The Fibre Channel Industry Association (FCIA) took on the topic of FICON (Fibre Channel Connection) in a FICON 101 webcast now available on demand. During the presentation, our experts Patty Driever, IBM; Howard Johnson, Broadcom and J Metz, Cisco, answered questions, some of which are presented in this blog.

To receive more in-depth information, read “FICON – Well, Isn’t That Special,” by Patty Driever in the 2018 Fibre Channel Solutions Guide available on http://fibrechannel.org.

Q. What is meant by FICON?

A. FICON (Fibre Channel Connection) is an upper-level protocol supported by mainframe servers and attached enterprise-class storage controllers that utilize Fibre Channel as the underlying transport. Mainframes are built to provide a robust and resilient IT infrastructure, and FICON is a key element of their ability to meet the increasing demands placed on reliable and efficient access to data.

Q. What makes FICON so special?

A. Mainframe environments require special characteristics to achieve the reliability, availability, scalability and security that customers demand. Fibre Channel captures these characteristics in the FC-SB architecture and the FICON transport defines a system with superior abilities to share IO across multiple systems, maintain application performance over distance, insure data integrity and security, and provide optimal protocol efficiency. It’s this combination of characteristics that makes FICON so special.

Q. How exactly does FICON provide optimal protocol efficiency?

A. Enterprise class I/O performance is more than just a measure of the data transfer rate on a single link. It also includes efficiencies built into the Upper Layer Protocol (ULP) for the exchange of commands and data. An example of this is how the S/390 (mainframe) I/O architecture works in conjunction with the FICON protocol to allow an application to pass a series of commands (possibly thousands) that include a mixture of read and write operations to the HBA with a single invocation from the host. In addition, FICON allows a host to access non-contiguous portions of a disk in a single I/O operation. These characteristics of FICON improve application work efficiency, which is the ultimate purpose.

Q. Can you describe how FICON helps share IO across multiple systems?

A. When it comes to scale, FICON leverages and extends the value of the mainframe I/O subsystem to uniquely provide extreme levels of virtualization and sharing. Even in an I/O intensive workload environment, the host processors are able to focus their time and energy on the business logic of the workload, while the I/O subsystem and FICON HBAs handle the tasks of path selection and I/O operation initiation, execution and completion.

Q. Do you see the FICON link speed ‘sweet spot/adoption’ moving from 4 Gb to 16 Gb with the introduction of FEC (forward error correction)?

A. Yes, Gen5 Fibre Channel will become the next “sweet spot” largely due to the tremendous benefits of FEC. It was introduced as an optional technology and those who have deployed 16GFC with FEC end-to-end have experienced a significant improvement in reliability.  In fact, the introduction of FEC at 16GFC laid the framework for incorporation of FEC in Gen6 and beyond.

Q. Are there planned improvements in FICON to address the fact that underlying storage is under migration to randomly accessible media (SSD)? In other words, NVMe for FICON?

A. SSD/FLASH storage represents a significant disruption in storage and will no doubt become the defacto standard in the future. The optimal protocol for memory-based storage is one that exploits the performance characteristics of the media while maintaining the benefits of the overall storage solution.  SCSI, NVMe, and FICON are upper layer protocols that provide unique capabilities.

Although SCSI and FICON were originally crafted for a specific device architecture (SCSI uses Fixed Block, while FICON uses Extended Count Key Data) and media type (originally spinning disk), today many enterprise-class storage controllers that support FICON and SCSI protocols already utilize all-flash media (SSD) storage solutions on the backend, providing high-performance, high-capacity, flexible and resilient storage systems.  It’s also interesting to note that the Transport Mode of operation defined in the FICON FC-SB-5 standard was the first mapping of protocols other than SCSI to the FCP transport protocol, and FC-NVMe is the second!

 

For additional information on FC, please visit the Fibre Channel Industry website at https://fibrechannel.org/.  This site contains resources such as QuickLinks to the FC roadmap, a library of all FC webcasts, our latest FC Solutions Guide and more.

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