HP StorageWorks 2/24 FW 07.00.00/HAFM SW 08.06.00 McDATA Products in a SAN Env - Page 116

Fabric Initialization, Installing high-port count directors such as the Intrepid 10000

Page 116 highlights

Planning Considerations for Fibre Channel Topologies 3 Fabric Initialization When multiple directors or switches are connected, E_Port (ISL) communication must be established between fabric elements and the fabric must be initialized. During fabric initialization, the fabric elements: • Establish the operating mode for connected E_Port pairs and exchange link parameters (E_Port names, timeout values, classspecific information, and flow control parameters). • Exchange fabric parameters, select a principal switch, and assign Domain_IDs to all switches. • Employ a routing protocol to establish the shortest path through the fabric and program route tables for each fabric element. • Exchange the active zone set to ensure uniform zoning is enforced between all fabric elements. Fabric initialization is not a serial process. The process executes concurrently across all ISLs in the fabric, causing a massive flood of Class F traffic that must processed to the embedded port of each fabric element within a specified (fabric-wide) E_D_TOV. If the fabric consists of a large number of elements (and therefore ISLs), Class F traffic may not be processed within the E_D_TOV, resulting in error recovery operations, timeouts, segmented links, or fabric failure. Because of these problems, a fabric with a high ISL count is more difficult to build. Problems associated with a large fabric are not directly related to the large number of fabric elements but to the large number of ISLs associated with the elements. Installing high-port count directors (such as the Intrepid 10000 Director) as SAN building blocks provides a larger number of non-blocking Fibre Channel ports. Large fabrics built around these directors require fewer additional fabric elements (smaller directors and fabric switches) and ISLs. The Intrepid 10000 Director also supports high-bandwidth (10.2000 Gbps) ISLs that reduce the fabric's total ISL count. In addition, fabrics and sub-fabrics can be merged or maintained as separate entities through flexible partitioning provided by the Intrepid 10000 Director. Large fabrics benefit from deterministic non-blocking performance, less ISL congestion, and better cable management - performance that is not possible from a fabric constructed with smaller port-count switches interconnected with multiple ISLs. 3-30 McDATA Products in a SAN Environment - Planning Manual

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3
3-30
McDATA Products in a SAN Environment - Planning Manual
Planning Considerations for Fibre Channel Topologies
Fabric Initialization
When multiple directors or switches are connected, E_Port (ISL)
communication must be established between fabric elements and the
fabric must be initialized. During fabric initialization, the fabric
elements:
Establish the operating mode for connected E_Port pairs and
exchange link parameters (E_Port names, timeout values, class-
specific information, and flow control parameters).
Exchange fabric parameters, select a principal switch, and assign
Domain_IDs to all switches.
Employ a routing protocol to establish the shortest path through
the fabric and program route tables for each fabric element.
Exchange the active zone set to ensure uniform zoning is enforced
between all fabric elements.
Fabric initialization is not a serial process. The process executes
concurrently across all ISLs in the fabric, causing a massive flood of
Class F traffic that must processed to the embedded port of each
fabric element within a specified (fabric-wide) E_D_TOV. If the fabric
consists of a large number of elements (and therefore ISLs), Class F
traffic may not be processed within the E_D_TOV, resulting in error
recovery operations, timeouts, segmented links, or fabric failure.
Because of these problems, a fabric with a high ISL count is more
difficult to build. Problems associated with a large fabric are not
directly related to the large number of fabric elements but to the large
number of ISLs associated with the elements.
Installing high-port count directors (such as the Intrepid 10000
Director) as SAN building blocks provides a larger number of
non-blocking Fibre Channel ports. Large fabrics built around these
directors require fewer additional fabric elements (smaller directors
and fabric switches) and ISLs. The Intrepid 10000 Director also
supports high-bandwidth (10.2000 Gbps) ISLs that reduce the fabric’s
total ISL count. In addition, fabrics and sub-fabrics can be merged or
maintained as separate entities through flexible partitioning
provided by the Intrepid 10000 Director.
Large fabrics benefit from deterministic non-blocking performance,
less ISL congestion, and better cable management - performance that
is not possible from a fabric constructed with smaller port-count
switches interconnected with multiple ISLs.