You're right, spanning tree's intention is to prevent network loops. But this technology comes with penalties. A network loop can destroy a whole network in seconds, it can be a catastrophe that is easily made. So the small concept of preventing network loops is a massive counter-measure.
A lot of problems are introduced with spanning-tree and the way it interacts switch a switch. There are 2 types of BPDU, a TCN and configuration. The problem is, every time a TCN (topology change notification) is generated the spanning-tree topolgy will eventually receive an update. If for whatever reason you have a port flapping or several users connect/disconnect or similar situations, when the root bridge updates the topology, the max age timer will expire then update the configuration BPDU.
As a result of this, the cam table will drop. If the cam table drops, you will get a lot of ARP. So, let's filter the BPDU and see if it clears up. Or, disable spanning-tree all together, either or, which I don't recommend removing spanning tree because if someone decides to get smart and hook up a small hub and make a loop, you will get hurt, quickly.
-Tom
Please mark answered for helpful posts
-Tom
Please mark answered for helpful posts
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