Control Plane and Data Plane
The control plane of the VPLS PE has the following functions:
l
Member discovery: To find all the other PEs in the same VPLS, implement it by manually
configuring or by automatically running certain protocols. Automatically running the
protocols is called "automatic discovery".
l
Signaling mechanism: The signaling protocol establishes, maintains and removes the PW
between the PEs in the same VPLS.
The data plane of the VPLS PE has the following functions:
l
Encapsulation: After receiving Ethernet frames from a CE, a PE sends them to the PSN
after encapsulation.
l
Forwarding: After receiving Ethernet frames, a PE forwards the frames according to the
inbound interface and the destination MAC address of the frames.
l
Decapsulation: After receiving Ethernet frames from a packet switched network, a PE
decapsulates the frames, and then forwards the frames to CEs.
The S7700 supports the implementation of the VPLS functions of the control plane in the BGP
or the LDP signaling mode:
l
Kompella VPLS: adopts BGP as signaling. Automatic member discovery of VPLS is
implemented by configuring VPN targets. If you want to add or delete a PE, only the
operations on one of its peer PEs are needed. Kompella VPLS has better expansibility.
l
Martini VPLS: adopts LDP as signaling. The PE peer must be manually specified because
the PEs are fully connected in a VPLS. When adding a new PE, you must modify the
configuration on all the related PEs. Since PW is a point-to-point link, the LDP mode
establishes, maintains and removes the PWs more effectively.
Flooding
The Ethernet broadcasts the packets with unknown addresses. Therefore, in VPLS, the received
packets with unknown unicast addresses, broadcast addresses, or multicast addresses are flooded
to all the other ports. If multicast needs to be used, PEs need to adopt other methods such as
Internet Group Management Protocol (IGMP) snooping and Protocol Independent Multicast
(PIM) snooping.
Access Mode
On the S7700, the PE supports the following AC interfaces:
l
XGE interfaces
l
XGE sub-interfaces
l
GE interfaces
l
GE sub-interfaces
l
Ethernet interfaces
l
Ethernet sub-interfaces
l
Eth-Trunk interfaces
l
Eth-Trunk sub-interfaces
l
VLANIF interfaces
Quidway S7700 Smart Routing Switch
Configuration Guide - VPN
7 VPLS Configuration
Issue 01 (2011-07-15)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
671
