Reference Guide

16 Fabric OS FCIP Administrator’s Guide
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FCIP trunking
2
Design for redundancy and fault tolerance
Multiple FCIP tunnels can be defined between pairs of 7800 switches or FX8-24 blades, but doing
so defeats the concept of a multiple circuit FCIP tunnel. Defining two tunnels between a pair of
switches or blades is not as redundant or fault tolerant as having multiple circuits in one tunnel.
FCIP tunnel restrictions for FCP and FICON acceleration features
Multiple FCIP tunnels are not supported between pairs of 7800 switches or FX8-24 blades when
any of the FICON emulation/acceleration features or FCP acceleration features are enabled on the
tunnel, unless TI Zones or LS/LF configurations are used to provide deterministic flows between
the switches. These features require deterministic FC Frame routing between all initiators and
devices over multiple tunnels. Noncontrolled, parallel (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.
Note these additional restrictions:
• FICON networks with FCIP emulating and nonemulating tunnels do not support DPS (aptpolicy
3) configurations.
• If one end of a FICON emulating tunnel runs Fabric OS v7.0.0 or later, both ends of the tunnel
must run Fabric OS v7.0.0 or later.
FCIP circuits
The following list describes FCIP circuit characteristics, restrictions, and usage:
• General tunnel and circuit requirements:
- A circuit can have a maximum commit rate of 1 Gbps on 1 GbE ports or 10 Gbps on 10
GbE ports.
- The minimum committed rate allowed on a circuit is 10 Mbps.
- In a scenario where an FCIP tunnel has multiple circuits of different metrics, circuits with
higher metrics are treated as standby circuits and are not used until all lower metric
circuits fail. Refer to “FCIP circuit failover capabilities” for a more detailed description.
- A circuit defines source and destination IP addresses on either end of an FCIP tunnel.
- If the circuit source and destination IP addresses are not on the same subnet, an IP static
route must be defined that designates the gateway IP address.
- There are no addressing restrictions for IPv6 and IPv4 when using switches or blades
operating with Fabric OS v7.0.0 or later.
- Committed bandwidth on both sides of the tunnels and circuits must be the same.
- When load leveling across multiple circuits, the difference between the committed rate of
the slowest circuit in the FCIP trunk and the fastest circuit should be no greater than a
factor of four (for example, a 100 Mbps and a 400 Mbps circuit will work, but a 10 Mbps
and a 400 Mbps circuit will not work). This ensures that the entire bandwidth of the FCIP
trunk can be utilized. If you configure circuits with the committed rates that differ by more
than a factor of four, the entire bandwidth of the FCIP trunk cannot be fully utilized.