Configuring FabricPath in Transit Mode

This chapter contains the following sections:

Information about FabricPath in Transit Mode

In transit mode, all the incoming traffic is mapped to one internal bridge-domain (VLAN). A pure Layer 2 spine node does not learn the MAC addresses; however, the packet is switched based on the switch ID lookup table in the FabricPath header.

In a FabricPath network, the Layer 2 spine node can be configured in Transit mode. After the spine is configured in the Transit mode, uni-destination traffic received on the spine is forwarded based on the FTAG (forwarding tag) and destination switch ID. For multi-destination traffic, the traffic on the spine is forwarded based on FTAG, which is the identifier of the multi-destination traffic that is selected by the ingress switch.

The spine will forward all the fabric-path data for all VLANs. For any other traffic, for example, carrier ethernet ports or SVI or Layer 3-specific data, processing is dependent on the SVI or Layer 3 configuration, based on SVI enabled on the spine switch.

Guidelines and Limitations

The following are the guidelines and limitations for configuring FabricPath in Transit mode:

  • Ensure that a minimum of one VLAN is enabled in FabricPath mode. The default VLAN “VLAN1” can be enabled as FabricPath mode. However, we recommend you to set another VLAN as FabricPath mode.
  • In case a SVI is enabled on spine node, the SVI is only intended to be used as management purpose. It should not carry data traffic because data traffic in that SVI VLAN may not be forwarded correctly on transit mode spine.

Configuring FabricPath in Transit Mode

To configure the FabricPath in transit mode, perform the following.

Procedure

Step 1 Enter the global configuration mode:

switch# configure terminal
switch(config)#
 

Step 2 Install the FabricPath feature set on the switch.

switch(config)# install feature-set fabricpath
 

Step 3 Enables the FabricPath feature set on the switch.

switch(config)# feature-set fabricpath
 

Step 4 Configure the FabricPath in transit mode:

switch(config)# fabricpath mode transit
 

Step 5 Copy and save the running configuration to the startup configuration.

switch(config)# copy running-config startup-config
 

Step 6 Reload the spine for transit mode to take effect.

switch(config)# reload

 

Example: Configuring FabricPath in Transit Mode

This example shows a running configuration, followed by a verification command that displays the configuration details for Cisco FabricPath in Transit Mode.

switch(config)# fabricpath mode transit
Enabling transit mode. Please save configuration and reload
 
switch(config)# show fabricpath mode
Switch is configured in transit mode. Please save configuration and reload to run in transit mode
 
switch (config)# copy running-config startup-config
[########################################] 100%
Copy complete, now saving to disk (please wait)...
 
switch (config)# reload
 
 
 

The following is the output for the show fabricpath mode command.

switch# show fabric path mode
Switch is configured and running in transit mode.
 

Feature History for Configuring FabricPath in Transit Mode

The following table lists the release history for these features.

Table 6-1 Feature History for Configuring FabricPath in Transit Mode for Nexus 6000 switches

Feature Name
Releases
Feature Information

FabricPath in Transit Mode

7.0(0)N1(1)

This feature was introduced.