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

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

򐂰 Enterprise connectivity support is offered through many features, such as:

– TN3270 Server, which provides

workstation connectivity over TCP/IP networks to

access z/OS and enterprise SNA applications.

– Enterprise Extender, which allows SNA Enterprise applications to communicate

reliably over an IP network, using SNA HPR and UDP transport layer protocols.

– IPv4 and IPv6 networking functions are provided by the TCP/IP stack operating in a

standard dual-mode setup where IPv4 and IPv6 connectivity and applications are

supported concurrently by a single TCP/IP stack instance.

– Sockets programming interface support for traditional z/OS workloads provide IP

connectivity to applications written in REXX, COBOL, PL/I. Sockets programming

interfaces are supported in various environments, such as TSO, batch, CICS, and IMS.

򐂰 Network Security protects sensitive data and the operation of the TCP/IP stack on z/OS,

by using:

– IPsec/VPN functions that enable the secure transfer of data over a network using

standards for encryption, authentication, and data integrity.

– Intrusion Detection Services (IDS), which evaluates the stack for attacks that would

undermine the integrity of its operation. Events to examine and actions to take (such as

logging) at event occurrence are defined by the IDS policy, which is downloaded from

an LDAP server.

–

Transport Layer Security (TLS) enablement ensures data is protected as it flows

across the network.

– Kerberos and GSSAPI support is provided for selected applications.

򐂰 Network Management support collects network topology, status, and performance

information and makes it available to

network management tools, including:

– Local management applications that can access management data via a specialized

high-performing network management programming interface that is known as

NMI.

– Support of remote management applications through the SNMP protocol. CS z/OS

supports the latest SNMP standard, SNMPv3. CS z/OS also supports standard

TCP/IP-based Management Information Base (MIB) data.

– Additional MIB support is also provided by Enterprise-specific MIB, which supports

management data for Communications Server TCP/IP stack-specific functions.

1.3 How CS for z/OS IP is implemented

CS for z/OS IP provides TCP/IP support for the native MVS and UNIX System Services

environment. It is implemented within a z/OS address space and runs within the native MVS

environment, and consequently it has RACF, DFSMS, and z/OS UNIX file system

dependencies.

1.3.1 Functional overview

CS for z/OS IP takes advantage of Communications Storage Management (CSM) and of

VTAM's Multi-Path Channel (MPC) and Queued Direct I/O (QDIO) capabilities in its TCP/IP

protocol implementation. This tight coupling with VTAM provides enhanced performance and

serviceability.

As illustrated in Figure 1-1 on page 5, there are many data link control (DLC) protocols

provided the Communications Server. These DLCs are provided by the VTAM component.