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Distance requirements - The distance between elements in a
fabric affects the type of optical port transceiver and cabling
required. In addition, variables such as the number of
connections, grade of fiber-optic cable, device restrictions,
application restrictions, buffer-to-buffer credit limits, and
performance requirements can affect distance requirements.
Consider the following:
— If the distance between two fabric elements is less than 250
meters (at 1.0625 Gbps), 120 meters (at 2.1250 Gbps), or 75
meters (at 10.2000 Gbps) any port transceiver (shortwave or
longwave laser) and any fiber-optic cable type (50-micron
multimode, 62.5-micron multimode, or 9-micron singlemode)
can be used to create an ISL. Cost or port availability may be
the determining factor.
— If the distance between two fabric elements is between 250 and
500 meters (at 1.0625 Gbps), 120 and 300 meters (at 2.1250
Gbps), or 75 and 150 meters (at 10.2000 Gbps) any port
transceiver (shortwave or longwave laser) and 50-micron
multimode or 9-micron singlemode fiber-optic cable can be
used to create an ISL.
— If the distance between two fabric elements exceeds 500
meters (at 1.0625 Gbps), 300 meters (at 2.1250 Gbps), or 150
meters (at 10.2000 Gbps) only longwave laser port transceivers
and 9-micron singlemode fiber-optic cable can be used to
create an ISL.
— Distance limitations can be increased by using multiple fabric
elements. Each director or switch retransmits received signals,
thus performing a repeater and multiplexer function.
However, be aware that each connection introduces a nominal
signal loss of at least one dB through the ISL. If dB losses
introduced through multiple connections exceed the link
budget of the entire ISL, link errors occur. Refer to
Transmission Distance
budgets and distance limitations.
Distance limitations can also be increased by using a variety of
local area network (LAN), metropolitan area network (MAN)
or wide area network (WAN) extension technologies. For
additional information, refer to
Technologies.
Planning Considerations for Fibre Channel Topologies
Planning Considerations for Fibre Channel Topologies
for additional information about link
SAN Extension Transport
3
Data
3-21
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