Brocade Communications Systems Network Advisor 12.3.0, User Manual

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952 Brocade Network Advisor SAN User Manual
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Connecting cascaded FICON fabrics over FCIP
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Procedures in this section may refer to additional sections in this chapter or additional chapters in
this manual for more detailed information. This section assumes that the switches in the fabrics to
be merged have been configured for FICON operation using procedures under “Configuring a
switch for FICON operation”
Chapter 25, “FICON Environments” .
Planning the configuration
Create a drawing to summarize the following elements of your planned configuration.
•
IP network connections
-
Tunnels
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Addresses
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Bandwidth requirements for all circuits
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Label all circuits and tunnels
Determine how the IP network will be used by identifying redundant routes, network distance
for each route, and minimum and maximum bandwidth requirements. The FICON acceleration
feature is required for distances greater than 300 km. Before configuring this feature, Fabric
OS professional services are highly recommended.
•
Network distance
Make sure network distance is measured in actual network delay. The FICON Acceleration
license is required if distance exceeds 300 meters.
•
Traffic Isolation (TI) zones.
Determine the exact ports to use for TI zones.
TI zones are used to segregate traffic such as tape backup and production DASD traffic in
cascaded fabrics. If using TI zones, determine if zones should have failover disabled or
enabled.
The FICON acceleration feature emulates the device it for which it is enabled. Although it
effectively acts like the control unit cache, the control unit has a common processor that
coordinates data written to it from different interfaces. Therefore, you must force traffic to a
specific path using TI zones with failover disabled to ensure data is delivered in order. An
alternative to TI zones is to use independent fabrics to ensure only one path is available. You
can also use independent virtual fabrics.
•
Buffer-to-buffer credit management for long-distance links.
•
Use of dense wavelength division multiplexing (DWDM) or time division multiplexing (TDM)
interfaces and buffer-to-buffer credit management for these interfaces.
Typically the long distance BB credits are supplied if DWDM is used. Some older DWDM
interfaces do not supply BB credits (R_RDY) so check with the DWDM vendor. You may need to
calculate the correct number of BB credits required if using DWDM that does not provide BB
credits. Note that BB credits depend not only on distance, but average frame size as well. Be
sure and contact a Fabric OS support professional for assistance.
Double check the type of optics required since long wave optics are commonly ordered for
mainframe environments and occasionally DWDM interfaces use shortwave optics. Also find
out if a TDM card is being used as you will need to follow procedures under
“Configuring
DWDM links to use R_RDYs” on page 955.