The Enterprise Extender (EE) network connection is a simple set of extensions to the existing open high-performance routing (HPR) technology. It performs an efficient integration of the HPR frames using UDP/IP packets. To the HPR network, the IP backbone is a logical link. To the IP network, the SNA traffic is UDP datagrams that are routed without any hardware or software changes to the IP backbone. Unlike gateways, there is no protocol transformation and unlike common tunneling mechanisms, the integration is performed at the routing layers without the overhead of additional transport functions. The advanced technology enables efficient use of the intranet infrastructure for support of IP-based client accessing SNA-based data (for example, Telnet emulators or web browsers using services such as IBM's Host On-Demand) as well as SNA clients using any of the SNA LU types.
Enterprise Extender seamlessly routes packets through the network protocol edges, eliminating the need to perform costly protocol translation and the store-and-forward associated with transport-layer functions. Unlike Data Link Switching (DLSw), for example, there are no TCP retransmit buffers and timers and no congestion control logic in the router because it uses connectionless UDP and the congestion control is provided end system to end system. Because of these savings, the edge routers have less work to do and can perform the job they do best, which is forwarding packets instead of incurring protocol translation overhead and maintaining many TCP connections. Data center routers can handle larger networks and larger volumes of network traffic, thus providing more capacity.
Enterprise Extender supports both the IPv4 and IPv6 addressing models. For more information about EE, see z/OS Communications Server: SNA Network Implementation Guide and the EE information in Migrating Subarea Networks to an IP Infrastructure Using Enterprise Extender (IBM® Redbooks®).
You can use QDIO inbound workload queueing on an OSA-Express3 feature (or later feature) to improve throughput for both inbound Enterprise Extender (EE) packets and for inbound non-EE traffic over the same interface. For more information, see QDIO inbound workload queueing.