Configuration Guide User guide

1188 FastIron Configuration Guide
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Modifying and displaying Layer 3 system parameter limits
Modifying and displaying Layer 3 system parameter limits
This section shows how to view and configure some of the Layer 3 system parameter limits.
Layer 3 configuration notes
• Changing the system parameters reconfigures the device memory. Whenever you reconfigure
the memory on a Brocade device, you must save the change to the startup-config file, and then
reload the software to place the change into effect.
• The Layer 3 system parameter limits for FastIron IPv6 models are automatically adjusted by the
system and cannot be manually modified. Refer to “FastIron second generation modules” on
page 1190.
FWS with base Layer 3
NOTE
This section applies to the FastIron WS base Layer 3 code. It does not apply to the FastIron X Series
and Brocade FCX Series devices.
The base Layer 3 code uses ternary content-addressable memory (TCAM) for IP routing, access
lists, MAC-based VLANs, and other features. The default value for TCAM is 256 routes.
You can set the TCAM number reserved for IP routing using the system-max command.
Brocade(config)#system-max hw-ip-route-tcam 450
Syntax: [no] system-max hw-ip-route-tcam <num>
The <num> variable specifies a value from 64 through 1020. The default is 256.
The show ip route command displays the usage of TCAM in routing.
In this example, add HW route failure shows the number of failures in installing routing TCAM.
The base Layer 3 code installs routing TCAM for the interface subnet and static routes. A packet is
routed in hardware if its destination IP address matches the interface or stack route subnet, and
the next hop or destination ARP is resolved. The unknown unicast packets have destination IP
addresses that do not match any static route or interface subnets.
The handling of unknown unicast packets differs depending on TCAM availability. For example, for
a system that never encounters an out-of-TCAM situation, If the default route is not configured or its
next hop ARP is not resolved, all unknown unicast packets are handled based on the default Layer
2 behavior. They are either dropped in hardware if route-only is configured or VLAN-flooded in
hardware.
Brocade#show ip route
Total number of IP routes: 29
Route TCAM: total 64, used 64, add HW route failure=34
Start index: 1 D:Connected R:RIP S:Static O:OSPF *:Candidate default
Destination NetMask Gateway Port Cost Type
1 2.2.10.0 255.255.255.0 0.0.0.0 v10 1 D
2 2.2.11.0 255.255.255.0 0.0.0.0 v11 1 D
...