Specifications

DATA CENTER BEST PRACTICES
SAN Design and Best Practices 40 of 84
fig28_SAN_Design
N_Port E_Port F_Port VE_Port VEX_Port EX_Port
IP
Cloud
Edge
Fabric
Brocade DCX
with FX8-24
Brocade
7800
FCIP Tunnel
Isolated Remote Edge Fabric
Isolated Edge Fabric
Figure 28. Edge-remote edge architecture.
Another design consideration with “X” ports is: How many can be in a path? This is indeed limiting. If you start
from inside an FC Router (refer to Figure 29) and move toward the initiator or target, you may only pass through
1 “X” port along the way. If you pass through 2 “X” ports to get to the initiator or target, the architecture is
not supported.
fig30_SAN_Design
VE “backbone”
Best Practice
Combination 2
Source
Destination
FC
Router
FC
Router
Edge
Fabric B
Edge
Fabric A
edge EX
EX edgeVE
VEX “remote edge”
Combination 1
Source
Destination
FCIP Link
edge EX EVE
VEX “remote edge”
Pass thru 2 EX/VEX
Not Supported
Source
Destination
FCIP Link
edge EX EX edgeVE
Figure 29. “X” ports along a path.
The Integrated Routing (IR) license, which enables FCR on Brocade switches and directors, is needed only on the
switches or directors that implement the “X” ports. Any switches or directors that connect to “X” ports and have
no “X” ports of their own do not need the IR license. The IR license is not needed on the E_Port/VE_Port side to
connect to the EX_Port/VEX_Port side.
FCIP with FICON Environments
In a mainframe environment, FCR cannot be used, because the FICON protocol is not supported. Most often, VFs
are used on a Brocade DCX platform forming multiple LSs. One LS is designated as the fabric to be extended.
The other LSs are used for production trafc. Only channels and control units that must communicate across the
channel extenders are connected to this LS. These LS fabrics merge across the WAN, forming a single fabric.
This is acceptable because the number of devices is limited to just those that are communicating across the
WAN, which tend not to be in production. In other words, they are backup tape or an RDR application—namely
IBM XRC. If the production fabrics were to be exposed to the WAN they might be vulnerable to the type of outage
previously described.