Specifications

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Cisco ME 3400 Ethernet Access Switch Command Reference
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Chapter 2 Cisco ME 3400 Ethernet Access Switch Cisco IOS Commands
sdm prefer
The default templates balances the use of system resources. Do not use the default template if you do
not have routing enabled on your switch. Using the balanced template prevents Layer 2 features from
using the memory allocated to unicast routing in the default template.
Do not use the layer-2 template if the switch is routing packets. The layer-2 template does not support
routing and forces any routing to be done through software. This overloads the CPU and severely
degrades routing performance.
If you try to configure IPv6 features without first selecting a dual IPv4 and IPv6 template, a warning
message appears.
The dual-stack templates provide in less allowable TCAM capacity for each resource. Do not use them
if you plan to forward only IPv4 traffic.
Table 2-4 lists the approximate number of each resource supported in each of the two IPv4 templates for
a switch running the metro IP access image. The values in the template are based on eight routed
interfaces and approximately 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 2-5 defines the approximate feature resources allocated by each dual template. Template
estimations are based on a switch with 8 routed interfaces and approximately 1000 VLANs.
Ta b l e 2-4 Approximate Number of Feature Resources Allowed by Each Template
Resource Layer-2 Default
Unicast MAC addresses 8 K 5 K
IPv4 IGMP groups + multicast routes (default only) – 1 K
IP v4 IGMP groups (layer-2 only) 1 K –
IPv4 multicast routes (layer-2 only) 0 –
IPv4 IGMP groups and multicast routes 1 K –
IPv4 unicast routes 0 9 K
• Directly connected IPv4 hosts – 5 K
• Indirect IPv4 routes – 4 K
IPv4 policy-based routing ACEs
1
1. ACEs = Access control entries.
0 0.5 K
IPv4 or MAC QoS
2
ACEs
2. QoS = Quality of service.
0.5 K 0.5 K
IPv4 or MAC security ACEs 1 K 1 K
Ta b l e 2-5 Approximate Feature Resources Allowed by Dual IPv4-IPv6 Templates
Resource
IPv4-and-IPv6
Default
IPv4-and-IPv6
Routing
IPv4-and-IPv6
VLAN
Unicast MAC addresses 2 K 1.5 K 8 K
IPv4 IGMP groups and multicast routes 1 K 1 K 1 K
Total IPv4 unicast routes: 3 K 2.75 K 0
• Directly connected IPv4 hosts 2 K 1.5 K 0