IBM eServer zSeries 990 Technical Guide

164 IBM ^ 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 GBps. A maximum of 32 IC links can

be defined per z990.

򐂰 ICB-4: Copper links are 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 2 GBps. ICB-4 links can only be defined in Peer mode.

Maximum number of ICB-4 links is 16 per z990.

򐂰 ICB-3: Copper links are available to connect 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 GBps. ICB3 links can only be defined in

Peer mode. Maximum number of ICB-3 links is 16 per z990.

򐂰 ICB-2: Copper links are available to connect a z990 to 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 MBps. Maximum number of ICB-2 links is eight 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 200 MBps for distances up to 10 km, and 100MBps 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 7-3 z990 Coupling Link maximums

Link Type z990 Max

IC 32

ISC-3 48

a

ICB-2 8

ICB-3 16

ICB-4 16