FCIA
FIBRE CHANNEL
and Link Layer (Layer 2) routing. The FCoE, L2 routing, and Data Center Bridging (DCB) protocols are being developed by three different industry standards bodies, each focusing on technology areas that fall under a specific domain of expertise:
INCITS Technical Committee T11: FCoE FCoE (figure 2) and FIP are defined in FC-BB-5, which describes how Fibre Channel protocol is encapsulated, transported and mapped over lossless Ethernet. The T11 committee completed its technical work for FC-BB-5 in June 2009, and forwarded the draft standardto INCITS, where it was approved and will be published soon.
IEEE: Data Center Bridging Data Center Bridging development by an IEEE 802.1 work group is aimed at adding new extensions to bridging and Ethernet so that it becomes capable of converging LAN and storage traffic on a single link. DCB is designed to make Ethernet more like Fibre Channel, because the new features being added to Ethernet are solving issues that Fibre Channel faced in the past and successfully resolved. IEEE is expected to complete its work on the various components of DCB in the second half of 2010. The new enhancements are:
802.1Qbb: Priority-based Flow Control (PFC) Establishes eight priorities for flow control based on the priority code point field in the IEEE 802.1Q tags. This enables control over individual data flows on shared lossless links. PFC allows Fibre Channel storage traffic encapsulated in FCoE frames to receive lossless service from a link that is being shared with traditional LAN traffic, which is loss-tolerant.
PFC provides link level congestion control that alleviates flow control difficulties common in TCP/IP environments.
802.1Qaz: Enhanced Transmission Selection (ETS) ETS provides the capability to group each type of data flow, such as storage or networking, and assigns an identification number to each of the traffic class groups. The value of this new feature lies in the ability to manage bandwidth on the Ethernet link by allocating portions (percentages) of the available bandwidth to each of the groups. Bandwidth allocation allows traffic from the different groups to receive their target service rate (such as 8 Gbps for storage and 2 Gbps for LAN). Bandwidth allocation provides
Figure 2
quality of service to applications sharing a common transport medium.
ETS incorporates Data Center Bridging Exchange (DCBX), a discovery and initialization protocol that discovers the resources connected to the Enhanced Ethernet cloud and establishes its limits. DCBX distributes the local configuration and detects the misconfiguration of ETS and PFC between peers. It also provides the capability for configuring a remote peer with PFC, ETS, and application parameters. The application parameter is used for informing the end station which priority to use for a given application type (e.g. FCoE, iSCSI). DCBX leverages the capabilities of IEEE 802.1AB Link Layer Discovery Protocol (LLDP).
802.1Qau: Quantized Congestion Notification (QCN) This end-to-end congestion management mechanism enables the throttling of traffic at the edge nodes of the network in the event of traffic congestion.
QCN is an independent protocol and PFC and ETS do not require QCN to deliver FCoE over lossless DCB links.
IETF: TRILL Internet Engineering Task Force (IETF) is developing a new shortest path frame routing protocol in multi hop environments. The new protocol is called Transparent Interconnection of Lots of Links (TRILL) and is expected to be completed in the second half of 2010:
TRILL provides a Layer 2 multipath alternative to the single-path and network bandwidth-limiting Spanning Tree Protocol (STP) currently deployed in data center networks.
TRILL also provides Layer 2 multi-hop routing capabilities that are essential for expanding the deployment of DCB/FCoE solutions beyond access layer server I/O consolidation and into larger data center networks.
WWW.SNSEUROPE.COM SUMMER 10
13
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44