Catalyst 3750 Metro Switch Software Configuration Guide, 12.2(58)SE
Configuring SDM Templates
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Configuring SDM Templates

Table Of Contents

Configuring SDM Templates

Understanding the SDM Templates

Dual IPv4 and IPv6 SDM Templates

Configuring the Switch SDM Template

Default SDM Template

SDM Template Configuration Guidelines

Setting the SDM Template

Displaying the SDM Templates


Configuring SDM Templates


This chapter describes how to configure the Switch Database Management (SDM) templates on the Catalyst 3750 Metro switch.


Note For complete syntax and usage information for the commands used in this chapter, see the command reference for this release.


This chapter consists of these sections:

Understanding the SDM Templates

Configuring the Switch SDM Template

Displaying the 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 use the SDM templates for IP Version 4 (IPv4) and select a template to provide maximum system usage for some functions or to use the default template to balance resources.

The templates prioritize system resources to optimize support for these types of features:

Routing—The routing template maximizes system resources for unicast routing, typically required for a router or aggregator in the center of a network.

VLANs—The VLAN template disables routing and supports the maximum number of unicast MAC addresses. It would typically be selected for a Layer 2 switch.

Default—The default template gives balance to all functions.

The dual IPv4 and IPv6 templates also enable a dual stack environment. See the "Dual IPv4 and IPv6 SDM Templates" section.

Table 6-1 lists the approximate numbers of each resource supported in each of the three supported IPv4 templates.

.

Table 6-1 Approximate Number of Feature Resources Allowed by Each Template 

Resource
Template
Default
Routing
VLAN

Unicast MAC addresses

6 K

3 K

12 K

IGMP groups and multicast routes

1 K

1 K

1 K

Unicast routes

8 K

11 K

0

Directly connected hosts

6 K

3 K

0

Indirect routes

2 K

8 K

0

Policy-based routing ACEs

0

512

0

QoS classification ACEs

512

512

512

Security ACEs

1 K

1 K

1 K

Layer 2 VLANs

1 K

1 K

1 K


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 Templates

You can select SDM templates to support IP Version 6 (IPv6). For more information about IPv6 and how to configure IPv6 routing, see Chapter 37, "Configuring IPv6 Unicast Routing." For information about IPv6 MLD snooping, see Chapter 38, "Configuring IPv6 MLD Snooping." For information about configuring IPv6 ACLs, see Chapter 39, "Configuring IPv6 ACLs."

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 templates allow 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. Do not use them 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, multicast, routing, QoS, and ACLs for IPv4; and Layer 2, routing, and ACLs for IPv6 on the switch.

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 on the switch.

Dual IPv4 and IPv6 VLAN template—supports basic Layer 2, multicast, QoS, and ACLs for IPv4, and basic Layer 2 and ACLs for IPv6 on the switch

This software release does not support IPv6 multicast routing or IPv6 QoS.


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.


Table 7-2 defines the approximate feature resources allocated by each dual template. Template estimations are based on a switch with 8 routed interfaces and approximately 1000 VLANs.

Table 6-2 Approximate Feature Resources Allowed by Dual IPv4-IPv6 Templates 

Resource
Default
Routing
VLAN

Unicast MAC addresses

2 K

1536

8 K

IPv4 IGMP groups and multicast routes

1 K

1 K

1 K

Total IPv4 unicast routes:

3 K

2816

0

Directly connected IPv4 hosts

2 K

1536

0

Indirect IPv4 routes

1 K

1280

0

IPv6 multicast groups

1 K

1152

1 K

Total IPv6 unicast routes:

3 K

2816

0

Directly connected IPv6 addresses

2 K

1536

0

Indirect IPv6 unicast routes

1 K

1280

0

IPv4 policy-based routing ACEs

0

256

0

IPv4 or MAC QoS ACEs (total)

512

512

512

IPv4 or MAC security ACEs (total)

1 K

512

1 K

IPv6 policy-based routing ACEs1

0

255

0

IPv6 QoS ACEs

510

510

510

IPv6 security ACEs

510

510

510

1 IPv6 policy-based routing is not supported in this release.


Configuring the Switch SDM Template

This section describes how to configure the SDM template to be used on the switch. This section contains this configuration information:

Default SDM Template

SDM Template Configuration Guidelines

Setting the SDM Template

Default SDM Template

The default template is the default (nondual) template.

SDM Template Configuration Guidelines

Follow these guidelines when selecting and configuring 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 try to configure IPv6 features without first selecting a dual IPv4 and IPv6 template, a warning message appears.

Using the dual-stack templates results in less TCAM capacity allowed for each resource. Do not use them 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 resources:

 
Command
Purpose

Step 1 

configure terminal

Enter global configuration mode.

Step 2 

sdm prefer {default | dual-ipv4-and-ipv6 {default | routing | vlan} | routing | vlan}

Specify the SDM template to be used on the switch:

The keywords have these meanings:

default—Set the switch to the balance system resources between Layer 2 and Layer 3 functions.

dual-ipv4-and-ipv6—Select a template that supports both IPv4 and IPv6 routing.

default—Balance IPv4 and IPv6 Layer 2 and Layer 3 functionality.

routing—Provide maximum usage for IPv4 and IPv6 routing, including IPv4 policy-based routing.

vlan—Provide maximum usage for IPv4 and IPv6 VLANs.

routing—Maximize routing on the switch.

vlan—Maximize VLAN configuration on the switch with no routing supported in hardware.

Step 3 

end

Return to privileged EXEC mode.

Step 4 

reload

Reload the operating system.

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 "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:                         512 
 number of security aces:                    1K 
  
 On next reload, template will be "desktop vlan" 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]

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 | vlan} routing | vlan] 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.

Switch# show sdm prefer
 The current template is "desktop default" 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:             6K
  number of igmp groups + multicast routes:    1K
  number of unicast routes:                    8K
    number of directly connected hosts:        6K
    number of indirect routes:                 2K
  number of policy based routing aces:         0
  number of qos aces:                          512
  number of security aces:                     1K

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

Switch# show sdm prefer routing
"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 policy based routing aces:         512
  number of qos aces:                          512
  number of security aces:                     1K

This is an example of output from the show sdm prefer dual-ipv4-and-ipv6 default command entered on a switch:


Note When non-IP host mac-addresses are learned, the "IPv4" directly connected route space is used. (The IPv4 directly connected route space is always used, even when the learned MAC address is not routed, or has no associated IP address.)


Switch# show sdm prefer dual-ipv4-and-ipv6 default
 "desktop IPv4 and IPv6 default" 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:                    3K
    number of directly-connected IPv4 hosts:        2K
    number of indirect IPv4 routes:                 1K
  number of IPv6 multicast groups:                  1K
  number of directly-connected IPv6 addresses:      2K
  number of indirect IPv6 unicast routes:           1K
  number of IPv4 policy based routing aces:         0
  number of IPv4/MAC qos aces:                      0.5K
  number of IPv4/MAC security aces:                 1K
  number of IPv6 policy based routing aces:         0
  number of IPv6 qos aces:                          0.5K
  number of IPv6 security aces:                     0.5K