Abstract: Data loss is reduced and bandwidth efficiency improved while tuning an optical add/drop device comprising a hitless wavelength-tunable optical filter. The hitless wavelength-tunable optical filter includes a broadband reflective surface and a tunable filter surface, the reflective surface and filter surface positioned adjacent to each other. Hitless tuning of the device is accomplished by changing the point at which an optical beam strikes the filter surface along a constant wavelength channel track whenever the beam is incident to the filter surface region. Realignment to a position associated with a new wavelength channel track is performed with the optical beam incident to the reflective surface region. Repositioning the optical beam to the filter region occurs at a location corresponding to the new wavelength to be added/dropped and subsequent optical beam realignment within the filter region is along the new wavelength channel track.

Abstract: The specification relates to a broadband multiple access protocol for bi-directional hybrid fiber/coax (HFC) networks and other shared media networks. The protocol supports downstream broadcast transmission from headend to cable modem, and also provides for allocation of bandwidth for cable modems to transmit back to the headend. The HE transmits and receives control messages in either ATM or VL format, depending upon CM capability, the determination of CM capability ascertained by the HE during the message flows interchanged between HE and CM while establishing a data link. Although the present invention is described in relation to an HFC network, it is also equally applicable to other shared media networks. The protocol supports different data access modes such as STM, ATM, and VL; within each subframe of a subframe/frame/masterframe structure.

Abstract: The specification relates to a broadband multiple access protocol for bi-directional hybrid fiber/coax (HFC) networks. The protocol supports downstream broadcast transmission from headend to cable modem, and also provides for allocation of bandwidth for cable modems to transmit back to the headend. Although the present invention is described in relation to an HFC network, it is also equally applicable to a cellular wireless communications environment. The protocol supports different access modes such as STM, ATM, and VL; within each subframe of a subframe/frame/masterframe structure. The protocol adapts to changing demands for a mix of circuit and packet mode applications and allocates upstream and downstream bandwidth in response to the a variety of bursty and isochronous traffic sources.

Abstract: The call processing capacity of the of a telecommunications network by forming the communication switches forming the network into respective groups of communication switches. The communication switches forming a respective group of switches are fully interconnected to one another and then each of the communications switches forming a respective group is connected at least one other group of telecommunication switches as a way of interconnecting the groups with one another.

Abstract: The efficiency of a telecommunications network is enhanced by associating each of the communication switches forming the network with an external connection control processor and forming the switches into respective groups of communication switches. The communication switches forming a respective group of switches are fully interconnected to one another and then each of the communications switches forming a respective one of the groups is connected at least one other group of telecommunication switches as a way of interconnecting the groups with one another.