IPSANET: Yesterday, Today and Tomorrow

David Chivers, Manager of IPSANET Development London

IPSANET, I. P. Sharp's communications network, is now undergoing its most significant upgrade since the introduction of packet-switching in 1976.

Net 90, as the network development project is known, will culminate in a communications network for the 1990s. Some users will begin to see some benefits as early as 1987, while most benefits will be provided by the early 1990s.

At the start of 1985, an intensive examination into future needs for network services revealed that we should continue specializing in the fast, efficient, and reliable distribution of text and data. Hence, Net 90 is building on the strengths of IPSANET; namely, its reliability, global reach, system security, fast response and efficiency.


IPSANET consists of over 226 Computer Automation's Alpha minicomputers and communications controllers such as the IBM 3705 or Amdahl 4705, known as nodes, located at various points throughout the network and interconnected by leased telecommunications lines. The original IPSANET Alpha nodes were designed in 1973. Today, the same Alpha computers still function as network nodes with many upgrades of software and some of hardware.

IPSANET now has multiple routes, with automatic selection of the best available route. For terminal connection, speeds have increased from the original 30 characters per second (cps) for dumb hardcopy terminals to 480 cps. In addition to flow control, echoplex, and bulk input, several more complex interconnection protocols have been provided, such as X.25 and binary synchronous (bisync). Node reliability and availability have been much improved. Network operations anywhere on the network now rely on full screen displays of complete network status.

IPSANET tomorrow

Current IPSANET users will be pleased to learn that the proposed changes introduced by Net 90 will be transparent to them. Most upgrades will be upwardly compatible enhancements to the existing network.

To meet the growing and changing demands for network services, a new type of node with a new hardware design and new software will interwork with the existing nodes. IPSANET's new microprocessors will increase the reliability, availability and security of network services. These features are extremely important for all applications, especially for sophisticated international trading systems and the collection and distribution of real-time data via the network.

The Net 90 nodes will be capable of transmitting data more efficiently. The new communications processors are designed to handle line speeds several times faster than the present limit.

To meet the rapid growth of X.25 and bisync use, the enhanced IPSANET will ease some of the configuration restrictions and improve the efficiency of providing such connections.

The Net 90 Project will increase the possibilities for interconnection between IPSANET and other networks and computer systems. IPSANET will interconnect under IBM’s SNA environment, and through the emerging open systems interconnection (OSI) standards and to local area networks (LAN).

Net 90 will allow for a greater variety of operating modes and communication protocols at the user terminal connection, including more cost-effective and flexible connection of 3270 terminals to IPSANET.

Net 90 will take advantage of changes in government regulations. Throughout the world, there is steady and significant progress to liberalize communications regulations. As a result, IPSANET will carry traffic which is not dependent on SHARP APL. As well as opening up new business areas for us in the value added network services (VANS) market, this increased use of the network will reduce the cost of providing network services to each user.

Enhancing IPSANET

The new node is based on a complex of identical processors, each specializing in providing part of the node's function. Clusters of these microprocessors, interconnected at the same site by the new IBM token ring LAN, will start to be phased in to the network next year. The LAN will support both our chosen node processors: the first based on an IBM PC/AT and the other will be specialized hardware.

The first node is based on the IBM. PC/AT: each AT will form one processor on the LAN, and allow the connection of up to 10 communication ports. Macrodata of Amsterdam, who have for many years supplied our communications interfaces for the Alpha nodes, will supply the communications coprocessor cards.

About a year later. Net 90 will introduce a second type of node which will be specialized communication hardware built entirely by Macrodata. The node will use the same microprocessors as the IBM PC/AT, but without the PC packaging. This is intended for the larger nodes in the network, since it will meet higher performance standards at a lower cost per port.

Both nodes will have local disk storage which will save copies of the node software. New versions of software will be loaded through the network to the local disk while the node continues its normal operation. Eventually the disk may also be used for storage of user data, for such applications as a newswire service.

The new processors will work alongside the existing nodes, without interrupting service to our users. New nodes will be created providing additional power where needed. Most importantly, new processors and nodes will introduce improved network services.

Future possibilities

Future development plans for the new nodes are very wide in scope. The large memory available in each processor and the possibility of adding further specialized processors will enable more sophisticated processing to be done at each node. The direction of this development will be guided by market demands, and may change as circumstances change. Some of the potential applications include:

•Connecting to non-SHARP APL systems, thus considerably increasing the availability of services to potential users. IPSANET today makes many assumptions that our users are connecting to SHARP APL systems. By rewriting network functions so they are not dependent on SHARP APL, I. P. Sharp Associates (IPSA) could provide network services to link distributed computer systems such as IBM S/36, Wang and Tandem.

•Automatically reestablishing a user's network signon call to a new route, if available, should the old route fail.

•Further expanding asynchronous communications to handle new types of terminals (including 3270 terminal emulation), or communications with new types of remote systems. For example, you might have direct access to computer services operating on non-IBM hardware.

•Distributing data similar to a newswire service, which would either broadcast the same data to many clients or exploit the local disk storage at each node to hold pages of data accessible on demand.

•Moving the network management of IPSANET from SHARP APL on the mainframe onto another system (such as APL on a PC). As a result, IPSANET hardware and software could be provided as a stand-alone package to companies wishing to run their own private networks.

IPSANET is one of I. P. Sharp Associates' key technologies. As such, IPSANET is always evolving to meet the needs of our clients by providing state-of-the-art network services. The Net 90 project is the base for further growth and development of IPSANET.


Terms to help you understand ipsanet


(Italicized words from the articles "IPSANET: Yesterday, Today and Tomorrow" and "Using 3270 Applications through ipsanet" are defined.)


asynchronous Data transmission without regular time relationship. Asynchronous devices are typically low speed (30 – 480 cps), dumb terminals. Each character is transmitted when typed.


*binary synchronous (bisync) Data transmission in which synchronization of characters is controlled by timing signals generated at the sending and receiving stations. Contrast with asynchronous transmission.

local area network (LAN) A collection of pc's connected together so that they can communicate with one another and with shared network resources such as mass storage devices, printers, modems, and gateways to other networks or mainframe computers.


node The switching computer that provides IPSANET functions.

*open systems interconnection (OSI) The use of standardized procedures to enable the interconnection of data processing systems in networks.


*packet-switching The process of routing and transferring data by means of addressed packets so that a channel is occupied only during the transmission of a packet; upon completion of the transmission, the channel is made available for the transfer of other packets.

port An access point into or out of IPSANET. A port may be asynchronous (30 – 480 cps) or synchronous (SDLC or bisync) and may connect IPSANET to an end-user terminal or other communications device.


*synchronous data link control (SDLC) A discipline for managing synchronous, code-

transparent, serial-by-bit information transfer over a link connection. SDLC enables 3270 devices to operate in SNA environments and, at the same time, access IPSANET.


*systems network architecture (SNA) The description of the logical structure, formats, protocols, and operational sequences for transmitting information units through and controlling the configuration and operation of networks. SNA lets end users be independent of the way in which specific SNA network services and facilities used for information exchange are provided.

value added network services

(VANS) The supplier of such a service is providing some communications function:

protocol conversion, speed change, character code translation or something more complicated like trading systems or electronic mail. This service adds value to the basic communications service (point-to-point) which can be obtained from the telephone company.


X.25 This interconnection protocol is recommended by the International Telegraph and Telephone Consultative Committee (CCITT), the world telecommunications standards committee, for the "interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit". It is one of a series of recommendations for data communications network interfaces.

This glossary includes definitions from the "Vocabulary for Data Processing, Telecommunications, and Office Systems", seventh (July 1981) edition, published by IBM Corporation. These definitions are identified by an asterisk.