6947ch03.fm Draft Document for Review April 7, 2004 6:15 pm
78 IBM eServer zSeries 990 Technical Guide
Figure 3-3 STIs and I/O cage connections
A Memory Bus Adapter (MBA) STI connector, located in a book, can be connected to one of
the following:
򐂰An eSTI-M card, which creates up to four secondary STI links to connect I/O cards
򐂰An STI-2 Extender card, which has up to two ICB-2 links
򐂰An STI-3 Extender card, which has up to two ICB-3 links
򐂰An ICB-4 link, which attaches directly to an STI port
eSTI-M card
For each z990 I/O cage domain, the MBA-to-I/O card connectivity is achieved using an
eSTI-M card and a 2 GB/sec STI cable. These half-high eSTI-M cards plug into specific slots
(5, 14, 23, and 28) in the z990 I/O cage. Physical slot locations 5, 14, and 23 house two
half-high eSTI-M cards, while slot 28 has only one half-high card plugged in the top.
The eSTI-M card (Feature Code 0322) takes the 2 GB/sec link from an MBA’s STI and
creates four secondary STI links, which are connected to the I/O and cryptographic cards
through the I/O cage board. The bandwidth of the secondary link is determined by the feature
card it is attached to:
򐂰333 MB/sec for ESCON
򐂰500 MB/sec for ISC-3
򐂰1 Gb/sec for FICON, OSA-E, PCIXCC and PCICA

I/O Cage

ICB-2
(333 MB/Sec)
STI-2 Extender
ICB-3
(1 GB/Sec)
STI-3 Extender
ICB-4
(2 GB/Sec)

CEC Cage

2 GB/sec
STIs
Book
M
B
A
s
ESCON
eSTI-M OSA-E
PCIXCC
STI
500 MB/Sec PCICA
STI
333 MB/Sec
STI
1 GB/Sec
ESCON
eSTI-M OSA-E
ISC-3
STI
500 MB/Sec
FICON
Express
STI
333 MB/Sec
STI
1 GB/Sec
12 STIs
STI
1 GB/Sec
I/O Cards
Crypto
Cards