Wholesale Ethernet access – the E-NNI places three new requirements on the service provider

CEN Feature (Jul 29 2010) Business Ethernet , Wholesale

1. 

   Last week we discussed how wholesale Carrier Ethernet access services have become the latest high speed tool for service providers to reach their business customers.  And we remarked on the MEF’s new global connectivity initiative and the emergence of the Ethernet external network-to-network interface or E-NNI.  This week, we’ll explore some of the challenges of using this new toolkit.  The early adopters have learned a few lessons that those who follow their path should consider. 

    

   In the past year, we have seen the emergence of Ethernet exchanges offering to streamline the interconnection among carriers and service providers for these Ethernet access lines.  As exciting as the concept of the exchange is, many service providers operate in geographies that will remain unserved for some time.  For these providers, the vast number of wholesale Carrier Ethernet access circuits will be provided directly from the local operators.  

    

   We have heard, for example, from a large North American CLEC who has established co-location with several incumbent operators and at least one cable MSO in order to reach their target customer base.  They are evaluating the Carrier Ethernet exchanges, but for the time being have not been satisfied with the geographic coverage, and are “going it alone.”  In the process of this footprint expansion, the CLEC has discovered a number of interesting facts – some associated with their partner providers and others with their customers and services.

    

   First, they discovered that each of their access partners had a different way of handling class of service and none supported the 6 service classes they had been offering premium customers for years. 

    

   So, somehow they are going to need to map the customer priority to the partner providers’ service class and then into their own service class.  The bottom line:  the network needs to support three levels of VLAN tag and CoS marking and must support the mapping of CoS markers among multiple class of service schemes.

    

   Secondly, they learned that significantly more of their service traffic was local to the co-location site than they had first expected.  In fact, of the initial orders they received, nearly 40 percent required connectivity for E-LAN or E-Line services to multiple sites served by the same co-location facility.  

    

   Unfortunately, the small metro Ethernet switch they had selected was not capable of hairpinning the traffic that comes in from customer site “A” with VLAN ID “A” on the Carrier Ethernet E-NNI back out onto the same physical interface but with a different VLAN ID “B” needed to guide it back to customer site “B.”  An additional capability required for this hairpinning application is per-VLAN queuing and shaping.  This proved to be yet another area where the metro Ethernet switch came up short.

    

   Finally, they were reminded that a number of business locations were still unreachable with the combination of on-net fiber and wholesale Ethernet access.  The Vertical Systems Group maintains that fewer than 25 percent of business locations in North America are fed by fiber.  To reach these non-fiber sites, they will continue to provide Ethernet over the readily available TDM infrastructure – T1/E1, DS3 and SONET/SDH. 

    

   The good news for this CLEC was that the purpose-built Carrier Ethernet aggregation platform they were already evaluating in the lab was able to handle all of these requirements and allowed them to roll out the service. 

   Bookmark or Share this article

Login to comment.