This topic explains how IEEE 802.1D defines and manages multicast addresses for Spanning Tree protocols, including address handling and forwarding behavior on switches depending on the spanning-tree state.
Spanning Tree address management explains how switches handle specific multicast addresses, as defined by IEEE 802.1D, based on their Spanning Tree state.
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IEEE 802.1D specifies 17 static multicast addresses (0x0180C2000000 to 0x0180C2000010) for bridge protocols.
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These addresses are static and cannot be removed from the switch configuration.
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Switches receive packets destined for addresses between 0x0180C2000000 and 0x0180C200000F, but do not forward them, regardless of Spanning Tree state.
Spanning Tree address handling and forwarding behavior
Spanning Tree address management determines how your switch forwards and receives packets, depending on whether spanning tree is enabled or disabled.
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If Spanning Tree is enabled, the CPU on your switch (or each switch in the stack) receives packets destined for 0x0180C2000000 and 0x0180C2000010.
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If Spanning Tree is disabled, your switch (or each switch in the stack) forwards those packets as unknown multicast addresses.