Method and apparatus for linking SNA terminals to an SNA host over a packet switched communications network
First Claim
1. A data communications system for establishing a communications path from an SNA host computer over a packet switched network to an SNA terminal, comprising:
- a front end processor having a first SNA interface means coupled to said SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said host with an SNA protocol and said packet switched network with a packet switched protocol;
a remote access facility having a second SNA interface means coupled to said SNA terminal and a second packet switched interface coupled to said packet switched network;
for transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol;
said front end processor further comprising;
a plurality of SNA PU2 channel interfaces coupled to said SNA host;
means for dynamically allocating to one of said plurality of PU2 channel interfaces, a SNA logical unit from a pool of a plurality of available SNA logical units in response to said remote access facility requesting over said packet switched network, that a communications path be established with said SNA host.
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Accused Products
Abstract
The invention disclosed herein provides the basic operation capabilities of SNA data communications for host-to-remote terminal 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 connctionless 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 a SNA LU2 definition to the host to allow it to carry out regular SNA sessions over the packet switched network to remote terminal users. The second concept is providing primary SNA PU5 support, in the Remote Access Facilities (RAF). This enables each RAF to control all the SNA terminals and devices attached to it as a separate network. The RAF and the FEP working together imbed the SNA protocols in the IP datagrams and provide the proper SNA connections and control. This technique allows any terminal to access any host for which it has authorization.
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Citations
25 Claims
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1. A data communications system for establishing a communications path from an SNA host computer over a packet switched network to an SNA terminal, comprising:
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a front end processor having a first SNA interface means coupled to said SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said host with an SNA protocol and said packet switched network with a packet switched protocol; a remote access facility having a second SNA interface means coupled to said SNA terminal and a second packet switched interface coupled to said packet switched network;
for transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol;said front end processor further comprising; a plurality of SNA PU2 channel interfaces coupled to said SNA host; means for dynamically allocating to one of said plurality of PU2 channel interfaces, a SNA logical unit from a pool of a plurality of available SNA logical units in response to said remote access facility requesting over said packet switched network, that a communications path be established with said SNA host. - View Dependent Claims (2, 3, 4, 5)
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6. A data communications system for establishing a communications path from an SNA host computer over a packet switched network to an SNA terminal, comprising:
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a front end processor having a first SNA interface means coupled to said SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said host with an SNA protocol and said packet switched network with a packet switched protocol; a remote access facility having a second SNA interface means coupled to said SNA terminal and a second packet switched interface coupled to said packet switched network, for transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol; said remote access facility further comprising; a SNA PU5 host for providing an SNA systems services control point function for said SNA terminal coupled to said remote access facility. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A data communications system for establishing a communications path from an SNA host computer over a packet switched network to an SNA terminal, comprising:
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a front end processor having a first SNA interface means coupled to said SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said host with an SNA protocol and said packet switched network with a packet switched protocol; a remote access facility having a second SNA interface means coupled to said SNA terminal and a second packet switched interface coupled to said packet switched network, for transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol; a network control front end processor having a third SNA interface means coupled to an SNA network control host computer and having a third packet switched interface coupled to said packet switched network, for transferring control messages between said network control host with an SNA protocol and said packet switched network with a packet switched protocol. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A data communication system for establishing a communications path from an SNA host computer over a packet switched network to an SNA terminal, comprising:
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a front end processor having a first SNA interface means coupling to said SNA host and having a first packet switched interface coupled to said packet switched network, for transferring data and control messages between said host With an SNA protocol and said packet switched network with a packet switched protocol; a remote access facility having a second SNA interface means coupled to said SNA terminal and a second packet switched interface coupled to said packet switched network, for transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol; a second front end processor having a third SNA interface means coupled to a second SNA host computer and having a third pocket 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 second front end processor further comprises; an SNA PU4 interface coupled to said second SNA host, for establishing a communications path between said second SNA host and said first said SNA host. - View Dependent Claims (21, 22, 23, 24)
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25. In a data communications system, a method of establishing a communications path from a SNA host computer over a packet switched network to a SNA terminal, comprising the steps of:
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transferring data and control messages between said host with a SNA protocol and said packet switched network with a packet switched protocol using a front end processor having a first SNA interface means coupled to said SNA host and having a first packet switched interface coupled to said packet switched network; transferring said data and control messages between said terminal with said SNA protocol and said packet switched network with said packet switched protocol using a remote access facility having a second SNA interface means coupled to said SNA terminal and said packet switched network; dynamically allocating to one of a plurality of channel interfaces on said front end processor, a SNA logical unit from a pool of a plurality of available SNA logical units in response to said remote access facility requesting over said packet switched network, that a communications path be established with said SNA host.
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Specification