Fibre Channel provides a bi-directional, physical or logical point-to-point, low latency connection between two devices at a time.  Like other serial interfaces such as Serial Attached SCSI (SAS), in Fibre Channel data is transmitted over the physical medium in serial fashion as opposed to parallel methods, which are used in SCSI and ATA physical interfaces. Serial transmission enables much longer connection distances as compared to parallel transmission methods, because far fewer signal lines are required, thereby reducing noise created by multiple signal lines all switching at the same time (cross talk).

A primary use for Fibre Channel is in the transport of block oriented storage traffic in SAN (Storage Area Network) applications. There are also specialized upper layer Fibre Channel protocols that are used in Defense and Avionics applications, to transport video streams for heads-up displays, for example.

Fibre Channel is designed to work with either optical fiber physical medium or copper cables in many connector and cable type configurations.  Copper cables are relatively inexpensive, but they are useable only for shorter distances, in the range of 10 meters maximum. In general the higher the transmission speed, the shorter the distance that can be reliably supported by copper cable technology.  A variety of copper solutions are available, the most commonly used being copper SFP (Small Form-factor Pluggable) or more recently SFP+ copper cables. SFP and SFP+ optical cabling solutions are also available, supporting reliable transmission distances greater than 10 meters, up to about 10 kilometers.

Fibre Channel is a layered protocol, and is modeled loosely on the OSI model for networks. In the OSI model, and in the case of Fibre Channel, each layer provides specific services and makes the results available to the next layer.  Figure 1 below compares the defined OSI layer to the defined Fibre Channel layers.

The layers in the table represent different functions and services that exist within the Fibre channel protocol definition. As with the other communication standards, protocol level analysis is often focused at the link layer (FC-2) and above.

Fibre Channel, like any network architecture, transports blocks of user or application related information called payloads. Before sending a payload over the physical link, additional Fibre Channel specific control bytes are added to both the start and the end of the payload data. The combination of the control bytes and the payload data is called a frame, which is the basic unit of information in Fibre Channel.  A minimum of 60 bytes of overhead data surround each frame for the purposes of maintaining minimum separation between frames, mark the start and end of a frame, and to check for transmission errors. Within a frame the actual user data being transported can vary from 0 to a maximum of 2112 bytes. Fibre Channel transfers data through switched or direct point-to-point connections which work by creating temporary connections between the source and destination devices.  These connections last only until the transfer is completed and can be temporarily preempted by higher priority transfer requests.

Connections are made on Fibre Channel systems through “interconnect components” such as switches, hubs, and bridges. The ability of Fibre Channel to use different interconnect devices makes it flexible and scalable depending on user needs. For small Fibre Channel networks, inexpensive hubs and loop-switches may be used for connecting devices in a topology called Fiber Channel Arbitrated Loop (FC- AL). As Fibre Channel networks get larger and network bandwidth demands increase, full matrix switching may be implemented. A fully switched Fibre Channel network is called a Fabric topology.

Fabric topology permits multiple alternative paths to be established between any two ports in the Fabric. Loop (FC-AL) topology, on the other hand, is like a string of Christmas tree lights where the path goes serially from one device to the next and finally back to the originating device.  In this type of topology if one device or the path between any two devices fails, the entire string of devices lose their connection.  Loop and Fabric topologies can be combined to provide both low cost connectivity and high performance.

Fibre Channel protocol is designed to support very low latency and high data transfer rates. The currently approved standard supporting up to 8.5Gb/s, is generally referred to as 8GFC. Server virtualization and storage virtualization are broad trends that are driving the need for higher bandwidth.  The need for high bandwidth in the network infrastructure is just now beginning to drive the replacement of previous product generations of 1, 2, and 4GFC by 8GFC.

Fibre Channel is a good choice for any environment with many servers needing access to centralized storage, computer data centers for example. Because of this, Fiber Channel enjoys over 80% market share as the network interface used in external storage systems such as SAN environments.

Leveraging LeCroy's extensive expertise in high-speed serial data analysis, the SierraFC is the latest addition to the Sierra family of powerful storage protocol analyzer products. Highly functional as stand-alone test systems, the flexible Sierra family products can also be linked together in cascade configurations to provide additional recording channel capacity. The SierraFC system provides 8 Gb/s Fibre Channel data capture and protocol verification for developers in storage networking, avionics, and embedded applications. Available with either 2 or 4 recording channels, the SierraFC offers world-class protocol analysis capabilities at a price point within reach of every budget. The SierraFC platform can be licensed to support either 8 Gb/s or 4 Gb/s signaling rates and is field upgradeable.

SierraFC Introduction series of video demos

	Title	Time
	Chapter 1: Introduction. LeCroy SierraFC M8-4	3:27
	Chapter 2: Easy Mode. LeCroy SierraFC M8-4	8:35
	Chapter 3: Advanced Mode. LeCroy SierraFC M8-4	5:24
	Chapter 4: Default View. LeCroy SierraFC	6:20
	Chapter 5: Other Views. LeCroy SierraFC	5:00

• 8 Gb/s FC protocol analysis system
• Lower cost 4Gb/s version also available
• Highly flexible architecture
• Cascade capability up to 32 FC ports
• Sync with other Sierra family analyzers to support higher port counts
• Available rack-mount adapter kit
• Sophisticated 24 level triggering
• Hardware filtering
• Automatic error detection
• Comprehensive decoding of FCP & SCSI operations FC-SW-5, FCAL, SBC, basic and extended link services, FC-GS-6 transactions, and more
• Logical & chronological traffic displays
• Statistical reporting
• Trace memory up to 8 GB
• Gigabit Ethernet/USB 2.0 host interfaces

The SierraFC's expert analysis software provides unmatched flexibility with data displays that can be customized to show only events of interest. FC-4 layer decoding provides superior visibility for troubleshooting application layer issues. LeCroy's signature packet view allows users to easily track Fibre Channel exchanges from end-to-end in an intuitive logical display. Easy drill-down to frame and link layer events is always available to help uncover lower-level problems. SierraFC's protocol-specific decoding, combined with comprehensive search, filters, and traffic metrics allows developers to quickly pinpoint root cause problems.

The SierraFC is a highly cost-effective test platform that is easily integrated within a 19" rack or deployed as a bench top instrument, and is small enough to easily carry into the field. The system is available with either 4 or 8 GB of recording memory and comes with both USB and GbE interface ports for maximum connection flexibility to the PC hosting the analysis software. Convenient status LEDs provide information on negotiated link speed, link activity and line errors. Multiple Sierra systems can be combined to tackle complex high-port count applications, while providing substantial cost savings and flexibility for design verification.

Intelligent triggering and real-time filtering are the keys to solving complex Fibre Channel problems in production SAN environments. SierraFC's advanced triggering features save time and improve Engineer's productivity with the ability to capture precise traffic conditions such as timing between events or changes in link state. Spend more time on engineering and less time searching for things that may not be present in the trace capture.

The Graphical State Machine view of the advanced triggering dialog makes it easy for users to visually construct or follow even the most complex scenarios. The trigger capabilities include up to a 24-level state sequencer, 4 independent timers, multiple counters, the ability to pre-filter at each state, and the ability to assign individual triggers to each port pair.

When developing or debugging, one size does not fit all. The SierraFC provides several trace display choices so that you can view the traffic in the format most meaningful for the task.

The familiar spreadsheet view offers users an easy-to understand columnar format, that can be customized, by adding or deleting columns, and marking frame and event types with user-defined colors to speed the eye through complex traces.

An important adjunct to the Spreadsheet View is the Frame Inspector View, which provides a detailed window into each frame and ordered set in several helpful formats. Spec View shows frames in the same format as you'd see them in the technical specification documents

The Field view provides frame details of each layer of Fibre Channel traffic in an expandable tree structure.

The text view facilitates visualization of traffic flows between ports.

The packet view is specifically designed to aid understanding or application layer traffic, logically assembling frames and primitives relative to exchanges in the captured data. This capability is especially useful in environments with outstanding exchanges, large gaps of traffic between exchange start and exchange completion. The exchanges can then be expanded to view the sequence and frame layers for a deeper view of the underlying traffic.

Statistical reports analyze and summarize the contents of a captured trace. A large number of settings are available to fit most any analysis need. This provides the ability to identify critical events and navigate directly to items of interest, such as primitive sequences, task management sequences, SCSI commands, incomplete exchanges, and CRC errors.

LeCroy's Dare-to-Compare Features

1. Advanced Triggering – Flexible comparators can simultaneously monitor up to eight (8) independent frames in addition to four (4) unrelated ordered sets to create sophisticated trigger scenarios. The competition is limited in its ability to perform multiple or sequential event triggering.

Create advanced triggering logic capable of monitoring multiple independent or sequential events

2. Conditional Branching - Find root cause issues faster with advanced triggering logic that can track sequences of events based on timers, counters or arbitrary frame sequences. The competition is only capable of recording based on limited 2 level arm-trigger sequences.

Using counters and timers SierraFC can trigger only after ten REPORT_LUN commands are issued with no response within a 10ms time interval

3. Back to Back Event Triggering – The SierraFC's ability to trigger on back-to-back frames at full 8G line rate highlights the advanced recording capabilities that address real-world debug challenges. The competition is unable to detect when arm / trigger events occur in back-to-back frames.

Trigger on back-to-back frames such as ISL_Request followed by specific ISL_Reject code

4. Auto-Speed Detection – Resolving speed negotiation issues are easier with SierraFCs unique ability to detect and track speed change signaling during link initialization. The competition is limited to recording only the speed selected at runtime.

View and analyze all traffic instantly including speed negotiation sequences

5. Logical Grouping of Fibre Channel Exchanges – Quickly and easily see all frames related to individual exchanges by clicking on the Exchange level button. The competition does not provide automatic grouping of exchange level traffic and instead requires multiple hiding steps to view related frames.

All transactions are automatically grouped into logical exchanges with easy drill down to the packet level

6. Dynamically Allocated Capture Memory – SierraFC's shared memory pool allocates capture resources where they're needed most. The competition limits memory usage to the capacity onboard each blade.

Enjoy better utilization with shared memory across all 4 recording ports

7. Intelligent Data Payload Viewer - Look across multiple frames to view the entire payload for a given exchange. The competition can only view one data frame at a time.

Click on the Data button to view multiple payloads in single convenient window

8. Custom Event Views – Completely customizable spreadsheet view allows color coding of frame types for faster identification of specific traffic. The competition is unable to assign colors to frame types or ordered sets of interest.

9. USB and Gigabit Ethernet host ports – Get fast and convenient access to captured trace data over Gigabit Ethernet or USB. The competition only offers LAN connectivity to the analyzer.

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10. Fully-enabled, Free Analysis Suite – Download and use the SierraFC Analysis suite without limitation. The competition only provides basic trace viewer with no access to advanced features.

11. Avoid Maintenance Headache – Upgrading the SierraFC software on a single client PC doesn't require fork-lift upgrade of all Fibre Channel analyzers in the lab. The competition forces every client to upgrade network-wide.

12.Unbelievable Value! – Not only does the SierraFC M8-4 provide you with all the world class features you were asking for, but it does it at literally half the price of competitive offering. Ask for a quote today !