Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 77/116
9es3s1c3.doc
Rev 5.9
02/12/2003
For the disk resources, LUN masking technologies can be involved, either at the server level or disk
array level. Zoning can also be used to create virtual networks and simplify the management.
6.3. The Design of a SAN Infrastructure
Fibre channel is the single technology available on the market that allows to deploy SANs with a high
level of performance. It is a highly reliable, gigabit interconnect technology allowing concurrent
communications among servers, data storage systems, and other peripherals using SCSI and IP
protocols. One of the advantages of the fibre channel technology is the high flexibility of the network
design: the use of switches and hubs allows to create large infrastructures, with a high level of
performance and interconnecting different equipment.
6.3.1. Media Speed
Fibre Channel technology can operate at 100MB/s or 200MB/s. But it is not yet the ultimate evolution
of this technology: the 400 MB/s speed is standardized, but no products are available today.
6.3.2. Cabling
The Fibre Channel standards have defined several media. The most frequently used solutions and their
characteristics are described in the next table.
Media Maximum cable length
Typical
connector
Cable
structure
50 µm multi-mode optical fibers 500 m SC 2 fibers
62.5 µm multi-mode optical fibers 175 m SC 2 fibers
9 µm single mode optical fibers 10 km ST, SC 2 fibers
50 µm multi-mode optical fibers 300 m LC 2 fibers
9 µm single mode optical fibers 10 km ST, LC 2 fibers
copper
30 m (active interface)
3-15 m (passive interface)
DB9, HSSDC 4 wires
50 µm multi-mode optical fibers is the preferred cable for Fibre Channel. 62.5 µm has been introduced
to reuse LAN cabling, where this type of fibers is widely used. Single mode fibers are reserved for
specific applications, such as long distance interconnection for site interconnection and/or disaster
recovery solutions. This type of cabling enables connections far above the 10 km defined by the
standard, using more powerful laser and/or more sensitive receivers.
Copper cabling has been widely used due to its lower cost. It is now less and less used, because the
price of optical equipment rapidly decreases, and because of the sensitiveness of the copper
technology to EMI, ESD and ground problems. The copper cables are specific for the Fibre Channel
technology, and are not compatible with UTP or STP cables used in LANs, or with copper cables used
in telco.