Huawei Quidway S9300

Control Plane and Data Plane
The control plane of a VPLS PE provides the following functions:
l Member discovery: indicates the process of finding all the PEs in the same VPLS. This can
be implemented through manual configurations or the automatic discovery function of
protocols. The latter is called automatic discovery.
l Signaling mechanism: PWs between PEs in the same VPLS are established, maintained,
and torn down by using signaling protocols.
The data plane of a VPLS PE has the following functions:
l Encapsulation: After receiving Ethernet frames from a CE, a PE encapsulates the frames
before sending them to a PSN.
l Forwarding: Packets are forwarded according to the interfaces through which the packets
are received and the destination MAC addresses of the packets.
l Decapsulation: After a PE receives an Ethernet frame from a PSN, the PE decapsulates the
frame and then delivers it to a CE.
The S9300 supports the implementation of the VPLS functions on the control plane through
BGP or LDP, which are called Kompella VPLS and Martini VPLS respectively.
l Kompella VPLS: adopts BGP as signaling. Automatic discovery of VPLS members is
implemented by configuring VPN targets. The operation of adding or deleting a PE is
simple. Kompella VPLS thus has better extensibility.
l Martini VPLS: adopts LDP as signaling. Peers of PEs must be manually specified because
the PEs are fully meshed in a VPLS network. When adding a PE, you must modify the
configuration on all the related PEs. The Martini VPLS thus has poor extensibility. A PW
is actually a point-to-point (P2P) link. Thus, using LDP to create, maintain, and delete the
PW is more effective.
MAC Address Learning
An Ethernet network sends broadcast packets, multicast packets, and unicast packets with
unknown destination MAC addresses to all the other interfaces on the same Ethernet segment.
In VPLS, a PSN stimulates a bridge device and PEs perform MAC address learning. To forward
packets, a PE must be able to associate destination MAC addresses with related PWs. A PE
learns the remote MAC address through a PW and learns the directly connected MAC address
through an AC.
The modes of MAC address learning are as follows:
l Qualified: A PE learns MAC addresses according to MAC addresses and VLAN tags
contained in Ethernet frames sent by users. That is, the learning is based on every VLAN
of every VSI. In this mode, each user VLAN has its own broadcast domain and independent
MAC address space.
l Unqualified: A PE learns MAC addresses only according to MAC addresses contained in
Ethernet frames sent by users. That is, the learning is based on every VSI. In this mode, all
the user VLANs share the same broadcast domain and MAC address space. The MAC
address of each user VLAN must be unique.
If a PE receives broadcast traffic from a local user, the PE forwards it to all the other interfaces
and to all the other PEs in the same VPLS network.
6 VPLS Configuration
Quidway S9300 Terabit Routing Switch
Configuration Guide - VPN
6-4 Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Issue 03 (2009-08-20)