Scalable Wireless Mesh - Carrier Ethernet ExtensionWireless extension to carrier backhaul is critical to both telephony and data networks and carriers should no longer depend on T1/E1’s

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Scalable Wireless Mesh - Carrier Ethernet Extension The development of high performance, robust and scalable wireless mesh networking has revolutionized Wi-Fi access and provides the extension of the robust services that carrier Ethernet provides. Wireless mesh, also referred to as wireless Ethernet, takes the benefits of WiFi and makes the planning, deployment, and operations of such networks substantially more cost effective than its wired counterparts. Wireless Ethernet is designed to provide fast internet access, transparent LAN services, metro Ethernet extension, private networks intra-connection, MDU/MTU backhaul, DSLAM/NGDLC backhaul and cellular base station backhaul. The architecture delivers Large-scale city-wide, metropolitan and country-wide deployments implemented with equal performance at half the cost of a wired network. In competitive situations where access to customers is blocked by a competitive provider, wireless services provide equal, if not greater, ability to attract new and existing customers as compared to any wired options, as geography creates additional potential expense. Wiring hundreds, and potentially thousands, of nodes across tens or hundreds of square miles is not always feasible for wired networks, so wireless backhaul extension can be implemented to extend those services while additionally offering new mobile services along the way. The mobility-aspect of wireless Ethernet coupled with future high bandwidth wireless technologies enables the mobility and pervasiveness of voice, video and data applications. Contrary to some thoughts regarding WiMAX’s ubiquitous capabilities, it is less likely that WiMAX by itself will be used to build these networks. Due to the benefits and success of Wi-Fi, and the improvements in wireless mesh technologies, it is the wireless broadband technology of choice. Each of these wireless networks serves a population of users, providing coverage in areas unreachable by WiMAX alone, while as a complimentary technology, WiMAX provides high bandwidth backhaul. The delivery of high speed wireless Ethernet creates demand for Next Generation Networks. The demand exists today - the market for embedded Wi-Fi clients (including mobile PCs, PDAs and phones) is expected to grow at a 66.2% Compound Annual Growth Rate (CAGR). This means that 226.0 million units will ship in 2008, and in 2009 In-Stat expects the Wi-Fi chipset market ship 430 million units.

The applications of wireless Ethernet is not limited by any boundaries and enables 100% reach-ability and 100% mobility. Wireless Ethernet provides a natural extension for carrier Ethernet services, a singular homogeneous network for 2G and 3G transport and enable



ubiquitous set of services such as Voice over IP to a larger distributed population with both lower CAPEX and OPEX. Wireless Ethernet provides theoretical throughput of up to 108Mbps and the architecture allows for the continual expansion and re-shaping of the network providing optimal CAPEX and OPEX. The service requires few truck roles and is automatically self-optimizing and self-healing. Service priorities and quality of service are enabled and provide the hand-shake between the wired and wireless network. Deployments are not limited in size and Ethernet technology has been used in every network around the globe and is a natural step for enterprises as well as residential subscribers to embrace this technology. Entire markets of opportunity exist where successful deployments are occurring today. These include: 1) Carrier Access 2) Municipal and Metropolitan 3) Government (local, state, federal) 4) Large distributed enterprise 5) Country-wide 6) Hot-Spots, Hot-Zones, Hi-speed roaming

Carrier Access Carriers are spending great efforts to implement converged networks, migrating from the old telecom to Next Generation networks. While this continues, carriers can, at a minimum, capitalize on the successes taking place today in wireless mesh networking for municipal and metropolitan networks. A key advantage is that carriers can utilize existing infrastructure without the need to build-out new facilities. New services can be delivered faster with a minimum of effort in the form of hot-zones as well as municipal and metropolitan networks. Wireless Ethernet networks allow carriers to immediately capitalize on competitive business by enabling wireless access over and around a competitor’s territory. Wireless extension to carrier backhaul is critical to both telephony and data networks and carriers should no longer depend on T1/E1’s for transport of this traffic. As an excellent alternative, Wireless Ethernet extension is a cost effective method for transport of converged fixed-mobile access networks, as well as for "all IP" 2G and 3G mobile access networks. The solution is not only cost effective, but provides two to four times the revenue potential. Wireless Ethernet solutions provide the performance, resilience and redundancies required to offer an extension to traditional metro-Ethernet services with least cost while providing the control and flexibility of wired networks. This reduces the costs of leased T1/E1 lines from Telco intermediaries and enables carriers to deploy ten times the capacity of T1/E1.



Municipal and Metropolitan Areas Municipal and Metropolitan city-wide wireless projects are opportunities for carriers to generate revenues by providing and managing the wireless network infrastructure currently being bid or deployed by other competitive service providers and systems integrators. Within these municipalities, government agencies are seeking ways to minimize capital, deployment and operational expenses as they deploy high-performance broadband wireless technologies to improve communication services for first responders, businesses and local residents. The need to increase the speed, detail and accuracy of information has reached critical interest. The current requirements for wireless mesh networking is in demand at the state, local and federal levels with the requirement to deliver versatile, resilient and reliable high performance wireless network infrastructure for data, voice and video services. Government Local and state government agencies seek ways to minimize capital, deployment, and operational expenses. While this is also true for Federal government, the applications for each are as different as night and day, however, both need high speed data, voice and video deployed for stationary or temporary mobile emergency networks, military and civilian services personnel. Wireless Ethernet is designed for quick deployment and provides robust self-configuring and self-tuning capabilities needed to support all situations. Offering the highest throughput, lowest latency and greatest scalability possible will immediately improve communications services to first responders, businesses and residents while enabling a new generation of communications to support future data, voice and video applications. Large Distributed Enterprise Enterprises are quickly realizing the benefits that deploying wireless LANs can bring to their organizations. Improvements in worker productivity, network flexibility, and reduced IT expenses are driving the tremendous growth that we are seeing in enterprise adoption of wireless Ethernet. Business-critical applications require a high degree of network integrity, security, performance and quality of service. Data applications have extended to the PDA and phone, yet existing wireless network infrastructure and cellular (even 3G) technologies have proven insufficient. Enterprises' need the bandwidth to support increasing levels of data encryption and streaming video, as well as low-latency for voice. Wireless Ethernet extends the capabilities of the carrier’s wired network and delivers the differentiated services, QoS and security demanded by the Enterprise. Country-Wide In developing countries, wireless Ethernet networks are easily deployed and provide a cost-effective method to facilitate voice and data communications, leap-frog the competition, and bring more citizens into the world economy. Wireless Mesh network infrastructure is the new requirements for countries that otherwise have no data and voice services. Wireless Ethernet networks provide advanced real-time voice, data and streaming video services. By utilizing Session Initiation Protocol (SIP) over wireless Ethernet, carrier voice services can be provided that are otherwise not offered by an incumbent carrier. There is no need to build-out traditional communications infrastructure because all voice, data and video can be provided over a single IP connection to businesses and residences. This reduces the initial capital costs, but in addition, as more services are delivered, and due to low operational expense, the total long-term costs of acquisition and operations are minimized. Hot-Spots, Hot-Zones and Hi-speed Roaming Cellular wireless technologies have failed to provide the bandwidth, throughput, robustness and features required by mobile users. Wi-Fi and wireless Ethernet has



influenced growth in wireless world-wide hot-spots which have doubled from 57,000 in 2005 to over 100,000 in 2006. Store chains, airports, governments etc - all are implementing wireless technologies but most are deploying wireless Ethernet networks due to the known ease-of-use, reliability and performance gains seen in live installations. Architecture The wireless Ethernet architecture delivers high throughput, low latency, and end-to-end quality of service between wireless consumer devices, wireless mesh nodes and mesh links up to a theoretical 108Mbps. Ethernet connectivity is fully compatible and interoperable with all Ethernet switching and routing protocols (including IPv6, VPN tunnels, VLANs, OSPF, BGP, RIP, Multicast, MPLS, etc.). This allows multiple wireless mesh networks, potentially from different vendors, to be internet-worked at Layer 2 or Layer 3 including both IPv4 and IPv6 protocols. To ensure interoperability, any proprietary mesh traffic and routing between modes is transparent to any Ethernet devices connected to the mesh network. As a virtual Ethernet switch, wireless mesh functions take place transparently and therefore have no impact on applications such as AppleTalk, IPX, NetBIOS/BEUI, SNA, etc.

The technology provides full-duplex capabilities to each node; provides multiple connections to other mesh devices in the network, and simultaneously maintains multiple backhaul connections. Each function - both access to customers and backhaul - are provided by utilizing individual radios. Each utilizes the highest available throughput automatically.

The primary difference between wired Ethernet and wireless Ethernet is the use of CSMA/CD versus CSMA/CA. Ethernet utilizes carrier Sense Multiple Access / Collision Detection. CSMA/CD is used to physically monitor the traffic on the line at participating stations. In contrast wireless Ethernet utilizes CSMA/CA. Carrier Sense Multiple



Access/Collision Avoidance is a protocol for carrier transmission in 802.11 networks. Unlike CSMA/CD (Carrier Sense Multiple Access/Collision Detect) which deals with transmissions after a collision has occurred, CSMA/CA acts to prevent collisions before they happen. As soon as a node receives a packet that is to be sent, it checks to be sure that no other node is transmitting. If the channel is clear, then the packet is sent. If the channel is not clear, the node waits for a randomly chosen period of time and then checks again to see if the channel is clear. This period of time is called the backoff factor and is counted down by a backoff counter. If the channel is clear when the backoff counter reaches zero, the node transmits the packet. If the channel is not clear when the backoff counter reaches zero, the backoff factor is set again and the process is repeated.

Carrier Ethernet networks connect into the wireless Ethernet mesh via a 10/100Mb layer-2 or layer-3 Ethernet switch. At that point all transport takes place over layer-2. Any services can be provided without contention and the network is built to a desired egress point. Once the network is up, it automatically adjusts to the conditions of the environment, self-healing and optimizing connections.

Wireless Ethernet architectures utilize the capabilities of 802.11a, b, g and complimentary switching and routing technologies that enable the creation, maintenance and fast redirection of mesh network links. 802.11 applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS). The counter-parts to 802.11 which enable wireless communications at defined set of speeds and coverage are currently 802.11a, 802.11b and 802.11g. • 802.11a – is an extension to 802.11 that applies to wireless LANs and provides up to

54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS.

Recommended as the backhaul technology for wireless Ethernet networks, 802.11a’s 5.8 Ghz frequency is not commonly used by consumer devices which results in less interference. A potential downside of the technology is that signal strength drops off more quickly as you go farther from the access point. However, because there's less interference, 802.11a works well for Wi-Fi backhaul coverage. “Turbo A” defines the increase in performance for 802.11a up to a theoretical 108Mbps.

• 802.11b - is an extension to 802.11 that provide 11 Mbps transmission (with a

fallback to 5.8, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet.

The 802.11b wireless networking standard was the first widely available wireless consumer networking solution and is widely utilized for the vast majority of public wireless hot-spots, hot-zones and larger scale deployments.



• 802.11g -- applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.

The 802.11g utilizes the 2.4 Ghz frequency and provides the highest theoretical maximum speed of 54 Mbps. Performance has been doubled by product manufactures. “Super G” defines the increase in performance for 802.11g up to a theoretical 108Mbps. • Wireless Mesh Networking is an evolving standard based on the fundamentals of

Ethernet switching and wired mesh networks. 802.11s is one implementation of wireless Ethernet which takes into consideration the efforts by two groups of vendors, neither group (Wi-Mesh and SEEMesh (SEE standards for Simple, Efficient and Extensible Mesh)) includes the manufactures deploying the most wireless Mesh Networks and gaining the most experience.

Both 802.11b and 802.11g typically have only 3 possible non-overlapping channels. In contrast, 802.11a does not have this limitation. There is also less radio interference (from other laptops, cordless phones, etc) and a wider spectrum. For these reasons, 802.11a is used for the backhaul mesh infrastructure formation. The number of permitted 802.11a channels depends on the regulatory domain. For example, the United States FCC regulatory domain reserves four bands in the 5GHz range for unlicensed use. These four bands are designated as Unlicensed National Information Infrastructure (UNII) bands and there are a total of 24 possible channels. Another advantage of 802.11a compared to 802.11b or 802.11g is that all of the available channels are non-overlapping so you can have wireless nodes in adjacent channels and they won’t create interference with each other. In some countries around the world it may not be possible to take advantage of the 802.11a spectrum. However, in an ideal network the wireless connections between nodes can be made using 802.11g as well as 802.11a. Both provide similar bandwidth and throughput characteristics, and both support the high-speed modes. Another consideration is radio interference. Today 802.11b and 802.11g are the two most common technologies used by enterprises and service providers for wireless user coverage. And since a majority of wireless mesh deployments use 802.11b for their wireless backhaul infrastructure, it's easy for their network backhaul bandwidth to be affected by radio interference from neighboring devices that operate in the same band. Radio interference can also cause transmission errors and these errors can compound. Interference may vary in different parts of the network. In Single and dual radio approaches which operate on the same backhaul channel across the network overall network, performance degrades for each radio is they are not dedicated to a specific function. The wireless Ethernet approach utilizing a minimum of three radios can mitigate the issues related to interference. The multi-radio "structured mesh" approach to wireless Ethernet provides several dedicated link interfaces where at least three radios are used per network node, including one radio for wireless client traffic (typically 802.11b/g), a second radio for ingress of 802.11a wireless backhaul traffic, and a third radio for egress of 802.11a backhaul traffic. This approach to wireless Ethernet networking offers significantly better performance than either the single or dual radio approaches. It allows for dedicated mesh backhaul links that can transmit and receive simultaneously because each link is on a separate channel. Because the three functions of client ingress, backhaul egress, and backhaul



ingress are handled by dedicated radios, high throughput is maintained across multiple hops, per-hop latency is no more than to 3 - 5 milliseconds, which is a total of 50 milliseconds over 10 hops with each radio supporting QoS over multiple nodes and VLANs. The inherent technical issue resolved by the wireless Ethernet architecture is the reduced contention on radios thereby increasing the rate at which traffic can be (is) switched. Bandwidth degradation can be most severe when the backhaul is shared. This commonly takes place in single and dual radio mesh configurations. In these cases, each time the aggregated traffic “hops” from node to node, throughput is cut in half. To compliment this discussion, the following diagram is provided:

Given that 100% represents the maximum bandwidth (whether you take the best-case theory of 1/n degradation, where n is the number of hops, or the worst-case theory of 1/2n-1 degradation) the amount of bandwidth reduction to the 10th hop is substantial. Taking this into account, wireless Ethernet deployments extend carrier network services with little or no depreciation in performance and promote the triple play and next generation services provided by the carriers Ethernet network.

The self-healing and self-maintaining nature of wireless Ethernet architecture preserves the performance and quality of the core network as each node in the network automatically re-evaluates its path to the closet neighbor. Based on optimal latency, throughput and noise will quickly make decisions and self-tune to maintain its performance at peak levels. If a data path is lost, or if RF interference affects performance, the network self-heals by re-routing traffic so all nodes remain connected and optimized for transport. In dense areas with obstructions, the wireless Ethernet architecture automatically adjusts to environmental conditions and switches traffic around large physical objects, such as buildings and trees and will forward network traffic around an object via intermediate relay

nodes. All self-tuning and self-healing processes are dynamic, occurring in the background and in real time transparent to the user and without the need for human intervention. At the core of the wireless Ethernet network is distributed localized node intelligence. Without the ability to perform localized decisions, a large-scale wireless mesh network will fail to deliver the quality and resilience specified in service-level agreements. As the network is built, automatic network discovery is performed. The topology is automatically configured, adjusting and optimizing based on key criteria. First the nodes perform airspace scanning. This process is continuous and measures signal strength, round-trip delay and congestion. During this time pre-configured parameters are reviewed and checked against new learned information.



As the network maintains a “real-time” database, all previous information is updated with new information while the old information is no longer useful. Best paths for primary and secondary transport are set while real-time backhaul path analysis, congestion avoidance and optimal channel reuse occurs. All nodes monitor the health of its own area. Each neighboring nodes in the network are aware of the best path for a given user and backhaul ingress and egress. Any failures are immediately mitigated as each node is constantly scanning for the next path and utilizes a threshold-based instant re-route algorithm for zero-loss seamless hand-off. This hand-off enables roaming across large geographic areas without need for user intervention.

Security is a major concern for wireless networks. Administrative and customer traffic and backhaul must be secured. Outside devices, called “rogues”, must not only be detected but prohibited from accessing internal mesh traffic. Rogue detection and isolation is a requirement of wireless Ethernet networks. Every point in the network is potentially accessible. It’s therefore, the responsibility of the administrator to secure these areas, however with the innovation of rogue detection and link encryption, the requirement for administration is less than it would be with an alternative wireless solution. Mesh communications is secured as well as any packet transporting across the network and additional levels of authentication and encryption may be applied as needed. Industry standards such as 128-bit and 256-bit AES encryption provide very effective security equivalent to wired networks. And because the network is based on layer-2, any end-to-end security provisions, such as virtual private networks (VPNs), may be used without need for reconfiguration of the network. Wireless Ethernet facilitates end-to-end QoS provisions utilizing Ethernet Class of Service (CoS) tagging. In combination with CoS, VLANs and SSIDs are associated to enable end-to-end services. Voice over IP, Video and high bandwidth low-latency applications may be provisioned over the mesh as needed on a per customer basis. As the network grows, it automatically adjusts to the needs of the environment while maintaining configured service levels. The IEEE is working on a comprehensive standard (802.11e) to provide a single method of enabling end-to-end QoS. This should improve upon the techniques already in place and reduce configuration requirements. Considerations There are several approaches to mesh networks, but only one method is provides the throughput, low latency and resiliency required for wireless Ethernet. The multi-radio, multi-channel, multi-RF system provides the full-duplex capabilities required to extend carrier Ethernet infrastructure to commercial and residential customers. Any approach other than multi-radio will provide less than adequate performance and result in additional costs. Carrier-grade Ethernet service levels are enforced over the wireless Ethernet by the strict adherence to the following concepts: 1. High throughput across multiple, typically 3 to 10, hops. The mesh backbone supports the total aggregate traffic through the each mesh node supporting the wireless Ethernet backbone. The ability to provide high throughput equates directly to the number of voice and data users supported. Inadequate bandwidth across multiple hops results in unsatisfactory user density and requires additional equipment and a greater number of wired termination points within the network.



2. Low latency across multiple hops. High throughput is not enough. To avoid jitter, each hop must minimize the packet latency. The holding time of a packet at any node in the mesh must be minimized (ideally to a negligible 5 milliseconds per hop). As such, a single packet is typically forwarded even before all of the packets in a particular data stream are received from a previous node. Like Ethernet, transport of data across the mesh is asynchronous as oppose to synchronous. 3. End-to-end QoS and packet prioritization of voice. High throughput and low latency in and of themselves are not enough when the network is loaded. To deal with contentions and spontaneity of load demand, voice streams must be prioritized across the entire mesh backbone and terminated with end-to-end traffic prioritization. It is not adequate to provide a class of service just between the end-user device and the wireless node. Wireless Ethernet mesh enables QoS to be distributed across the entire mesh backbone. This reduces contention that may occur at each hop in the mesh. This class of service is driven by the infrastructure, is automatic, and is best handled utilizing separate service set identifiers (SSIDs) and VLANs dedicated to voice. 4. Optimal Layer 2 switched fabric. The wireless Ethernet mesh is a Layer 2 network. It provides the optimal foundation for enhanced services while all mesh network decisions occur transparently and without need for user intervention. This optimal architecture takes wireless mesh another step forward and sets-up the ability to provide ubiquitous roaming at high speed with zero perceived latency. In contrast Layer 3 networks require careful planning around different type of higher level protocols. Both of these factors contribute to performance issues and protocol configuration issues. Layer 2 wireless networks, act and perform as a sophisticated "wire". Business Case for Wireless Ethernet Networks Capital costs, the amount paid per radio and the cost to deploy that radio at the required density to meet the subscriber needs threshold is a key factor. A single radio provides up to a theoretical 108Megabits of bandwidth. That bandwidth equates to a given number of users based on how much bandwidth is allocated to each. A multi-radio, multi-RF, and multi-channel wireless Ethernet architecture provides for the maximum number of radios for the most cost effective deployments. It costs less per megabit to purchase and deploy one six-radio node, versus three two-radio nodes. A sectorized multi-radio node (sectorization increases coverage and density) is capable of handling a minimum of three times the number of concurrent data connections or voice over IP calls compared to a typical single -or- dual-radio node. Operational costs mainly occur with the respect to the reduction of multiple costly T1 connections to the wireless node at the wired termination point. Irrespective of choice, the wireless Ethernet network offers a 10/100Mb interfaces into the network and is not restricted to anything less. The purpose of these connections typically performs the function of “bandwidth injection” for internet services. With regard to bandwidth injection, which may take place at several locations within the mesh network, it’s important to understand, from a cost perspective, the issues related to single and dual-radio solutions. Single and dual-radio systems normally require many T1 connections in contrast with a multi-radio solution which utilizes T3 connections due to the efficiencies in handling multi-hop connectivity. While one T3 is equivalent to 30 T1s in terms of bandwidth, a T3 costs approximately three times that of a T1. The price of a T3 is 1/10 the cost of a T1 in terms of bandwidth. Therefore, a T3 is more cost effective than 30 T1’s or three T3’s are more cost effective than 90 T1’s. In terms of the deployment, a T3 link, for example, allows for ten times more wireless mesh nodes per PoP, enabling providers to cost effectively utilize all of the T3 bandwidth. The only way to accomplish



this is with a multi-radio, multi-RF, and multi-channel wireless Ethernet architecture that allows for the most productive and efficient use of a wired PoP. For example, with a single-radio node, one would require 10 termination points per 5 square miles, whereas with a multi-radio node, one wired termination point may be sufficient. Ultimately, the deployment costs and ongoing expense of bandwidth is reduced by the number of actual backhaul connections required. Multi-radio, multi-RF nodes cost less per radio, are cheaper to install per radio, and enable far more cost effective utilization of broadband termination points by utilizing larger pipes that cost less per megabit. Summary Wireless Ethernet networks extend carrier services. Those services can be reliably delivered given the defined wireless Ethernet architecture utilizing the multi-radio, multi-channel, multi-RF architecture. Services can be easily delivered to the Municipal, Metropolitan, Government and Enterprise markets while capital outlay is preserved and operational expenses reduced while performance, security, and resiliency are tied to robust new carrier offers, with minimal cost for network extension. Increased customer penetration and new reoccurring revenues are also gained. A cost-effective deployment with the necessary capacity and coverage for high throughput, low latency, and high priority voice traffic mesh network requires high capacity nodes with dedicated client ingress, mesh backhaul ingress, and mesh backhaul egress. High capacity, multi-radio nodes enable a service provider to extend carrier Ethernet services and meet the density-of-bandwidth and subscribers-per-square-mile metrics required to purchase, install, and operate a service with the desired business model and return.

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Scalable Wireless Mesh - Carrier Ethernet ExtensionWireless extension to carrier backhaul is critical to both telephony and data networks and carriers should no longer depend on T1/E1’s