and with redundant Switch Fabric Modules installed, if you remove both switch fabric modules or if both fail, the switch removes power from all switching modules; only the supervisor engine remains active.

Configuring an LCD Message

To configure a message for display on the LCD, perform this task:

Command
Purpose

Router(config)# fabric lcd-banner d message d

Configures a message for display on the LCD.

Router(config)# no fabric lcd-banner

Clears the message displayed on the LCD.


When configuring a message for display on the LCD, note the following syntax information:

The d parameter is a delimiting character. You cannot use the delimiting character in the message. The delimiter is a character of your choice—a pound sign (#), for example.

You can use the following tokens, in the form $(token), in the message text:

$(hostname)—Displays the switch's host name.

$(domain)—Displays the switch's domain name.

Monitoring the Switch Fabric Module

The Switch Fabric Module supports a number of show commands for monitoring purposes. A fully automated startup sequence brings the module online and runs the connectivity diagnostics on the ports.

These sections describe how to monitor the Switch Fabric Module:

Displaying the Module Information

Displaying the Switch Fabric Module Redundancy Status

Displaying Fabric Channel Switching Modes

Displaying the Fabric Status

Displaying the Fabric Utilization

Displaying Fabric Errors


Note The Switch Fabric Module does not require any user configuration.


Displaying the Module Information

To display the module information, perform this task:

Command
Purpose

Router# show module {5 | 6 | 7 | 8}

Displays module information.


This example shows how to display module information:

Router# show module 5
Mod Ports Card Type                              Model              Serial No.
--- ----- -------------------------------------- ------------------ -----------
  5    0  Switching Fabric Module                WS-C6500-SFM       SAD04420JR5

Mod MAC addresses                       Hw    Fw           Sw           Status
--- ---------------------------------- ------ ------------ ------------ -------
  5  0001.0002.0003 to 0001.0002.0003   1.0   6.1(3)       6.2(0.97)    Ok

Displaying the Switch Fabric Module Redundancy Status

To display the switch fabric module redundancy status, perform this task:

Command
Purpose

Router# show fabric active

Displays switch fabric module redundancy status.


Router# show fabric active 
Active fabric card in slot 5
No backup fabric card in the system
Router#

Displaying Fabric Channel Switching Modes

To display the fabric channel switching mode of one or all modules, perform this task:

Command
Purpose

Router# show fabric switching-mode [module {slot_number | all]

Displays fabric channel switching mode of one or all modules.


This example shows how to display the fabric channel switching mode of all modules:

Router# show fabric switching-mode all 
bus-only mode is allowed
Module Slot     Switching Mode
1               Bus
2               Bus
3               DCEF
4               DCEF
5               No Interfaces
6               DCEF
Router#

Displaying the Fabric Status

To display the fabric status of one or all switching modules, perform this task:

Command
Purpose

Router# show fabric status [slot_number | all]

Displays fabric status.


This example shows how to display the fabric status of all modules:

Router# show fabric status all
   slot    channel      module               fabric
   status               status
   1          0          OK                   OK
   3          0          OK                   OK
   3          1          OK                   OK
   4          0          OK                   OK
Router#

Displaying the Fabric Utilization

To display the fabric utilization of one or all modules, perform this task:

Command
Purpose

Router# show fabric utilization [slot_number | all]

Displays fabric utilization.


This example shows how to display the fabric utilization of all modules:

Router# show fabric utilization all
    slot    channel  Ingress %   Egress %
       1          0          0          0
       3          0          0          0
       3          1          0          0
       4          0          0          0
       4          1          0          0
       6          0          0          0
       6          1          0          0
       7          0          0          0
       7          1          0          0
Router#

Displaying Fabric Errors

To display fabric errors of one or all modules, perform this task:

Command
Purpose

Router# show fabric errors [slot_number | all]

Displays fabric errors.


This example shows how to display fabric errors on all modules:

Router#  show fabric errors 
    slot    channel  module   module  module  fabric
                        crc    hbeat    sync    sync
       1          0       0        0       0       0
       3          0       0        0       0       0
       3          1       0        0       0       0
       4          0       0        0       0       0
       4          1       0        0       0       0
       6          0       0        0       0       0
       6          1       0        0       0       0
       7          0       0        0       0       0
       7          1       0        0       0       0
Router#