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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter6 Administering the Swi tc h Optimizing System Resources for User-Selected Features
Using the Templates
Follow these guidelines when using the SDM templates:
•The maximum number of resources allowed in each template is an approximat ion and depends upon
the actual number of other features configured. For example, in the default template for the Catalyst
3550-12T, if your switch has more than 16 routed interfaces configured, the number of multicast o r
unicast routes that can be accommodated by hardware mig ht b e few er t han show n.
•Using the sdm prefer vlan global configuration command disables routing capability in the switch.
Any routing configurations will be rejected after the reload, and thos e o ptions might be lost. When
the switch reloads, the message “Running Layer2 Switching Only Image” appe ars, even though you
are really running a Layer 3 image with the routing functionality disabled . Use the sdm prefer vlan
global configuration command only on switches intended for L aye r 2 swit chi ng wi th no ro ut ing.
•Do not use the routing template if you do not have the enhanced multilayer software image installed
on your switch. Entering the sdm prefer routing global configuration command on a switch that
does not have the enhanced multilayer software image would not enable routing, but it would
prevent other features from using the approximately 17 K of memory allocated t o unicast an d
multicast routing in the routing template.
This procedure shows how to change the SDM template from the default. The switch must reload before
the configuration takes effect. If you use the show sdm prefer privileged EXEC command before the
switch reloads, the previous configuration (in this case, the default) is displayed.
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 use the show sdm prefer command befor e the reload pri vilege d
EXEC command, the previous template is displayed instead of the new one.
To return to the default template, use the no sdm prefer {access | routing | vlan} global configuration
command.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 sdm prefer {access | routing | vlan} Specify the SDM template to be used on the switch:
The keywords have these meanings:
•access—Maximizes the use of QoS classification ACEs and
security ACEs on the switch.
•routing—Maximizes routing on the switch.
•vlan—Maximizes VLAN configuration on the switch with no
routing allowed.
The default template (if none of these is configured) balances the use
of unicast MAC addresses, IGMP groups, QoS ACEs, security
ACEs, unicast and multicast routes, routed interfaces, and Layer 2
VLANs.
Step3 end Return to privileged EXEC mode.
Step4 copy running-config startup-config Save your entries in the configuration file.
Step5 reload Reload the operating system.