Fibre Channel · Overview of the Technology

Executive Summary
Fibre Channel Standards
Interoperability
Storage
Storage Devices and Systems
Storage Area Network
Networks
Technology Comparison
Why Fibre Channel?
Fibre Channel Systems

Executive Summary

The information explosion and the need for high-performance communications for server-to-storage and server-to-server networking have been the focus of much attention during the 90s. Performance improvements in storage, processors, and workstations, along with the move to distributed architectures such as client/server, have spawned increasingly data-intensive and high-speed networking applications. The interconnect between these systems and their input/output devices demands a new level of performance in reliability, speed, and distance. Fibre Channel, a highly-reliable, gigabit interconnect technology allows concurrent communications among workstations, mainframes, servers, data storage systems, and other peripherals using SCSI and IP protocols. It provides interconnect systems for multiple topologies that can scale to a total system bandwidth on the order of a terabit per second. Fibre Channel delivers a new level of reliability and throughput. Switches, hubs, storage systems, storage devices, and adapters are among the products that are on the market today, providing the ability to implement a total system solution.

Fibre Channel Standards

After a lengthy review of existing equipment and standards, the Fibre Channel standards group realized that channels and networks should be able to share the same fiber. (Note that "fiber" is used throughout this book as a generic term which can indicate either an optical or a copper cable.)

IT systems frequently support two or more interfaces, and sharing a port and media makes sense. This reduces hardware costs and the size of the system, since fewer parts are needed. Fibre Channel, a family of ANSI standards (see Chapter 8), is a common, efficient transport system supporting multiple protocols or raw data using native Fibre Channel guaranteed delivery services. Profiles define interoperable standards for using Fibre Channel for different protocols or applications.

The ambitious requirements given the standards group:

• Performance from 266 megabits/second to over four gigabits/second
• Support for distances up to 10 km
• Small connectors
• High-bandwidth utilization with distance insensitivity
• Greater connectivity than existing multidrop channels
• Broad availability (i.e., standard components)
• Support for multiple cost/performance levels, from small systems to supercomputers
• Ability to carry multiple existing interface command sets, including Internet Protocol (IP), SCSI, IPI, HIPPI-FP, and audio/video.

Fibre Channel, a channel/network standard, contains network features that provide the required connectivity, distance, and protocol multiplexing. It also supports traditional channel features for simplicity, repeatable performance, and guaranteed delivery. Fibre Channel also works as a generic transport mechanism.

Fibre Channel architecture represents a true channel/network integration with an active, intelligent interconnection among devices. All a Fibre Channel port has to do is to manage a simple point-to-point connection. The transmission is isolated from the control protocol, so point-to-point links, arbitrated loops, and switched topologies are used to meet the specific needs of an application. The fabric is self-managing. Nodes do not need station management, which greatly simplifies implementation.

Storage

Storage Devices and Systems

Storage Area Network

The network behind the servers linking one or more servers to one or more storage systems. Each storage system could be RAID, tape backup, tape library, CD-ROM library, or JBOD (Just a Bunch of Disks). Fibre Channel networks are robust and resilient with these features:

• Shared storage among systems
• Scalable network
• High performance
• Robust data integrity and reliability
• Fast data access and backup

In a Fibre Channel network, legacy storage systems are interfaced using a Fibre Channel to SCSI bridge. IP is used for server to server and client/server communications.

Storage networks operate with both SCSI and networking (IP) protocols. Servers and workstations use the Fibre Channel network for shared access to the same storage device or system. Legacy SCSI systems are interfaced using a Fibre Channel to SCSI bridge.

Fibre Channel products have defined a new standard of performance, delivering a sustained bandwidth of over 97 MB/second for large file transfers and tens of thousands I/Os per second for business-critical database applications on a Gigabit link. This new capability for open systems storage is the reason Fibre Channel is the connectivity standard for storage access.

Networks

Fibre Channel networks provide enterprises new levels of performance and reliability. The many network applications for Fibre Channel include:

• Nonstop corporate backbone
• High-performance CAD/CAE network
• For movie animation and post-production projects to reduce the time to market.
• Quick-response network for imaging applications.

Fibre Channel was developed by the computer industry for IT applications. Its development focused on removing the performance barriers of legacy LANs. Among the performance-enhancing features of Fibre Channel for networking are:

• Confirmed delivery, enhancing the reliability of the protocol stack or the option of bypassing the protocol stack for increased performance.
• Complete support for traditional network self discovery. Full support of ARP, RARP, and other self-discovery protocols.
• Support for dedicated bandwidth point-to-point circuits, shared bandwidth loop circuits, or scalable bandwidth switched circuits.
• True connection service or fractional bandwidth, connection-oriented virtual circuits to guarantee quality of service for critical backups or other operations.
• The option of real circuits or virtual circuits.
• Instant circuit setup time measured in microseconds using hardware enhanced Fibre Channel protocol.
• Extremely low-latency connection and connectionless service.
• Automatic self-discovery of Fibre Channel topology.
• Full support for time synchronous applications like video, using fractional bandwidth virtual circuits.
• Efficient, high-bandwidth, low-latency transfers using variable length (0-2KB) frames. Highly effective for protocol frames of less than 100 bytes as well as bulk data transfer using the maximum frame size.

In the early days, a single computer vendor provided a proprietary solution to a single buyer, the data processing manager. With the minicomputer, the process changed, and departments bought their own computing solution. The market transitioned to multiple solutions sold to multiple buyers, resulting in incompatible, proprietary data processing systems. Over time users realized they needed to combine all data processing into an integrated environment. This requirement opened the door for open standards-based solutions. Now, companies are connecting their mainframes with enterprise and department servers for distributed client/server architectures.

Distributed computing and parallel processing has resulted in a significant increase in process-to-process communications. At the same time, the data storage requirements have exploded. This new paradigm only works if data can be moved and shared quickly. The need for very high-bandwidth and extremely low-latency I/O is paramount. Fibre Channel is the solution that delivers.

Fibre Channel is attractive because it offers a standards-based solution. With the emphasis on open systems, end-users are shying away from proprietary solutions and vertically integrated, single provider solutions. Today, they are integrating the best industry offers into integrated, seamless systems.

These new systems are being driven by the technology and marketing forces associated with client/server implementations. Fibre Channel is the only technology available with the reliability, responsiveness, scalability, high-throughput, and low-latency needed to meet the broad range of market and technology requirements.

Users enjoy these advantages:

• Scalable systems
• More cost effective systems
• Straightforward migration to Fibre Channel
• Continued support of legacy systems
• Graceful upward migration

Fibre Channel's scalability provides a continued return on investment long into the future.

Technology Comparison

Fibre Channel is a product of the computer industry. Fibre Channel was specifically designed to remove the barriers of performance existing in legacy LANs and channels. In addition to providing scalable gigabit technology, the architects provided flow control, self-management, and ultra-reliability.

Gigabit Ethernet is designed to enable a common frame from the desktop to the backbone. However, Fibre Channel is designed to be a transport service independent of protocol. Fibre Channel's ability to use a single technology for storage, networks, audio/video, or to move raw data is superior to the common frame feature.

ATM was designed at a wide area network with the ability to provide quality of service for fractional bandwidth service. The feature of fractional bandwidth with assured Quality of Service is attractive for some applications.

For the more demanding applications, Class 4 Fibre Channel provides guaranteed delivery and gigabit bandwidth as well as fractional bandwidth quality of service.

Fibre Channel's use in both networks and storage provides a price savings due to economies of scale associated with larger volumes. Users can expect their most cost-effective, highest-performance solutions to be built using Fibre Channel.

As shown in Table 3.1 below, Fibre Channel is the best technology for applications that require high-bandwidth, reliable solutions that scale from small to very large.

Why Fibre Channel?

Fibre Channel is the solution for IT professionals who need reliable, cost-effective information storage and delivery at blazing speeds. With development started in 1988 and ANSI standard approval in 1994, Fibre Channel is the mature, safe solution for gigabit communications.

Today's data explosion presents unprecedented challenges incorporating data warehousing, imaging, integrated audio/video, networked storage, real-time computing, collaborative projects and CAD/CAE. Fibre Channel is simply the easiest, most reliable solution for information storage and retrieval.

Fibre Channel, a powerful ANSI standard, economically and practically meets the challenge with these advantages:

• Price Performance Leadership - Fibre Channel delivers cost-effective solutions for storage and networks.
• Solutions Leadership - Fibre Channel provides versatile connectivity with scalable performance.
• Reliable - Fibre Channel, a most reliable form of communications, sustains an enterprise with assured information delivery.
• Gigabit Bandwidth Now - Gigabit solutions are in place today! On the horizon is two gigabit-per-second data delivery.
• Multiple Topologies - Dedicated point-to-point, shared loops, and scaled switched topologies meet application requirements.
• Multiple Protocols - Fibre Channel delivers data. SCSI, TCP/IP, video, or raw data can all take advantage of high-performance, reliable Fibre Channel technology.
• Scalable - From single point-to-point gigabit links to integrated enterprises with hundreds of servers, Fibre Channel delivers unmatched performance.
• Congestion Free - Fibre Channel's credit-based flow control delivers data as fast as the destination buffer is able to receive it.
• High Efficiency - Real price performance is directly correlated to the efficiency of the technology. Fibre Channel has very little transmission overhead. Most important, the Fibre Channel protocol, is specifically designed for highly efficient operation using hardware.

Corporate information is a key competitive factor, and Fibre Channel enhances IT departments' ability to access and protect it more efficiently.

In fact, multiple terabytes of Fibre Channel interfaced storage are installed every day! Fibre Channel works equally well for storage, networks, video, data acquisition, and many other applications. Fibre Channel is ideal for reliable, high-speed transport of digital audio/video. Aerospace developers are using Fibre Channel for ultra-reliable, real-time networking.

Fibre Channel is a fast, reliable data transport system that scales to meet the requirements of any enterprise. Today, installations range from small post-production systems on Fibre Channel loop to very large CAD systems linking thousands of users into a switched, Fibre Channel network.

• Fibre Channel is ideal for these applications:
• High-performance storage
• Large data bases and data warehouses
• Storage backup systems and recovery
• Server clusters
• Network-based storage
• High-performance workgroups
• Campus backbones
• Digital audio/video networks

Fibre Channel Systems

Fibre Channel systems are assembled from adapters, hubs, storage, and switches. Host bus adapters are installed into hosts like any other SCSI host bus adapter. Hubs link individual elements together to form a shared bandwidth loop. Disk systems integrate a loop into the backplane. A port bypass circuit provides the ability to hot swap Fibre Channel disks and Fibre Channel links to a hub. Fibre Channel switches provide scalable systems of almost any size.

IT systems today require an order of magnitude improvement in performance. High-performance, gigabit Fibre Channel meets this requirement. Fibre Channel is the most reliable, scalable, gigabit communications technology today. It was designed by the computer industry for high-performance communications, and no other technology matches its total system solution.