Appendix: Cascade Connection - NEC SigmaBlade N8406-040(F) User Manual

Appendix: Cascade Connection

N8406-040/042 8G FC Switch can be subjected to cascade connection with each other, or between the
8G FC Switch and iStorage WB51xA(NF9340-SS025/SS026) fibre channel switch, or between the 8G
FC Switch and iStorage WB65xx(NF9350-SS040/SS041/SS042/SS043/SS044)
Cascade Connection
The cascade feature of the 8G FC Switch is characterized as follows:
The 8G FC Switch subjected to cascade connection can share the external devices connected to
them.
The 8G FC Switch subjected to cascade connection can share the CPU blade connected to each of
the 8G FC Switch.
Cascade connection of up to three hops is supported.
Zoning can be provided among 8G FC Switch subjected to cascade connection.
When a Fabric is constructed by cascading the 8G FC Switch, one of the 8G FC Switch in the
Fabric operates as a Principal switch. A single 8G FC Switch without cascading always operates a
Principal switch.
All 8G FC Switch except the Principal switch operates as Subordinate switches.
NOTE:
Any 8G FC Switch in the Fabric can be set to be a Principal switch by "fabricprincipal"
command.
Cascading path between 8G FC Switch can be connected by multiple connections.
Influence to the Fabric when a single cascading path failure occurred can be avoided by
making cascading path redundant or routing path between 8G FC Switch redundant.
IMPORTANT:
The maximum transmission rate among 8G FC Switch subjected to cascade
connection is 8G bps per one cascade path.
Any cascade connections of more than three hops are not supported.
The 8G FC Switch can make cascade connection with N8406-040/042 and iStorage
WB51xA(NF9340-SS025/SS026). Cascade connection with any other FC switch is not
supported.
The 8G FC Switch can make cascade connection with N8406-040/042 and iStorage.
WB65xx(NF9350-SS040/SS041/SS042/SS043/SS044) Cascade connection with any
other FC switch is not supported.
The 8G FC Switch in the same Blade Enclosure (SIGMABLADE) cannot make cascade
connection with each other.
The role of the 8G FC Switch (Principal or Subordinate) may be changed by the Fabric
reconstruction.
When cascade connection is made, a Fabric construction process is done in the 8G FC
Switch connected. Influence to I/O operation in the Fabric may occur during the Fabric
construction process (including reconstruction process).
A Fabric reconstruction process occurs if the Principal switch is removed from the
Fabric by the cascading path failure.
Even if the cascading path or routing path between 8G FC Switch is redundant, A
Fabric reconstruction occurs at other switches if the Principal switch is removed from
the Fabric when a failure occurs at the Principal switch.
When setting of Zoning is done in the 8G FC Switch with cascading connection, the
ports used for cascading path between 8G FC Switch must not be set zone. The
cascading path is used by all zones. It may become a cause of failure of device
recognition if setting of Zoning is done with the zone including the ports used for
cascading path.
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