Cisco WS-C3560E-48PD-SF Command Reference - Page 363

Chapter 2 Catalyst 3560 Switch Cisco IOS Commands sdm prefer 78-16405-05 The access template maximizes system resources for access control lists (ACLs) as required to accommodate a large number of ACLs. The default template 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 | vlan} global configuration command divides resources between IPv4 and IPv6, limiting those allocated to IPv4 forwarding. Table 2-15 lists the approximate number of each resource supported in each of the IPv4-only templates for a 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 2-15 Approximate Number of Feature Resources Allowed by Each Template Resource Access Unicast MAC addresses 4 K IGMP groups and multicast routes 1 K Unicast routes 6 K • Directly connected hosts 4 K • Indirect routes 2 K Policy-based routing access control entries 512 (ACEs) Quality of service (QoS) classification ACEs 512 Security ACEs 2 K Layer 2 VLANs 1 K Default 6 K 1 K 8 K 6 K 2 K 0 512 1 K 1 K Routing 3 K 1 K 11 K 3 K 8 K 512 512 1 K 1 K VLAN 12 K 1 K 0 0 0 0 512 1 K 1 K Table 2-16lists the approximate number of each resource supported in each of the IPv4-and IPv6 templates for a switch. Table 2-16 Approximate Feature Resources Allowed by Dual IPv4-IPv6 Templates Resource Unicast MAC addresses IPv4 IGMP groups and multicast routes Total IPv4 unicast routes: • Directly connected IPv4 hosts • Indirect IPv4 routes IPv6 multicast groups Default 2 K 1 K 3 K 2 K 1 K 1 K VLAN 8 K 1 K 0 0 0 1 K Catalyst 3560 Switch Command Reference 2-331