Administrator Guide

Dell(conf-if-te-0/1)#vlan-stack trunk
Dell(conf-if-te-0/1)#show config
!
interface TenGigabitEthernet 0/1
no ip address
portmode hybrid
switchport
vlan-stack trunk
shutdown
Dell(conf-if-te-0/1)#interface vlan 100
Dell(conf-if-vl-100)#untagged tengigabitethernet 0/1
Dell(conf-if-vl-100)#interface vlan 101
Dell(conf-if-vl-101)#tagged tengigabitethernet 0/1
Dell(conf-if-vl-101)#interface vlan 103
Dell(conf-if-vl-103)#vlan-stack compatible
Dell(conf-if-vl-103-stack)#member tengigabitethernet 0/1
Dell(conf-if-vl-103-stack)#do show vlan
Codes: * - Default VLAN, G - GVRP VLANs
Q: U - Untagged, T - Tagged
x - Dot1x untagged, X - Dot1x tagged
G - GVRP tagged, M - Vlan-stack
NUM Status Description Q Ports
* 1 Inactive
100 Inactive U Te 0/1
101 Inactive T Te 0/1
103 Inactive M Te 0/1
Debugging VLAN Stacking
To debug VLAN stacking, use the following command.
● Debug the internal state and membership of a VLAN and its ports.
debug member
The port notations are as follows:
● MT — stacked trunk
● MU — stacked access port
● T — 802.1Q trunk port
● U — 802.1Q access port
● NU — Native VLAN (untagged)
Dell# debug member vlan 603
vlan id : 603
ports : Te 1/47 (MT), Te 2/1(MU), Te 2/25(MT), Te 2/26(MT), Te 2/27(MU)
Dell#debug member port tengigabitethernet 1/47
vlan id : 603 (MT), 100(T), 101(NU)
VLAN Stacking in Multi-Vendor Networks
The first field in the VLAN tag is the tag protocol identifier (TPID), which is 2 bytes. In a VLAN-stacking network, after the
frame is double tagged, the outer tag TPID must match the TPID of the next-hop system.
While 802.1Q requires that the inner tag TPID is 0x8100, it does not require a specific value for the outer tag TPID. Systems may
use any 2-byte value. The switch uses 0x9100 (shown in the following) while non-Dell Networking devices might use a different
value.
If the next-hop system’s TPID does not match the outer-tag TPID of the incoming frame, the system drops the frame. For
example, as shown in the following, the frame originating from Building A is tagged VLAN RED, and then double-tagged VLAN
PURPLE on egress at R4. The TPID on the outer tag is 0x9100. R2’s TPID must also be 0x9100, and it is, so R2 forwards the
frame.
Given the matching-TPID requirement, there are limitations when you employ Dell Networking systems at network edges, at
which, frames are either double tagged on ingress (R4) or the outer tag is removed on egress (R3).
Service Provider Bridging
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