On Wed, 30 Aug 2017 09:11:45 +0000 Andreas Dobloug email@example.com wrote:
I'm still assuming the issue here is that NAV still says that X is connected to Y. So now you have shutdown X. Is Y shutdown also, or has it been connected to something else?
Y is connected to a different port or different switch. X is in shutdown. Topology still shows the old port even though the port on switch X is in shutdown.
In the report system, there is a report titled "Direct neighborship candidates". Can you find any candidate neighbors for port X there?
The switch shouldn't provide any, since the port is shut down, but if they still are reported by the switch (or not being removed from NAV), then resulting topology may be stale.
There is an idea, that hasn't been implemented, that the topology detector should remove topology information for a port that is down, if the old neighboring port is still up - which would be an indicator of your case, where the link has been taken away and one of the ports reused for another link.
OTOH, we know of several weaknesses in the topology detector come from simply using the same topology deduction algorithm for LLDP and CDP data as is used for CAM-based data. We are working on a rewrite of the topology detector to use more reasonable algorithms with data provided from LLDP and CDP , which should hit NAV 4.8 sometime this fall.