FW 07.00.00/HAFM SW 08.06.00 McDATA Products in a SAN Environment Planning Manual (620-000124-500, April 2005)

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McDATA Products in a SAN Environment - Planning Manual
Planning Considerations for Fibre Channel Topologies
• Bandwidth - ISL connections can be used to increase the total
bandwidth available for data transfer between two directors or
switches in a fabric. Increasing the number of ISLs between
elements increases the corresponding total ISL bandwidth but
decreases the number of port connections available to devices.
Table 3-1 illustrates ISL transfer rate versus port availability for a
fabric consisting of two Intrepid 6064 Directors.
• Load balancing - Planning consideration must be given to the
amount of data traffic expected through the fabric or through a
fabric element. Because the fabric automatically determines and
uses the least cost (shortest) data transfer path between source
and destination ports, some ISL connections may provide
insufficient bandwidth while the bandwidth of other connections
is unused.
To optimize bandwidth use and automatically provide dynamic
load balancing across multiple ISLs, consider purchasing and
enabling the OpenTrunking feature key. For information about
the feature and managing multiple ISLs, refer to OpenTrunking
and General Fabric Design Considerations.
Table 3-1 ISL Transfer Rate Versus Fabric Port Availability
(Two-Director Fabric)
Number of
ISLs
ISL Data Transfer Rate
(at 1.0626 Gbps)
ISL Data Transfer Rate
(at 2.1250 Gbps)
Available
Fabric Ports
1 1.0625 Gbps 2.1250 Gbps 126
2 2.1250 Gbps 4.2500 Gbps 124
3 3.1875 Gbps 6.3750 Gbps 122
4 4.2500 Gbps 8.5000 Gbps 120
5 5.3125 Gbps 10.6250 Gbps 118
6 6.3750 Gbps 12.7500 Gbps 116
7 7.4375 Gbps 14.8750 Gbps 114
8 8.5000 Gbps 17.0000 Gbps 112