What Is Proposal And Agreement In Rstp
• The next downstream switch will see the top BPDU and move its non-peripheral ports to the designated and rejected states, restarting the proposal/agreement process. SWB will put all its ports in the reject state and send its own BPDU proposal to its downstream neighbors, if it receives a response from its downstream neighbors, it will move its root port to the transfer state and send a BPDU agreement to SWA set to 1 and the suggestion bit to 0. SWA ports are forwarded to the forwarder. When a switch receives a BPDU with a suggestion bit on its root port, it places all non-peripheral ports in a failed state. This process is called Sync. A switch in the synchronization state is isolated from the network so that no loop is transmitted over the network. In the example, the root switch sends the proposal. Switch A has its switch port P1 in the specified rejection state and passes a BPDU suggestion. The BPDU of the root switch is higher than that of the A switch.
Therefore, switch A is immediately ignored on all non-peripheral ports to prevent a Layer 2 loop. Основное – стоит флаг proposal, роль порта – designated, указаны параметры root bridge (priority – 0, vlan id – 1, mac-address). When a new connection is created between root and switch 1, both ports go into a certain blocking state until they receive a BPDU from their counterpart. The suggestion bit on BPDUs is set and sent only when a particular port is in the reject or learn state. This process takes place for port P0 of the root bridge. Because Switch 1 receives high-quality information, Switch 1 immediately knows that port P1 is the new root port. Switch 1 then ensures that all ports are synchronized with this new information. Imagine that we have two SWA and SWB switches, and when those switches are turned on, both switches claim to be the segment root switch and both start replacing the BPDUs.
SWA sends a configuration BPDU with the suggestion bit at 1, if SWB receives this BPDU and sees that it is a HIGHER BPDU, does it consider the port it receives this BPDU as the root port, am I right? Switch A responds to the root switch with a transfer agreement. Both switch ports quickly enter the transfer state with the peace of mind that there are no layer 2 loops. .