User Guide

33-10
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 33 Configuring NDE
Configuring NDE
Populating Additional NDE Fields
With Release 12.1(13)E and later releases, you can configure NDE to populate the following additional
fields in the NDE packets:
• IP address of the next hop router
• Egress interface SNMP ifIndex
• Source autonomous system number
• Destination autonomous system number
Not all of the additional fields are populated with all flow masks. See the “NDE Versions” section on
page 33-3 for additional information.
To populate the additional fields in NDE packets, perform this task:
This example shows how to populate the additional fields in NDE packets:
Router(config)# mls nde interface
Configuring the MLS Aging Time
The MLS aging time applies to all MLS cache entries. The aging-time value is applied directly to
destination mode aging. The MLS aging time value is divided by two to obtain the source-to-destination
mode aging time and divided by eight to obtain the full-flow aging time. The default MLS aging time
value is 256 seconds.
You can configure the normal aging time in the range of 32 to 4092 seconds in 8-second increments. Any
aging-time value that is not a multiple of 8 seconds is adjusted to the closest multiple of 8 seconds. For
example, a value of 65 is adjusted to 64 and a value of 127 is adjusted to 128.
Other events might cause MLS entries to be purged, such as routing changes or a change in link state
(PFC link is down).
Note If the number of MLS entries exceeds 32K, only adjacency statistics might be available for some flows.
To keep the MLS cache size below 32K entries, enable the following parameters when using the mls
aging command:
• normal—Configures the wait before aging out and deleting shortcut entries in the Layer 3 table.
• fast aging—Configures an efficient process to age out entries created for flows that only switch a
few packets and then are never used again. The fast aging parameter uses the time keyword value
to check if at least the threshold keyword value of packets have been switched for each flow. If a
flow has not switched the threshold number of packets during the time interval, then the entry in the
Layer 3 table is aged out.
• long—Configures entries for deletion that have been up for the specified value even if the Layer 3
entry is in use. Long aging is used to prevent counter wraparound, which can cause inaccurate
statistics.
Command Purpose
Router(config)# mls nde interface
Populates additional fields in NDE packets.
Router(config)# no mls nde interface
Disables population of the additional fields.