This chapter is an introduction to the part of the book titled Part 3, "Configuration and Management Specifics". It gives an overview of possible applications for Network Utility and describes how the other chapters document some of these applications.
Using IBM's Multiprotocol Access Services software technology, Network Utility supports a variety of networking functions. The Network Utility is specifically designed for CPU and memory-intensive functions at network positions requiring a small number of physical interfaces.
Key applications of Network Utility by model include:
TN3270E Server
The TN3270E Server function provides SNA host application access to IP desktop users.
One or more Network Utilities can be positioned at a regional office or host data center to provide access for medium-to-large numbers of TN3270 clients distributed throughout an IP network.
Network Utility Model TN1 also supports all the functions of Model TX1.
Data Link Switching (DLSw)
DLSw provides native SNA end-station (workstation, controller, FEP, or host) connectivity across IP backbone networks. It also performs DLC type conversion like that done in FRAD and X.25 PAD products.
One or more Network Utilities can be positioned at a regional office or host data center to terminate TCP connections from smaller DLSw routers in many branch offices.
Advanced Peer to Peer Networking (APPN)
APPN provides native SNA end-station (workstation, controller, FEP, or host) connectivity across SNA backbone networks. The Enterprise Extender feature allows this same connectivity across IP backbone networks.
Network Utilities can be positioned wherever a high-capacity APPN network node is required. You can place one at the edge of an IP network to receive traffic from other Enterprise Extender products. A Network Utility could also provide extended border node function when connecting two different APPN networks.
Channel Gateway
Network Utility supports both ESCON (fiber-optic cable) and Parallel Channel (bus and tag cable) adapters. Using one of these adapters, a Network Utility can serve as a gateway routing both SNA and IP traffic from a S/390 host to local LANs, an ATM network, or to a high-speed serial line.
Network Dispatcher
This function allows a number of IP-based application servers (for example, TN3270 servers, HTTP web servers, or FTP servers) to present a single IP address appearance to client workstations on an intranet or on the Internet. The network dispatcher function fields TCP connection requests from these clients and routes them to an available server. It provides both load balancing among the servers, and high "logical server" availability by bypassing failed physical servers.
The Network Utility can be placed at a host data center in front of hosts providing these server functions, or in front of multiple Network Utility Model-TN1s that are providing TN3270E Server function.
High-speed media conversion
Network Utility can serve as a high-speed bridge between interfaces on its supported adapters.
Virtual Private Networking (VPN)
The VPN function consists of a suite of tunneling and security protocols: L2TP, L2F, PPTP, IPSEC, IKE, PKI, Diffserv and LDAP. Taken together, these protocols allow a Network Utility to be configured to use the public Internet as an extension of an enterprise's own private network instead of private WANs and LANs. When so configured, the Network Utility can act as a tunnel termination point for network traffic to an enterprise's remote offices, suppliers and customers. Security policies configured on the router determine dynamically if network traffic needs to be authenticated and/or encrypted, or can flow in the clear. The security policies ensure that the enterprise data can move through the public network as securely, reliably, and flexibly as if they were traversing private lines, and at a significant cost savings.
The Network Utility can be positioned at the boundary point between the Internet and an enterprise's intranet to terminate a large number of either Layer 2 or IPSEC tunnels. These tunnels become an extension of the enterprise network, leveraging the economies and ubiquity of the public Internet.
In this book, we have selected a key subset of the above functions for expanded discussion and example configurations. The chapters that follow cover:
For help in understanding and configuring Network Utility functions other than these, consult the core software publications:
You may also find configuration help in the following IBM Redbooks. Although they are specific to the IBM 2216 Model 400, some of the configuration scenarios may apply.
Chapters 12 through 20 of this book are organized as follows.
Each of the four key functions (TN3270E Server, Channel Gateway, Data Link Switching and VPN) is covered by two chapters:
The configurations shown and described in the four "Example Configuration " chapters are actual working configurations. Binary configuration files matching these configurations are downloadable from the World Wide Web. To access these files, follow the Support and Downloads links from:
http://www.networking.ibm.com/networkutility
In addition, Chapter 18, "Sample Host Definitions" provides detailed examples for configuring IBM host software products to match Network Utility configurations.
The configuration parameter tables used in the four "Example Configuration" chapters all follow the same format. Table columns and conventions are as follows:
If the configuration program panel shows parameters not listed in the table, we used their default values. Your configuration must be for a Network Utility and not a 2216-400 to have the correct default values.