hi Martin,

On 28/02/2011, at 10:16 AM, Martin Clifton wrote:
> I have a concern about the table that is displayed when you enter the command 
> "sh otv route".   This table shows entries for "site" (ie local) and 
> "overlay" (ie other DC)  mac addresses.    The issue is with the "Uptime" 
> data.  For the overlay addresses this will randomly reset to zero and all 
> addresses will reset to zero at the one time.   The frequency of this reset 
> seems to be a function of the number of vlans ie the more vlans I add to the 
> overlay, the more often the value resets.   With 100 or more vlans the value 
> may build up to a minute or two but will often only get to a few seconds 
> before resetting.

i would not expect the "uptime" in "show otv route" to be resetting.  that, to 
me, indicates that the MAC address(es) are moving/oscillating between ports on 
the originating device.
with OTV we still do hardware-based MAC learning for L2 switching but whenever 
a MAC address is learnt or moves that is picked up by control-plane and 
advertised accordingly.

for one of those mac addresses, suggest you look into whether it is in fact 
moving - and more importantly - why.  it could be a misconfiguration (like Port 
Channel "mode on" on one device and no Port Channel defined on the other end.
it could be misconfigured hosts - set up with NIC teaming or Link Aggregation 
incorrectly.
it could be unstable L2 at one side. 
t could be a loop.  (but i'd expect that to be having more noticable impacts on 
the network :) ).

pick one of the N7Ks where you see the change originating from and do a few 
"show hardware mac address-table <slot-number> | grep <macaddr>" and see if its 
moving.  that shows the h/w mac table.  you may also see the same moving of mac 
addresses in "show mac address-table" but the h/w one will show updates sooner.


cheers,

lincoln.
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