Glenn Parsons

Ethernet Bridging Architecture [Standards Topics]

A review of the guiding principles of the IEEE 802 architecture is presented followed by the origin and goals of the ITU-T functional architecture. The applicability of these architectures to Ethernet bridging standards is shown, specifically, how these architectures enabled 802.1Q to evolve from the enterprise to the carrier. Further, the application of ITU-T modeling to Ethernet bridging enabled simplified management for operators but also has exposed the limitations of using only a connection-oriented model.

Ethernet WAN transport

varied set of circumstances has converged to create broad interest in transporting Ethernet data frames over public wide area networks (WANs). On the end user enterprise network side, the factors include: * Ethernet has come to dominate the LAN at layers 1 and 2. That is, all enterprise equipment (e.g.. desktop computers, servers, hubs, bridges, and routers) has an Ethernet physical interface (layer 1) and an Ethernet medium access control (MAC) (layer 2). As a result, it is a familiar technology to corporate enterprise network administrators, and volumes of scale have made Ethernet interfaces very cost effective. Internet use for business applications has become increasingly important, continually growing the traffic on the Ethernet LAN. * Data traffic between different offices within corporations has become increasingly important (e.g., to access common databases, for networked meetings. that substitute for expensive travel, to reduce the cost of shared resources through centralization), again increasing traffic on the Ethernet LAN. * Applications that use Ethernet encapsulation are already widely deployed for carrying voice, video, and data information. For WAN providers, which are mainly the existing telephone network providers and service providers, the factors include: The existing technologies for data transport have limitations with respect to scalability for bandwidth and network management complexity, Enterprise customer requests for incrementally higher bandwidth services are increasing. The bursting of the “telecom bubble” has left carriers with the double-edged problem of no capital to build new overlay networks and a strong desire to provide new revenue-generating services. * New layered applications that use the Internet are competing with currently installed legacy solutions.

Carrier scale Ethernet [Guest Editorial]

The articles in this feature topic cover some of the following topics: an overview of the activity in developing Ethernet solutions in standards bodies; an economic perspective suggesting how a carrier might choose to partition its network to optimize cost and functionality, and also demonstrating how carrier scale Ethernet could complement and interoperate with other technologies; a tutorial on work in the IEEE 802.1 committee related to provider backbone bridging (PBB) and discussion of PBB-TE (PBB with traffic engineering);contrasting approaches to implementing control planes for Ethernet; and a description of Synchronous Ethernet standards being developed to allow transportation of synchronization information over Ethernet.

Mobile backhaul for small cells [Guest Editorial]

Mobile broadband services have expanded considerably in recent years, driving operators to improve and densify their radio access network (RAN). It has become clear that small cells as well as macrocells must be included in a heterogeneous network, due to the scale of densification required. In order to maximize the end user experience, some level of radio coordination between these small and macrocells is needed - this coordination will be signaled across a mobile backhaul network. Mobile backhaul typically refers to the network between the base station site and the network controller site, but can also include interconnection between base station sites. Mobile backhaul includes a spectrum of networks and network technologies, including the RAN and core networks. There is considerable market interest on the development of small cell backhaul solutions that are an evolution of existing backhaul networks. Packet synchronisation mechanisms that are being developed are key to support the mobile backhaul application. Various standards bodies such as the Next Generation Mobile Networks Alliance (NGMN), Small Cell Forum (SCF), Metro Ethernet Forum (MEF), and Broadband Forum (BBF) are also studying what the implications would be on their defined mobile backhaul network architectures.

Guest editorial - Ethernet transport over public wide area networks

here has been much progress in the area of Ethernet transport over WANs since the March 2004 issue feature topic on this subject. In terms of standards progress, the ITUT SG15 has approved standards for Ethernet private line and virtual private line service (G.8011.1 and G.8011.2, respectively), UNI/NNI (G.8012), and carrier network equipment functional requirements (G.8021). Work on virtual private LAN services and Ethernet-based protection are in progress. ITU-T SG15 is also well along in defining transport MPLS standards (G.8110.1, G.motnni, G.8121) for carrier-grade transport of Ethernet over MPLS-based transport networks. ITU-T SG13 is well along in defining carrier-grade operations, administration, and maintenance (OAM) for Ethernet networks (Y.17ethoam). The MEF standards describing services from the customer perspective are now approved (MEF 6 and 10) along with UNI requirements (MEF 11). The IEEE has approved the resilient packet ring standard (802.17) and is well along on its work for Ethernet extensions to support provider bridged networks (802.1ad) and Ethernet OAM (802.1ag). The work on provider backbone bridged networks (802.1ah) has also started. Together, these standards provide a very powerful toolbox for both providing Ethernet connectivity services through the carrier networks, or using Ethernet technology as a carrier network data transport technology. For example, MPLS, 802.1ad, and 802.1ah provide frame tagging mechanisms for distinguishing different Ethernet connections within a shared channel and routing them through a WAN. The 802.1ad and 802.1ah techniques allow the carrier to use Ethernet as its transport technology for carrying client Ethernet services. Carrier-grade data services obviously require a comparable level of OAM to what is currently provided in carrier networks. The ITU-T and IEEE standards are thus a critical step for Ethernet WAN services. Meanwhile, integrated circuit and equipment manufacturers continue to evolve their designs to support the new functions and capabilities. More important, carriers are now rolling out Ethernet transport services on an increasing scale. Initially, these services have been private lines or virtual private lines. The articles in this feature topic address a variety of topics associated with Ethernet WAN transport. In “Why Ethernet WAN Transport,” we have an overview of both the justification for providing Ethernet WAN transport and also some of the remaining open issues that require further work. “Utah’s UTOPIA: An Ethernet-Based MPLS/VPLS Triple Play Deployment” gives an example of Ethernet transport services provided in the context of a new network deployed by municiGUEST EDITORIAL