+
+/*
+ * PIDs for use with OUI_CISCO.
+ */
+#define PID_CISCO_CDP 0x2000 /* Cisco Discovery Protocol */
+#define PID_CISCO_VTP 0x2003 /* Cisco VLAN Trunk Protocol */
+#define PID_CISCO_DTP 0x2004 /* Cisco Dynamic Trunk Protocol */
+#define PID_CISCO_UDLD 0x0111 /* Unidirectional Link Detection */
+#define PID_CISCO_PVST 0x010b /* Per VLAN Spanning Tree+ and RPVST+ */
+#define PID_CISCO_VLANBRIDGE 0x010c /* "VLAN Bridge", according to Wireshark */
+
+/*
+ * PIDs for use with OUI_RFC2684.
+ */
+#define PID_RFC2684_ETH_FCS 0x0001 /* Ethernet, with FCS */
+#define PID_RFC2684_ETH_NOFCS 0x0007 /* Ethernet, without FCS */
+#define PID_RFC2684_802_4_FCS 0x0002 /* 802.4, with FCS */
+#define PID_RFC2684_802_4_NOFCS 0x0008 /* 802.4, without FCS */
+#define PID_RFC2684_802_5_FCS 0x0003 /* 802.5, with FCS */
+#define PID_RFC2684_802_5_NOFCS 0x0009 /* 802.5, without FCS */
+#define PID_RFC2684_FDDI_FCS 0x0004 /* FDDI, with FCS */
+#define PID_RFC2684_FDDI_NOFCS 0x000a /* FDDI, without FCS */
+#define PID_RFC2684_802_6_FCS 0x0005 /* 802.6, with FCS */
+#define PID_RFC2684_802_6_NOFCS 0x000b /* 802.6, without FCS */
+#define PID_RFC2684_BPDU 0x000e /* BPDUs */