As an IBM mainframe shop, you have inevitably encountered the dilemma of migrating from ESCON to FICON channel technologies. You have weighed the pros and cons of this major overhaul, but you are still undecided if it is worth the time, effort and cost. In this article, we will examine why ESCON has been so widely adopted into the mainframe world, and then make the case for why migrating to FICON is ultimately the best choice for your business. At the end of this article, you may be asking yourself, is 2008 the year for your FICON migration?

ESCON: A Look Back

As you know, ESCON (Enterprise Systems Connection) is a marketing name for a set of IBM and vendor products that interconnect S/390 computers with attached storage, locally attached workstations, and other devices using optical fiber technology and dynamically modifiable switches called ESCON Directors. In IBM mainframes, the local interconnection of hardware units is known as channel connection (and sometimes as local connection to distinguish it from remote or telecommunication connection). ESCON's fiber optic cabling can extend this local-to-the-mainframe network up to 60 kilometers (37.3 miles) with chained Directors. The data rate on the link itself is up to 200 Mbps (million bits per second) and somewhat less when adapted to the channel interface. Vendor enhancements may provide additional distance and higher amounts of throughput.

In the beginning, ESCON was viewed as a great improvement over its predecessor, bus and tag, where many wires were used to move data simultaneously and in parallel fashion between the mainframe and peripherals. ESCON moved beyond the huge copper cable system bus and tag and countered the physical restrictions to offering a serial approach by using optical fiber. Though commonly assumed that the speed and benefits of ESCON were apparent, adoption took time as significant testing and proof proceeded adoption. Throughout the early 1990s, ESCON eventually replaced much of the bus-and-tag cable and the parallel bit attachment using serial bit-by-bit technology. ESCON, considered the original storage networking technology developed for the mainframe environment, was viewed as a highly successful technology and has since been installed in the majority of the world's data centers. After a short time, ESCON was recognized as a significant improvement, but it wasn't long before ESCON was believed to be constrained by its container approach and one-way-at-a-time operation.

The Next Step: FICON

Building on the success of ESCON but incorporating a concurrent approach, FICON (for Fiber Connectivity) is a high-speed input/output (I/O) interface for mainframe computer connections to storage devices. As part of IBM's S/390 server, FICON channels increase I/O capacity through the combination of a new architecture and faster physical link rates to make them up to eight times as efficient as ESCON (Enterprise System Connection), IBM's previous fiber optic channel standard. With the FICON channel, a mapping layer based on the ANSI standard Fibre Channel-Physical and Signaling Interface (FC-PH), specifies the signal, cabling, and transmission speeds. With greater flexibility in terms of network layout, greater distances in bi-directional link rates can be achieved. FICON requires only one channel address and offers full-duplex data transfers, which enables simultaneous reading and writing of data over a single link multiplexing, which enables small data transfers to be transmitted with larger ones, rather than having to wait until the larger transaction is finished.

FICON connectivity is now offered in three flavors: FICON (1Gbs), FICON Express (2Gbs) and FICON Express 4 (4Gbs). Although their rated speeds vary, you would need to migrate to the latest z9 processors to realize any significant performance improvement from the latest offering.

Based on Fibre Channel, FICON is often considered the next generation of mainframe I/O channel technology as it promises far greater connectivity, flexibility and performance in comparison to ESCON. Each FICON channel is capable of supporting the same capacity as up to eight ESCON channels. FICON is mapped over the Fibre Channel FC-2 protocol layer in both one and two Gigabit/sec implementations. Within the Fibre Channel Standard, FICON is defined as a level-4 protocol called SB-2, which is the generic terminology for IBM's single byte command architecture for attached I/O devices. FICON and SB-2 are interchangeable terms; it is a connectionless point-to-point or switched point-to-point Fibre Channel topology. FICON can support multiple concurrent data transfers as well as full duplex channel operations (multiple simultaneous reads and writes), compared to the half duplex operation of ESCON.

FICON is an I/O protocol used between IBM (and compatible) mainframes and storage arrays. FICON takes the higher-layer ESCON protocol, analogous to SCSI, and maps it onto a Fibre Channel transport. Fibre Channel is the dominant technology used today in storage networks for open systems. Simply put, FICON takes ESCON to the next level. FICON's ability to multiplex multiple channel programs is like being able to send many messages in different containers in both directions at the same time. It is an undeniably compelling technology, and there are many enterprises that have been waiting to install it and reap the rewards. For others, it is important to look beyond the technological justification and to determine how best to implement the FICON technology to maximize the return on investment.

With FICON, history has repeated itself in many ways. Launched by IBM on S/390 in 1997, it was clearly a technically superior product in the many ways described in this bulletin. For almost four years, the only devices that would connect via FICON were tape drives (an important improvement for backup and recovery) and printers. Only in 2001 did IBM finally add FICON connectivity to its Enterprise Storage Server (a.k.a. "Shark"). But there are significant differences this time around, and there was an accelerated rate of FICON adoption in 2002.

This time the concept of fiber is not new and SAN technology is widely accepted in and outside the mainframe world. Storage and mainframes continue to have strong growth. Today's directors, first developed to accommodate ESCON, are now based on standard Fibre Channel, and FICON is deployed on those same directors. Furthermore, FICON will evolve as Fibre Channel (FC) and those directors evolve, albeit a little behind the FC evolution, because FICON does so much more. History indicates that the time is right for FICON.

The Plunge

So your company has decided to take the plunge and has planned for an IBM mainframe migration from ESCON to FICON channel in 2008. You have negotiated the budget dollars and justified the long-term benefits such as increased performance and ability to support data over long distances; however, you don't know where to start. You feel overwhelmed, even paralyzed, but don't panic, there are some innovative new methodologies that can get you through this migration with very little pain.

Taking Action Requires Planning: What to Consider

Organizations that plan an ESCON to FICON migration in their mainframe environments should consider not only the benefits of the protocol but also the advantages of implementing it in a robust, scalable environment designed for long-term growth. Before implementation can begin, there are several factors to consider when you are undertaking a major infrastructure overhaul such as this.

You should make sure that your company:

1. Considers the overall cost versus the promised savings

2. Evaluates the bandwidth needs and determines requirements

3. Prioritizes which peripherals to migrate first

4. Considers FICON to ESCON switches to preserve your investment in ESCON

peripherals

You should also anticipate some inevitable obstacles that you will occur during migration. Be sure not to:

1. Believe your existing systems will work without changes

2. Rely on existing cable connections

The Great Migration

Once you have followed these guidelines, you are ready for the ESCON to FICON migration. If properly planned and executed, a FICON migration can bring tremendous technical, management, and business benefits to a company. Unfortunately, migrating to FICON can be a time-consuming, expensive, and not necessarily simple process. It generally requires new processors, disk, tape, printers, and extension devices, and will impact issues related to your storage technologies, disaster recovery planning and initial costs for staffing and hardware expenditures.

When you are planning for a FICON migration, it is important to provide a connectivity solution that enables an investment protection for your existing ESCON devices. FICON migration at the host level without the disruption and cost of upgrading to FICON devices offers IT managers many potential advantages including relief for ESCON channel constraints, consolidation or elimination of ESCON director infrastructure that can be costly to maintain, and the ability to progress to a single and consistent cable infrastructure.

Fortunately, there are alternatives to doing a "forklift upgrade" on your existing ESCON system. If you're experiencing very high rates in traffic growth over your storage network or if you need to connect multiple remote storage centers, you may well want to do a total replacement. If your needs are more moderate, there are a couple of money-saving strategies for integrating FICON into your enterprise.

One alternative is to use a FICON bridge on an existing ESCON installation. The bridge connects the existing ESCON director to a FICON adapter on the mainframe and gives the advantages of FICON between the mainframe and the director. Depending on the user profile, this can provide a significant improvement in performance without having to upgrade peripherals.

Another option is running both ESCON and FICON simultaneously by adding a FICON director to the system and migrating the fastest-growing and most performance-hungry parts of the storage system to FICON. This preserves the investment in ESCON and still gives the benefits of full FICON for the most critical parts of the system.

It is not always necessary to do a full platform replacement when migrating from ESCON to FICON. There are a number of products available on the marketplace that use board-based adapters to provide channel connectivity. In these instances the upgrade is simply replacing the ESCON adapter with a FICON adapter. This approach offers a minimal amount of disruption in the data center and can be very cost-effective. Adapter vendors, such as Bus-Tech, Inc. offer this upgradeability for their line of storage products.

Why FICON Migration is Worth the Undertaking: Benefits of FICON

Now that you have invested the time, energy and money into this migration, was it worth it? The benefits from FICON connectivity can be seen almost immediately once it is implemented, and the cost rewards will definitely justify the effort. Once deployed, companies will benefit from FICON's ability to greatly improve application performance through increased throughput. This enables you to perform business transactions much quicker while increasing productivity.  FICON also enhances network performance over long-distance connections. Whereas ESCON performance will significantly decrease over a distance of 5 miles, the FICON channel performance degradation does not begin to occur until beyond 60 miles. This is accomplished by a technique known as cascading directors which is in effect a type of channel extension. With cascading directors FICON can be extended up to 100km without any performance degradation.

FICON connectivity provides peak data transfer rates almost six times faster than ESCON technology and also relieves constraints on storage configurations, because it supports disk storage configurations up to six times larger than with ESCON. You should also note that ESCON cabling cannot be used by FICON at all. They work under different frequencies. FICON, which is based on Fibre Channel topology, can use Fibre Channel cabling as a transport.

Another benefit is FICON's use of management. Since FICON greatly increases the bandwidth capacity over ESCON (FICON 1Gb/s, FICON Express 2 2Gb/s or FICON Express 4 4Gb/s with full duplex, ESCON 17MB/s half duplex) companies can enjoy dramatic simplification of their fabric due to the transition from multiple ESCON channels onto a single FICON channel. Also, reducing the channels leads to fewer connections, which means fewer cables to monitor. Mainframe customers have a single point of control and centralized and proactive management capabilities of the entire FICON environment.

And best of all is cost. Migrating to a FICON environment often makes it possible to consolidate storage, reducing the number of tape drives, storage arrays, controllers and directors required. This cost benefit alone can save a company hundreds of thousands of dollars per year.

Is Your Company's New Year Resolution FICON?

Whether your company is still evaluating the benefits, on the verge of a decision or even ready to undertake this migration, switching over from ESCON to FICON is a large commitment from a budgetary, staffing and time perspective. An infrastructure overhaul of this magnitude should not be entered into lightly, but the long-term benefits of FICON are very compelling and ultimately undeniable. With all innovative technologies, there is always an adoption cycle where a few brave companies will take the plunge early on and the rest will prudently wait and see if the technology will prove itself to be the better choice. After ten years of implementation and solid performance and ROI results, the time seems right for widespread adoption of FICON. Is 2008 the year for your Great Migration?

SIDEBAR: A Tale of Two Channels: The History of ESCON and FICON

It was the best of times, it was the worst of times...well, at least we can agree, that it is a far, far better thing to have FICON channel than the good old days of "bus and tag." Let's go back to the very beginning...35 years ago there were Parallel connections that evolved into ESCON, which finally produced Fibre Channel and FICON. This progression is important to understand, not so much in regards to technology, but for the rate of adoption and the barriers along the way. IBM's first general-purpose connection from mainframe to peripherals (like disk, printers and tape) deployed a parallel approach, not unlike the many wires and pins that have been used for years to connect desktop printers to personal computers. The many wires were used to move data simultaneously (in a parallel fashion). In mainframes, this was called "bus and tag." The physically huge connector and cable system was the only way to connect until ESCON came on the scene in 1990.

ESCON, the original storage networking technology developed for the mainframe environment in the early 1990s, was a highly successful technology that is installed in the majority of the world's data centers. FICON's predecessor, ESCON, was a great improvement over ESCON's predecessor, bus and tag. ESCON was superior and significantly faster than bus and tag, at least on paper, but adoption required a lot of testing and convincing before acceptance. About four years passed before adoption became widespread.

With FICON, history has repeated itself in many ways. Launched by IBM on S/390 in 1997, it was clearly a technically superior product in the many ways described in this bulletin. For almost four years, the only devices that would connect via FICON were tape drives (an important improvement for backup and recovery) and printers. Only in 2001 did IBM finally add FICON connectivity to its Enterprise Storage. This time the concept of fiber is not new and SAN technology is widely accepted in and outside the mainframe world.

FICON is an undeniably compelling technology, and there are many enterprises that have been waiting to install it and reap the rewards. For others, it is important to look beyond the technological justification and to determine how best to implement the FICON technology to maximize the return on investment. Fibre Channel is the dominant technology used today in storage networks for open systems. Simply put, FICON takes ESCON to the next level.

Today's directors, first developed to accommodate ESCON, are now based on standard Fibre Channel, and FICON is deployed on those same directors. Furthermore, FICON will evolve as Fibre Channel (FC) and those directors evolve, albeit a little behind the FC evolution, because FICON does so much more. FICON has definitely proven itself as the future of the data center.

Jim O'Connor is the director of Product Marketing for Bus-Tech and has been at the company for more than 15 years. In this role, he helps set the strategic direction for both the company and two leading product lines while also driving visibility for the company. He has more than 35 years of experience in the computer industry.

 

 

 

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