Communications Server provides direct LAN communication and provides for point-to-point communication over S/390® channels (ESCON® or Block Multiplex) to several IBM® and equivalent other vendor devices.

• Direct LAN communication is provided by:
  • IBM Open Systems Adapter - Express®
  • IBM Open Systems Adapter
  • IBM 3172 Interconnect Controller
  • IBM 8232 LAN Channel Station
• Point-to-point communication over System z® channels is supported with the following devices:
  • IBM RS/6000®
  • IBM Channel-to-Channel Adapter
  • IBM 374X Communications Controller
  • IBM 2216 Multiaccess Connector
  • IBM Netfinity® Server
  • Cisco 7200 and 7500-series Channel Attached Routers
  • NSC Hyperchannel A220

A zEC12, z196, or z114 server is required to use the following functions:

• Support for z/OS® Communications Server for intra ensemble networks
• OSA-Express4S QDIO IPv6 checksum and segmentation offload

A zEC12,, z196, z114, or System z10™ server is required to use the following functions:

• OSA-Express optimized latency mode
• OSA-Express inbound workload queueing
• Support for z/OS Communications Server for intra ensemble networks

A zEC12,, z196, z114, System z10, or System z9® server is required to use the following functions:

• OSA-Express network traffic analyzer
• OSA-Express virtual MAC
• QDIO diagnostic synchronization
• QDIO support for OSA interface isolation

A zEC12, z196, z114, System z10, or System z9 server is required to use the following functions:

• ICSF encryption/decryption instructions, called crypto assist, which provide synchronous clear key support for DES, TDES, and SHA-1 algorithms for IPSEC.
• The checksum offload of IPv4 packets enhancement. An OSA-Express with a supporting level of microcode is also required.
• IPv4 Broadcast support for HiperSockets™.
• Segmentation Offload (Large Send). An OSA-Express with a supporting level of microcode is also required.