[c-nsp] VLAN mystery

[B]

On Fri, Oct 16, 2015 at 08:11:18AM +1100, Andrew Miehs wrote:
>
> switchport trunk encapsulation dot1q is missing on the port on second switch.

After seeing that many times, I'm compelled to ask:  Are people reading
the problem description before responding?  One of the VLANs works, the
other VLAN doesn't, neither VLAN is native.  That's not what an ISL vs.
802.1Q mismatch gets you.

(He has dot1q on both ends.  On the 2924 because he configured it.  On
the 2950 because it doesn't do ISL (and doesn't have "sw tr enc ..." in
its command set, since there's no need).)

My money is on the 2924 not maintaining a separate MAC address database
per VLANs (causing problems because in his topology, the router will
use the same MAC address on both subinterfaces, but the switches will
see the far-end router's MAC address on one port for one VLAN and a
different port for a different VLAN).  But I don't know if the 2924
actually has that limitation or not.