Data Center Bridging - Other Groups

Other Groups

• The IETF TRILL (Transparent Interconnection of Lots of Links) standard provides least cost pair-wise data forwarding without configuration in multi-hop networks with arbitrary topology, safe forwarding even during periods of temporary loops, and support for multipathing of both unicast and multicast traffic. TRILL accomplishes this by using IS-IS (Intermediate System to Intermediate System) link state routing and by encapsulating traffic using a header that includes a hop count. TRILL supports VLANs and frame priorities. Devices that implement TRILL are called RBridges. RBridges can incrementally replace IEEE 802.1 customer bridges. TRILL Working Group Charter

• IEEE 802.1aq Shortest Path Bridging (IEEE 802.1aq) 802.1aq specifies shortest path bridging of unicast and multicast Ethernet frames, to calculate multiple active topologies (virtual LANs) that can share learnt station location information. Two modes of operation are described, depending on whether the source Bridge is 802.1ad(QinQ) which is known as SPBV or 802.1ah (MACinMAC), which is known as SPBM. SPBV supports a VLAN using a VLAN Identifier (VID) per node to identify the shortest path tree (SPT) associated with that node. SPBM supports a VLAN by using one or more Backbone MAC addresses to identify each node and its associated SPT, and it can support multiple forwarding topologies for load sharing across equal cost trees using a single B-VID per forwarding topology. Both SPBV and SPBM use link state routing technology. SPBM by virtue of its MACinMAC encapsulation is more suitable for a large data centre than SPBV. 802.1aq defines 16 tunable multipath options as part of the base protocol, with an extensible multipathing mechanism to allow many more multipath variations in the future. 802.1aq supports the dynamic creation of virtual LAN's that interconnect all members with symmetric shortest path routes. The virtual LAN's can be deterministically assigned to the different multi paths providing a degree of traffic engineering in addition to multipathing and can grow or shrink with simple membership changes. 802.1aq is fully backward compatible with all 802.1 protocols. 802.1aq became an IEEE standard in April 2012.

• Fibre Channel over Ethernet: T11 FCoE This project utilizes existing Fibre Channel protocols to run on Ethernet to enable servers to have access to Fibre Channel storage via Ethernet. As noted above, one of the drivers behind enhancing Ethernet is to support storage traffic. While iSCSI was available, it depends on TCP/IP and there was a desire to support storage traffic at layer 2. This gave rise to the development of the FCoE protocol, which needed reliable Ethernet transport. The standard was finalized in June 2009 by the ANSI T11 committee.

• IEEE 802.1p/Q provides 8 traffic classes for priority based forwarding.

• IEEE 802.3bd provided a mechanism for link-level per priority pause flow control.

These new protocols required new hardware and software in both the network and the network interface controller. Products were being developed by companies such as Avaya, Brocade, Cisco, Dell, EMC, Emulex, HP, Huawei, IBM, and Qlogic.