Design For Redundancy And Fault Tolerance - Brocade Communications Systems Brocade 8/12c User Manual

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FIGURE 282

Design for redundancy and fault tolerance

Multiple FCIP tunnels can be defined between pairs of 8 Gbps extension switches and 8 Gbps
extension Blades, but doing so defeats the concept of a multiple circuit FCIP tunnel. Defining two
tunnels between a pair of switches or blades rather than one tunnel with two circuits is not as
redundant or fault tolerant as having one multiple circuit tunnel.
FCIP tunnel restrictions for FCP and FICON emulation features
Multiple FCIP tunnels are not supported between pairs of 8 Gbps extension Switches and 8 Gbps
extension Blades when any of the FICON or FCP emulation features are enabled on the tunnel
unless TI Zones or LS/LF configurations are used to provide deterministic flows between the
switches. The emulation features require deterministic FC Frame routing between all initiators and
devices over multiple tunnels. If there are non-controlled parallel (equal cost) tunnels between the
same SID/DID pairs, emulation (Fast Write, Tape Pipelining, IBM z/OS Global Mirror (z Gm) or
FICON Tape Pipelining) will fail when a command is routed via tunnel 1 and the responses are
returned via tunnel 2. Therefore multiple equal cost tunnels are not supported between the switch
pairs when emulation is enabled on any one or more tunnels without controlling the routing of
SID/DID pairs to individual tunnels using TI Zones or LS/LF configurations.
FCIP Trunk configuration considerations
There are several points to consider when configuring an FCIP trunk:
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Document Title
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IP Router
10.0.0.1
FCIP Circuits
FCIP tunnel and FCIP circuits
Each FCIP circuit is assigned a pair of IP addresses, one source IP address, and one
destination IP address.
The source IP address is used to determine which GbE interface to use. The GbE IP address
must be on the same IP subnet as the source IP address. IP subnets cannot span across the
GbE interfaces.
The destination IP address is used to determine routing. If the destination IP address is also on
the same subnet as the GbE interface, packets are routed over that subnet. If the destination
IP address is on a different subnet, traffic must be routed to an IP gateway address.
An FCIP circuit can have a maximum commit rate of 1,000,000 Kbps.
WAN
IP Router
10.0.1.1
FCIP Tunnel
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FCIP trunking
FCIP Circuits
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