Specifications

6 Getting Started with the McDATA Intrepid FICON Director
򐂰 A FICON channel in Fibre Channel Protocol (FCP) mode can access FCP devices in one
of two ways:
– Through a FICON channel in FCP mode through a single Fibre Channel switch or
multiple switches to an FCP device
– Through a FICON channel in FCP mode through a single Fibre Channel switch or
multiple switches to a Fibre Channel-to-SCSI bridge
1.3 FICON channel topology
A FICON channel in FICON native (FC) mode uses the Fibre Channel communication
infrastructure supported by the zSeries and 9672 G5/G6 servers to transfer channel
programs (CCWs) and data via its FICON and FICON Express features to another
FICON-capable node, such as a storage device, printer or server (channel-to-channel).
A FICON channel (in conjunction with the McDATA FICON Director) can operate in two
topologies:
򐂰 Switched point-to-point (through a single FICON Director to FICON-capable control units)
򐂰 Cascaded FICON Directors (through two FICON Directors to FICON-capable control
units)
The FICON channel in FICON native (FC) mode supports multiple concurrent I/O
connections. Each concurrent I/O operation can be to the same FICON control unit (but to
different devices/CU images), or to different FICON control units.
1.3.1 Switched point-to-point configuration
In a switched point-to-point connection, at least two Fibre Channel (FC) links are needed in
the channel-control unit path. One is between the FICON channel card (N_Port) and the
FICON Director port (F_Port), then internally within the switch (through the backplane) to
another port (F_Port) and then via the second link to a FICON adapter card in the control unit
(N_Port).
The FICON channel determines whether the associated link is in a point-to-point or switched
topology. It does this by logging into the fabric, fabric login (FLOGI ELS), and checking the
accept response to the fabric login (ACC ELS). The FLOGI-ACC (accept) response indicates
if the channel N_Port is connected to another N_Port (point-to-point) or an F_Port (fabric
port).
An example of a switched point-to-point topology is shown in Figure 1-3.
Multiple channel images and multiple control unit images can share the resources of the Fibre
Channel link and the Fibre Channel switch, such that multiplexed I/O operations can be
performed.
Note: The 9672 G5/G6 processors only support a single switch topology, known as
switched point-to-point, whereas, the zSeries processors support single and dual
switch topologies. A two-switch configuration is known as cascaded FICON Directors.
Note: The 9672 G5/G6 processors do not support FICON channels in FCP mode.
Point-to-point and arbitrated loop topologies
are not supported as part of the zSeries
FCP enablement. This mode is only supported in conjunction with Linux environments.