[c-nsp] Sup720-3B Gig port mac address strangeness

Ross Vandegrift ross at kallisti.us
Fri May 29 15:12:36 EDT 2009

On Fri, May 29, 2009 at 10:09:37AM -0700, Jared Gillis wrote:
> Phil Mayers wrote:
> > IIRC SVIs use the chassis mac address, and routed ports use the phy MAC
> > address. L2 PDUs (STP, CDP, LLDP) always use the phy mac.
> I believe that is true as well, however I'm not using any SVIs on the interface
> I'm looking at. In fact, the interface I'm looking at is unconfigured and shut.
> I've even verified that there's no internal vlan assigned to it, so it should
> definitely be using the phy mac, but it's not, hence my confusion and email =)

Hmmm - on a lab box, the sup interfaces take their MAC from the
range on the sup.  Both are currently configured as switchports, and
SVIs are indeed all using the chassis MAC.

router.lab>show interface gi5/1 | include Hardware
  Hardware is C6k 1000Mb 802.3, address is 0019.e7d3.94c4 (bia 0019.e7d3.94c4)
router.lab>show interface gi5/2 | include Hardware 
  Hardware is C6k 1000Mb 802.3, address is 0019.e7d3.94c5 (bia 0019.e7d3.94c5)
router.lab>show catalyst6000 chassis-mac-addresses 
  chassis MAC addresses: 1024 addresses from 0011.5d4a.9480 to 0011.5d4a.987f
router.lab>show mod 5
Mod MAC addresses                       Hw    Fw           Sw           Status
--- ---------------------------------- ------ ------------ ------------ -------
  5  0019.e7d3.94c4 to 0019.e7d3.94c7   5.4   8.5(2)       12.2(2009050 Ok

I haven't tried swapping my sups, but the only reason I can imagine it
would stick is if I hot-swapped SUPs.  A cold restart, I would bet,
changes that interface MAC.

Weird :)

Ross Vandegrift
ross at kallisti.us

"If the fight gets hot, the songs get hotter.  If the going gets tough,
the songs get tougher."
	--Woody Guthrie

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