US 5,021,949 A · Method and apparatus for linking an SNA host to a remote SNA host over a packet switched communications network

Abstract

The invention disclosed herein provides the basic operating capabilities of SNA data communications for host based application-to-application sessions across a packet switched network such as the Defense Data Network (DDN). The problem that is presented by the integration of these two technologies is that SNA is a connection oriented technology and DDN is a connectionless technology that requires an Internetting Protocol (IP) header on all information transmitted through the network and across multiple networks. One of the concepts of the invention is the definition of a localized SNA network to each SNA host by the channel attached Front End Processors (FEPs). These FEPs present an SNA PU4 definition to the host to allow it to carry out regular SNA sessions over the packet switched network to another host through its own respective FEP. The two FEPs working together imbed the SNA protocols in the IP datagrams and provide the proper SNA connections and control. This technique also allowed any host to access any other host for which it has authorization.

Claims20

Dependent claims

A data communications system for establishing a communications path from a first SNA host computer over an IP packet switched network to a second SNA host computer comprising:

a first front end processor having a first SNA interface means coupled to said first SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said first host with an SNA protocol and said packet switched network with a packet switched protocol;
a second front end processor having a second SNA interface means coupled to said second SNA host and having a second packet switched interface coupled to said packet switched network, for transferring data and control messages between said second host with an SNA protocol and said packet switched network with a packet switched protocol;
said first interface means including a first SNA PU4 interface in said first front end processor coupled to said first SNA host, for imbedding SNA protocol information in an IP datagram for messages transmitted from said first host;
said second interface means including a second SNA PU4 interface in said second front end processor coupled to said second SNA host, for extracting said SNA protocol information from said IP datagram for said messages transmitted from said first host and received by said second front end processor.

1 more element

In a data communications system, a method for establishing a communications path from a first SNA host computer over an IP packet switched network to a second SNA host computer, comprising:

transferring data and control messages between said first host with an SNA protocol and said packet
switched network with a packet switched protocol, using a first front end processor having a first PU4 SNA interface means coupled to said first SNA host and having a first packet switched interface coupled to said packet switched network;
imbedding SNA protocol information in an IP datagram, using said first front end processor, for messages transmitted from said first host;
transferring data and control messages between said second host with an SNA protocol and said packet switched network with a packet switched protocol using a second front end processor having a second PU4 SNA interface means coupled to said second SNA host and having a second packet switched interface coupled to said packet switched network, and
extracting said SNA protocol information from said IP datagram, using said second front end processor, for said messages transmitted from said first host and received by said second front end processor.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for linking an SNA host to a remote SNA host over a packet switched communications network

Life of this patent

Method and apparatus for linking an SNA host to a remote SNA host over a packet switched communications network

Life of this patent

Abstract

Claims20