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Catalyst 3750 Switch Command Reference
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Chapter 2 Catalyst 3750 Switch Cisco IOS Commands
sdm prefer
Do not use the routing template if you do not have routing enabled on your switch. Entering the sdm
prefer routing [desktop] 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} [desktop] global configuration command
divides resources between IPv4 and IPv6, limiting those allocated to IPv4 forwarding.
Table 2-17 lists the approximate number of each resource supported in each of the IPv4-only templates
for a desktop or aggregator switch. The values in the template are based on eight routed interfaces and
approximately one thousand 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 2-18 lists the approximate number of each resource supported in each of the dual IPv4-and IPv6
templates for a desktop or aggregator switch.
Ta b l e 2-17 Approximate Number of Feature Resources Allowed by IPv4Templates
Resource
Desktop Templates Aggregator Templates
Access Default Routing VLAN Access Default Routing VLAN
Unicast MAC addresses 4 K 6 K 3 K 12 K 6 K 6 K 6 K 12 K
Internet Group Management Protocol (IGMP)
groups and multicast routes
1 K 1 K 1 K 1 K 1 K 1 K 1 K 1 K
Unicast routes 6 K 8 K 11 K 0 12 K 12 K 20 K 0
• Directly connected hosts 4 K 6 K 3 K 0 6 K 6 K 6 K 0
• Indirect routes 2 K 2 K 8 K 0 6 K 6 K 14 K 0
Policy-based routing access control entries
(ACEs)
512 0 512 0 512 0 512 0
Quality of service (QoS) classification ACEs 512 512 512 512 896 896 512 896
Security ACEs 2 K 1 K 1 K 1 K 4 K 1 K 1 K 1 K
Layer 2 VLANs 1 K 1 K 1 K 1 K 1 K 1 K 1 K 1 K
Ta b l e 2-18 Approximate Feature Resources Allowed by Dual IPv4-IPv6 Templates
Resource
Desktop IPv4-and-IPv6 Templates Aggregator IPv4-and-IPv6 Templates
Default Routing VLAN Default Routing VLAN
Unicast MAC addresses 2 K 1536 8 K 2 K 2K 8 K
IPv4 IGMP groups and multicast routes 1 K 1K 1 K 1 K 1 K 0
Total IPv4 unicast routes: 3 K 2816 0 3 K 8K 0
• Directly connected IPv4 hosts 2 K 1536 0 2 K 2K 0
• Indirect IPv4 routes 1 K 1280 0 1 K 6K 1 K
IPv6 multicast groups 1 K 1152 1 K 1 K 2176 1 K
Total IPv6 unicast routes: 3 K 2816 0 3 K 8K 0
• Directly connected IPv6 addresses 2 K 1536 0 2 K 2K 0
• Indirect IPv6 unicast routes 1 K 1280 0 1 K 6K 0