User guide

September 2009
Page 14 of 79 OmniSwitch 6400/6850/6855/9000/9000E—Release 6.4.2.R01
Paths (LSPs), also referred to as MPLS tunnels. These tunnels provide the foundation necessary to
provision VPLS.
MPLS Software Licensing Requirement. The MPLS feature, including the VPLS application,
requires the purchase of an Alcatel-Lucent software license. The licenses are available through the
Alcatel-Lucent Software License portal.
VPLS Support
A Virtual Private LAN Service (VPLS) is a Virtual Private Network (VPN) technology that allows
any-to-any (multipoint) connectivity. The provider network emulates a LAN by connecting all the
remote customer sites at the edge of the provider network to a single bridged LAN. A full mesh of
pseudo-wires (PW) is established to form a VPLS.
A VPLS-capable network consists of Customer Edges (CE), Provider Edges (PE), and a core MPLS
network. The IP/MPLS core network interconnects the PEs but does not participate in the VPN
functionality. Traffic is simply switched based on the MPLS labels.
This implementation of VPLS makes use of a service-based architecture that provides the following
logical entities that are required to provision a service:
• Customers (subscribers). An account is created for each customer and assigned an ID. The
customer ID is required and associated with the service at the time the service is created.
• Service Access Points (SAPs). Each subscriber service type is configured with at least one
SAP. A SAP identifies the point at which customer traffic enters the service.
• Service Distribution Points (SDPs). A SDP provides a logical point at which customer
traffic is directed from one PE to another PE through a one-way service tunnel.
MPLS Static Fast Re-Route
MPLS forwarding is performed by routers called Label Switching Routers (LSRs). A Label Switched
Path (LSP) is a path through one or more LSRs.
There are two types of LSPs that are configurable using MPLS:
• Static LSPs. A Static LSP specifies a statically defined path of LSRs. Configuration of label
mappings and MPLS actions is required on each router that will participate in the static path.
No signaling protocol, such as the Label Distribution Protocol (LDP), is required, and there is
no dependence on a gateway protocol topology or local forwarding table. Static LSPs are able
to cross an Autonomous System (AS) boundary.
• Signaled LSP. The LSPs are set up using a signaling protocol, such as LDP. The signaling
protocol allows the automatic assignment of labels from an ingress router to the egress router.
Signaling is triggered by the ingress router, therefore configuration is only required on this
router. A signaled LSP is confined to one gateway protocol area and, therefore, cannot cross
an AS boundary.
In addition to static LSPs, a static Fast Reroute (FRR) feature is available that allows the configuration
of backup static LSP tunnels. FRR uses these backup tunnels to provide alternate routes in the event an
LSP goes down.