R&M Data Center Handbook

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Arbitrated Loop (FC-AL) is also known as Low Cost Fibre Channel, since it is a popular choice for entry into the
world of Storage Area Networks. FC-AL implementations are frequently found in small clusters in which it is
possible for multiple physical nodes to directly access a common mass storage system. FC-AL makes it possible
to operate up to 127 devices on one logical bus. All devices share the data transmission rate that is available
there (133 Mbit/s to 8 Gbit/s, depending upon the technology in use). Cabling is implemented in a star shape over
a Fibre Channel hub. However, it is also possible to connect devices one after the other, since many Fibre
Channel devices have two inputs or outputs available. Implementing cabling as a ring is not common.
Fibre Channel Switched Fabric (FC-SW) is the implementation of Fibre Channel which provides the highest performance
and greatest degree of failure safety. Switched fabric is generally meant when the term Fibre Channel is
used. The Fibre Channel switch or director is located at the center of the switched fabric. All other devices are
connected with one another through this device, so it is possible to switch direct point-to-point connections between
any two connected devices via the Fibre Channel switch.
In order to increase failure safety even more, many installations are moving to redundant dual fabric in their Fibre
Channel implementations. This system operates two completely independent switched fabrics; each storage subsystem
and each server is connected to each of the two fabrics using at least one HBA (Host Bus Adapter). In
addition to the failure of specific data paths, the overall system can even cope with the failure of one entire fabric,
since there is no longer one single point of failure. This capability plays an important part in the area of high
availability, and therefore in the data center as well.
Fibre Channel Applications for Fiber Optic Cables with OM1 – OM4 & OS2
Fiber type acc. ISO/IEC
11801
OM1 OM2 OM3 OM4 OS2
Wavelength 850nm 1300nm 850nm 1300nm 850nm 1300nm 850nm 1300nm 1310nm 1550nm
Overfilled modal
bandwidth (MHz*km)
200 500 500 500 1500 500 3500 500
Eff. laser launch modal
bandwidth (MHz*km)
2000 4700 NA NA
1G Fibre Channel 100-
MX-SN-I (1062 Mbaud)
1G Fibre Channel 100-
SM-LC-L
2G Fibre Channel 200-
MX-SN-I (2125 Mbaud)
2G Fibre Channel 200-
SM-LC-L
4G Fibre Channel 400-
MX-SN-I (4250 Mbaud)
4G Fibre Channel 400-
SM-LC-M
4G Fibre Channel 400-
SM-LC-L
8G Fibre Channel 800-
M5-SN-I
8G Fibre Channel 800-
SM-LC-I
8G Fibre Channel 800-
SM-LC-L
(4250 Mbaud)
10G Fibre Channel
1200-MX-SN-I
(10512 Mbaud)
10G Fibre Channel
1200-SM-LL-L
16G Fibre Channel
1600-MX-SN
(10512 Mbaud)
16G Fibre Channel
1600-SM-LC-L
16G Fibre Channel
1600-SM-LC-I
Source: thefoa.org
300m
3dB
150m
2.1dB
70m
1.8dB
33m
2.4dB
500m
3.9dB
300m
2.6dB
150m
2.1dB
50m
1.7dB
82m
2.2dB
35m
1.6dB
860m
4.6dB
500m
3.3dB
380m
2.9dB
150m
2.0dB
300m
2.6dB
100m
1.9dB
860m
4.6dB
500m
3.3dB
400m
3.0dB
190m
2.2dB
300m
2.6dB
125m
1.9dB
10km
7.8dB
10km
7.8dB
4km
4.8dB
10km
7.8dB
1.4km
2.6dB
10km
6.4dB
1km
6.0dB
10km
6.4dB
2km
2.6dB
In summary, Fibre Channel-based storage solutions offer the following advantages:
• Very broad support is provided by hardware and software manufacturers.
• At this point, the technology has reached a high level of maturity.
• The system is very high-performance.
• High-availability solutions can be set up. (redundancy)
R&M Data Center Handbook V2.0 © 08/2011 Reichle & De-Massari AG Page 103 of 156