z/OS Communications Server

z/OS® Communications Server provides Application Programming Interfaces (APIs) and networking protocol support to enable SNA and TCP/IP applications running on z/OS to communicate with partner applications or users on the same system, other systems within a single data center, or in distant locations. The main features of z/OS Communications Server are in the areas of:

• IPv6 Enablement

• High-Bandwidth and High-Speed networking technologies

• High Availability

• Enterprise Connectivity

• System and Data Security

• Network Management

To learn more about the new features specific to V1R13, please refer to What's New in z/OS V1R13 Communications Server.

IPv6 Enablement: IPv6 is an evolution of the current version, IP Version 4 (IPv4), and is designed to improve upon the older protocol. Most of today's Internets use IPv4, which is now approximately 30 years old and beginning to experience challenges. IPv6 improves upon IPv4 in a number of ways. For example, IPv6 uses 128-bit addresses, an address space large enough to last for the foreseeable future. It also adds many improvements to IPv4 in areas such as configuration, administration, and management. The major benefits of IPv6 fall into the following categories:

• Increased Scalability

• Potential to Reduce Administration Costs

• Simplified Configuration

• Support for Renumbering

• Application Compatibility

High Speed Connectivity: Communications Server provides support for High-Bandwidth and High-Speed networking technologies.

• Gigabit Ethernet with OSA Express QDIO for TCP/IP

• High-speed communication between logical partitions (LPARs) using Hipersockets

High Availability: Communications Server provides high availability to z/OS applications over both SNA and TCP/IP networks. z/OS Parallel Sysplex® technology is utilized to enable high availability application support.

• APPN High Performance Routing (HPR) provides end-to-end session continuity by supporting non-disruptive path switch around failed network components

• SNA Generic Resources function provides workload balancing for multi-instance applications within a parallel Sysplex in order to maximize availability and efficiency of application data sharing

• Multi-node Persistent Sessions provides session recovery for SNA applications

• Dynamic VIPA (Virtual IP Address) provides TCP/IP application availability across z/OS systems in a Sysplex and allows participating TCP/IP stacks on z/OS to provide backup and recovery for each other for both planned or unplanned TCP/IP outages

• Sysplex Distributor provides intelligent load balancing for TCP/IP application servers in a Sysplex and, along with Dynamic VIPA, provides a single system image for client applications connecting to these servers

Enterprise Connectivity: Communications Server includes many features that support Enterprise Connectivity.

• TN3270 Server provides workstation connectivity over TCP/IP networks to access z/OS and enterprise SNA applications

• Enterprise Extender allows SNA Enterprise applications to communicate reliably over an IP network using SNA HPR and UDP transport layer protocols

• APPN Extended Border Node (EBN) provides a replacement for 3745/NCP based SNA Network Interconnect (SNI)

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

• IPSEC/VPN functions enable the secure transfer of data over a network using standards for encryption, authentication, and data integrity
• Intrusion Detection Services (IDS) evaluates the stack for attacks that would undermine the integrity of its operation. Events to examine and actions to take (e.g., logging) at event occurrence are defined by IDS policy which is downloaded from an LDAP server
• TLS/SSL enablement for key applications ensures data is protected as it is flowing across the network(s):
  • FTP client and server
  • TN3270 server
• Kerberos5 and GSSAPI support is provided for the following applications:
  • FTP client and server
  • Unix rshd server
  • Unix System Services telnet server (supports only Kerberos5)

Network Management: Network Management support collects network topology, status and performance information and makes it available to network management tools.

• VTAM supports the traditional Common Management Information Protocol (CMIP) network management protocol for managing SNA network topology along with providing other management interfaces for performance monitoring

• Managing TCP/IP, the SNMPv3 protocol is supported

• Communications Server provides support for standard SNMP applications and also for IETF standard TCP/IP protocol MIBs

• Additional MIB support is also provided by the IBM MVS® TCP/IP Enterprise-specific MIB which supports management data for Communications Server TCP/IP stack-specific functions