Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 1: Base Functions, Connectivity, and Routing

52 Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 1 - Base Functions, Connectivity, and Routing

Dependencies

In order to achieve a successful implementation of the z/OS Communications Server -

TCP/IP component we identified certain dependencies:

򐂰 Implement a

full-function UNIX System Services system on z/OS. Details are available in

the z/OS V1R7.0 UNIX System Services Planning, GA22-7800-08;z/OS V1R7.0 Program

Directory, GI10-0670-07 (http://publibz.boulder.ibm.com/epubs/pdf/i1006707.pdf);

and z/OS V1R7.0 MVS Initialization and Tuning Reference. SA22-7592-11.

򐂰 Define a RACF environment for the z/OS Communications Server - TCP/IP component.

This includes defining RACF groups to z/OS UNIX groups to manage resources, profiles,

user groups, and user IDs. An OMVS UID must be defined with UID (0) and assigned to

the started task name of the CS for z/OS IP system address space. Details are available

in Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 4 - Security,

SG24-7172; z/OS V1R7.0 Security Server RACF Security Administrator's Guide,

SA22-7683-07; z/OS V1R7.0 Security Server RACF System Programmer's Guide,

SA22-7681-06; z/OS V1R7.0 Security Server RACF Command Language Reference,

SA22-7687-08.

򐂰 Customize SYS1.PARMLIB members with special reference to BPXPRMxx to use the

integrated sockets INET with the AF_INET and AF_INET6 physical file system. Details are

available in the z/OS V1R7.0 MVS Initialization and Tuning Reference, SA22-7592-11;

z/OS V1R7.0 UNIX System Services Planning, GA22-7800; and z/OS V1R7.0 Program

Directory, GI10-0670.

򐂰 Customize the TCP/IP configuration data sets:

–PROFILE.TCPIP

–TCPIP.DATA

– Other configuration data sets

򐂰 Fully functional VTAM to support the interfaces used by TCP/IP.

Advantages

The advantages of a single stack are:

򐂰 Less CPU cycles spent on processing TCP/IP traffic, since there is only one logical

instance of each physical interface in a single stack environment versus a multiple stack

environment.

򐂰 Servers use fewer CPU cycles when certain periodic updates arrive (OMPROUTE

processing routing updates). Multiple stacks mean multiple copies of OMPROUTE.

򐂰 Each stack requires a certain amount of storage, the most significant being virtual storage.

Considerations

When creating a TCP/IP stack we need to consider the other requirements upon which the

successful initialization of the stack depends. Very often the initial problems encountered are

related to the omission of tasks that were not performed by other disciplines such as RACF

administration.

CS for z/OS TCP/IP exploits the tightly coupled design of the z/OS

Communications Server, the integration of z/OS and UNIX System Services, and the

provision of RACF services. Coordination is the key to a successful implementation the

TCP/IP stack.

3.3.2 Multiple stacks

A multiple stack environment consists of more than one stack running concurrently in a single

LPAR. They exist independent of each other, with the ability to be uniquely configured. Each

stack can support different features and provide different functions. Each stack is configured