The public network is getting interesting again. In the early '90s, the buzz was about the Internet's rise and the advent of frame relay. Today, it's about PBT, T-MPLS and next-generation networks, such as Verizon's FiOS and BT's 21CN.
Wade through all the acronyms, and it becomes clear that carriers and network equipment providers are focusing on injecting more intelligence into public networks. That is making them more reliable and responsive, as well as capable of handling a variety of business-critical applications. On tap are managed services for security, storage, collaboration, disaster recovery and other business essentials.
It comes down to this: "If carriers have a simpler, more flexible and more manageable network infrastructure, then enterprises get a better quality of service because it is deliverable," Distributed Networking Associates president, Steve Taylor, said.
Debating MPLS versus PBT
This carrier overhaul is a direct result of the recent focus on IP. This WAN technology is far more unwieldy than older ones, such as ATM or frame relay, which were more point-to-point in nature and easier to manage at the carrier level. "If you don't know where the traffic is, you can't guarantee it, and therein lies the problem with IP," president of technology assessment firm CIMI, Thomas Nolle, said. "The adaptive behaviour of IP tends to destroy control over just where the traffic is going in the network."
This uncertainty means carriers have been struggling to provide the requisite QoS and uptime assurances for a range of emerging IP business applications. In a frame relay environment, carriers may have been able to guarantee five-nines of uptime per 24 hours, but they cannot get close to that level for today's VPNs. Sometimes those service-level agreements (SLA) guarantee five-nines over a month instead of 24 hours. "An IP service just doesn't have the meticulously orderly behaviour that a frame relay service does," Nolle said.
That's why carriers are pursuing more deterministic IP-transport mechanisms, such as Transport Multi-protocol Label Switching (T-MPLS) and the new Provider Backbone Transport (PBT), also called Provider Backbone Bridging-Traffi c Engineering (PBB-TE). Both technologies support multi-protocol packet transport and scale globally, key requirements for next-generation networks.
For now, carriers and equipment makers are hedging their bets. BT, for example, has been fairly public in its support for Nortel's PBT gear, announcing it is purchasing the vendor's 8600 Metro Ethernet Switch and 1850 Metro Ethernet Services Unit for use in its next-generation 21st-Century Network (21CN) program. However, the carrier is also highly supportive of MPLS as a managed-services-enabler in the WAN. "We're looking at PBT, but there's nothing that we see in there that we cannot deliver through our MPLS network today," vice-president of IT transformation at BT, Stefan Van Overtveldt, said.
The T-MPLS-or-PBT decision clearly means more to the carriers than their customers. "The argument behind PBT is it gives carriers a lower cost of ownership and management, so in theory, they can pass along that savings to customers. Obviously, there's an advantage to that, but enterprises can get the same services no matter which technology is used," Nemertes Research president, Johna Till Johnson, said.
The commonality between these competing technologies is that they make it easier for carriers to manage their next-generation networks. And with easier management comes the ability to concentrate on supporting higher-level emerging IP services. While converging their voice, data, video and wireless infrastructures, carriers hope to provide enterprise users with the same level of service and quality of experience, no matter where they are located or what device they are using. "Service providers will be able to personalise and manage individual sessions and applications differently, while at the same time guaranteeing SLAs to the enterprise," Redback Networks vice-president, Arpit Joshipura, said.
Redback provides multi-protocol routers for several next-generation carrier networks.
He uses the example of an ad hoc videoconference: "A year from now, when these networks migrate, we will be able to videoconference through our PCs with built-in cameras and microphones via a secure IP VPN on the fly. The carriers will give us a secure videoconference with high-definition-equivalent bandwidth on the click of a button. That's what things are moving toward."
Another example is BT's Corporate Fusion offering, available in Europe now and in the US by year-end. Companies with the service issue each employee a dual-mode mobile or VoIP phone that works over regular mobile and Wi-Fi networks.
Corporate Fusion determines which type of service is available and the least expensive at the time the employee makes a call.
"If you're home, you make the call over your broadband DSL or cable modem line, and if you're in the office, you call over the Wi-Fi that's connected into your PBX that then goes out into the public telephone system," BT's Van Overtveldt said. "It's a much cheaper way of communicating, and it comes with the additional plus of only one contact list, so there's no need to look up a number on a mobile phone and dial it from a regular phone." Future carrier networks will also supposedly handle many applications that today are managed at the enterprise level such as security, single contact and calendar, storage and disaster recovery.
"Managed security services for things like DDoS [viruses and spam] make sense, and another example is storage applications," Nemertes' Johnson said. "I don't see any good way you can get very high-speed, very distributed storage without involving the network, so the carriers have a play there, too. I can see enterprises migrating that way."
Next-generation carrier networks could also handle disaster recovery and server virtualisation services.
More public than private
Enterprise networks of the future will increasingly rely on key services provided by the carriers and their public infrastructures as these next-generation networks mature.
"It's really a continuum of what functions are delivered by the carrier network and what functions are delivered at the enterprise - where is that demarcation point?" Taylor said.
"We started building private data networks 20 years ago, not because it was absolutely the best idea in the world but because it was the only way you could get the services you needed. The service providers were dragging their feet too much.
"Now, with these next-gen networks, the service providers should be able to lead the way," he said. "The opportunity is theirs to lose."