HP Mainframe Connectivity Design Guide

Table 1 Fibre Channel protocol layers (continued)
CCWsSCSI commandsProtocol
Encode/decode and link controlFC-1 layer
Physical linkFC-0 layer
FICON supports the following Fibre Channel ports:
• N_Ports, F_Ports, and E_Ports
• G_Ports that have adopted the characteristics of an N_Port, F_Port, or E_Port
NOTE: Loop ports are not supported by FICON.
FICON SAN infrastructure
You use FICON directors to create the SAN communication paths. The number of mainframes,
storage systems, and other peripherals that you connect is determined by the number of ports
available and other hardware constraints.
SANs enable expansion and high availability by scaling capacity across several systems and over
long distances. Scaling increases the number of devices and connections allowed in a SAN.
Fabrics
A fabric is a single director or set of directors connected in a network. Fabric services manage
device names and addresses, timestamps, and other functionality for the directors.
A set of directors can be connected as a single fabric or partitioned into logical, separate virtual
fabrics (LSANs for B-series or VSANs for C-series) to form an interconnected network of independent
fabrics. Typically, all FICON ports are in the same virtual fabric or zone; all FCP ports are in other
virtual fabrics or zones.
SAN scaling
You can increase SAN connectivity by adding directors to an existing SAN, by using directors
with more ports, or by adding port cards to existing directors. When designing a SAN, you must
ensure compliance with FICON standards and director specifications.
For scaling, consider the following factors:
• Fibre Channel/FICON architecture
Fibre Channel supports a maximum of 239 directors in a single fabric. Because of the FICON
hop limitation, you cannot have this number of FICON directors in the same fabric. FICON
and FCP can coexist in the same fabric; therefore, an intermix fabric can be much larger than
a FICON-only fabric. For more information about intermix, see “FICON SAN best practices”
(page 154).
HP specifies support based on rules for the maximum number of directors and maximum
number of ports in a single fabric. Using several directors to obtain a high number of ports is
unacceptable if the fabric exceeds the maximum number of directors. Likewise, using several
large-capacity directors can create a network that exceeds the maximum number of ports.
FICON SAN infrastructure 11