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IBM-AUSTRIA - PC-HW-Support 30 Aug 1999 |
Description
Description
The IBM Fibre Channel Hub is a 7-port central interconnection for Fibre Channel Arbitrated Loops that
follow the ANSI FC-AL standard.
Each Fibre Channel Hub port receives serial data from an attached node and retransmits the data out
of the next hub port to the next node attached in the loop.
Each reception includes data regeneration (both signal timing and amplitude) supporting
full-distance optical links.
The Fibre Channel Hub detects any loop node that is missing or is inoperative and automatically routes the data
to the next operational port and attached node in the loop.
LED indicators provide status information to indicate
whether the port is active or bypassed.
Each port requires a Gigabit Interface Converter (GBIC) to connect it to each attached node.
The Fibre Channel Hub supports any combination of short-wave or long-wave optical GBICs.
The GBICs are hot-pluggable into the Fibre Channel Hub, which means you can add host computers,
servers, and storage modules to the arbitrated loop dynamically without powering off the
Fibre Channel Hub or any connected devices.
If you remove a GBIC from a Fibre Channel Hub port, that port is automatically
bypassed. The remaining hub ports continue to operate normally with no degradation of system performance.
Conversely, if you plug a GBIC into the Fibre Channel Hub, it will automatically be inserted and become a node
on the loop if valid Fibre Channel data is received from the device.
Data transfer within the Fibre Channel Hub is implemented in serial differential
Positive Emitter Coupled Logic (PECL) AC coupled logic.
Each Fibre Channel Hub port monitors the serial data input stream as well as the GBIC connected to it.
The following conditions will cause the Fibre Channel Hub to bypass a port:
- TX_FAULT: Detects a GBIC transmitter fault.
- RX_LOS: Detects a loss of received signal amplitude from the device.
- MOD_DEF: Detects the absence of a GBIC.
The Fibre Channel Hub circuitry detects off-frequency data, excessive jitter,
or inadequate edge transition density on a per-port basis.
The Fibre Channel Hub uses the standardized AMP SCA2 20-pin connector to implement
hot plugging. Surge currents, caused by hot plugging, are minimized by slow-start circuitry
and a pin-sequencing procedure on the GBIC.
Electrostatic discharge (ESD) transients are minimized by means of sequenced connector contacts.
The Fibre Channel Hub includes a universal power supply that can operate from 95 to 250 V ac and from 50 to 60 Hz.
Fibre Channel Long-Wave GBIC
Features of the long-wave optical GBIC include:
- Full-speed: 1.0625 Gbps
- Uses single-mode 9 um fiber
- Wavelength: 1310 nm
- Non-OFC laser
- Uses dual SC fiber optic connectors
- Fiber lengths: 2 meters minimum, 10 kilometers maximum
Fibre Channel Short-Wave GBIC
Features of the short-wave optical GBIC include:
- Compliant with Fibre Channel FC-PH-2 physical layer option 100-M5-SN-I
- Full-speed: 1.0625 Gbps Type 3523 Fibre Channel Hub and GBIC 7
- Wavelength: 780 nm
- Non-OFC laser
- Supports multimode 50 um fiber (2 meters/minimum, 500 meters/maximum)
- Uses dual SC fiber optic connectors
Fibre Channel-Arbitrated Loop
The Fibre Channel-Arbitrated Loop (FC-AL) is an ANSI standard (X3T11) product
designed to provide shared bandwidth over low-cost media.
Early adapters primarily use the SCSI protocol transported over Fibre Channel for
distributed server and storage-cluster applications.
The Fibre Channel Hub is a central point of interconnection designed to maintain
a fault-tolerant physical loop topology.
The Fibre Channel Hub can also be used to implement configurations which extend
the size of the FC-AL loop to its maximum size of 127 active loop ports
(includes one optional Fabric-Loop port).
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