HP Mainframe Connectivity Design Guide

• Reduces application latency caused by tape read and write operations, XRC operations, and
other control unit operations over long-distance FCIP ISLs
• Can increase the supported distances for these applications from 300 km to several thousand
km, depending on available bandwidth and application requirements
Before you configure the Advanced FICON Accelerator:
• Configure the fabric to support Cascaded FICON
• Configure the FCIP interfaces and circuits
• Disable the FCIP tunnels
You can enable the FCIP tunnels after the accelerator is configured.
FCIP trunks are not supported with the Advanced FICON Accelerator.
You must use zoning or TI zones to ensure determinist routes for each device supported by the
Advanced FICON Accelerator across the FCIP ISLs. For more information about using TI zones
with the Advanced FICON Accelerator, see “TI zones with the Advanced FICON Accelerator”.
Advanced FICON Accelerator single FCIP path requirement
The Advanced FICON accelerator provides long-distance extension of supported FICON devices
by intercepting all exchanges between a CHPID and a CU and emulating FICON commands and
responses for these devices. This improves application performance over distance while maintaining
data integrity. For the accelerator to function correctly, all exchanges between a CHPID and CU
must use a single FCIP path. There are two ways to ensure a single FCIP path for emulated FICON
devices:
• Define only one FCIP tunnel between sites.
• Use a TI zone to assign a specific FCIP tunnel to the CHPID and CU ports on the directors.
Single FCIP tunnel with the Advanced FICON Accelerator
The 1606 Extension SAN Switch and DC Dir Switch MP Extension Blade use FCIP trunking features
to overcome the limitation of one tunnel per Ethernet interface. In FOS V6.3.x and later, an FCIP
tunnel can be created with multiple FCIP circuits on different GbE IP interfaces to provide WAN
load balancing and failover recovery in the event of a limited WAN outage. If the FCIP circuits
take different physical paths to the remote site, the tunnel remains active if one circuit fails, although
the tunnel will have less available total bandwidth. This provides a highly-redundant FCIP
configuration for the fabric.
One FCIP tunnel can consist of up to 4 circuits on separate 1-GbE ports, or up to 10 circuits on a
10-GbE port. Each FCIP circuit has a maximum throughput speed of 1-Gb/s on both the 1-GbE
and 10-GbE ports.
TI zones with the Advanced FICON Accelerator
When using the Advanced FICON Accelerator, if multiple FCIP tunnels are available from the
CHPID to the device, even if the FCIP tunnels are on different directors, zoning must be used to
ensure that each emulated device uses the same FCIP tunnel each time. TI zones are used to create
dedicated paths for specific traffic. They allow you to control which ISL (E_Port) a pair of N_Ports
uses to communicate with each other. When using the Advanced FICON Accelerator, TI zones
ensure that all FICON frames for each CHPID to CU device use a specific FCIP tunnel. Therefore,
all commands, data, and status information for each emulated device always flows on the same
FCIP tunnel.
A TI zone contains a set of N_Ports (CHPIDs and CUs) and E_Ports (ISLs & FCIP tunnels). Only
those E_Ports contained in the TI Zone are used by the N_Ports in that same TI zone. For emulated
devices, only one E_Port is included in the TI zone, and failover is disabled. This forces all devices
144 FICON and FICON SAN extension