IP over everything?

Service providers have a range of technological options but which, with their customers increasingly informed about the flexibility and other benefits of IP, are most attractive to users? Simon Marshall reports...

There's a classic black and white photograph of internet pioneer Vinton Cerf taken when the network was just several rudimentary computers and some cabling strewn around a couple of US campuses. He's wearing a T-shirt with the message 'IP Over Everything', an evangelical show of enthusiasm for the protocol behind almost all of today's network traffic.

He may have been even more prophetic than even he realised at the time. European service providers are currently caught in the grip of unprecedented belt-tightening that means, by and large, they are indeed looking at how they can transport IP traffic over everything. Or their existing Synchronous Digital Hierarchy (SDH) network, to be precise.

However IP traffic is transported – either over SDH or an IP overlay network - the aim is to provide a multiservice network capable of great things.

In practice, the former involves finding a method of utilising traditional SDH infrastructure to transport IP using time-honoured protocols such as ATM and Frame Relay. The aim is to save on the capital expenditure of building a dedicated IP network, the cost of which is testified to from the absence of native IP network players where once there were many hopeful start-ups.

Not that transporting IP over SDH is a straightforward proposition. SDH provides the reliability of circuit-switched pathways and resiliency should there be a fault but it is overly complex and not nearly as flexible as a native IP architecture when it comes to supporting Ethernet services, for example.

"There are many advantages inherent in native IP networks, notably, that capacity can be used much more efficiently because complex SDH layers are stripped out," explains Eirwen Nichols, analyst at UK firm Ovum. "But service providers have the usual problem of migrating from one approach to another, and they already have SDH."

Ethernet services will offer enterprises the ability to simply plug into a relatively inexpensive Ethernet port for simplified metropolitan networking with the added bonus of almost instantly upgradeable IP bandwidth by the megabit.

"The advantage for the enterprise is that it can have 100 megabits on our network for the price of 34 megabits on an SDH network," says Paul Momtahan, Ethernet product managing director at UK-based Neos Networks. The service provider uses Ethernet to transport IP traffic over optical wavelengths, coupled with Multiprotocol Label Switching (MPLS), which it claims guarantees the timely delivery of the packets.

"The advantage for us is price performance, because there are fewer layers of equipment in our network compared to SDH, which makes our price per Ethernet port lower than for a port over SDH," says Momtahan. "We can offer more bandwidth for less money because our operating expenditures are lower," he adds, getting at the crux of most service provider's concerns.

Neos exemplifies the next generation approach to transporting IP – while offering enterprise benefits – where service providers such as Pangea and KPNQwest failed so visibly due to funding problems. Neos was acquired by Scottish and Southern Energy in April, staving off any similar concerns about its business. It claims about 100 customers across several verticals but that's not to say it's going to have things its own way – far from it.

The big UK service providers, notably BT and Cable & Wireless, still hold the bulk of the IP market and are working towards increasingly innovative use of their existing SDH assets.

Here, the benefits to the enterprise are often talked of in terms of wider coverage, higher fault resiliency and ultimately more potential uptime. These guys have plentiful SDH at their disposal and capex is relatively low having not encountered sizeable IP build-out cost. Now, they're concentrating on tailoring their infrastructure for the enterprise.

"We've already launched our IP VPN QoS network and that is connected using SDH infrastructure but uses Cisco Systems core routing technology," says Rob Thomas, product marketing director at C&W. In essence, C&W's SDH assets are being used to connect up IP routers and then customer site traffic is fed in over traditional leased lines. This hybrid approach will become more common as service providers try to answer enterprise IP transport demands by adapting what they already have.

Granted, this sort of approach is unlikely to offer the same rapid basic service provisioning and bandwidth upgrade times as the sort of service Neos Networks offers. But it may well provide the basis for the mythical multiservice network, where enterprises will be able to access any number of services simply and quickly.

"A multiservice [network] is very much a service aspiration," says Thomas. "In the UK and Europe, we've already been building out multiservice points of presence. In each location, we have an IP VPN router, SDH optical equipment and a Frame Relay node."

Of course, if every service provider manages to reuse their SDH this way, it ceases to be a differentiator to enterprise customers. Ovum's Nichols reckons it's therefore only a matter of time before service providers have to accept that a native IP network offers lower ongoing opex than SDH.

"There's a lot of price competition out there, so there will have to be a move to IP sometime soon," she says. "Because Level 3, for example, can successfully argue that its network is less expensive to operate than one based purely on SDH."

All of which leaves enterprises in line for more service choice, as multiservice nodes go live, and in a longer-term IP future, more flexibility and lower prices. We hope.

Go to www.silicon.com/ip for more on IP.