Chapter 3. Connectivity 147
3.9 Parallel Sysplex channels
Parallel Sysplex technology is a highly advanced, clustered, commercial processing system.
It supports high-performance, multisystem, read/write data sharing, enabling the aggregate
capacity of multiple z/OS and OS/390 systems to be applied against common workloads.
The systems in a Parallel Sysplex configuration have all the capabilities of the standard z900
or S/390 system and run the same applications. This allows users to harness the power of
multiple z900 and S/390 systems as if they were a single logical computing system.
The Parallel Sysplex technology represents a synergism between hardware and software and
is comprised of Parallel Sysplex-capable servers, the z900 Coupling Facility, high-speed links
(ISC-3, ICB-3), Sysplex Timer, shared disks, and software (both system and subsystem)
designed for parallel processing (see Figure 3-32).
Figure 3-32 Parallel Sysplex connectivity
The architecture is centered around the implementation of a Coupling Facility running the
Coupling Facility Control Code (CFCC) and high-speed coupling connections for intersystem
communications. The Coupling Facility is responsible for providing high-speed data sharing
with data integrity across multiple z900 and S/390 systems.
The Parallel Sysplex technology is an integral part of the z900 and G5/G6 server platforms,
and is the foundation on which a growing number of new subsystem and operating system
enhancements are based. With the delivery of sysplex exploitation by the traditional OLTP,
batch, and decision support workloads well underway, focus has shifted to support of new
application execution environments. These include commercial parallel Web server
applications and cluster-enabled object-oriented servers to distributed clients.
The Parallel Sysplex technology is fundamental to the z900 and G5/G6 server’s competitive
posture in the large-scale commercial processing arena, providing the scalability, dynamic
workload balancing, and continuous computing characteristics that customers are
increasingly coming to depend upon.
DASD DASD DASD
ESCON / FICON
* in compatibility mode only
G5/G6 serverz900 server
ETR links required to a
CF on a turbo model
148 IBM eServer zSeries 900 Technical Guide
Coupling channel modes
There are several types of coupling channels on the z900 server:
InterSystem Channels (ISC-3)
– ISC-3 Peer mode
– ISC-3 Compatibility mode
Integrated Cluster Bus Channels (ICB-3)
– ICB-3 Peer mode
– ICB Compatibility mode
Internal Coupling (IC-3) Channels
– IC-3 Peer mode only
The ISC-3 and ICB-3 Coupling links can use Peer or Compatibility mode support depending
on the configuration and the type of servers that are connected. Compatibility mode is used to
connect z900 server Coupling Facility (CF links) to G5/G6 and earlier generation servers.
Table 3-11 specifies the possible combinations of ISC-3 and ICB-3 Coupling links by server
Table 3-11 ISC-3 and ICB-3 Coupling channel options
1. The G3 server introduced HiPerLinks, now referred to as ISC-2.
2. The G5 server introduced the CF link called Integrated Cluster Bus (ICB).
The z900 server introduced a new mode of operation that is supported on the ISC-3, ICB-3,
and IC-3 channels, called “Peer mode.” Peer mode operates at a much faster data rate than
the previously released CF channels. The z900 also maintains compatibility with these earlier
ISC and ICB channels by operating in what is called “Compatibility mode.”
A coupling channel operating in Peer mode may be used as both a sender and receiver at the
same time. This means that it may be shared by several LPARs and also the CF logical
partition (LP) within the same CPC.
Gb = Gigabit
N/A N/A N/A
N/A N/A 333 MBps
MB = MegaByte
z900 ISC-3 N/A 2 Gbps N/A N/A
N/A N/A 333 MBps N/A
N/A N/A N/A 1 GBps
GB = GigaByte