Telcordia Technologies

About: Telcordia Technologies is a based out in . It is known for research contribution in the topics: Network packet & Node (networking). The organization has 3097 authors who have published 4737 publications receiving 237882 citations.

Constrained multicast routing in WDM networks with sparse light splitting

Abstract: As wavelength division multiplexing (WDM) technology matures and multicast applications become increasingly popular, supporting multicast at the WDM layer becomes an important and yet challenging topic. In this paper, we study constrained multicast routing in WDM networks with sparse light splitting, i.e., where some switches are incapable of splitting light (of copying data in the optical domain) due to evolutional and/or economical reasons. Specifically, we propose four WDM multicast routing algorithms, namely, re-route-to-source, re-route-to-any, member-first, and member-only. Given the network topology, multicast membership information, and light splitting capability of the switches, these algorithms construct a source-based multicast "light-forest" (consisting one or more multicast trees) for each multicast session. While the first two algorithms can build on a multicast tree constructed by IP (which does not take into consideration the splitting capability of the WDM switches), the last two algorithms attempt to address the joint problem of optimal multicast routing and sparse splitting in WDM networks. The performance of these algorithms are compared in terms of the average number of wavelengths used per forest (or multicast session), average number of branches involved (bandwidth) per forest as well as average number of hops encountered (delay) from a multicast source to a multicast member. The results obtained from this research should present new and exciting opportunities for further theoretical as well as experimental work.

Method for revoking computer backup files using cryptographic techniques

Abstract: A system enables a user to remove a file from a file system and from all backup tapes without ever mounting a single tape. When a file is backed up, it is first encrypted using a randomly generated key and then backed up. When the user wishes to remove the file from the backup tape, the key used to encrypt the file is deleted. Deleting the encryption key renders the data on the tape inaccessible. No one, including the file owner, can ever access the file again. The encrypt before-backup method is completely transparent to the user. Only the computer system's operating system knows which key was used to encrypt the file during backup. This ensures that when the operating system is instructed to delete the encryption key, the key is "lost" forever and thus the backed up files become unreadable. Unlike prior cryptographic file systems, the revoked backup files are inaccessible to both the user and others.

Gate-voltage-dependent effective channel length and series resistance of LDD MOSFET's

Abstract: A measurement algorithm to extract the effective channel length and source-drain series resistance of MOSFET's is presented. This extraction algorithm is applicable to both conventional and LDD MOSFET's. It is shown that the effective channel length and the source-drain series resistance of an LDD device are gate-voltage dependent. The effective channel length of an LDD device is not necessarily the metallurgical junction separation between the source and drain as it is commonly seen in a conventional device. A more generalized interpretation of effective channel length is introduced to understand the physical meaning of this gate-voltage dependence. The result also indicates that the effective channel length and source-drain resistance are two inseparable device parameters regardless of LDD or conventional FET's.

Access subnetwork controller for video dial tone networks

Abstract: An access subnetwork provides broadcast access transport as well as selective allocation of resources for interactive communications sessions dedicated to individual end users. The access subnetwork has specified broadcast and interactive service interfaces, both for communications to and from an information provider and for communication to and from customer premises equipment. An Access Subnetwork Controller provides a single point of control contact within the access subnetwork. Any other subnetwork (typically an element of a higher level control subnetwork) needing a control function in the access subnetwork always sends the request for that function to the Access Subnetwork Controller. The primary responsibility of the Access Subnetwork Controller is to control resources, provide requested resources and monitor the use of resources within in the realm of the access subnetwork. The Access Subnetwork Controller functions essentially in a similar manner to provide every type of requested connection, whether the connection is for broadcast, pay-per-view or Interactive Multimedia Television (IMTV). Specifically, the Access Subnetwork Controller reserves and enables access subnetwork resources for a particular user connection and reports connections back to higher level control elements.

Optimization of Insertion Compounds Such as LiMn2 O 4 for Li-Ion Batteries

Abstract: The spinel LiMn 2 O 4 , whose electrochemical activity with Li was discovered in the early 1980s, was put forth in the early 1990s as a possible alternative to LiCoO 2 as a positive electrode material for Li-ion batteries. Ten years later, the Li-ion LiMn 2 O 4 /C cells are on the verge of entering the portable electronics and electric/hybrid vehicle market. This paper retraces the key steps of this decade that were necessary to master the intimate physical/electrochemical relationship of LiMn 2 O 4 , and that led to the development of rechargeable Li-ion LiMn 2 O 4 /C technology. During the long development period, the early supremacy of LiMn 2 O 4 as the only alternative to LiCoO 2 diminished with the development of positive electrode materials that present abundance and cost advantages. Despite the uncertainty of the future of the spinel, successfully translating a fundamental success into a commercial one, we stress that the long learning experience will benefit the scientific battery community aiming at rapidly optimizing the electrochemical performance of alternative materials, such as LiFePO 4 .