Connection-oriented Ethernet

Connection-oriented Ethernet refers to the transformation of Ethernet, a connectionless communication system by design, into a connection-oriented system. The aim of connection-oriented Ethernet is to create a networking technology that combines the flexibility and cost-efficiency of Ethernet with the reliability of connection-oriented protocols. Connection-oriented Ethernet is used in commercial carrier grade networks. Connection-oriented Ethernet refers to the transformation of Ethernet, a connectionless communication system by design, into a connection-oriented system. The aim of connection-oriented Ethernet is to create a networking technology that combines the flexibility and cost-efficiency of Ethernet with the reliability of connection-oriented protocols. Connection-oriented Ethernet is used in commercial carrier grade networks. Traditional carrier networks deliver services at very high availability. Packet-switched networks are different, as they offer services based on statistical multiplexing. Moreover, packet transport equipment, which makes up the machinery of data networking, leaves most of the carrier-grade qualities such as quality of service, routing, provisioning, and security, to be realized by packet processing. Addressing these needs in a cost-efficient way is a challenge for packet-based technologies. The IP-MPLS approach aims at providing guaranteed services over the Internet Protocol using a multitude of networking protocols to create, maintain and handle packet data streams. While this approach solves the problem, it inevitably also creates a great deal of complexity. This has resulted in the emergence of connection-oriented Ethernet which includes a variety of methodologies to utilize Ethernet for the same functionalities otherwise based on extensive IP protocols. The challenge of carrier Ethernet is to add carrier-grade functionality to Ethernet equipment without losing the cost-effectiveness and simplicity that makes it attractive in the first place. To meet this challenge, common connection-oriented Ethernet solutions have chosen to rid themselves of the complex parts of packet transport to achieve stability and control. Key connection-oriented Ethernet technologies used to achieve this include mainly IEEE 802.1ah, Provider Backbone Transport and MPLS-TP, and formerly T-MPLS. Provider Backbone Transport (PBT) is connection-oriented switch operation scheme and network management architecture. PBT was invented by British Telecom (BT) and developed by Nortel (now Avaya). It defines methods to emulate connection-oriented networks by providing 'nailed-up' trunks through a packet-switched network. Key data-plane differences from PBB include the static configuration of forwarding tables within Ethernet switches, dropping of multicast packets and the prevention of 'flooding' of frames to unknown destination addresses. Configuration is performed by a centralized management server like in SDH networks, though in the future a control plane may be added. PBT has been presented to IEEE802 and a new project has been approved to standardize it under the name of Provider Backbone Bridge Traffic Engineering (PBB-TE) (IEEE 802.1Qay), a modification to PBB. Provider Backbone Bridges (PBB) is an Ethernet data-plane technology invented in 2004 by Nortel Networks (now Avaya). It is sometimes known as MAC-in-MAC because it involves encapsulating an Ethernet datagram inside another one with new source and destination addresses (termed B-SA and B-DA). IEEE802 is standardizing the technology as (IEEE 802.1ah), currently under development. PBB is the original data-plane chosen by British Telecom for their new PBT-based Ethernet transport.