The role of the FCoE protocol is actually very simple, which is used to encapsulate the FC protocol into Ethernet. The biggest advantage is the expectation of converged networks and future high-speed bandwidth, but it needs to work with specific devices and run on enhanced Ethernet.
Fibre Channel over Ethernet (FCoE) is a transport protocol standard for encapsulating frames in Fibre Channel (FC) into an enhanced Ethernet (Ethernet) application and component storage network. There are many networks on the introduction of FCOE, but most of them are scattered. This article summarizes the technical details of FCoE in eight, and sorts out the knowledge that must be understood in the storage network FCoE.
1. FCoE uses Ethernet to transmit FC:
The full name of FCoE is Fiber Channel over Ethernet, which aims to directly transmit the fiber protocol through Ethernet, so that the data in the storage network can easily cross the boundary between the fiber and the Ethernet, and transmit through the same physical medium (Ethernet) while retaining. The characteristics of the upper layer protocol in the FC, such as data consistency, flow control, etc., but do not use the physical lines and interfaces of the original fiber network. The goal is to reduce the cost and complexity of users in the construction and management of storage networks.
2. The advantage of FCoE is the expectation of converged networks and future high-speed bandwidth:
The advantages of FCoE are obvious. After deploying FCoE, enterprises only need to use Ethernet to build a data center network, instead of using a combination of fiber network and Ethernet. At the same time, reduce the total number of lines, the total number of host interface cards (HBA, network card). The two will be integrated into the same interface device - Converged Network Adapter (CNA) to handle FC protocol and TCP / IP protocol at the same time, to ensure that the storage network and IP network are isolated on the same host interface. In addition, FCoE may provide more bandwidth than FC networks in the future. FCoE is currently starting with 10 Gb Ethernet, and 40 Gbps and 100 Gbps Ethernet are also expected to be launched in the near future. On the other hand, 8Gb and 16Gb are the mainstream, and the latest 32Gb has just appeared, but it is still a bit less than the 100Gb Ethernet in the initial stage.
3. The FCoE main protocol is still FC, but it is transmitted in Ethernet media after encapsulation:
The invention of the FCoE protocol is very simple and is used to encapsulate the FC protocol into Ethernet. The following picture shows clearly which parts of an FCoE frame are included. FC frame and Ethernet frame, the transmission in FCoE is a 1:1 correspondence, without any packet and combining multiple FC frames to one Ethernet frame. Therefore, on each node of the FCoE data transmission (network card, switch), you need to enable Jumbo Frame to support the transmission of Ethernet frames after the packet (the original default frame of Ethernet is up to 1500 bytes, and the transmission of FC frames is 2112). . The default JTU of the product of different vendors is different. For example, the default value of Cisco's Nexus is 2158.
4. FCoE needs to work with a specific device and runs on an enhanced Ethernet:
FCoE can't run on ordinary 10/100Mb, 1Gb and 10Gb Ethernet networks. Because ordinary Ethernet is not Lossless Ethernet, it does not contain any retransmission (retransmission is controlled by the upper TCP protocol) and flow control technology. Transfer and other functions. The Ethernet network that FCoE runs is an enhanced Ethernet that can include these features. Different vendors have different names for this enhancement. Cisco calls it Data Center Bridging (DCB), which Brocade and other vendors call Converged Enhanced Ethernet (CEE).
Existing CAT-5 and CAT-6 cables supporting RJ45 for 1Gb Ethernet cannot support FCoE products. Users who transfer to FCoE can select existing fiber cables and a new type of flat cable (Twin Axial). Transmission medium. FCoE also needs to work with Converged Network Switch (CNS) as a bridge between Ethernet and fiber networks.
5.Enhanced/Lossless Ethernet adds some flow control protocols to ordinary Ethernet;
The original Ethernet uses a mechanism called PAUSE. The PAUSE mechanism prevents unnecessary frame loss when buffer overflow occurs due to transient overload, and implements a simple stop-equal flow mechanism to improve the quality of the transmission. The original PAUSE mechanism does not have a priority control when it decides to stop a specific port. Enhanced Ethernet solves this problem by adding some extended protocol mechanisms to the original Ethernet, making Ethernet more suitable for storage networks. This control mechanism mainly includes the following:
Priority Flow Control (IEEE 802.1Qbb) and Enhanced Transmission SelecTIon (IEEE 802.1Qaz), their role is to adjust the transmission priority of the frame. For example, the priority of the frame of the storage network is increased to obtain higher bandwidth to ensure the speed and quality of the storage network transmission.
The CongesTIon NoTIficaTIon (IEEE802.1Qau) function is a mechanism for simultaneously stopping the source and destination of the collision in the Ethernet.
In addition, the enhanced Ethernet also provides a multi-path mechanism for the Layer 2 network, replacing the original Spanning Tree Protocol (STP) with only a single path.
6. The ports in the FCoE network are similar to the FC network, except that they are called differently:
N_Ports (HBA and storage FC front ports) are called VN_Ports in FCoE (CNAA and storage FCoE ports)
F_Ports (Fabric ports) are called VF_Ports in FCoE (ports of FCoE switches)
E_Ports (FC switches to FC switches) are called VE_Ports in FCoE (ports interconnected by FCoE Ethernet switches)
7. The FCoE application scenario is an extension of the existing storage architecture, not as an alternative to iSCSI or NAS:
If your business deploys storage on Ethernet, if your size is not large, both iSCSI and NAS are good choices on the BLOCK and FILE side. If your enterprise already has a larger storage network, in the case of a new infrastructure, using a converged FCoE network can simultaneously take care of both BLOCK and FILE storage. 10Gb speed can also be used to support FCoE, iSCSI, NAS, and future Ethernet. The rapid development of the network will also enable enterprises to benefit from the deployment of FCoE.
8. EMC's storage products fully support FCoE:
EMC's storage products have been gradually supporting FCoE networks since 2010. EMC supports FCoE's product list reference: FCoE compatibility list for EMC products
6.3 Mm Audio Jack,Trs Audio Jack,Stereo Headphone Jack,6.35Mm Trs Audio Jack
Dongguan Swan Electronic Technology Co., Ltd , https://www.swanconnector.com