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Riverstone gets serious about VPNs

Riverstone is getting serious about virtual private networks.

Riverstone has rolled out line cards to support Layer 2 MPLS virtual private networks (VPNs) running over Sonet networks, expanding its ability to support a service that is gaining ground on both legacy and Ethernet networks. In light of the guiding principle in the company's strategy -- staying one step ahead of Cisco -- IP VPN capabilities are sure to follow.


Riverstone has been shipping line cards for multiprotocol label switched (MPLS) VPNs over Ethernet for several months, but with the introduction of the packet-over-Sonet (POS) card, it can support Layer 2 VPNs on both Ethernet and Sonet.

With incumbent carriers holding off on large-scale Ethernet network deployments, Riverstone has been compelled to find other ways to pump up its revenue. Last month, the company unveiled plans to integrate line cards with Cisco's flavor of resilient packet ring technology to go after cable providers, next-generation wireless carriers and interexchange carriers looking for simpler ways to provide transit circuits. In broad terms, its VPN strategy is similar. Riverstone gear will be cheaper than that of Cisco, since it integrates Layer 2 and Layer 3 functionality into a single box. Cisco is already going after Riverstone, so there's little risk in being explicit about its intention of taking on the networking equipment giant.


The competitive landscape is likely to shift once Juniper's acquisition of Unisphere closes, as both companies have made inroads. Riverstone's attention, however, is clearly focused on Cisco, which it sees as its primary rival for the metro router market. Riverstone maintains it has an architectural advantage over Cisco -- its boxes integrate Layer 2 Ethernet transport and Layer 3 routing protocols with MPLS capabilities -- but Cisco is not easily displaced.


MPLS has caught on for VPNs because the technology is far less cumbersome than the widely used VLAN tagging. MPLS creates tunnels with a software overlay that sets up label-switched paths across network, creating a virtual closed network. VLAN tagging is far more complicated and creates management headaches for telcos, which have to set up and maintain the networks manually. Riverstone will use the Martini draft for the tunneling feature. The company has been one of the early proponents of the technology, and has several deployments in Asia.

IP VPNs create networks between Internet routers and typically use IPSec to create a security overlay across the network. Riverstone reckons that it can integrate the Layer 2 transport protocols through MPLS with the IP functionality and routing protocols on a single box.

MPLS relies on encapsulation -- basically wrapping the packet in a header -- so the overarching technology is the same whether the packet is in the Ethernet or the Sonet protocol. However, the traffic still has to be mapped to the underlying protocol, and so in the case of its Sonet line card, Riverstone has integrated a field programmable gate array onto a Sonet blade to perform the mapping.

Most vendors in the space -- Cisco, Unisphere and Juniper -- have already implemented MPLS VPNs on Ethernet and haven't been definite about their plans to add Sonet capabilities. Riverstone argues that integrating both on the same box allows the customer interface to be MPLS-over-Ethernet and the interface to the metro core MPLS-over-Sonet.


Ethernet MPLS-based VPNs are good for connecting disparate LANs, but Riverstone believes Sonet-based VPNs expand the technology's capabilities to metro and even regional VPNs. Since MPLS-based VPNs are far easier to manage and set up than the VLANs -- their technological predecessors -- the company is betting that their use will eventually become ubiquitous. For instance, VPNs from enterprises to datacenters or storage facilities, or from customers to large vendors will become more common, the company argues.

Some have criticized MPLS tunneling as lacking the ability to scale, since the label-switched paths have to be maintained in a central database. But in comparison to VLANs, the technology constitutes a leap in network management. Despite the skepticism, momentum is slowly building for MPLS, if a plethora of MPLS interoperability and demos planned for SuperComm is any indication.

Since Riverstone was one of the first companies to 'productize' the Martini draft of the protocol, the company wants to differentiate itself now that the market has become crowded. The Sonet line card will be of interest to some carriers, but the integration of Layer 3 IP VPN capabilities with its existing MPLS VPN capabilities will be a shot across the bows of Cisco.

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