Configuration Overview

This chapter provides an introduction to the configuration files that you need to tailor Cisco IOS for S/390 to your site's requirements.

This chapter contains the following sections.

• Configuration Files

Describes the Cisco IOS for S/390 configuration members

• Configuration File Roadmap

Displays the configuration files and their functions

• Task Groups

Provides task group descriptions

Configuration Files

The Cisco IOS for S/390 configuration members are described briefly below. See Table 1-1.

Table  1-1: Configuration Member Descriptions

Member Name	Description
IJTCFGxx	IJTCFGxx holds parameters for address space services provided by the IJT task group, including timing services, message logging, SMF parameters and exit points. This member also holds the software authorization key for your copy of Cisco IOS for S/390.
APPCFGxx	APPCFGxx contains configuration statements to describe applications such as Telnet, FTP, and SMTP that run over Cisco IOS for S/390.
TCPCFGxx	TCPCFGxx contains configuration statements to describe Cisco IOS for S/390 as a host system, its network interfaces and control values, its routing tables, and the TCP/IP and UDP services.
APPLUPxx	APPLUPxx contains VTAM LU names for use with Server Telnet applications, and rules for selecting them.
GTDCFGxx	GTDCFGxx contains configuration statements for using the GateD routing protocol. This file is needed only for Fault Tolerant Cisco IOS for S/390.
DNRCFGxx	DNRCFGxx is the main DNR configuration member specifying DNR storage pools, DNR control values, and member names for other DNR configuration files.
DNRALCxx	DNRALCxx contains alias names for Cisco IOS for S/390 and other hosts.
DNRHSTxx	DNRHSTxx contains a table of host names and their internet addresses.
DNRNETxx	DNRNETxx has a table of network names and their internet addresses.
DNRNPCxx	DNRNPCxx is a list of networks in preferred routing order for DNR queries to DNR servers on remote hosts that are multihomed.
DNRNSCxx	DNRNSCxx is a table of domain names with the assigned DNR servers and their internet addresses.
DNRPRTxx	DNRPRTxx holds a table of protocol names and their numbers.
DNRRPCxx	This file is a table of RPC names and the corresponding RPC program numbers.
DNRSLCxx	DNRSLCxx holds a list of domain name suffixes to be combined with partial domain names to make fully qualified domain names for DNR queries.
DNRSVCxx	DNRSVCxx is a table of protocol name and service name pairs and their corresponding port numbers.
MAPCFGxx	This member contains parameters to control the Port Mapper component of Cisco IOS for S/390.
SNMCFGxx	SNMCFGxx contains parameters to control the SNMP agent within Cisco IOS for S/390, mainly SNMP storage pool specifications, authorized management stations, and the data to which they are given access.

Configuration File Roadmap

The following diagrams show each of the configuration members and the functionality associated with each member (Figure 1-1 through Figure 1-4).

APPCFGxx

Figure 1-1: APPCFGxx Functions

TCPCFGxx

Figure 1-2: TCPCFGxx Functions

IFS Services, SNMP, and Portmapper

Figure 1-3: IJTCFGxx, MAPCFGxx, and SNMCFGxx Functions

DNR Files

Figure 1-4: DNR Configuration Member Functionality

Task Groups

An IFS system application address space consists of the IFS jobstep task and one or more application-defined subtask groups (one or more MVS subtasks performing a common function and dispatching work from a common queue). Subtask groups are also called task groups. Each task group has a three-character Task Group Identifier (TGI). The task groups and their functions within the Cisco IOS for S/390 address space are shown below.

Table 1-2 describes each of the IFS task groups in more detail.

Table  1-2: Task Group Descriptions

Task Group	Description
TCP	The application layers of the Internet protocol suite are implemented in the Transmission Control Protocol (TCP) task group. This includes TCP, UDP, IP, and network hardware interface drivers. The TCP task group uses the services of the DNR task group to perform name resolution.
APP	The Application Program Interface (API) task group provides an interface for transport protocol users to the transport protocol provider. The provider is the TCP Task Group that specifically provides the TCP and UDP transport protocols. Applications include Client FTP, Client FTP2, Client FTP3, Server FTP, Server Telnet, VTAM Client Telnet, Server SMTP, Client SMTP, and TSO Client Telnet.
DNR	The Domain Name Resolver (DNR) task group supports dynamic domain name resolution for the TCP task group. It also provides support for users in other address spaces via an API using MVS cross-memory services. The DNR task group implements the protocols necessary to interface with domain name servers at your site or on the Internet. It resolves domain-style names into Internet addresses. DNR also performs other useful name resolution functions, including resolving service and protocol names. The DNR task group uses the services of the TCP task group.
IJT	The IFS Jobstep Task (IJT) task group consists of the Cisco IOS for S/390 jobstep task. It initializes the address space and provides the first-level handling of operator commands.
MAP	The Port Mapper (MAP) task group is a Remote Procedure Call (RPC) server that maps RPC-based application programs to specific port numbers. This service is required by application programs that use the RPC interface of the API.
SNM	The Simple Network Management (SNM) task group is an SNMP agent that provides network management stations with data about the Cisco IOS for S/390 host. This service is based on UDP and uses the API interface.