Information About MAC/ARP Hardware Resource Carving Template
On the Cisco Nexus device, the IPv4/IPv6 and unicast/multicast entries share the same tables. In addition, the same tables are shared by Station Table Management (STM) and the Host Route Table (HRT). STM is the part of the host table that holds the MAC entries. HRT is the part of the host table that holds ARP, IPv6 ND, and /32 host routes. The STM/HRT template profile feature is specific to the Cisco Nexus device. This feature provides you with a flexibility to carve STM & HRT table sizes per their requirements. The total table size is 256k. You can apply any of the following four pre-defined templates:
HRT size: 128k, STM size: 128k (default size)
HRT size: 96k, STM size: 160k
HRT size: 64k, STM size: 192k
HRT size: 32k, STM size: 224k
The hrt-96-stm-160 and hrt-32-stm-224 template profiles are not recommended in the presence of IPv6 entries. This is because these two profiles result in an odd number of SRAMs available for the HRT table. Insertion of IPv6 entries need free spaces in 2 consecutive SRAMs.
The recommended maximum ARP percentage of the configured value is 50%. The recommended maximum MAC percentage of the configured value is 90%. For example, if the profile is set to hrt-96-stm-160, 50% of 96k (48k) is the recommended maximum ARP entries that a switch can have.
When applying or unapplying a template profile, you need to enter the copy running-config startup-config command and reload the switch in order to activate the newly applied/default template. These commands are per-switch based, therefore they need to be configured explicitly on a vPC peer switch.
Configuring the MAC/ARP Hardware Resource Template
Rebooting the switch applies the default template (hrt-128-stm-128).
Verifying the MAC/ARP Hardware Resource Carving Template Configuration
To display MAC/ARP Hardware Resource Carving Template configuration information, enter one of the following commands:
show hardware profile route resource template
Displays all existing templates including the default.
show hardware profile route resource templatetemplate-name
Displays the details of a specific pre-defined template.
show hardware profile route resource template default
Displays the details of the default template.
show running-config hardware profile route resource template
Displays the running configuration information related to the template manager. Displays the currently applied non-default stm/hrt template. If the default template is applied, nothing is displayed here.
show startup-config hardware profile route resource template
Displays the startup configuration information related to the template manager. When entering the copy running-config startup-config command, the currently applied non-default stm/hrt template is displayed. If the default template is applied, nothing is displayed.