Fabric OS Administrator's Guide v7.0.0 (53-1002148-02, June 2011)

70 Fabric OS Administrator’s Guide
53-1002148-02
Inter-chassis links
4
cost of the ISL path being lesser or greater than the ICL path between the two switches. For
instructions on how to cable ICLs, refer to the Brocade DCX Backbone Hardware Reference Manual
and the Brocade DCX-4S Backbone Hardware Reference Manual. Figure 11 illustrates a triangular
topology.
FIGURE 11 ICL triangular topology
Virtual Fabrics considerations
In Virtual Fabrics, the ICL ports can be split across the logical switch, base switch, and default
switch. The triangular topology requirement must be met for each fabric individually. The present
restriction on the ICL being part of logical switches with only the “Allow XISL Use” attribute off
applies.
64 Gbps inter-chassis links
The 64 Gbps ICLs feature maximizes the performance, scalability, port density, and flexibility of
SAN fabrics. You can have up to 32 by 64 Gbps QSFP ports in a Brocade DCX 8510-8 chassis or a
16 by 64 Gbps QSFP ports in a Brocade DCX 8510-4 chassis, with up to 2 Gbps ICL bandwidth and
support for up to 50 meters of universal optical cables.
Brocade DCX 8510 switches with core blade ICL ports use laser transmission for data traffic. The
distance limit is extended up to 50m. This enables the use of ICLs, instead of ISLs, for regular
connections between switches. The longer cable length allows for flexible topologies while
connecting different Brocade DCX 8510 platforms.
This is in contrast to the restrictions imposed by shorter ICL cables on Brocade DCX/DCX-4s that
limited the number of topologies using ICLs. For example, Figure 12 shows up to five Brocade DCX
8510 chassis connected using ICLs.
ICL 3
ICL 1 ICL 2
Chassis 2
Chassis 1 Chassis 3