FC Fabric Extension Issues

Charles Monia

Nishan Systems Corporation

August 13, 2003

T11/03-499v0

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Which Development Direction?

• Common fabric extension architecture or

• vSANs orthogonal to other partitioned fabric Architectures

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Proposed Architectures

• Issues addressed:– Partition the physical network to achieve Increased connectivity,

physical resource sharing and fault isolation.

– Legacy device support

• vSANs (03-220v0, 03-352v0, 03-354v0)– Partitions physical fabric into isolated virtual fabrics

• Inter-Fabric FC Architecture (03-219v1)– Defines multi-fabric SAN with inter-fabric connectivity

• “Fabric Expansion Requirements” (03-332v0)– fabric partitioned into “sub fabrics” similar to inter-fabric FC

architecture.

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Basis for common architecture

• All extensions define a two-level hierarchical address space.– vSAN I/D + 24-bit FC address– Fabric I/D + 24-bit FC address

• Suggests that it may be possible to define a common extended frame format and architecture– vSAN becomes a special case

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Goals of a common architecture

• Reduce complexity– One Extended Frame Format– Common architectural elements, such as:

• Switching function• Gateway function

• Make vSANs more extensible• Incorporate vSAN-style resource partitioning within a

single physical box (as suggested by 03-219v1).• Per T11/03-332 Requirements

– Preserve inter-fabric and vSAN fault isolation– Support legacy devices

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SANInter Fabric Addressing

Inter Fabric Services

Extended SANFabrics/vSANs

Switch Function

End-Device

Fabric/vSAN A

Fabric/vSAN B

Fabric/vSAN C

Gateway Function

Inter FabricNetwork

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Ingredients

• Common elements– Hierarchical address format– Tagged frame format

• Added components (from 03-219v1, 03-332v0)– Gateway– Extended routing architecture

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FC Extended Address

• Hierarchical address space:– Fabric/vSAN Identifier– Standard, 24-bit N_Port I/D

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Tagged Frame Format

Tagging Header

FC Frame Body

Contains source vSAN/FabricI/D and destination vSAN/FabricI/D

Contains 24-bit D_ID andS_ID

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Functional Components

• Switch Function– Provides fabric attachment for a collection

of E_Ports or F_Ports belonging to the same vSAN or fabric.

– Per 03-219v1, 03-354v0, physical switch may house several switch functions.

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Functional Components (con’t)

• Gateway Function (from 03-219v1)– Provides inter-fabric access for the

N_Ports within a fabric.– Several gateway functions may be housed

within a physical switch or gateway

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Routing Extensions

• FC-SW Extensions– Define routing plane for inter-fabric traffic

• Routes tagged frames to the appropriate gateway for forwarding

• Routing policy applies to tagged frames within a fabric or the inter-fabric network.

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Gateway Function

• Handles all Inter-fabric Frame Traffic

• Supports inter-fabric access by non-extended N_Ports– Maps extended N_Port addresses on

remote fabrics to 24-bit addresses on local fabric.

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Gateway Function

Untagged Frames

Tagged Frames

Outbound Frames::

Convert D_ID to Extended Address

Inbound Frames:

Convert Extended Address to S_ID

Tagged Frames

Inter-fabric Traffic

Local Fabric Traffic