Brocade FICON Administrator's Guide v7.1.0 (53-1002753-01, March 2013)

FICON Administrator’s Guide 51
53-1002753-01
FICON emulation overview
4
FIGURE 13 Tape Read Pipelining
FICON and ESCON conversion support
The Brocade 7800 switch and FX8-24 blade can operate with the Prizm FICON to ESCON converter
and ESBT Bus/Tag Interface Module for Prizm from Optica Technologies, Inc. This allows FICON
tape emulation when connecting to ESCON and to bus and tag devices including 3480, 3490, and
3590 controllers. Discovery of these devices is automatic when FICON emulation is enabled on an
FCIP tunnel.
Printer emulation
The Brocade 7800 switch and FX8-24 blade can operate with a Prizm FICON to ESCON converter
and an ESBT Bus/Tag Interface Module for Prizm from Optica Technologies, Inc. This allows FICON
printer emulation when connecting to printers such as the 1043, 3203, 3211, 3800, 4245, 4248,
6262, Xeros Printer Access Facility (XPAF), and Intelligent Printer Data Stream (IPDS) models.
Discovery of these devices is automatic when FICON emulation is enabled on an FCIP tunnel.
For printer emulation, basic write streams are emulated to help resolve link latency resulting from
channel programming and associated FICON protocols. Because most supported printers will be
connected through the Prizm FICON to ESCON converter or ESBT Bus/Tag Interface Module,
resolving latency on the WAN is not required. The bottleneck will be the remote channel connection
where it is more important to have outstanding commands queued. Basic read commands known
to be part of the write command chain, typically those that read printer page counters, will be
handled locally without waiting for the actual read data from the device.
This emulation provides the following benefits:
• Optimized performance for FICON printers over distance when printers are extended through
an FCIP tunnel with FICON emulation.
Brocade
extension blade
with emulation
for FICON
FICON
Director(s)
Brocade
extension switch
with emulation
for FICON
Virtual Tape
Controller
Tape
Library
System z
hosts
Local host held off with command retry
awaiting read data to be delivered
Read emulation indication
sent to remote
Read command
IP network
1
3b
4b
5b
6b
Read commands are satisfied locally
2
3a
4a
5a
Read data is streamed to host
6a
Local response
Read command
Read channel programs
are presented locally
to the tape device
3
4
5
6