Quality the key to Ethernet service

Craig Stephens, head of Tellabs in Australia, discusses how service providers can evolve their networks while ensuring that customers need not compromise on the service guarantees they have grown to expect.

Migration to internet protocol (IP) and ethernet services is almost universally acknowledged by service providers as the future of business. There are a few hitches, however. Customers must not be asked to make radical changes on their service provider's timetable -- overnight replacement of reliable legacy equipment is not an option. Nor will many give up the mission-critical data and communications delivery guarantees they currently enjoy. Ethernet access technology must rise to these challenges.

No matter how low the price, sacrificing quality would wind up costing the customer more. Imagine an accountant offering a graduated pricing structure: a gold service with a 3% error guarantee or a cut-price service with a 15% error guarantee, both with limited liability should an audit ensue. Even the gold service, no matter how fast or convenient, would make compliance-sensitive customers nervous.

Telecommunications customers who are used to guaranteed quality with TDM, frame relay and ATM services could face a similar choice as service providers rush to deploy fast, lower-costed IP/Ethernet services.

Class vs quality

Standard ethernet's shortcomings are well known. Even with the aid of IP/multi-protocol label switching (MPLS) capabilities, ethernet offers quality controls only in terms of service classes. This approach ensures one train car will arrive sooner than another, but not that each passenger will arrive at the time promised.

Ethernet equipment should employ more than mechanisms to prioritise applications or users into class of service queues, like the kind of per-session QoS offered by ATM's constant bit-rate or constant information rate offered via frame relay.

Ultimately, the test of ethernet service will be its ability to enable SLAs incorporating guarantees based on granular, per-session latency, jitter and packet loss metrics. The expectations benchmark is the standard already achieved by legacy ATM.

Service providers should recognise that any ethernet solution that does not incorporate deterministic QoS capabilities will hit a wall in satisfying demanding enterprise customers.

Access interworking: leveraging legacy QoS

Rare will be the enterprise customer willing to throw out functioning frame relay, ATM or TDM gear to meet their provider's timetable for change. Customers must be able to leverage the QoS of their legacy solutions while introducing ethernet on a phased basis, such as for new business locations.

Heightened industry consolidation means many large enterprises end up with mixed ATM, TDM, frame relay or ethernet network access. These customers have an immediate and long-term need for seamless, multi-service networking from any site to any other, regardless of access protocol.

Customers who are empowered to introduce ethernet on their own terms and are not asked to compromise on mission-critical QoS guarantees are more likely to remain customers.

Ultimately, the test of ethernet service will be its ability to enable SLAs incorporating guarantees based on granular, per-session latency, jitter and packet loss metrics.

About the author: Craig Stephens is the Australian head of operations for telecoms equipment vendor Tellabs. Stephens has more than 25 years' experience in the Australian ICT industry, in sales, marketing and management roles. He has been with Tellabs since its direct entry to the Australian market in 2004.

This story originally appeared in Voice & Data magazine

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