Normal BPDU gets discarded if the message age field reaches max age.
I'd like to know if it's the same for TCN BPDUs on their way up to the root bridge.
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Note that true TCN BPDUs were only used in the original STP. RSTP uses RST BPDUs with the TC bit set which have message/max age fields and are discarded when aged out.
True TCN BPDUs have no age fields, but as far as I understand it, they're not forwarded. A bridge receiving a TCN BPDU may (and probably will) decide to send TCN BPDUs on its own though.
The Topology Change Notification BPDU doesn't have a message age field. This is the format from the IEEE 802.1D-2004 standard: