Patents by Inventor Rajiv Ramaswami

Rajiv Ramaswami has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5825877
    Abstract: A form of authentication is provided wherein a trusted third party signs a certificate to identify the author of a program and to secure its integrity. The program code is encapsulated or otherwise associated with the certificate and an access control list (ACL). The access control list describes the permissions and resources required by the code. An enforcement mechanism which allocates system permissions and resources in accordance with the ACL. In a preferred embodiment, a code production system communicates with a certification agency, which is a trusted third party. The certification agency issues a certificate for the code and a certificate for the access list of that code. Once the certificate is issued it is not possible for any party to modify the code or access list without invalidating the certificate. The code and its ACL, along with their certificates are stored on a server.
    Type: Grant
    Filed: June 11, 1996
    Date of Patent: October 20, 1998
    Assignee: International Business Machines Corporation
    Inventors: Asit Dan, Rajiv Ramaswami, Dinkar Sitaram
  • Patent number: 5825949
    Abstract: A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: October 20, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael M. Choy, Paul Eliot Green, Jr., William Eric Hall, Frank James Janniello, Jeff Kenneth Kravitz, Karen Liu, Rajiv Ramaswami, Franklin Fuk-Kay Tong
  • Patent number: 5793746
    Abstract: A wiring scheme for providing loop-back capability for individual failed channels around a ring network composed of nodes with limited space-switching. With this invention each node has a switch for interconnecting channels between incident links of the node. Each secure channel i has a backup channel B(i). In the normal mode of operation, the switch is configured so that the ports for channel B(i) of the incident links are connected to each other. Upon failure of channel i in one of the incident links of the node, the port for channel i of the failed link is connected to the port for channel B(i) on the other incident link of the node. With this invention when there is a failure of channel i on one of the links, the connection using this failed channel can be restored by switch configurations at only two nodes of the ring since the backup channels at the other nodes are already connected to each other.
    Type: Grant
    Filed: April 29, 1996
    Date of Patent: August 11, 1998
    Assignee: International Business Machines Corporation
    Inventors: Ornan Alexander Gerstel, Rajiv Ramaswami
  • Patent number: 5781537
    Abstract: An efficient distributed technique for setting up, taking down, and updating connections in a communications network, which is robust in the presence of failures. More specifically with this invention a path for a connection is computed and reservation requests are simultaneously sent through separate channels to each of a set of nodes of the path for the connection to reserve and determine if resources are available for the connection. Upon acknowledgement that the links for the connection are available and have been reserved, a setup message is sequentially transmitted between the adjacent nodes along the path until the setup messages reaches the destination node. The switches in each node then configure themselves in response to the setup message so as to establish the connection.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: July 14, 1998
    Assignee: International Business Machines Corporation
    Inventors: Rajiv Ramaswami, Adrian Segall
  • Patent number: 5729527
    Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail.Another set of methods reroute up to two failed channels on to spare channels in the event of channel failures. With this method only the failed channels are rerouted. However the failed channels may have to be routed through a slightly larger, but minimal, number of additional hops than with the first method.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: March 17, 1998
    Assignee: Tellabs Operations, Inc.
    Inventors: Ornan Alexander Gerstel, William Eric Hall, Rajiv Ramaswami, Galen Hajime Sasaki
  • Patent number: 5515361
    Abstract: A method and apparatus for monitoring links in an optical star network along with means for taking down a link in the event of a failure without disruption to other parts of the network, bringing back the link into operation once the failure is corrected, while adhering to eye-safety regulations. More specifically, when one link of a pair of links connecting a station to a star coupler fails, the failure is detected by a monitor and the links of the pair are connected to each other by a switch. This connection of the two links provides a look from the transmitter of the station through the pair of links and to the receiver of the station. This connection also disconnects the station from the star network. When the pair of links again become operable, a signal is detected as passing from the transmitter through the loop and back to the receiver. Detection of the signal by the receiver then results in switching the pair of links back to the star coupler, thereby reconnecting the station to the star network.
    Type: Grant
    Filed: February 24, 1995
    Date of Patent: May 7, 1996
    Assignee: International Business Machines Corporation
    Inventors: Chung-Sheng Li, Rajiv Ramaswami
  • Patent number: 5487120
    Abstract: A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs.
    Type: Grant
    Filed: February 9, 1994
    Date of Patent: January 23, 1996
    Assignee: International Business Machines Corporation
    Inventors: Michael M. Choy, Paul E. Green, Jr., William E. Hall, Frank J. Janniello, Jeff K. Kravitz, Karen Liu, Rajiv Ramaswami, Franklin F. Tong
  • Patent number: 5253274
    Abstract: A method of transmitting data and commands on a communication link so as to efficiently distinguish between commands and data. This invention encodes information symbols before transmission on the communication link. A unique code symbol S which does not equal any encoded information symbol is defined along with a unique encoded command symbol ESOTX. Encoded data information symbols are transmitted by sending S followed by ESOTX, and then the encoded data information symbols. Encoded command information symbols, not including ESOTX, are transmitted by sending S immediately followed by the encoded command information symbols. The receiver interprets any encoded information symbol immediately following S as a command. If the encoded command equals ESOTX, the following symbols are treated as data until S is received again. If the encoded command is not ESOTX, the following symbols are treated as commands until S is received again.
    Type: Grant
    Filed: April 15, 1992
    Date of Patent: October 12, 1993
    Assignee: International Business Machines Corporation
    Inventors: Frank J. Janniello, Rajiv Ramaswami, David G. Steinberg