IBM eServer zSeries 900 Technical Guide

Chapter 3. Connectivity 127

More information about the FC standards can be obtained from the following Web sites:

http://www.t10.org

http://www.t11.org

3.6 Open Systems Adapter-2 channel

The Open Systems Adapter-2 (OSA-2) features were designed to provide direct, industry

standard, local area network and ATM network connectivity in a multi vendor networking

infrastructure.

OSA-2 features were the first features to bring the strengths of the S/390 architecture to the

network environment, namely: security, availability, enterprise-wide access to data, and

systems management. The following OSA-2 features continue to be supported in

z/Architecture for z900 servers:

򐂰 OSA-2 FDDI (feature code 5202)

򐂰 OSA-2 Ethernet/Token Ring (ENTR, feature code 5201) for Token Ring only.

For z900 server, this feature is called the OSA-2 Token Ring feature, and can only be

configured as two 4/16 Mbps Token Ring ports.

As well as the OSA-2 Token Ring feature, other OSA-2 features for Fast Ethernet and ATM,

have been superseded by OSA-Express features; see “OSA-Express channel” on

page 131.

z900 server OSA-2 features provide SNA/APPN/HPR and TCP/IP connectivity (see

Figure 3-27) for the following LAN and network types:

򐂰 100 Mbps Fiber Distributed Data Interface (FDDI)

򐂰 4/16 Mbps Token Ring (T/R)

The OSA-2 features have been implemented as a channel type on the z900 server, and are

defined (CHPID type OSA) using the Hardware Configuration Definition (HCD). Each feature

port appears to the application software as a channel-attached device.

Note: IBM Statement of Direction, effective October 2001

z900 will be the last family of servers to provide an FDDI feature.

Note: Effective October 2001:

򐂰 OSA-2 Token Ring feature (feature code 5201) is superseded by the OSA-Express

Fast Ethernet feature (feature code 2366), and OSA-Express Token Ring feature

(feature code 2367), as required.

򐂰 OSA-2 Token Ring feature (feature code 5201) is not carried forward on G5/G6

server to z900 server upgrades.

򐂰 OSA-2 Token Ring feature (feature code 5201) is carried forward on z900 server to

z900 server upgrades only if the new configuration retains parallel channel and/or

OSA-2 FDDI features, and there are available slots in the Compatibility I/O cage(s).

128 IBM eServer zSeries 900 Technical Guide

,

Figure 3-27 OSA-2 connectivity

OSA-2 modes

The z900 server OSA-2 FDDI and OSA-2 Token Ring features are supported by the Open

Systems Adapter Support Facility (OSA/SF) program product. OSA/SF allows you to

customize the OSA-2 features to run in different modes. This product delivers a simple means

to configure and manage OSA-2 and to download software updates (to the OSA-2 feature) for

supported applications.

A default configuration is loaded in the OSA-2 feature during manufacturing. OSA/SF is used

to change the manufacturing default configuration, if required.

In LPAR mode, OSA-2 ports can be shared by any or all logical partitions on the server

platform. This is called

port sharing

. Port sharing support is customized in the configuration of

the OSA-2 features by using the OSA/SF program product.

Using OSA/SF, the OSA-2 FDDI and OSA-2 Token Ring features can be configured into

several modes, depending on your system and network requirements, as follows:

򐂰

TCP/IP Passthru mode (non-shared port)

In this mode, an OSA-2 port is capable of transferring TCP/IP LAN traffic to and from just

one TCP/IP host or logical partition. This is the default mode of OSA-2 and does not

require configuration using OSA/SF.

򐂰

TCP/IP Passthru mode (shared port)

In this mode, an OSA-2 port is capable of transferring TCP/IP LAN traffic to and from more

than one TCP/IP host within multiple logical partitions. The use of OSA/SF is required for

this configuration.

򐂰

SNA mode (non-shared port)

In this mode, an OSA-2 port is capable of transferring SNA LAN traffic to and from just one

LPAR. The use of OSA/SF is required for this configuration.

򐂰

SNA mode (shared port)

In this mode, an OSA-2 port is capable of transferring SNA LAN traffic to and from multiple

LPARs. The use of OSA/SF is required for this configuration.

Token Ring

FDDI

z900 server

100 Mbps

4/16 Mbps