Hi everyone!
I'm trying to build a simple lab about Multiple Spanning Tree Protocol, and I have found something interesting.
The lab topology is given as:
In this lab, I need to load balance the traffic of vlan 2 and vlan 3 over SW1, SW3 and SW2,SW3 links, respectively.
So, I have created two instance, the first is mapped to vlan 2, and the second one mapped to vlan 3. In instance 1, SW1 is the root, and SW2 is the secondary root. In instance 2, Sw2 is the root, and SW1 is the secondary root.
What should happen based on my understanding of MSTP is as follow:
1- PC1, the member of vlan 2, will send a udp broadcast message.
2- SW3 will encapsulate this braodcast messge by vlan id 2.
3- SW3 will forward the broadcast message based on the vlan id added to it in the previous step.
4- SW3 will find that the link between SW2 and SW3 is bloked based on the stp instance one, so the broadcast packet will be forwarded through the other link.
At a the end, the link between SW2 and SW3 should never has a packet encapsulated by vlan id 2 until the primary link between SW3 and SW1 fail. But, when I made a test to the network, I found just one packet from vlan 2 in this bloked link. The loop doesn't occure, but I need to know if this is normal or a simulator problem.
