Sun Microsystems StorageTek 96257 - Manual (Page 37)

96257 Sun Confidential: Internal Only 2-37
Revision A
VTSS Configuration Planning
FICON Data Transfer Rates
The fastest native FICON channels are rated at 200 MB/sec., but actually can achieve a
maximum data rate of only 170 MB/sec. under optimum conditions. In actual practice, FI-
CON typically operates at 40-60 MB/sec. using the 32 KB block size commonly found in
tape workloads.
VCF3 cards support 2 Gb link speeds; actual throughput speed is determined by many
factors including block size, microcode level, etc.
FICON Cabling — Short-Wave vs. Long-Wave Connections
Currently, FICON channels send data via fiber-optic cables only; copper-wire cables are
not supported. Fiber-optic data communiction cables are either single-mode or multi-
mode, as summarized in
Table 2-5 , and have these characteristics:
• Single-mode cables have a smaller core size than multi-mode, typically 8.5 or 9 microns,
and use long wavelengths to transmit data over greater distances (up to 10 km; 20 km
with an RPQ)
1
• Multi-mode cables have a larger core size than single-mode cables, typically 50 or 62.5
microns, and use short wavelengths, which limits transmission range to distances less
than 500 m (1640 ft.). Multi-mode cables are more economical when long transmission
distances are not a requirement.
VCF2 (FICON) cards support both short- and long-wave connections through different
SFP connectors, which can be intermixed on individual cards. By default, VCF2 cards ship
with long-wave (LX) SFP connectors; an orderable option allows field upgrades to short-
wave (SX) connections.
LC Fibre connectors are used on both short- and long-wave SFPs, which requires use of
LC-LC or LC-SC cables for all VTSS-to-host connections.
Table 2-5. Single-Mode vs. Multi-Mode FICON Cabling
1. RPQ is not available with FICON channels rated at 200 MB/sec.
Mode Type Core Size Wavelength Color Max. Transmission Distance Relative Cost
Single-mode
(SM)
8.5 to 9
microns
Long (LX) Yellow
• 10 km (6.2 mi.)
• 20 km (12.4 mi.) with RPQ
• 100 km (62 mi.) with repeaters
More
Multi-mode
(MM)
50 to 62.5
microns
Short (SX) Orange
• 50 micron: ≤ 500 m (1640 ft.)
• 62.5 micron: ≤ 175 m (574 ft.) *
Less
Note:
*
Requires mode-conditioner patch (MCP) cables, used in pairs. Data rates >100 MB/sec. are not supported
when MCP cables are used.