How Much Ethernet OAM is Appropriate?

Michael Ritter
City scene

Another year, another Light Reading Ethernet Expo Americas. This show is the premier event covering the hot topic of Carrier Ethernet network technologies and services in the Americas. It was a must-attend Carrier Ethernet networking event also this year, where dozens of experts from the service provider, supplier and analyst community met in New York City.

The two-day event saw a series of informative presentations and panel discussions. Not so much on technology evolution and innovation anymore. Much more focused on how Carrier Ethernet is used and will be used in future networks. And a lot of discussions exploring how Carrier Ethernet will enable new applications including cloud services and how these applications will influence Carrier Ethernet equipment. One of the interesting debates was centered around OAM tools and their usage in today’s telecom networks. A multitude of tools for offering service level agreements across networks have been defined by the standard bodies and are broadly available in Carrier Ethernet solutions today. But how many are practically used in the networks and why?

First and foremost, it depends on the application. While providers of business services typically activate more Ethernet OAM to provide service differentiation and assure service level agreements to their customers, wholesalers tend to limit OAM usage to achieve operational simplicity, versatility and service scalability. Mobile backhaul service providers, in contrast, make heavy use of OAM tools to fulfill the strict performance requirements requested by mobile operators. The lack of service OAM with wholesale products in general is one of the challenges global and alternative service providers face when connecting their customers to their network in off-net locations.

There are quite a few Ethernet service providers, however, who started to turn on more OAM for their services. A general trend: Evolving from basic offerings to services including rich OAM. In addition to simplifying installation and troubleshooting, we see commercial Ethernet services offering performance reporting via customer portals. And some of them even offer it on a virtual circuit and class of service level. Some of the providers mentioned that it is better to monitor and report performance before customers start doing it – much less room for debate.

But there is more to come. Fault indication and signaling based on service performance starts to get introduced in production networks. Lots of open questions here: How to signal service degradation, vendor-specific interpretations and how to define the right threshold values for switching to an alternate path, due to increased loss rate or delay. There is a question of quality of service versus quality of experience. Assurance and performance measurement of timing and synchronization services delivered by access and backhaul operators is another open question.

The biggest challenge is seen, however, in the implementation complexity of powerful OAM tools. The more tools you activate and the more information you signal and expose to your customer, the more complex the service definition becomes. And the administrative effort for commissioning and maintenance increases rapidly. This requires powerful network and service management tools taking this burden away from the operator by automation. This is a new direction where we expect to see a lot of innovation at the next premier Carrier Ethernet event.

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