Nigel Bragg

Provider link state bridging

Wide area communications technology has been challenged to virtualize large numbers of Ethernet LAN segments. This is a consequence of a mismatch between the broadcast nature of the LAN segment and the extremely constrained connectivity implied by the p2p connections or tunnels available in the WAN environment, which have been combined to create virtual LAN segments. PBB-TE has been a practical demonstration of how filtering applied to a broadcast media can result in a connection. This article introduces provider link state bridging (PLSB), which adds a control plane to the PBB data plane in order to extend the techniques for manipulation of Ethernet bridges for unicast paths pioneered by PBB-TE. PLSB solves the problem of largescale virtualization of LAN segments over an Ethernet infrastructure by applying advances in computation performance to the multicast capabilities inherent in the Ethernet data plane. The result is that the fundamental primitives of connectivity today, the broadcast LAN segment and the connection, can be virtualized in a scalable manner on a common (but substantially larger and better utilized) Ethernet-based infrastructure.

Ethernet as carrier transport infrastructure

New innovations in the Ethernet space promise to significantly enhance both the scalability and capability of Ethernet as a networking technology. This article outlines how the convergence of hierarchy, OAM functionality, and enhanced forwarding capability combine to permit Ethernet to assume a much larger role in carrier networks with substantial economic and operational benefits.

Shortest path bridging: Efficient control of larger ethernet networks

This article provides an overview of IEEE 802.1aq shortest path bridging and outlines some application scenarios that will benefit from the new capabilities SPB offers. SPB is built on the IEEE 802.1 standards, and inherits unaltered the existing OAM and data plane scalability enhancements, such as the MAC-in-MAC forwarding paradigm. SPB introduces link state control for bridge networks, thus improving control plane scalability, network bandwidth utilization, and control of the forwarding paths. Furthermore, SPB minimizes latency by forwarding frames on the shortest path. Network-wide load balancing is also supported by spreading the traffic on multiple equal cost paths in a user controllable manner. Thus, SPB provides enhanced control for Ethernet networks in metro, RAN backhaul, or data center environments.