Carrier Ethernet Support of Multi-CoS is Here!

03/01/2012 |

Christopher Cullan

By Christopher Cullan, Product Marketing Manager, Business Services Solutions, InfoVista

As a card-carrying member of the Metro Ethernet Forum (MEF), I truly believe and support the organization’s goals and many of its deliverables. In my university days, I wrote a paper comparing LAN technologies: token-ring to Ethernet. You can imagine how long ago that may have been, especially with the technical conclusion of the token-ring’s superiority (yes, I was later working for IBM). But, one item I recall stating in that paper was the ‘holy’-trinity of Ethernet’s success—ubiquity, the UNIX tie-in and simplicity.

Fast-forward to 2012, one can see the Carrier Ethernet environment getting more and more complex, with a myriad of technologies, vendors and standards. The question is: how does one manage such complexity while ensuring that market problems are addressed? Never mind multiple classes of service (Multi-CoS)—what about dynamically provisioned and configured networks to support the cloud? Perhaps this will be assisted by Carrier Ethernet 2.0 launched last week.

Regardless of all the different service types and implementation agreements, the vast majority of services I’ve seen deployed are P2P E-Lines (EPL or EVPL), often the building blocks of more complex services. This is certainly the case in Ethernet mobile backhaul today- given its architecture and, in most cases, its simple-port based connections. These P2P services have delivered their promised benefits. If you compare a TDM service that has been replaced with fiber-based access in the 100M to 1G range, many of the 3G+ smartphone bandwidth problems  have been solved (at least where available). But, the law of diminishing returns is always present and bandwidth demand continues to escalate. So now, we see the need to better manage those “pipes”—enter Multi-CoS.

This isn’t new to networking or Carrier Ethernet, but it’s something that wasn’t part of the legacy T1/E1-based services world. The pure cost/capacity equation of port-based EVCs was more than enough to handle backhauling data traffic to date. Now the hope is that all of the great CoS-oriented work delivered by the MEF can actually be adopted!

The good news is better use of capacity, equating to more revenue/lower cost for the wholesaler, and the controlling of traffic and improving of end users’ quality of experience (QoE) for the mobile network operator. The bad news is that CoS is more complex and that complexity requires management.

It will be interesting to see the adoption rate of this implementation agreement and how the benefits are harvested while the complexity is addressed. Long live Ethernet!

Comments (2)

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  1. prabin says:

    i have one question regarding multi cos in carrier ethernet service 2. What is multi cos and how service provider compliant with multi cos?

  2. Hi – thanks for your comment!

    Best source for the information on Multi-CoS is the specifications themselves, which you can find published here “”.

    I assume you are referring to Carrier Ethernet 2.0 (CE 2.0) which was launched earlier this year by the Metro Ethernet Forum. CE 2.0 is essentially a branding of related specifications over the course of the last number of years to help the industry understand how Ethernet as a carrier service has evolved. One of those evolutions is the support for multiple classes of service which is critical for business services (aka, bronze, silver, gold) as well as making better use of any data service link such as those used in mobile backhaul where you have a combination of voice traffic, management and synchronization traffic, data and high-value video content. The implementation agreement within MEF 23.1 is really about defining a standard way for operators to align their CoS to promote interoperability in support of off-net access, wholesale mobile backhaul and other multi-operator services so that they can get to market faster. It also helps the Ethernet exchange market on a similar basis. An operator would merely have to use the defined labels (or potentially a subset/superset with appropriate mapping) knowing that on the other side of the ENNI – the labeling would be managed and understood the same way.

    The other items of note are the new performance metrics (Mean Delay and Delay Range) along with the 4 performance tiers with CoS performance objectives and that’s where InfoVista’s composite KPIs help by enabling high-level KQIs based on the CPO, which can then be used to drill down to the individual metrics, associated metrics such as traffic usage and resource health and finally manage adherence to the CPO.

    I hope that addresses your comment sufficiently.

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