Huawei quidway s7700 Configuration Manual page 687

Quidway S7700 Smart Routing Switch
Configuration Guide - VPN
The sub-interfaces can be dotlq sub-interfaces, QinQ sub-interfaces, VLAN mapping sub-
interfaces, or VLAN stacking sub-interfaces.
When XGE, GE, Ethernet, or Eth-Trunk interfaces are used as AC interfaces, the outer tags
carried in the packets sent from the AC to the PW are C tags (inserted by user devices, which
are meaningless to the SP) by default.
When sub-interfaces or VLANIF interfaces are used as AC interfaces, the outer tags carried in
the packets sent from the AC to the PW are S tags (inserted by SP devices, which are used to
differentiate user traffic) by default.
Processing Tags Carried in Packets by VPLS
The system process packets according to the AC interface type and PW encapsulation type.
The PW encapsulation types can be classified into Ethernet encapsulation and VLAN
encapsulation.
l
l
Table 7-1 Processing tags carried in packets from the AC by the PW
PW Encapsulation Type
VLAN encapsulation
Ethernet encapsulation
Issue 01 (2011-07-15)
NOTE
l By default, physical interfaces on the S7700 are Layer 2 interfaces. When using XGE, GE, Ethernet,
and Eth-Trunk interfaces on the S7700 as AC interfaces, you need to run the undo portswitch command
to switch Layer 2 interfaces to Layer 3 interfaces.
l When using Ethernet, GE, XGE, or Eth-Trunk interfaces as AC interfaces, ensure that these interfaces
do not contain any sub-interfaces.
l If a VLAN is configured with IGMP snooping or MLD snooping, the VLANIF interface of the VLAN
cannot be used as an AC interface. To bind the VLANIF interface to a VSI, delete the IGMP snooping
or MLD snooping configuration from the VLAN first.
l Do not configure VSI and VLAN mapping for the same VLAN on an interface; otherwise, either VSI
or VLAN mapping will take effect.
When VLANIF interfaces or sub-interfaces function as AC interfaces, the VLAN
encapsulation is adopted by default.
When Ethernet, GE, XGE, or Eth-Trunk interfaces function as AC interfaces, the Ethernet
encapsulation is adopted by default.
NOTE
When Dotlq or QinQ sub-interfaces function as AC interfaces, the Ethernet encapsulation cannot be used.
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Processing of the Tag
Do not process the S tag carried in a packet.
If an S tag is carried in a packet, delete the S
tag from the packet.
If no S tag is carried in a packet, do not
process the packet.
7 VPLS Configuration
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