Dell Force10 E300, Configuration Manual, Page: 952 / 1262

952 | Service Provider Bridging
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In at the access point of a VLAN-stacking network, service providers add a VLAN tag, the S-Tag, to each
frame before the 802.1Q tag. From this point, the frame is double-tagged. The service provider uses the
S-Tag, to forward the frame traffic across its network. At the egress edge, the provider removes the S-Tag,
so that the customer receives the frame in its original condition (
Figure 46-1 ).
Figure 46-1. VLAN Stacking in a Service Provider Network
Important Points to Remember
• Interfaces that are members of the Default VLAN and are configured as VLAN-Stack access or trunk
ports do not switch untagged traffic. To switch traffic, these interfaces must be added to a non-default
VLAN-Stack-enabled VLAN.
• Dell Force10 cautions against using the same MAC address on different customer VLANs, on the
same VLAN-Stack VLAN.
• You can ping across a trunk port only if both systems on the link are an E-Series. You cannot ping
across the link if one or both of the systems is a C-Series or S-Series.
• This limitation becomes relevant if you enable the port as a multi-purpose port (carrying single-tagged
and double-tagged traffic).
VLAN 300
VLA
N
10
0
IN
TE
RN
ET SERV
R R ICE PRO
VID
ER
w
R / VL
AN STA
T T CKIN
G
VL
AN
200
VLAN
100
VLAN 100
V
LA
N
100
tagged 100
tagged 100
TPID
(0x8100)
PCP CFI
(0) VID
(VLAN
Red )
TPID
(0x9100)
PCP DEI VID
(VLAN
300 )
access port
trunk port