6947ch07.fm Draft Document for Review April 7, 2004 6:15 pm
162 IBM eServer zSeries 990 Technical Guide
7.2.4 Coupling Facility link connectivity
The type of CF links you can use to connect a CF to an operating system logical partition is
important because of the impact of the link performance on response times and coupling
overheads. For configurations covering large distances, the time spent on the link can be the
largest part of the response time (mainly if the CF is defined on a z990 server).
The types of links that are available to connect an operating system logical partition to a
Coupling Facility are:
򐂰IC - Licensed Internal Code defined links to connect a CF to a z/OS logical partition in the
same z990 processor. IC links require two CHPIDs to be defined and can only be defined
in Peer mode. The link bandwidth is greater than 2 GB/sec. A maximum of 32 IC links can
be defined per z990.
򐂰ICB-4 - Copper links available to connect z990 to z990, or z890 processors; the maximum
distance between the two processors is 7 meters (maximum cable length is 10 meters).
The link bandwidth is 2GB/sec. ICB-4 links can only be defined in Peer mode. Maximum
number of ICB-4 links is 16 per z990.
򐂰ICB-3 - Copper links available to connect a z990 to z990, z890, z900, or z800 processors;
the maximum distance between the two processors is 7 meters (maximum cable length is
10 meters). The link bandwidth is 1 GB/sec. ICB3 links can only be defined in Peer mode.
Maximum number of ICB-3 links is 16 per z990.
򐂰ICB-2 - Copper links available to connect a z990 to a 9672 G5/G6 processors (you cannot
use ICB-2 to connect a z990 to a z900 or to another z990); the maximum distance
between the two processors is 7 meters (maximum cable length is 10 meters). The link
bandwidth is 333 MB/sec. Maximum number of ICB-2 links is 8 per z990.
򐂰ISC-3 - The z990 ISC-3 feature is compatible with Coupling Links/ISCs (referred to as a
Hiperlink on G5/G6 Servers) on S/390 generation 5 and generation 6 servers as well as
zSeries 890, zSeries 900 and zSeries 800. Each port is capable of 1 Gbps or 2 Gbps
depending upon the mode of operation selected in the Hardware Configuration Definition
(HCD) tool or IOCP. Ports are ordered in increments of one. The maximum number of
ISC-3 links per z990 is 48 in peer mode, and 32 ISC-3 links in compatibility mode.
– There are fiber links available to connect z990 to z990, z890, z900 or z800 processors;
the maximum distance is 10 km, 20 km with RPQ 8P2197 and 40 km with Dense Wave
Division Multiplexing (DWDM). ISC-3s operate in single mode only and link bandwidth
is 200MB/sec for distances up to 10 km, and 100MB/sec when RPQ 8P2197 is
installed. ISC-3 links should be defined in peer mode. The peer mode is used between
zSeries servers only.
– There are fiber links available to connect z990 to G5 and G6 servers. The z990 ISC-3
feature is compatible with Coupling Links/ISCs (referred to as a Hiperlink) on G5/G6
servers. Compatibility mode is used between the z990 and G5/G6 servers. The port is
defined as a sender/receiver (CFS/CFR) channel and the link is capable of 1 Gbps.
Table 7-2 z990 Coupling Link maximums
Link Type z990 Max
IC 32
ISC-3 48a
ICB-2 8
ICB-3 16
ICB-4 16