|Issue:||North America 2008|
|Topic:||Ethernet for wireless backhaul|
|Author:||Charles R. Kenmore|
|Title:||President and CEO|
As President and CEO of ANDA Networks, Charles R. Kenmore leads the Silicon Valley-based low-cost provider of application-specific access products for carriers and service providers. A telecom industry veteran with more than 30 years of progressive responsibilities in senior executive and general management roles, nineteen of which were as CEO, President or Vice President/GM, Mr.Kenmore has directed domestic and international business, marketing, sales, engineering, customer support, finance and operations functions. He has established four start-up businesses within larger companies and has successfully managed companies during prosperity and economic downturns. Prior to joining ANDA Networks, Mr Kenmore’s most recent responsibilities included President of ADC International; Vice President and General Manager of the international division of the information systems group at Motorola; founding head of Sprint International; and Vice-President and General Manager of the international systems integration division at Comsat. He is a frequent speaker at investment banking and institutional investor conferences. Mr.Kenmore also serves on the board of TechNet and is a member of the TIA CEO Council.
Wireless is usually only wireless at the customer access end of the network. The 3G and 4G wireless broadband networks operators are rolling out need in an economical way to backhaul the traffic they generate to the core network; and a standardised way to track and maintain the quality of service that demanding applications such as video require. Ethernet-based backhaul is economical, provides the needed quality control and is easily integrated into multi-vendor environments; it is increasingly the solution operators choose.
Wireless’s dirty little secret has always been that it is only wireless at the access network level; backhaul uses T1/E1, Ethernet or other wired technologies. With the migration to third generation (3G) and fourth generation (4G) video dominated bandwidth-consuming applications, quality becomes more important for wireless. Dropped video packets are more alarming than dropped voice packets. Moreover, as the use of mobile for enhanced applications becomes more prevalent, service providers will demand quality of service (QoS) and the ability to offer service and application level agreements (SLAs) to customers. The service providers therefore want to be able to monitor networks and provision services efficiently even when mixing vendor equipment within their networks. Standards do exist for Ethernet, but do not eliminate all the complexity associated with managing equipment from disparate vendors. The key standards for Ethernet operations, administration, and maintenance (OAM) include the International Telecommunications Union ITU-T Y.1731, RFC 2544, Institute of Electrical and Electronics Engineers IEEE 802.3ah and IEEE 802.1ag and all are critical to guaranteeing that wireless SLAs are met. Initially, service providers, whether incumbent telcos, cable operators, or competitive providers, may use a combination of traditional leased lines, ATM and frame relay with Ethernet for backhaul. While Carrier Ethernet deployments in the metro area and wide area networks (WAN) have been growing, the transition away from traditional technologies will take several more years. Meanwhile, Ethernet-based wireless backhaul is one of the fastest growing areas in telecom. Wireless backhaul refers to the portion of the network that connects cellular base stations to mobile switching centres (MSCs) via circuit-switched or Internet Protocol (IP) metro and core networks. With over 213,000 cell sites in the United States and over two trillion minutes of mobile traffic at year-end 2007, according to the CTIA, the wireless trade organization, this is a large market for both business and consumer segments. Although traditionally, backhaul networks were constructed of T-1/E-1 links, service providers are deploying fibre, microwave or Ethernet to meet growing traffic needs and to do so more cost-effectively. T-1 is very expensive for backhaul, accounting for as much as 75 per cent of total operating costs for a transmission network. Ethernet provides about a 20-per cent saving compared to the alternatives and offers ten times the bandwidth. Mobile traffic is rapidly increasing due to increased subscribership and enhanced features such as text messaging, web browsing, video, digital photos, gaming, and mobile data traffic, which third-generation (3G) CDMA-EV networks enable. The combination of business data services and consumer applications, where users may be running multiple applications simultaneously, greatly taxes the network. Unlike their wired counterparts, mobile operators have been quicker to offer advanced features that result in viral growth. As traffic increases, providers need to increase capacity in the backhaul perhaps by a factor of 20 times per site because each individual IP-based application requires approximately 100 Kbps-to-5 Mbps bandwidth per subscriber. Without Ethernet backhaul, mobile networks would not be able to handle the increase in traffic from only five per cent of total subscribers for simultaneous, peak-hour video streaming for applications such as YouTube, MobiTV, or business applications including ON24, or CNN streaming broadcasts, etc. As networks further evolve to 4G WiMAX, 3GPP long-term evolution (LTE) and orthogonal frequency-division multiplexing (OFDM), the bandwidth challenge will become even greater. Moreover, service providers are faced with balancing the need to upgrade networks and offer the most advanced services with that of keeping spending in check and increasing operating margins in light of declining revenue per subscriber even with added applications. Using carrier class Ethernet to backhaul traffic from wireless base stations provides significant cost benefits compared with leased lines. Assuring scalability and reliability, however, involves addressing major integration and operational hurdles associated with operations, administration, and maintenance. With, what is now called carrier Ethernet 1.0, carriers were able to reduce costs. Now with the emergence of advanced OAM (operation, administration, and maintenance) functionality in carrier Ethernet 2.0 service providers, both retail and wholesale, are being asked by customers to enforce strict SLAs. Service providers must assure quality metrics for existing services and applications that accommodate new protocols, services and network-compatible devices. SLA management is crucial to a service provider. If a provider’s network is not able to support the new media rich applications, customers will turn to providers that can offer these services. If providers cannot live up to their SLAs, they risk losing corporate customers as well having a detrimental effect on their bottom line. Mobile carriers are redefining themselves as more than just voice providers and need to migrate to high capacity, high-performance IP networks, with increased management capabilities. Ethernet management capabilities – OAM – encompass the tools needed to install, monitor, and troubleshoot the network, assuring application specific service level agreements. The OAM system provides a view into the network to detect faults, failures, loss of connections and to monitor overall network performance. It is vital that a provider recognize a problem before it has an impact on the customer. When monitoring, detection and restoration can be done remotely, the service provider also saves the cost of a service call and decreases mean time to repair, thus increasing overall customer satisfaction. OAM systems typically need to be integrated into a multi-vendor environment, as service providers will usually specify best-of-breed solutions rather than purchasing products from a single equipment provider from the core to the edge. This integration is the result of standardization, which provides a roadmap for interoperability. Standards enable the efficient operation and management of Ethernet networks for backhaul and other applications. PBB is an enhancement to standard Ethernet and acts as a means for interconnecting provider backbone networks. It is generally used for Ethernet-based point-to-multipoint transport in larger metropolitan and regional networks. PBB uses MAC-in-MAC encapsulation to transport the MAC address across the backbone network and conceal customer information; this decreases complexity, improves security and reduces Capital Expenditure (Capex). By only revealing MAC addresses, not customer addresses, it reduces memory requirements and processing power. Another standard, IEEE’s 802.1ag, covers fault detection, isolation and notification through the use of continuity check messages, which as the name implies, monitors for interruption in service. If a fault is detected, a loopback message is sent to determine between which two end points the problem occurred by pinpointing which end point did not reply to the loopback. Once the failure has been identified, alarms are set in the service provider’s management system. This standard enables a service provider to manage each customer’s virtual Ethernet connection separately for quicker detection and resolution. The ITU-T Y.1731standard specifies both the calculation of frame losses by monitoring the transmission of continuity check messages via point-to-point Ethernet services and the calculation of latency by placing a time stamp in the delay measurement. RFC2544 allow carriers to remotely test the frame loss, latency, throughput and other characteristics of carrier Ethernet networks, which contribute to monitoring SLAs. These tests include comparing the number of frames sent and received and measuring the time it takes for a frame to travel from the network to the device. In summary, wireless services are becoming increasingly sensitive to latency and delay due – in addition to traditional voice traffic – to the explosion of new data and IP-based mobile services. As a result, it is vital that service providers now offer higher bandwidth services with the ability to track, monitor and isolate potential faults to handle increased data volumes and avoid transmission interruptions. OAM standards will play an important role in ensuring that SLAs are met during this high growth phase of new mobile data services. In the end, that dirty little secret called Ethernet wireless backhaul may not be the next iPhone, but it is absolutely vital to the delivery of iPhone and other high bandwidth services whilst maintaining a consistent end-user experience.