POWER7 information

Expansion unit configuration rules

Learn about important configuration rules that must be followed when connecting expansion units to system units.

When you set up an expansion unit, observe the configuration rules in the following list:

Expansion units must be connected to system units with 12X cables in a loop topology. Doing so produces redundancy in the 12X connections so that a single cable failure does not result in loss of communication between the system unit and one or more expansion units.
Expansion units must be connected to system units with SPCN cables in a loop topology. Doing so produces redundancy in the SPCN connections so that a single cable failure does not result in loss of communication between the system unit and one or more expansion units.
Expansion units with 12X SDR capability cannot be in the same 12X loop as expansion units with 12X DDR capability. The following expansion units have 12X SDR capability:
- 7314-G30
- 5796
- 5797
- 5798
The following expansion units have 12X DDR capability:
- 5802
- 5803
- 5873
- 5877

The following table specifies configuration limitations related to 12X loops.

Table 1. 12X loop configuration limitations
Machine type and model	Supported expansion units	Maximum number of loops	Maximum number of expansion units per loop	Maximum number of supported expansion units
8202-E4B 8202-E4C 8202-E4D	7314-G30 5796 5802 5877	Maximum number of loops: 1 loop	7314-G30 = 4 5796 = 4 5802 = 2 5877 = 2	7314-G30 = 4 5796 = 4 5802 = 2 5877 = 2
8205-E6B 8205-E6C 8205-E6D	7314-G30 5796 5802 5877	Maximum number of loops: 2 loops	7314-G30 = 4 5796 = 4 5802 = 2 5877 = 2	7314-G30 = 8 5796 = 8 5802 = 4 5877 = 4
8231-E2C 8231-E2D 8246-L1S 8246-L2T	5802 5877	Maximum number of loops: 1 loop	5802 = 2 5877 = 2	5802 = 2 5877 = 2
8233-E8B	7314-G30 5796 5802 5877	The maximum number of loops varies with the number of processor cards, with a maximum of four processor cards: 1 processor card = 1 loop 2 processor cards = 2 loops 3 processor cards = 2 loops 4 processor cards = 2 loops	7314-G30 = 4 5796 = 4 5802 = 2 5877 = 2	7314-G30 = 8 5796 = 8 5802 = 4 5877 = 4
8248-L4T Note: The 16-way, 24-way, and 32-way configurations support expansion units. The 8-way configuration does not support expansion units. 8408-E8D Note: The 16-way, 24-way, and 32-way configurations support expansion units. The 8-way configuration does not support expansion units. 9109-RMD Note: The 24-way, 36-way, and 48-way configurations support expansion units. The 12-way configuration does not support expansion units.	5802 5877	Maximum number of loops: 2 loops	5802 = 2 5877 = 2	5802 = 4 5877 = 4
8412-EAD 9117-MMB 9117-MMC 9117-MMD 9179-MHB 9179-MHC 9179-MHD	7314-G30 5796 5802 5877	The maximum number of loops is equal to two loops per processor drawer in the system configuration: 1 processor drawer = 2 loops 2 processor drawers = 4 loops 3 processor drawers = 6 loops 4 processor drawers = 8 loops	7314-G30 = 4 5796 = 4 5802 = 2 5877 = 2	7314-G30 = 32 5796 = 32 5802 = 16 5877 = 16
9119-FHB	5797 5798 5803 5873	The maximum number of loops is equal to two loops per processor drawer in the configuration: 1 processor book = 4 loops 2 processor books = 8 loops 3 processor books = 12 loops 4 processor books = 16 loops 5 processor books = 20 loops 6 processor books = 24 loops 7 processor books = 28 loops 8 processor books = 32 loops	5797 = 1 5798 = 1 5803 = 1 5873 = 1	5797 = 32 5798 = 32 5803 = 32 5873 = 32
8231-E1C 8231-E1D 8231-E2B 8236-E8C 8246-L1C 8246-L1D 8246-L1T 8246-L2C 8246-L2D 8246-L2S 8268-E1D	System does not support expansion units.	Not applicable.	Not applicable.	Not applicable.

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Last updated: Tue, September 30, 2014