[c-nsp] disabling 3750 mac address learning

[Paul Cosgrove]

sthaug at nethelp.no wrote:
>> Noticed that the 3750 ios 12.2(46)SE release supports the disabling of
>> mac address learning per vlan.  Does anyone have any experience with
>> this release yet?
>>
>> The feature seems to have been introduced earlier in the 3650s and has
>> obviously been in ME switches for a while.
> 
> The feature has been there longer, in the form of an RSPAN-enabled VLAN.
> 
> Steinar Haug, Nethelp consulting, sthaug at nethelp.no
> 

Thanks Steinar,

I think there are a few differences between these.  The command docs say
the following about RSPAN VLANs:
- All traffic in the RSPAN VLAN is always flooded.
- No MAC address learning occurs on the RSPAN VLAN.
- RSPAN VLAN traffic only flows on trunk ports.
- RSPAN VLANs must be configured in VLAN configuration mode by using the
remote-span VLAN configuration mode command.
- STP can run on RSPAN VLAN trunks but not on SPAN destination ports.
- An RSPAN VLAN cannot be a private-VLAN primary or secondary VLAN.

The first and third points suggests that for RSPAN VLANs you:
- cannot use static mac assignments
- cannot use access ports

Paul.

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