Since PVST+ is based on STP, and Rapid-PVST+ is based on RSTP, TCN BPDUs are sent only in PVST+ and not in Rapid-PVST+ mode.
For introductory information about STP BPDUs, see the section TCN BPDUs.
| Header/field |
Standard IEEE STP TCN BPDU (64B with padding) |
PVST+ untagged TCN BPDU (64B with padding) |
PVST+ tagged TCN BPDU (68B with padding) |
|---|---|---|---|
| MAC SA | 6B | 6B | 6B |
| MAC DA | 0180C2.000000 (6B) | 030408.000700 (6B) | 030408.000700 ((6B) |
| Length | 2B | 2B | - |
| Type | - | - | 81 00 (2B) |
| 802.1q tag | - | - | 4B |
| SSAP | 42 03 | AA 03 | AA 03 |
| DSAP | 42 | AA | AA |
| Cisco OUI | - | 02 04 08 | 02 04 08 |
| PVST PID | - | 01 0B | 01 0B |
| LLC | 3B | 8B | 8B |
| SNAP | 4B | Entire BPDU with type = TCN 35B | Entire BPDU with type = TCN 35B |
| Header/field |
Standard IEEE STP TCN BPDU (64B padded) |
PVST untagged TCN BPDU (64B padded) |
PVST tagged TCN BPDU (68B padded) |
|---|---|---|---|
| MAC SA | 6B | 6B | 6B |
| MAC DA | 0180C2.000000 (6B) | 01000C.CCCCCD (6B) | 01000C.CCCCCD (6B) |
| Length | 2B | 2B | - |
| Type | - | - | 81 00 (2B) |
| 802.1q tag | - | - | 4B |
| SSAP | 42 03 | AA 03 | AA 03 |
| DSAP | 42 | AA | AA |
| Cisco OUI | - | 00 00 0C | 00 00 0C |
| PVST PID | - | 01 0B | 01 0B |
| LLC | 3B | 8B | 8B |
| SNAP | - | Yes | Yes |
| IEEE TCN BPDU INFO | 4B | Entire BPDU with type = TCN 35B | Entire BPDU with type = TCN 35B |