Hi Per,
RSTP is in fact build on the top of STP. It's true that timers have little use in a network properly configured for RSTP. However, there are some few cases where RSTP falls back into an STP like mode of operation and where the timers will be useful:
- when dealing with shared segment (it has been improved in the latest spec but not yet updated in our implementation).
- when interacting with legacy STP bridges.
About the max-age timer in particular.It's true that max-age will not be used directly to age out information (3xhello-time is used instead). However, the age of BPDU received on the root port are still increased by one when transmitted on designated port. As a result, in a pure RSTP network, the age is used as a kind of hop count, and max-age represent the maximum number of bridge a BPDU can go through before being discarded.
I did not really get your "blocking state" statement though. Let me know if you still have any doubt.
Regards,
Francois
