Browse Prior Art Database

Multiple-Protocol LAN Interface for IBM 370 Systems

IP.com Disclosure Number: IPCOM000038547D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Linehan, MH: AUTHOR

Abstract

The present invention relates to a single control unit which multiplexes a single local area network (LAN) connection among a plurality of higher-level protocols without modifying the operating systems of an IBM 370 mainframe in the network. According to the invention, there is a "destination service access point field" in each data frame and the contents of such fields map to device addresses on the 370 channel of the LAN. Local area networks provide basic communications paths among multiple devices, such as desktop workstations and mainframe computers. Higher-level network protocols, such as SNA and TCP/IP, can be utilized with LANs to integrate these devices into wide-area networks. The IEEE 802.

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Multiple-Protocol LAN Interface for IBM 370 Systems

The present invention relates to a single control unit which multiplexes a single local area network (LAN) connection among a plurality of higher-level protocols without modifying the operating systems of an IBM 370 mainframe in the network. According to the invention, there is a "destination service access point field" in each data frame and the contents of such fields map to device addresses on the 370 channel of the LAN. Local area networks provide basic communications paths among multiple devices, such as desktop workstations and mainframe computers. Higher-level network protocols, such as SNA and TCP/IP, can be utilized with LANs to integrate these devices into wide-area networks. The IEEE 802.2 logical link control standard defines a method of differentiating among multiple higher-level protocols via an abstraction known as a "service access point". Fields representing the "source" and "destination" service access points are included in each data frame transmitted on the LAN. The destination service access point field identifies the network protocol that should be used to process each frame. In an IBM 370 mainframe, each higher- level protocol is supported by its own specialized software executing in a specific virtual machine or address space. Hence, data frames coming from the LAN must be routed to appropriate 370 mainframe software. The destination service access point field provides the basis for this type of routing. However, software routing within the 370 main...