Chapter 21 VLAN Stacking
GS3700/XGS3700 Series User’s Guide
171
Figure 106
VLAN Stacking Example
21.2 VLAN Stacking Port Roles
Each port can have three VLAN stacking “roles”, Normal, Access Port and Tunnel Port (the latter
is for Gigabit ports only).
• Select Normal for “regular” (non-VLAN stacking) IEEE 802.1Q frame switching.
• Select Access Port for ingress ports on the service provider's edge devices (1 and 2 in the VLAN
stacking example figure). The incoming frame is treated as "untagged", so a second VLAN tag
(outer VLAN tag) can be added.
Note: Static VLAN Tx Tagging MUST be disabled on a port where you choose Normal or
Access Port.
• Select Tunnel Port (available for Gigabit ports only) for egress ports at the edge of the service
provider's network. All VLANs belonging to a customer can be aggregated into a single service
provider's VLAN (using the outer VLAN tag defined by the Service Provider’s (SP) VLAN ID
(VID)).
Note: Static VLAN Tx Tagging MUST be enabled on a port where you choose Tunnel
Port.
21.3 VLAN Tag Format
A VLAN tag (service provider VLAN stacking or customer IEEE 802.1Q) consists of the following
three fields.
Table 77
VLAN Tag Format
Type
Priority
VID