Abstract: For a survivable portion of a network, a backup port for a first router of the survivable network, to reach a destination node in the event of a single link failure, may be determined by (a) accepting a routing path graph having the destination node, wherein the routing path graph includes one or more links terminated by one or more primary ports of the first router, and (b) for each router of at least a part of the routing path graph, (1) assuming that a link terminated by a primary port of the current router is removed, defining (A) a first part of the routing path graph including the destination node, and (B) a second part of the routing path graph separated from the first part wherein the second part defines a sub-graph, and (2) determining the backup port for the first router by examining the sub-graph with respect to the first part of the routing path graph.

Abstract: A scheme to achieve fast recovery from SRLG failures in the IP layer is described. An exemplary scheme, called multi-section shortest path first (“MSSPF”), builds on the idea of IP Fast Reroute (“IPFRR”), guarantees 100% recovery of SRLG failures and causes no dead loops.

Abstract: A router in a survivable portion of a network may forward packets to a destination node even in the event of a double-link failure. For a given destination node, the router has previously been configured with a primary port, a primary backup port, and a secondary backup port. The router receives a packet addressed to the destination node within the survivable portion of the network, wherein the packet includes information indicating that the packet has encountered a failure. The router then selects one of (A) the primary port, (B) the primary backup port and (C) the secondary backup port on which to forward the received packet, such that a backup path with no dead loops is defined. The router may obtain a recovery distance of at least one of (A) the primary backup port based on a backup path to which it leads, and (B) the secondary backup port based on a backup path to which it leads, and may further obtain counter information in a packet indicative of a failure distance.

Abstract: Backup ports for a first router of the survivable network are determined so that the first router can reach a destination node in the event of a double link failure. A routing path graph having the destination node is accepted. The routing path graph includes one or more links terminated by one or more primary ports of the first router. For each router of at least a part of the routing path graph, assuming that a link terminated by a primary port of the first router is removed, a first part of the routing path graph including the destination node and a second part of the routing path graph (sub-graph) separated from the first part are defined. Two exits for the sub-graph to reach the graph are determined. A primary backup port and a secondary backup port are determined for the first router using the determined two exits.

Abstract: For a survivable portion of a network, a backup port for a first router of the survivable network, to reach a destination node in the event of a single node failure, may be determined by (a) accepting a routing path graph having the destination node, wherein the routing path graph includes one or more links terminated by one or more primary ports of the first router; and (b) for each router of at least a part of the routing path graph, (1) assuming that the current router is removed, defining (A) a first part of the routing path graph including the destination node, and (B) a second part of the routing path graph separated from the first part wherein the second part defines one or more sub-graphs, and (2) determining the backup port for the first router by examining at least one of the one or more sub-graphs to find a link to the first part of the routing path graph.

Abstract: Backup ports for a first router of the survivable network are determined so that the first router can reach a destination node in the event of a double link failure. A routing path graph having the destination node is accepted. The routing path graph includes one or more links terminated by one or more primary ports of the first router. For each router of at least a part of the routing path graph, assuming that a link terminated by a primary port of the first router is removed, a first part of the routing path graph including the destination node and a second part of the routing path graph (sub-graph) separated from the first part are defined. Two exits for the sub-graph to reach the graph are determined. A primary backup port and a secondary backup port are determined for the first router using the determined two exits.

Abstract: A router in a survivable portion of a network may forward packets to a destination node even in the event of a double-link failure. For a given destination node, the router has previously been configured with a primary port, a primary backup port, and a secondary backup port. The router receives a packet addressed to the destination node within the survivable portion of the network, wherein the packet includes information indicating that the packet has encountered a failure. The router then selects one of (A) the primary port, (B) the primary backup port and (C) the secondary backup port on which to forward the received packet, such that a backup path with no dead loops is defined. The router may obtain a recovery distance of at least one of (A) the primary backup port based on a backup path to which it leads, and (B) the secondary backup port based on a backup path to which it leads, and may further obtain counter information in a packet indicative of a failure distance.

Abstract: For a survivable portion of a network, a backup port for a first router of the survivable network, to reach a destination node in the event of a single link failure, may be determined by (a) accepting a routing path graph having the destination node, wherein the routing path graph includes one or more links terminated by one or more primary ports of the first router, and (b) for each router of at least a part of the routing path graph, (1) assuming that a link terminated by a primary port of the current router is removed, defining (A) a first part of the routing path graph including the destination node, and (B) a second part of the routing path graph separated from the first part wherein the second part defines a sub-graph, and (2) determining the backup port for the first router by examining the sub-graph with respect to the first part of the routing path graph.

Abstract: In one embodiment, the extrusion process can comprise: feeding a thermoplastic polycarbonate resin to an extruder; heating the resin to a temperature sufficient to attain a melt viscosity of less than or equal to about 300 Pa.s; extruding the heated resin; and passing the extruded resin through a gap between two solid metal calendering rolls to produce a film. The film has a birefringence of less than or equal to about 50 nm.

Abstract: A process for producing a polycarbonate film suitable for optical media applications having a birefringence of less than about 50 nm and low stress wherein the polycarbonate has a weight average molecular weight of about 30,000 or less and preferably 13,000 to about 25,000, extruding the polycarbonate film at a temperature of about 275° C. to about 360° C., the polycarbonate has a melt viscosity of about 100 to about 275 Pascal and a thickness of about 100 to about 600 &mgr;m, advancing the melted polymer film into a gap between two calendering rolls which calendaring rolls are at a temperature below the glass transition temperature, advancing the melted polycarbonate film through the gap and cooling the polycarbonate film wherein the polycarbonate film is extruded at the rate of about 10 to 100 feet per minute; and to a polycarbonate film prepared by the process above described.

Abstract: A method of producing a polycarbonate film for optical recording media is provided. The polycarbonate film includes a plurality of layers, and the method includes arranging the plurality of layers so that a principal optical axis of a first layer is at an angle greater than zero degrees from a principal optical axis of a second layer.

Abstract: A radiation curable coating composition includes a mixture of an oligomeric acrylate having a crosslinkable acrylate functionality of 1 to 6, at least one of monomeric acrylates and dimeric acrylates, having a crosslinkable acrylate functionality of 1 to 6, an acrylated colloidal silica, and a photoinitiator.

Abstract: Disclosed is a low birefringence solvent cast film of optical quality comprising a blend of a cycloaliphatic polyester and a polycarbonate and method of preparing the film by casting a solvent containing dissolved cycloaliphatic polyester and a polycarbonate onto a support and evaporating the solvent to form a film.

Abstract: Color stable thermoplastic resin compositions include a polyetherimide resin, polyester resin and phosphorus and/or phenol containing color stabilizers, and exhibit resistance to elevated temperature, elimination of black specks, and improved mechanical properties.