3.17 Hubs

only for RuBoard - do not distribute or recompile

3.17 Hubs

FC_AL hubs connect devices to the loop. It is a simple way to connect participants in a private loop. There are two types of hubs:

  • Passive, which only reacts to ports being inserted into or removed from a loop.

  • Active, which are able to do configuration changes dynamically, based on some controlling protocol.

Some hubs can sense or manage configuration changes in the loop, including:

  • knowing when NL_Ports are added

  • knowing when NL_Ports are removed

  • knowing when address changes occur for an entire set of NL_Ports

  • switching NL_Ports into or out of a loop

Hubs also provide port bypass circuits to heal a loop when a device is removed or fails. This allows for less disruption in operations. Hubs help solve the problems of cabling devices and keeping track of which loop a device is on. With central cabling by way of the FC-AL hub, it is easy to add and remove devices from arbitrated loops .

There are some definite advantages to using Fibre Channel hub:

  • Extremely fast solution for connecting peripherals and hosts (nodes)

  • Up to 124 NL_Ports per loop

  • Loop topology eliminates wiring clutter

  • FC-AL hubs enhance subsystem availability

  • FC-AL hubs provide port bypass circuits to permit hot repair

only for RuBoard - do not distribute or recompile


Storage Area Networks. Designing and Implementing a Mass Storage System
Storage Area Networks: Designing and Implementing a Mass Storage System
ISBN: 0130279595
EAN: 2147483647
Year: 2000
Pages: 88

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