Packet structure for Ethernet frames with a Broadcom switch tag inserted

+--------------------------------+
| Broadcom switch tag (4 octets) |
+--------------------------------+
| Destination Address (6 octets) |
+--------------------------------+
|    Source Address (6 octets)   |
+--------------------------------+
|     Type/Length (2 octets)     |
+--------------------------------+
|            Payload             |
.                                .
.                                .
.                                .

Description

A Broadcom switch tag is prepended before the Ethernet header.