Cisco IE 3000 Software Configuration Guide, Release 12.2(58)SE

Configuring SDM Templates

Understanding the SDM Templates

You can use SDM templates to configure system resources in the switch to optimize support for specific features, depending on how the switch is used in the network.

You can select a template to provide maximum system usage for some functions or use the default template to balance resources.

To allocate ternary content addressable memory (TCAM) resources for different usages, the switch SDM templates prioritize system resources to optimize support for certain features. You can select SDM templates to optimize these features:

•Default—The default template gives balance to all Layer 2 functions.

•QoS—The QoS template maximizes system resources for quality of service (QoS) access control entries (ACEs).

•Routing—The routing template maximizes system resources for IPv4 unicast routing, typically required for a router or aggregator in the center of a network. You must use the routing template on switches running the IP services image for Layer 3 functionality.

Note The switch must be running Cisco IOS Release 12.2(52)SE or later to configure the routing template.

In addition, the dual IPv4 and IPv6 templates enable a dual stack environment. See the "Dual IPv4 and IPv6 SDM Default Template" section.

The first eight rows in the tables (unicast MAC addresses through security ACEs) represent approximate hardware boundaries set when a template is selected. If a section of a hardware resource is full, all processing overflow is sent to the CPU, seriously impacting switch performance. The last row is a guideline used to calculate hardware resource consumption related to the number of Layer 2 VLANs on the switch.

Dual IPv4 and IPv6 SDM Default Template

You can select an SDM template to support IP Version 6 (IPv6) switching. For more information about IPv6 and how to configure IPv6 routing, see Chapter 41 "Configuring IP Unicast Routing."

This software release does not support Policy-Based Routing (PBR) when forwarding IPv6 traffic. The software supports IPv4 PBR only when the dual-ipv4-and-ipv6 routing template is configured.

The dual IPv4 and IPv6 template allows the switch to be used in dual stack environments (supporting both IPv4 and IPv6). Using the dual stack templates results in less TCAM capacity allowed for each resource. You should not use this template if you plan to forward only IPv4 traffic.

These SDM templates support IPv4 and IPv6 environments:

•Dual IPv4 and IPv6 default template—supports Layer 2, QoS, and ACLs for IPv4; and Layer 2, IPv6 host, and ACLs for IPv6.

•Dual IPv4 and IPv6 routing template—supports Layer 2, multicast, routing (including policy-based routing), QoS, and ACLs for IPv4; and Layer 2, routing, and ACLs for IPv6.

Note You must use the dual IPv4 and IPv6 routing template on switches running the IP services image for Layer 3 IPv6 functionality. The switch must be running Cisco IOS Release 12.2(52)SE or later to configure the routing template.

Note An IPv4 route requires only one TCAM entry. Because of the hardware compression scheme used for IPv6, an IPv6 route can take more than one TCAM entry, reducing the number of entries forwarded in hardware. For example, for IPv6 directly connected IP addresses, the desktop template might allow less than two thousand entries.

Configuring the Switch SDM Template

These sections contain this configuration information:

•Default SDM Template

•SDM Template Configuration Guidelines

•Setting the SDM Template

Default SDM Template

The default template is the default.

SDM Template Configuration Guidelines

Follow these guidelines when selecting and configuring SDM templates:

•When you select and configure SDM templates, you must reload the switch for the configuration to take effect.

•Use the sdm prefer vlan global configuration command only on switches intended for Layer 2 switching with no routing. When you use the VLAN template, no system resources are reserved for routing entries, and any routing is done through software. This overloads the CPU and severely degrades routing performance.

•Do not use the routing template if you do not have routing enabled on your switch. The sdm prefer routing global configuration command prevents other features from using the memory allocated to unicast routing in the routing template.

•If you download the IP services image and plan to use Layer 3 functionality, you must use the routing SDM template..

•If you try to configure IPv6 features without first selecting a dual IPv4 and IPv6 template, a warning message is generated.

•Using the dual stack templates results in less TCAM capacity allowed for each resource, so do not use if you plan to forward only IPv4 traffic.

Setting the SDM Template

Beginning in privileged EXEC mode, follow these steps to use the SDM template to maximize feature usage:

After the system reboots, you can use the show sdm prefer privileged EXEC command to verify the new template configuration. If you enter the show sdm prefer command before you enter the reload privileged EXEC command, the show sdm prefer command shows the template currently in use and the template that will become active after a reload.

This is an example of an output display when you have changed the template and have not reloaded the switch:

Switch# show sdm prefer

 The current template is "default" template.

 The selected template optimizes the resources in

 the switch to support this level of features for

 0 routed interfaces and 1024 VLANs.

  number of unicast mac addresses:                  8K

  number of IPv4 IGMP groups:                       0.25K

  number of IPv4/MAC qos aces:                      0.375k

  number of IPv4/MAC security aces:                 0.375k

 On next reload, template will be "routing" template.

To return to the default template, use the no sdm prefer global configuration command.

This example shows how to configure a switch with the routing template.

Switch(config)# sdm prefer routing

Switch(config)# end

Switch# reload

Proceed with reload? [confirm]

This example shows how to configure the IPv4-and-IPv6 default template on a desktop switch:

Switch(config)# sdm prefer dual-ipv4-and-ipv6 default

Switch(config)# exit

Switch# reload

Proceed with reload? [confirm]

Displaying the SDM Templates

Use the show sdm prefer privileged EXEC command with no parameters to display the active template.

Use the show sdm prefer [default | dual-ipv4-and-ipv6 {default | routing} qos | routing] privileged EXEC command to display the resource numbers supported by the specified template.

This is an example of output from the show sdm prefer command, displaying the template in use.

This is an example of output from the show sdm prefer routing command:

Switch# show sdm prefer routing

 "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:                  2K

  number of IPv4 IGMP groups + multicast routes:    1K

  number of IPv4 unicast routes:                    4K

    number of directly-connected IPv4 hosts:        2K

    number of indirect IPv4 routes:                 2K

  number of IPv4 policy based routing aces:         0.5K

  number of IPv4/MAC qos aces:                      0.625k

  number of IPv4/MAC security aces:                 0.375k