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RST 802.1D 2004 interop with 802.1W 2001

IEEE 802.1w Port information state machine requires a "ConfirmedRootMsg" to complete RSTP sync process.
IEEE 802.1d , when the port is a root port  specifies to transmit "the first four components of the designated priority vector" ( § 17.6 page 144 )
and not the "first four components of the port priority vector"  as 802.1w require ( § page 29 ).


In the topology of 4 DUTs, running 2 of them on 802.1D and other 2 on 802.1W. When there is topology change and Sync process is in progress, the new root port on DUT running with 802.1W expects the ConfirmedRootMsg,  but as there is no such thing in 802.1D, sysc process never completes successfully.

Please suggest the solution how to resolve it.


  • LAN Switching and Routing
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