Chapter 3. I/O system structure 89
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IOCP. The CHPID assignment associates the CHPID number to a physical channel port
location (PCHID).
HiperSockets (IQD) and IC links (ICP) do not have PCHIDs, as they are virtual and not
physical links, but they do require CHPID numbers.
The PCIX Cryptographic Coprocessor (PCIXCC) and PCI Cryptographic Accelerator (PCICA)
features do not require CHPID numbers but are assigned PCHIDs.

z990 CHIPD Mapping Tool (CMT)

The z990 CHPID Mapping Tool (CMT) is available, and it is highly recommended for
PCHID-to-CHPID assignments. For complex configurations and configurations using multiple
Logical Channel Subsystems, using the CMT is strongly recommended.
CMT has a manual mapping and availability mapping function, which does the
PCHID-to-CHPID assignments for the best availability. For more information about the z990
CMT, see “IBM z990 CHPID Mapping Tool (CMT)” on page 116.
3.4 Connectivity
Input/output (I/O) channels are components of the z990 server Channel Subsystem (CSS).
They provide a pipeline through which data is exchanged between processors, or between a
processor and external devices or networks. The most common type of device attached to a
channel is a control unit (CU). The CU controls I/O devices such as disk and tape drives.
Server-to-server communications are most commonly implemented using Inter-System
Channels (ISC-3), Integrated Cluster Bus (ICB4, ICB-3 or ICB-2) links, or channel-to-channel
(CTC) connections.
Local Area Network (LAN) connectivity can be done by the OSA Express cards. There are
specific OSA Express cards to support Gigabit Ethernet (GbE), 1000BASE-T Ethernet,
100BASE-T Ethernet, 10BASE-T Ethernet and Token Ring networks. For additional, detailed
information about z990 connectivity, see the IBM Redbook IBM eServer zSeries Connectivity
Handbook, SG24-5444.

3.4.1 I/O and cryptographic features support and configuration rules

Table3-7 on page 90 summarizes all available I/O and cryptographic features on z990
servers, the maximum number of ports for each type, the number of I/O slots required to
achieve this number, and the port increments.
The I/O configuration rules are also provided, including the configuration requirements and
limitations.