What is an SDM Template and why should you care? SDM templates control how resources are allocated on a Cisco switch. There is a default template that is enabled by default that dedicates most resources to standard switching functions. SDM templates don’t work on all switches, but for the switches they do function on they can be an important feature to understand. The most common use is to change from the default template to the dual-stack template so as to enable IPv6 support.
Viewing the Current Template
To view the current SDM Template you can use the command
show sdm prefer. The output of this command indicates not only the current template but also how resources are allocated.
SW1#show sdm prefer The current template is "desktop routing" template. The selected template optimizes the resources in the switch to support this level of features for 8 routed interfaces and 1024 VLANs. number of unicast mac addresses: 3K number of igmp groups + multicast routes: 1K number of unicast routes: 11K number of directly connected hosts: 3K number of indirect routes: 8K number of qos aces: 0.5K number of security aces: 1K On next reload, template will be "desktop vlan" template.
Changing the Default Template
To change the default template you first need to know what templates are available. Use the
? to view these.
SW1(config)#sdm prefer ? default Default bias dual-ipv4-and-ipv6 Support both IPv4 and IPv6 lanbase-routing Lanbase routing qos QoS bias SW1(config)#sdm prefer
To make the change requires a reload.
SW1(config)#sdm prefer dual-ipv4-and-ipv6 default Changes to the running SDM preferences have been stored, but cannot take effect until the next reload. Use 'show sdm prefer' to see what SDM preference is currently active
Verifying the Change
After a reload you will now have the new SDM template applied and your resource allocations have been modified.
SW1#show sdm prefer The current template is "dual-ipv4-and-ipv6 default" template. The selected template optimizes the resources in the switch to support this level of features for 0 routed interfaces and 255 VLANs. number of unicast mac addresses: 8K number of IPv4 IGMP groups + multicast routes: 0.25K number of IPv4 unicast routes: 0 number of IPv6 multicast groups: 0.375k number of directly-connected IPv6 addresses: 0 number of indirect IPv6 unicast routes: 0 number of IPv4 policy based routing aces: 0 number of IPv4/MAC qos aces: 0.125k number of IPv4/MAC security aces: 0.375k number of IPv6 policy based routing aces: 0 number of IPv6 qos aces: 0 number of IPv6 security aces: 0.125k