Information About SDM Templates
You can use SDM templates to configure system resources to optimize support for specific features, depending on how your device is used in the network. You can select a template to provide maximum system usage for some functions.
Cisco Catalyst 9600 Series Switches support the following templates:
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Core
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SDA
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NAT
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Distribution
After you change the template and 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.
Customizable SDM Template
Overview of Customizable SDM Template
Switch Device Manager (SDM) templates can be used to configure system resources and optimize support for specific features. However standard SDM templates are defined based on how the device is deployed in the network.
A custom SDM template will allow you to configure the features of the template based on your requirements and not the location of the device in the network. A custom SDM template for forwarding features can be configured using the command sdm prefer custom fib .
A Customizable SDM template supports the following features:
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Unicast MAC addresses
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Layer 3 Unicast forwarding
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Layer 2 Multicast forwarding
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Layer 3 Multicast forwarding
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Ingress Netflow
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Egress Netflow
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SGT/DGT Index space / MPLS VPN Label space
The following table shows the minimum and maximum scale values that can be configured for each of the features, the step units and the default values that will be applied when no custom values are chosen for a feature.
Feature name |
Scale Values (Min-Max) |
Step Units |
Default Values |
---|---|---|---|
MAC addresses |
32768 - 131072 |
16384 |
32768 |
Unicast routes |
65536 - 262144 |
16384 |
65536 |
Layer 2 Multicast |
0, 16384 - 32768 |
16384 |
16384 |
Layer 3 Multicast |
0, 16384 - 32768 |
16384 |
16384 |
SG Hash/MPLS |
0, 32768 - 65536 |
32768 |
32768 |
Ingress Netflow |
0, 32768 - 65536 |
32768 |
32768 |
Egress NetFlow |
0, 32768 - 65536 |
32768 |
0 |
You can determine which features are allocated the resources first by assigning them a priority using the priority keyword.The lower the priority-value assigned to a feature the higher its priority in resource allocation. The total value that is assigned to all the features can exceed the maximum supported resource value of 416K, where K is equal to 1024 entries. The resource allocation algorithm will use the priority-values to determine the number of resources assigned to each feature.
Once you have configured a customized template the device will have to be reloaded for the template to take effect.
Note |
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System resource allocation for Customizable SDM Template
The total number of system resources assigned to a Customizable SDM Template is 416K for FIB features and 52K for ACL features. If the total number of all the resources specified exceeds 416K for FIB features or 52K for ACL features, the system starts to lower the number of allotted resources starting with the feature assigned the highest number. A higher priority value or number assigned to a feature indicates a lower priority.
When the total number of resources assigned in the Customizable SDM Template is less than 416K for FIB features or less than 52K for ACL features:
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All the features specified in the template are allotted resources as customized in the template. Any features not specified in the template are allotted the default number of resources.
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If the total number of resources assigned to the FIB features multicast layer 2 and layer 3 exceeds 48K, then the scale of the multicast feature assigned the lower priority is reduced until the total number of resources assigned is equal to 48K.
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Resources that aren't allotted won’t be distributed.
When the total number of resources assigned in the Customizable SDM Template is more than 416K for FIB features and more than 52K for ACL features:
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All the features for which a custom scale isn’t specified are allotted the default values.
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If the total number of resources assigned to FIB features multicast layer 2 and layer 3 exceeds 48K, then the scale of the multicast feature that is assigned the lower priority is reduced until the total number of resources assigned is less than or equal to 48K.
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The number of resources allotted to the feature with the highest priority value are decreased by the step value.
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If the total number of resources still exceeds 416K for FIB features or 52K for ACL features, the resources allotted to the next feature with the highest priority value are decreased by the step value.
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While lowering the resources allotted to a feature, the scale is lowered only until the default value for that feature. If further adjustment is required, the resources allotted to the next feature on the priority list are reduced.
Note |
The custom value entered by you for any feature is rounded up to the next step value. For example, if you enter a value of 40K for SGT it’s rounded up to 64K. |
Customizable SDM Template and High Availability
On a device which supports High Availability, when a Customizable SDM Template is configured on the active Supervisor it also takes effect on the standby Supervisor.
If the standby Supervisor is configured with a different custom template than the active Supervisor, the Customizable SDM Template of the active Supervisor is configured on the standby Supervisor during initialization.
Customizable SDM Template and StackWise Virtual
On a device which supports StackWise Virtual, when an SDM Template is configured on the active Supervisor it also takes effect on the standby chassis.
If the standby chassis is configured with a different custom template than the active Supervisor, the SDM Template of the active Supervisor is configured on the standby chassis during initialization. The standby chassis undergoes an extra reload for the template to take effect.
Customizable SDM Template and ISSU
When a device undergoes an In-Service Software Upgrade (ISSU) to a higher release and there’s a change in the resource allocation algorithm, this upgrade can result in a different scale for the same user input. The change in scale is detected and notified via a syslog message. The system continues to operate with the earlier scale.
You can view the change in scale by using the show sdm prefer custom scale-change command. You can apply this change in scale by using the sdm prefer custom commit command. The device has to be reloaded for the change to take effect.
When a device with a customizable SDM template for FIB features undergoes a downgrade to a release earlier than the Cisco IOS XE Amsterdam 17.3.1 release, you need to change the SDM template to a static SDM template before the downgrade. You can change the template using the sdm prefer template name command. Reload the system for the change to take effect before proceeding with the downgrade.
When a device with a customizable SDM template for ACL features undergoes a downgrade to a release earlier than the Cisco IOS XE Bengaluru 17.4.1 release, you need to change the SDM template to a static SDM template before the downgrade.
When a device has customizable SDM templates for both FIB and ACL features customized in the Cisco IOS XE Bengaluru 17.4.1 release and it downgrades to the Cisco IOS XE Amsterdam 17.3.1 release, the device will be restored with the customizations for the FIB features. The scale numbers for the ACL features will be alloted based on the scale values of the standard SDM template. The information about the customization of the ACL features will be preserved. The device will be restored with the customizations for the ACL features when it upgrades to the Cisco IOS XE Bengaluru 17.4.1 release.