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I do not have a spanning tree loop. I work in a manufacturing environment and roaming is prevalent. I don't want to see mac flaps or host flap messages on the wireless ports, I only want them for STP. How do I turn off one and not the other. Cisco, 4506 Thanks

denise
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One thing to consider is the rate of flapping. Having worked with a wireless environment with no channel plan or power adjustments and automatic adjustments and channel selection disabled, constantly seeing MAC flap notifications is indicative of a problem on the wireless side of your network.

Working with WAPs that allow you to adjust, either manually or automatically, the Tx power settings on your WAPs, you'll want to overlap your wireless coverage areas per WAP, called a cell, by about 40-60% to start out with and then dial that back until you've got effective coverage while minimizing WAP hopping from stationary clients. What you want to avoid is the overhead of having stationary clients flapping between WAPs, especially WAPs running in "bridge mode" ( Aruba terminology and the default behavior for Aerohive ), and the overhead of switches relearning port associations.

I'm not entirely certain, so take this with a grain of salt, but I think that learning MAC addresses is not an ASIC/forwarding plane operation, so you're using CPU cycles when this takes place.

Cell tuning can reduce hopping/flapping, but the roaming clients will remain. Another way to reduce the impact for network monitoring is to send all of your logging back to a syslog server which will allow you greater control over what you're viewing and how and possibly even discard notifications that you don't want to retain. Having greater flexibility here will make it easier to differentiate between normal roaming and spanning-tree issues.

I found this earlier discussion which might be informative: Mac-flap due to roaming clients on wireless.

Community
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Stuart Smith
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(I'm not sure what you mean w.r.t. STP vs. any of the other reasons for macflaps.)

There doesn't appear to be any way, at all, to disable this. Roaming wireless clients are simply going to be an unavoidable reality.

I'm assuming you don't have wireless lan controller(s) tunneling traffic back from each AP to the controller. That would, in theory, isolate clients from the switch(es).

Ricky
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I realize this is old but it still shows up in search results and I just learned about the logging discriminator command introduced to Cisco IOS in version 12.4 (2013-ish) which addresses the question of how to filter syslog messages.

Logging discriminator (link to search results rather than a doc Cisco will move) let's you specify a pattern to filter out specific syslog messages.

To create a syslog message discriminator, use the logging discriminator command in global configuration mode. To disable the syslog message discriminator, use the no form of this command.

logging discriminator discr-name [ [facility] [mnemonics] [msg-body] { drops string | includes string } ] [ severity { drops sev-num | includes sev-num } ] [ rate-limit msglimit ]

no logging discriminator discr-name

Syntax Description

discr-name | String of a maximum of eight alphanumeric, case-sensitive characters. Blank spaces between characters are not allowed.

facility | (Optional) Message subfilter for the facility pattern in an event message.

mnemonics | (Optional) Message subfilter for the mnemonic pattern in an event message.

msg-body | (Optional) Message subfilter for the msg-body pattern in an event message.

drops | Drops messages that match the pattern, including the specified regular expression.

includes | Delivers messages that match the pattern, including the specified regular expression string.

string | (Optional) Expression used for message filtering.

severity | (Optional) Message subfilter by severity level or group.

sev-num | (Optional) Integer that identifies the severity level or multiple levels. Multiple levels must be separated with a comma (,).

rate-limit | (Optional) Specifies a number of messages to be processed within a unit of time.

msglimit | (Optional) Integer in the range of 1 to 10000 that identifies the number of messages not to be exceeded.

Command Default: The logging discriminator function is disabled.

Dave Noonan
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