IBM Storage Networking SAN256B-7 Installation, Service And User Manual page 146

Table 30. External Port to slotShow Command Port Mapping for Core Blades
External Port Number
0
1
2
3
4
5
6
7
ICL trunking groups
Multiple directors can be connected through inter-chassis links (ICLs) between the Gen 7 ICL or
4x32Gb/s QSFPs installed on core routing blades. Each QSFP connection between two devices provides
128Gb/s bandwidth. Trunking optimizes the use of ICL bandwidth by allowing a group of links to merge
into a single logical link, called a trunk. Traffic is distributed dynamically and in order over this trunk,
achieving greater performance with fewer links. Within the trunk, multiple physical ports appear as a
single port, thus simplifying management. Trunking also improves system reliability by avoiding I/O
retries if one link within the trunk fails.
Since each port within a QSFP terminates on a different ASIC within each core blade, an ICL trunk cannot
be formed using the individual FC ports within the same QSFP. A trunk must be formed from individual FC
ports in different QSFP ports, which must reside in the same trunk group. To form an ICL trunk between
two devices, a minimum of two QSFPs within a port trunk group on a core blade installed in one device
must be connected to a pair of QSFPs within a trunk group on a core blade in another device.
Each CR64-4 blade on the SAN256B-7 Director has two ICL trunking groups consisting of the following
QSFP ports:
• 0, 1, 5, and 4
• 2, 3, 6, and 7
Ports belonging to the same trunking groups are indicated with the same color border under the ports on
the blade faceplate. These colors are also applied to the port map labels on each blade faceplate to
indicate ports belonging to the same trunking groups.
For more information on ICLs and configuring ICL trunking between core routing blades on different
directors, refer to "Inter-Chassis Links" in the Fabric OS Administration Guide.
Note: You cannot configure ISLs using ports on port blades and QSFP-based ICLs using ports on core
routing blades concurrently on the same chassis. ISLs and ICLs can co-exist between a pair of chassis if
the ISLs and ICLs are in different logical switches.
ICL cabling configurations
The following figures show acceptable cabling configurations for the ICL feature between QSFP ports in
core routing blades. The recommended topology is the "parallel" type where at least four QSFP cables
connect between both core routing blades on any two directors. This provides ICL trunking between
122 IBM Storage Networking SAN256B-7: SAN256B-7 Installation, Service, and User Guide
slotShow FC Port Numbers
0-3
4-7
8-11
12-15
16-19
20-23
24-27
28-31