ZyXEL VES1724-56B2 User Guide - Page 210

Chapter 23 VLAN Stacking 23.3 VLAN Tag Format A VLAN tag (service provider VLAN stacking or customer IEEE 802.1Q) consists of the following three fields. Table 88 VLAN Tag Format TPID Priority VID TPID (Tag Protocol Identifier) is a standard Ethernet type code identifying the frame and indicates whether the frame carries IEEE 802.1Q tag information. The value of this field is 0x8100 as defined in IEEE 802.1Q. Other vendors may use a different value, such as 0x9100. Tunnel TPID is the VLAN stacking tag type the Switch adds to the outgoing frames sent through a Tunnel Port of the service provider's edge devices (1 and 2 in the VLAN stacking example figure). Priority refers to the IEEE 802.1p standard that allows the service provider to prioritize traffic based on the class of service (CoS) the customer has paid for. • On the Switch, configure priority level of inner IEEE 802.1Q tag in the Port Setup screen. • "0" is the lowest priority level and "7" is the highest. VID is the VLAN ID. SP VID is the VID for the second (service provider's) VLAN tag. 23.3.1 Frame Format The frame format for an untagged Ethernet frame, a single-tagged 802.1Q frame (customer) and a "double-tagged" 802.1Q frame (service provider) is shown next. Configure the fields as highlighted in the Switch VLAN Stacking screen. Table 89 Single and Double Tagged 802.11Q Frame Format DA SA Len/Etype Data FCS Untagged Ethernet frame DA SA TPID Priority VID Len/Etype Data FCS IEEE 802.1Q customer tagged frame DA SA Tunnel Priorit VID TPID Priority VID Len/Etype Data FCS Double-tagged TPID y frame Table 90 802.1Q Frame DA SA Tunnel TPID VID Destination Address Priority 802.1p Priority Source Address Len/Etype Length and type of Ethernet frame Tag Protocol IDentifier added on a tunnel port Data Frame data VLAN ID FCS Frame Check Sequence 210 VES1724-56 User's Guide