Brocade Network Advisor SAN + IP User Manual v12.1.0 - Manual (Page 1165)

1112 Brocade Network Advisor SAN + IP User Manual
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Connecting cascaded FICON fabrics over FCIP
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Tape write pipelining
FICON tape write pipelining improves performance for a variety of applications when writing to tape
over extended distances. FICON tape write pipelining locally acknowledges write data records,
enabling the host to generate more records while previous records are in transit across the IP WAN.
If exception status is received from the device, the writing of data and emulation is terminated. The
FICON Tape Emulation License is required to enable FICON Tape Write Pipelining.
Tape read pipelining
FICON tape read pipelining improves performance for certain applications when reading from
FICON tape over extended distances. FICON tape read pipelining reads data from tape directly from
the tape device. Reading of tape continues until a threshold is reached. The buffered data is
forwarded to the host in response to requests from the host. When the host sends the status
accept frame indicating that the data was delivered, the read processing on the device side credits
the pipeline and requests more data from the tape. If exception status is received from the device,
the reading of data and emulation is terminated. The FICON Tape Emulation License is required to
enable FICON Tape Read Pipelining.
Teradata pipelining
Teradata emulation reduces latency on links to Teradata warehouse systems caused by WAN
propagation delays and bandwidth restrictions. It accomplishes this by processing selected FICON
commands for associated control, data, and status responses. FICON Teradata Emulation is
supported between FICON Channels and FICON Teradata controllers. This feature is available only
on 8 Gbps Extension Switch and Blade platforms operating with Fabric OS 6.4.1 and later.
Write pipelining
For write commands, control and status frames are generated for the host side of the WAN to
pipeline write commands over the same or multiple exchanges.
Read pipelining
For read operations received by the device side of the WAN, a number of anticipatory read
commands arAdde generated and transferred to the device. The data and status associated with
these commands are sent to the host side of the WAN and queued in anticipation of
host-generated read commands.
Connecting cascaded FICON fabrics over FCIP
This section provides a basic guide of IP best practices for connecting cascaded FICON fabrics over
an IP network through FCIP and merging the fabrics. Included are planning considerations, steps
for configuring an IP link between two Extension Switches and merging them into one fabric, and
steps for configuring DWDM links to use R_RDYs.
IP best practice for connecting the fabrics is to perform the following steps in order:
1. Configure all IP tunnels and circuits between the fabrics.
2. Merge the FICON fabrics.