MRV Products
What is VPLS?
Virtual
Private LAN Services, or Layer-2 VPNs, provide customers with an extension of
their local network. The customer network does not see the provider
network at all, and acts as if the provider network does not exist. This
allows the customer's network administrator complete control over how the
network should run.
To accomplish this, a combination of
technologies is required, including Ethernet 802.1q VLANs, MPLS, redundancy
technology (via Rapid Spanning Tree), and Quality of Service capabilities, using
MRV's Ethernet Circuit technology.
The basic idea is to take the
customer's Ethernet packets, including VLAN information, and move these packets
seamlessly to other locations without affecting them. To do this, the
packets are encapsulated using MPLS technology, which provides tunnels through
the provider network, independent of the customer traffic. Of course, in
order to provide this service, the provider network must be highly resilient, so
advanced fault-tolerance protocols, such as Rapid Spanning Tree, are used to
ensure that the packets always get to their destinations. To combat
congestion, MRV provides a sophisticated Quality of Service engine using
Ethernet Circuit technology, together with MPLS traffic engineering
capabilities.
One key feature of VPLS is simplicity. Instead
of requiring customers to connect to an IP network, with the complexity of IP
routing protocols, they connect with raw Ethernet, which allows a wider range of
network architectures, protocols, and capabilities. All of this is
provisioned using standards-based Ethernet and MPLS.
Who Uses VPLS?
VPLS is a
new, revenue generating, service that can be provided cost-effectively to a vast
number of Enterprise customers. VPLS is especially effective in today's
soft economy, where profitability is key. Instead of cost-prohibitive
routers and IP-tunneling equipment, simple Ethernet switching gear may be used
to build the access and back-end networks, which allows higher bandwidth service
for a lower cost of deployment. With VPLS, both point-to-point and
multi-point solutions are available. Providers can also leverage
Class-of-Service (CoS) technology to provide priority services, for example, for
voice-over-IP.
Local, regional, and even national or worldwide
providers use VPLS to provide a seamless solution for their multi-location
customers. In many cases, Utility companies will provide a metropolitan
service to other local providers. In this case, VPLS is extremely useful
to allow the customers to build their networks independent of physical
location.
How is VPLS
Deployed?
VPLS technology makes extensive use of both IEEE 802.1q and
the Martini-drafts (draft-martini-l2circuit-trans-mpls-08.txt and
draft-martini-l2circuit-encap-mpls-04.txt) for packet encapsulation and
transport. At the ingress of the network, typically at the customer
premises, an Ethernet switch encapsulates the customer packets with 802.1q
VLANs, even if the customer already has a VLAN network. This process,
referred to as VMAN, places an additional VLAN tag on the packet, which
identifies it to the provider network as belonging to the particular
customer. Any original tag is left in place, and will be regenerated on
egress from the network.
In the core of the provider network, there
are two basic options. First, if there are only a few customers (less than
4,000), the VMAN tag may be used directly to generate the connection, without
further modification. However, to scale the network to many thousands, or
tens of thousands of customers, the core network may be configured to
encapsulate with MPLS technology, which places labels in the packets to identify
to whom they belong and how they should be forwarded around the core
network.
Regardless of the core network architecture, at the
network egress, the original packet is restored, including any VLAN tag that the
packet may have had. This architecture allows the customer's network to be
independent of the configuration of the provider's network, a critical component
of any Virtual Networking service.
With VPLS, both point-to-point,
and multi-point services may be offered. In the multi-point case, the
equipment provides the additional function of learning which stations are where
on the network so that frames may be forwarded to the appropriate
location.
Of course, the provider's network must be able to deliver
service guarantees, and handle all cases of congestion. MRV provides the
Ethernet Circuit technology to solve this problem. With Ethernet Circuits,
the provider may control the bandwidth of the connection down to very fine
granularity, with exceptional control over the packet rates. In addition,
the provider can offer priority services, such as voice-over-IP or other
high-priority applications, by using MPLS and Ethernet CoS
capabilities.
Finally, reliability is a key component of any
provider network, especially when mission-critical multi-site networks are
involved. MRV provides full capabilities of redundancies, including both
Rapid Spanning Tree and physical layer redundancy.
VPLS technology allows
providers to offer profitable business services, with a low cost-of-entry.
The service is also fully scalable, enabling profitable services to be delivered
to a few customers or to tens or hundreds of thousands of customers without any
network overhauls along the way.
VPLS Links
