Configuring ECMP for Host Routes

This chapter describes how to configure the equal-cost multipathing (ECMP) protocol for host routes on the Cisco NX-OS switch.

This chapter includes the following sections:

Information About ECMP for Host Routes

When you enable ECMP support for host routes, all unicast host routes are programmed into the longest-prefix match algorithm (LPM) table. ECMP for host routes is provided in the switch hardware. You configure this feature in the CLI using the hardware profile unicast enable-host-ecmp command.

Note Host entries are stored in the LPM routing table instead of the host table when ECMP is configured for IPv4 (/32) routes and IPv6 (/128) routes.

Guidelines for ECMP for Host Routes

After enabling or disabling ECMP for host routes by using the [no] hardware profile unicast enable-host-ecmp command, ensure that you do the following:

  • Save the current configuration on the switch by using the copy running-config startup-config command
  • Reload the switch by using the reload command so that the configuration can be applied.

Licensing Requirements for ECMP for Host Routes

The following table shows the licensing requirements for this feature:

 

Product
License Requirement

Cisco NX-OS

ECMP for host routes requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.

Prerequisites for ECMP for Host Routes

ECMP for host routes has the following prerequisites:

  • Before you use this command, we recommend that you disable Unicast Reverse Path Forwarding (URPF) globally on the switch using the system urpf disable command, and then save the configuration and reload the switch. Disabling URPF globally extends the LPM table size.

Default Settings

ECMP for host routes is disabled by default.

Configuring ECMP for Host Routes

This section includes the following topics:

Enabling the ECMP for Host Routes Feature

You can enable the ECMP for host routes feature.

SUMMARY STEPS

1. configure terminal

2. (Optional) system urpf disable

3. hardware profile unicast enable-host-ecmp

4. copy running-config startup-config

5. reload

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

system urpf disable

 

Example:

switch(config)# system urpf disable

(Optional) Disables URPF globally on the switch.

Step 3

hardware profile unicast enable-host-ecmp

 

Example:

switch(config)# hardware profile unicast enable-host-ecmp

Enables ECMP for host routes globally on the switch.

Step 4

copy running-config startup-config

 

Example:

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

Saves this configuration change.

Step 5

reload

 

Example:

switch(config)# reload

WARNING: This command will reboot the system

Do you want to continue? (y/n) [n] y

Reloads the Cisco Nexus 3000 Series switch software.

Disabling the EMCP for Host Routes Feature

You can disable the ECMP for host routes feature.

SUMMARY STEPS

1. configure terminal

2. no hardware profile unicast enable-host-ecmp

3. copy running-config startup-config

4. reload

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

no hardware profile unicast enable-host-ecmp

 

Example:

switch(config)# no hardware profile unicast enable-host-ecmp

Disables ECMP for host routes globally on the switch and removes all associated configuration.

Step 3

copy running-config startup-config

 

Example:

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

Saves this configuration change.

Step 4

reload

 

Example:

switch(config)# reload

WARNING: This command will reboot the system

Do you want to continue? (y/n) [n] y

Reloads the Cisco Nexus 3000 Series switch software.

Verifying the ECMP for Host Routes Configuration

To display the ECMP for host routes configuration information, perform one of the following tasks:

 

Command
Purpose

show hardware profile status

Displays the unicast entries in hardware tables.

show running-config

Displays the running system configuration.

Configuration Examples for ECMP for Host Routes

This example shows how to disable URPF and configure ECMP for host routes:

switch# configure terminal
switch(config)# system urpf disable
switch(config)# hardware profile unicast enable-host-ecmp
switch(config)# copy running-config startup-config
switch(config)# reload
 

This example show how to disable ECMP for host routes:

switch# configure terminal
switch(config)# no hardware profile unicast enable-host-ecmp
switch(config)# copy running-config startup-config
switch(config)# reload

Additional References

For additional information related to implementing ECMP for host routes, see the following sections:

Related Documents

Related Topic
Document Title

ECMP for host routes CLI commands

Cisco Nexus 3000 Series Command Reference