Abstract: The invention relates to a communication system and a method for providing a mobile telecommunication service. A communication network transmits messages on the basis of at least one internet protocol. A network connection computer connects an access network for mobile computers and the communication network. The access network is equipped with several access points comprising corresponding access point connection computers, which are configured to create a communication connection between variable access points and the mobile computers. An authorization verification computer establishes and manages trusted relationships between several communication elements. The network connection computer and the access point connection computer are configured to execute packet filtering during the receipt and transmission of messages for the secure protection of the communication system.

Abstract: The invention relates to a communication system and a method for providing a mobile telecommunication service. A communication network transmits messages on the basis of at least one internet protocol. A network connection computer connects an access network for mobile computers and the communication network. The access network is equipped with several access points comprising corresponding access point connection computers, which are configured to create a communication connection between variable access points and the mobile computers. An authorization verification computer establishes and manages trusted relationships between several communication elements. The network connection computer and the access point connection computer are configured to execute packet filtering during the receipt and transmission of messages for the secure protection of the communication system.

Abstract: Messages are delivered in a communications network by monitoring an arrival rate of messages destined for a geographical area within a short time period. Then, upon reaching a threshold, a multicast group is established for routing the messages to the geographical area. Network devices responsible for delivering the messages join the multicast group and the messages are delivered to the geographical area upon establishment of the multicast group.

Abstract: A simple and efficient means of checking the registration authorization is proposed by the method and the device for checking the registration authorization prior to the start of the re-registration process based on a registration query from a mobile radio terminal to at least one access device for an intra-domain handover in a mobile communication network. In the network, a token which has been sent by an access device to a mobile radio terminal and has been stored in at least one trust table of at least one access device, is received by at least one further access device during a registration query from a mobile radio terminal and compared with tokens stored in at least one trust table prior to the start of the registration for the purpose of verifying the registration authorization, and the registration is started if an authorization is present.

Abstract: A simple and efficient means of checking the registration authorization is proposed by the method and the device for checking the registration authorization prior to the start of the re-registration process based on a registration query from a mobile radio terminal to at least one access device for an intra-domain handover in a mobile communication network. In the network, a token which has been sent by an access device to a mobile radio terminal and has been stored in at least one trust table of at least one access device, is received by at least one further access device during a registration query from a mobile radio terminal and compared with tokens stored in at least one trust table prior to the start of the registration for the purpose of verifying the registration authorization, and the registration is started if an authorization is present.

Abstract: The invention relates to a method for carrying out a QoS-oriented handoff between a first and a second IP-based, especially mobile IPv6-based, communication path, between a mobile node (MN) and a correspondent node (CN), the second communication path being part of a number of communication paths which can be accessed by the mobile node, with no, one, or a plurality of intermediate instances.

Abstract: Use of a boron-containing sinter additive when synthesizing aluminum-oxide ceramics makes it possible to carry out the sintering process at temperatures below 1500.degree. C., which means that ion-conducting aluminum-oxide ceramics can be obtained.

Abstract: The present invention provides a process for the production of a K- or Rb-.beta."- or -.beta.-aluminum oxide powder preparation, wherein a cubic densely packed aluminum oxide (.gamma.-aluminum oxide) or a precursor thereof is subjected to attrition together with a doping material or a precursor thereof, the so obtained mixture is calcined in an oxygen-containing atmosphere, potassium oxide or rubidium oxide or a precursor of these compounds is added to the calcination product obtained, the mixture is subjected to attrition and then calcined in an oxygen-containing atmosphere at a temperature greater than 900.degree. C. The present invention also provides a process for the production of a ceramic formed body in which a powder obtained by the above process is converted by attrition, isostatic pressing and sintering into a ceramic formed body. Such a ceramic formed body can be used as an ion conductor.

Abstract: Apparatus for helically curling longitudinally corrugated thin strip material into a flexible corrugated tube has a curling unit with driven input rollers forming a nip that matches the strip, and a cassette for a reel of the material which is connected to said unit and has strip guide rollers immediately adjacent the input rollers. The curling unit has driven output rollers on an upright support to drive the strip, and a spider which is vertically adjustable on the support and carries strip guide rollers which are on spindles equidistant from the longitudinal axis of the forming tube, and radially adjustable, so that adjustment of the spider on the support and the spindles on the spider permits the unit to form tubes of different diameters. A locking mechanism intermittently crimps overlapping parts of the forming tube. A bending device aids in forming relatively stiff strip stock, and also aids in forming softer stock into very small diameter tubes.

Abstract: A strip of longitudinally corrugated thin sheet metal is spirally coiled to form a tube with adjacent border portions of successive convolutions overlapping each other with at least one corrugation in the overlying border portion of one convolution fitting into one corrugation of the underlying border portion of an adjoining convolution, and the interfitting crests are provided with circumferentially spaced locking detents each of which has a flattened central area flanked by crimps along its marginal portions that extend downwardly and outwardly in substantial abutment with the lowermost portions of the crests in which the detents are located.

Abstract: A pipe clamp has a U-bolt with legs each of which is provided with first and second tandemly arranged frustoconical circumferential ribs with planar annular bases that define the distal margins of circumferential grooves in the U-bolt legs, and a C-shaped sheet metal saddle having a hollow body portion with inside edges that are separated by a space less than the maximum width of the body portion. The saddle has circumferentially slit extremities each of which has aligned transverse internal flanges with opposed inner margins that define split circular openings which are dimensioned to permit the flanges to snap around the circumferential ribs and engage in the grooves. The U-bolt and saddle are adapted to loosely encircle a pipe when the flanges are engaged in the first grooves, and are adapted to firmly clamp the pipe when the flanges are engaged in the second grooves.

Abstract: A strip of very thin flexible material has continuous longitudinal corrugations in the form of curved ridges and hollows, and may be curled helically to form a flexible tube. The strip has a first marginal ridge with a radius of curvature smaller than that of all other ridges, and a second marginal ridge with a radius of curvature larger than that of all other ridges. As the strip is curled with the first marginal ridge overlying a first intermediate ridge and the second marginal ridge underlying a second intermediate ridge, the marginal ridges are respectively spread over and closed under the intermediate ridges to conform to the curvature thereof.