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CAN CSA ISO/IEC TR 14165-117-08 (2018): Fibre Channel Backbone-2 (FC-BB-2) Architecture
An in-depth technical overview of the Canadian adoption of the international Technical Report for Fibre Channel backbone extension
The CAN CSA ISO/IEC TR 14165-117-08 (2018) is the Canadian adoption of the international Technical Report ISO/IEC TR 14165-117:2008, which specifies the Fibre Channel Backbone-2 (FC-BB-2) architecture. This document provides essential guidelines for interconnecting Fibre Channel fabrics over packet-switched backbone networks, enabling the extension of Storage Area Networks (SANs) across metropolitan or wide-area distances. The standard is identical to the international version (with Canadian editorial adjustments) and serves as a critical reference for SAN architects, network engineers, and storage administrators.
Scope and Purpose
The Technical Report defines the interface between a Fibre Channel fabric and a backbone network that does not natively support Fibre Channel protocols. It specifies three functional profiles (modes) for transporting Fibre Channel frames:
- Transparent Mode – Full frame encapsulation with preservation of frame ordering and all Fibre Channel framing information.
- Cut-Through Mode – Low-latency forwarding of frames based on header information, allowing reduced delay but potential for reordering.
- Translational Mode – Conversion of Fibre Channel frames into backbone-native frames (e.g., Ethernet frames with IP/UDP encapsulation), enabling interoperability with non-Fibre Channel aware networks.
The TR also covers connections between Fibre Channel nodes, the use of the Backbone Interface (BBI), and mechanisms for managing congestion, error recovery, and quality of service (QoS). The scope is limited to FC-BB-2 interfaces and does not address internal fabric operation or FC‑0 to FC‑3 layers.
Key Benefit: FC-BB-2 allows organizations to stretch Fibre Channel fabrics over existing IP or Ethernet infrastructure without dedicated optical links, reducing cost while enabling disaster recovery and business continuity.
Technical Architecture and Requirements
Frame Mapping and Encapsulation
Each FC-BB-2 mode defines distinct methods for encapsulating Fibre Channel frames. The table below summarizes the key technical characteristics:
| Parameter | Transparent Mode | Cut-Through Mode | Translational Mode |
|---|---|---|---|
| Frame encapsulation | Full FC frame (including SOF/EOF) in a backbone packet | Only FC header and payload; SOF/EOF may be omitted | FC frame converted to backbone protocol (e.g., FC encapsulated in IP or Ethernet) |
| Ordering of frames | Preserved (in-order delivery) | May be reordered; sequence reassembly required | Not required to preserve ordering |
| Latency characteristic | Low (minimal processing) | Very low (header-only processing) | Higher (conversion overhead) |
| Backbone network requirements | Low jitter, moderate bandwidth | High-speed, low-latency interconnect | Generic IP/Ethernet, QoS mechanisms needed |
| Use case examples | Datacenter interconnect (DCI) | High-performance computing (HPC) clusters | Multi-vendor SAN extension over WAN |
Connection Management and Virtual Fabrics
FC-BB-2 supports both point-to-point and switched fabric connections. The standard introduces the concept of virtual fabrics (based on Virtual SANs or VSANs), allowing multiple independent Fibre Channel fabrics to share the same backbone infrastructure. Each virtual fabric is identified by a Virtual Fabric Identifier (VF_ID) inserted into the frame header. The backbone network must ensure that frames belonging to different VF_IDs are isolated and cannot cross logical boundaries.
Quality of Service (QoS)
To meet Fibre Channel’s stringent timing requirements, FC-BB-2 mandates that the backbone network provide at least the following QoS parameters:
- Minimum bandwidth – Sufficient to carry peak FC frame rates;
- Maximum latency – Compatible with the Fibre Channel end-to-end timeout (E_D_TOV), typically 2 seconds;
- Jitter control – To prevent buffer underrun or overflow at the receiver.
Implementation Tip: When dimensioning backbone links, always include headroom for control frames (ELS, FC‑2 ID assignment) and consider that cut-through mode may increase out-of-order delivery rates, requiring sequence buffers at the destination.
Implementation Considerations
Deploying FC-BB-2 in a production environment requires careful planning. The following recommendations are derived from the Technical Report and industry best practices:
- Interoperability with FC-SW-5 – The backbone interface must properly handle routing of frames between Fibre Channel switches. Ensure that the backbone device (e.g., FC-to-IP gateway) supports the latest switch interoperability profiles (e.g., Fabric OS and Cisco NX-OS).
- Backbone redundancy – Implement redundant backbone paths and load-balancing mechanisms (e.g., multiple FC-BB-2 connections) to avoid single points of failure.
- Performance monitoring – Use tools that measure per‑VF_ID statistics, discards, and timeouts. The TR recommends monitoring frame loss ratio and average round-trip time.
- Security – Because the backbone may traverse untrusted networks, consider implementing IPSec or MACsec for confidentiality and integrity. The FC-BB-2 standard itself does not define security mechanisms, but its mapping can coexist with lower-layer security protocols.
Important: FC-BB-2 is a Technical Report, not a full International Standard. It provides informative guidance rather than normative requirements. Always refer to the latest Fibre Channel standards (e.g., FC‑FS‑4, FC‑LS‑2) for normative specifications.
Compliance and Adoption Notes for CAN CSA ISO/IEC TR 14165-117-08 (2018)
The Canadian adoption was published in 2018 by the Canadian Standards Association (CSA Group) and is identical to the 2008 international edition, except for minor editorial changes to align with Canadian referencing practices. This adoption reflects the Canada’s commitment to harmonize with international Information Technology standards.
- Regulatory status: The TR is a voluntary consensus document and does not carry mandatory force. However, it may be referenced by procurement specifications or building codes that require adherence to recognized SAN standards.
- Version identification: The “08” in the number indicates the original year of the international report (2008). The parentheses show the year of Canadian reaffirmation (2018). This TR is currently current as of the latest review cycle; users should check CSA’s website for the latest version.
- Industry relevance: Canadian telecommunications, financial services, and government data centers that deploy Fibre Channel for critical storage should use this TR to ensure their backbone designs are consistent with international best practices.
Compliance Pitfall: Mixing different FC-BB-2 modes on the same backbone without proper isolation can cause frame corruption or misrouting. Always configure a single mode per virtual fabric and ensure backbone devices enforce the selected mode’s rules.
Frequently Asked Questions
Q: What is the difference between FC-BB-1 and FC-BB-2?
A: FC-BB-1 (ISO/IEC TR 14165-111) focused on mapping Fibre Channel over ATM or SONET. FC-BB-2 expands support to packet-switched networks (IP, Ethernet) and introduces the three transmission modes (transparent, cut-through, translational). FC-BB-2 also adds support for virtual fabrics and more robust QoS models.
A: FC-BB-1 (ISO/IEC TR 14165-111) focused on mapping Fibre Channel over ATM or SONET. FC-BB-2 expands support to packet-switched networks (IP, Ethernet) and introduces the three transmission modes (transparent, cut-through, translational). FC-BB-2 also adds support for virtual fabrics and more robust QoS models.
Q: Is CAN CSA ISO/IEC TR 14165-117-08 (2018) identical to the ISO/IEC TR?
A: Yes. The CSA Group adopted the international TR without technical changes. Any deviations are limited to editorial modifications (e.g., Canadian spelling, correction of cross‑references to Canadian standards). The technical content, tables, and figures remain unchanged.
A: Yes. The CSA Group adopted the international TR without technical changes. Any deviations are limited to editorial modifications (e.g., Canadian spelling, correction of cross‑references to Canadian standards). The technical content, tables, and figures remain unchanged.
Q: Can FC-BB-2 be used with Fibre Channel over Ethernet (FCoE)?
A: FCoE is defined by separate standards (FC‑BB‑5, FC‑BB‑6). FC-BB-2 is intended for backbone networks that do not natively support Fibre Channel; FCoE uses an enhanced Ethernet layer (DCB) to carry native FC frames. Both can coexist, but they target different use cases – FC-BB-2 for long-distance extension, FCoE for rack-level convergence.
A: FCoE is defined by separate standards (FC‑BB‑5, FC‑BB‑6). FC-BB-2 is intended for backbone networks that do not natively support Fibre Channel; FCoE uses an enhanced Ethernet layer (DCB) to carry native FC frames. Both can coexist, but they target different use cases – FC-BB-2 for long-distance extension, FCoE for rack-level convergence.
Q: What are the E_D_TOV requirements for FC-BB-2 backbone links?
A: The Fibre Channel standard (FC‑FS‑4) sets E_D_TOV to 2 seconds by default. When using FC-BB-2, the backbone must be designed so that the worst‑case round‑trip time plus any queuing delay stays well below 2 seconds. The TR recommends using a backbone delay of less than 500 ms as a conservative guideline to avoid timeout expiration.
A: The Fibre Channel standard (FC‑FS‑4) sets E_D_TOV to 2 seconds by default. When using FC-BB-2, the backbone must be designed so that the worst‑case round‑trip time plus any queuing delay stays well below 2 seconds. The TR recommends using a backbone delay of less than 500 ms as a conservative guideline to avoid timeout expiration.
© 2026 – Published for informational purposes. Always verify the latest edition of the standard with the Canadian Standards Association (CSA Group) or ISO/IEC.