Carrier Ethernet access: encouraging progress toward network convergence

Michael Kennedy, Network Strategy PartnersAdoption of Carrier Ethernet access networks is accelerating. This is due, in my opinion, to strong demand for increased bandwidth in all market segments as well as the emergence of new technologies and standards that can affordably deliver the desired bandwidth.  This marks the final phase of the transition to end-to-end converged IP/Ethernet networking.

Modernization of the access network is the last phase of network convergence because it is so large, costly and hard to change. Copper feeder and distribution cable together with supporting outside plant apparatus--poles, conduit, manholes, and wiring terminals--comprise most access network investment. Replacing this infrastructure is like a public works project with progress measured in decades rather the two or three year cycles associated with the electro-optical systems used elsewhere in the network.

Access network modernization is accelerating in part due to end-user bandwidth requirements that can no longer be met by squeezing the last bit of bandwidth efficiency from copper cables. The issue is not whether more bandwidth can be delivered; it is whether additional bandwidth can be delivered at a price that is attractive to the user while being economically viable for the service provider.

This is especially the case for copper twisted-pair cables. For example, household bandwidth of about 20 Mbps is needed to support an Internet connection with 5 Mbps downstream and 2 Mbps upstream together with a single HDTV and several SDTV sets. This is pushing the economic limit of typical DSL and cable modem deployments.  However, the increasing use of over-the-top (OTT) video on the Internet, multiple HDTVs per household, and 4G mobile devices will require at least 40 Mbps bandwidth. The situation is much the same for enterprise users where similar use of video as part of enterprise applications and advanced wireless LAN (WLAN) will drive small enterprise establishments' bandwidth requirements beyond T1, DS3 and OC-3 leased line economic limits.  Similarly, current 3G wireless backhaul bandwidth requirements are stretching the capacity (affordability) of T1 backhaul and TDM leased lines are not economically attractive for 4G backhaul.

The new technologies and standards also are driving migration to Carrier Ethernet access. The Metro Ethernet Forum (MEF) has made excellent progress in defining a Carrier Ethernet UNI (User Network Interface). This standardization is essential to achieving the very low cost points needed to standardize access to all users. The MEF also has gained wide acceptance for Carrier Ethernet service specifications and certification of vendors' Carrier Ethernet products. These standardization efforts make it possible to break the link between Carrier Ethernet service delivery and vendors' products and solutions.  This is essential because many different communications media, technologies and vendor solutions are needed to meet all access network requirements.

Many different technologies must be deployed to meet access networks' diverse functional and economic requirements.  Wireless is obviously important to meet mobility requirements and is usually the low cost solution when users are geographically dispersed. Conversely, fiber is economically attractive when bandwidth requirements and user density is high. Hybrid solutions (copper/fiber/wireless combinations) are economically attractive in that they leverage embedded assets.

One certainty is that each solution must use optical transmission to some degree. While PON (Passive Optical Network) and Active Ethernet use fiber end-to-end, even wireless solutions require fiber transport. In fact emerging 4G wireless systems will be the primary driver of optical fiber demand over the next several years. Also, existing cable HFC/DOCSIS solutions will require that the fiber portion of the network be pushed closer to subscribers to reduce the number of subscribers sharing bandwidth on the coax portion of the network. Telecom operators also will need to push fiber closer to their subscribers so as to increase the bandwidth that can be delivered over the DSL portion of their access networks.

Carrier Ethernet services delivered over T1/E1, DS3/E3, and SONET/SDH facilities whether leased or owned will continue to have a role in converged networking in that successful network service offerings require ubiquity and it will be at least a decade before all these facilities are replaced with new infrastructure.

Carrier Ethernet access networks are emerging from their formative period and should see accelerating adoption rates over the next several years. Bandwidth demand requirements coming from the residential and wireless markets are driving adoption. Also a portfolio of Carrier Ethernet technology solutions that provide high scalability (very low cost per increased bandwidth unit) make this transition feasible by assuring an attractive price for users and sustainable profitability for service providers.

Michael Kennedy is a regular FierceTelecom columnist and is the co-founder and Managing Partner of Network Strategy Partners, LLC (NSP), management consultants to the networking industry. He can be reached at [email protected]