[c-nsp] switch mac address learning

[Brett Frankenberger]

On Sat, Nov 05, 2005 at 05:44:45PM -0500, Jon Lewis wrote:
> Someone emailed me privately asking for config from all the interfaces 
> involved, and I didn't realize until I was about to send it that it was a 
> private message.  Here's what I wrote, minus their reply.
> 
> Actually, someone else already mentioned this, and I only just 
> realized/confirmed it, but the 6509 uses the same MAC address on every 
> interface[1].  I thought it had a large range of MAC addresses and used unique 
> ones on each interface.
> 
> [1] This isn't entirely true.  It does seem to use the same MAC address on all 
> SVI's, and all L3 interfaces, which are effectively treated like SVIs. L2 
> interfaces get unique MAC addresses, but these aren't used in arp replies...the 
> SVI MAC address is used.  IOS will let you change the MAC address of an 
> interface...but in doing so, you change the MAC address for every SVI/L3 
> interface.  That was kind of scarey to find out the hard way.

What you describe is Sup2 behavior.  Sup1A, Sup720, and Sup32 allow the
MAC address to be set individually for SVIs and L3 interfaces.  (The
limitation is actually in the PFC, I think, so really, it's behavior
associated with the PFCs that are associated with each of the Sups I
listed above.)

     -- Brett