ZyXEL Communications XGS2220 Series, Руководство пользователя

Страница: 399 / 655

Chapter 59 VLAN Stacking
XGS2220 Series User’s Guide
399
Type is a standard Ethernet type code identifying the frame and indicates that whether the frame
carries IEEE 802.1Q tag information. SP TPID (Service Provider Tag Protocol Identifier) is the service
provider VLAN stacking tag type. Many vendors use 0x8100 or 0x9100.
TPID (Tag Protocol Identifier) is the customer IEEE 802.1Q tag.
• If the VLAN stacking port role is Access port, then the Switch adds the SP TPID tag to all incoming
frames on the service provider's edge devices (1 and 2 in the VLAN stacking example figure).
• If the VLAN stacking port role is Tunnel port, then the Switch only adds the SP TPID tag to all incoming
frames on the service provider's edge devices (1 and 2 in the VLAN stacking example figure) that
have an SP TPID different to the one configured on the Switch. (If an incoming frame’s SP TPID is the
same as the one configured on the Switch, then the Switch will not add the tag.)
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 the inner IEEE 802.1Q tag in the PORT > Port Setup screen.
• "0" is the lowest priority level and "7" is the highest.
VID is the VLAN ID. SPVID is the VID for the second (service provider’s) VLAN tag.
59.3.1 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 SWITCHING > VLAN Stacking screens.
59.4 Configuring VLAN Stacking
Click SWITCHING > VLAN Stacking to display the screen as shown.
Table 220 Single and Double Tagged 802.1Q 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 SPTPID Priority VID TPID Priority VID Len/Etype Data FCS Double-tagged
frame
Table 221 802.1Q Frame
DA Destination Address Priority 802.1p Priority
SA Source Address Len/Etype Length and type of Ethernet frame
(SP)TPID (Service Provider) Tag Protocol IDentifier Data Frame data
VID VLAN ID FCS Frame Check Sequence