Cisco Catalyst 3120 Command Reference Manual page 395

Chapter 2 Cisco Catalyst Blade Switch 3120 for HP Cisco IOS Commands
Follow these guidelines:
• All stack members use the same SDM desktop template that is stored on the stack master. When a
new switch member is added to a stack, the stored SDM configuration overrides the template
configured on an individual switch.
• The IPv6 packets are routed in hardware across the stack, as long as the packet does not have
exceptions (IPv6Options) and the switches have not run out of hardware resources.
If a stack member cannot support the template that is running on the master switch, the switch goes
•
into SDM mismatch mode, the master switch does not attempt to change the SDM template, and the
switch cannot be a functioning member of the stack.
For more information about stacking, see the "Managing Switch Stacks" chapter in the software
configuration guide.
Use the no sdm prefer command to set the switch to the default desktop template.
The access template maximizes system resources for access control lists (ACLs) as required to
accommodate a large number of ACLs.
The default templates balances the use of system resources.
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. Entering the sdm
prefer routing global configuration command prevents other features from using the memory allocated
to unicast routing in the routing template.
Do not use the ipv4-and-ipv6 templates if you do not plan to enable IPv6 routing on the switch. Entering
the sdm prefer ipv4-and-ipv6 {default | routing | vlan} global configuration command divides
resources between IPv4 and IPv6, limiting those allocated to IPv4 forwarding.
Table 2-15
templates for a desktop switch. The values in the template are based on 8 routed interfaces and
1024 VLANs and represent the 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.
Table 2-15
Resource
Unicast MAC addresses
Internet Group Management Protocol
(IGMP) groups and multicast routes
Unicast routes
Directly connected hosts
•
Indirect routes
•
Policy-based routing access control entries
(ACEs)
Quality of service (QoS) classification ACEs 0.5 K
Security ACEs
VLANs
OL-12248-01
lists the approximate number of each resource that is supported in each of the IPv4-only
Approximate Number of Feature Resources Allowed by IPv4 Templates
Access Default
4 K 6 K
1 K 1 K
6 K 8 K
4 K 6 K
2 K 2 K
0.5 K 0
0.5 K
2 K 1 K
1 K 1 K
Cisco Catalyst Blade Switch 3120 for HP Command Reference
sdm prefer
Routing VLAN
3 K 12 K
1 K 1 K
11 K 0
3 K 0
8 K 0
0.5 K 0
0.5 K 0.5 K
1 K 1 K
1 K 1 K
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