Optimization method for routing and logical network design in multi-service networks

A method of establishing a plurality of virtual paths in a communications network, said communications network being characterized by a set of switching nodes and a set of connecting links wherein each said virtual path is defined in terms of a subset of said set of nodes and a subset of said set of links, comprising the steps of:

• determining blocking probabilities of a plurality of services for links included in said plurality of virtual paths;
• determining sensitivities of network performance as a function of offered loads for a plurality of services and transmission rates:
• and
• selecting routes and allocating capacity for said virtual paths in relation to said offered loads based on said sensitivities and said blocking probabilities;
• wherein said steps of determining blocking probabilities and determining network performance sensitivities include a computational substep of applying successive asymptotic approximations, said substep operating to reduce computational complexity for said steps.

A method for determining virtual path routings and allocation of bandwidth thereto in a communications network, said communications network being characterized by a set of switching nodes and a set of connecting links, comprising the steps of:

• determining blocking probabilities and network performance sensitivities of a plurality of services for a subset of said set of connecting links based on offered loads for said plurality of services and a plurality of transmission rates and initial determination of said virtual path routings and bandwidth allocations;
• evaluating said network sensitivities with respect to a predetermined network performance criterion;
• iteratively applying said determining step using revised virtual path routings and bandwidth allocations until a network performance gradient is less than a selected threshold;
• wherein said step of determining blocking probabilities and network performance sensitivities includes a computational substep of applying successive asymptotic approximations, said substep operating to reduce computational complexity for said step.

An object-oriented software system for carrying out a network analysis methodology, and having as an output at least one network performance parameter, said software system comprising:

• a parser process for determining and compiling network topology data into an object file;
• a network solver process for determining network blocking probabilities in respect to a plurality of services and network performance sensitivities as a function of offered loads, said network solver process including a computational process for applying successive asymptotic approximations in said network blocking probability and said network performance sensitivity determinations, said substep operating to reduce computational complexity for said determinations;
• and
• an optimizer process for evaluating a resultant of said network solver process and causing said network process to be iteratively repeated until said resultant satisfies a defined criterion.

A method for logical network design in a multi-service communications network, said network including a set of switching nodes and a set of connecting links disposed to interconnect at least some of said nodes, comprising the steps of:

• determining blocking probabilities of a plurality of services for a subset of said set of links;
• determining sensitivities of network performance as a function of offered loads for a plurality of services and transmission rates:
• adjusting said network performance based on said sensitivities and said blocking probabilities;
• and
• dynamically bifurcating said network into a first network portion and a second network portion;
• wherein said application of said steps of determining blocking probabilities and determining network performance sensitivity to said first portion of said network includes an asymptotic analysis substep, said asymptotic analysis substep not being included in said application of said steps of determining blocking probabilities and determining network performance sensitivity to said second portion of said network.

A method of establishing a plurality of virtual paths in a communications network, said communications network being characterized by a set of switching nodes and a set of connecting links wherein each said virtual path is defined in terms of a subset of said set of nodes and a subset of said set of links, comprising the steps of:

• determining blocking probabilities of a plurality of services for links included in said plurality of virtual paths;
• determining sensitivities of network performance as a function of offered loads for a plurality of services and transmission rates:
• selecting routes and allocating capacity for said virtual paths in relation to said offered loads based on said sensitivities and said blocking probabilities;
• and
• further including a dynamic bifurcation of said network into a first network portion and a second network portion, wherein said application of said steps of determining blocking probabilities and determining network performance sensitivity to said first portion of said network includes an asymptotic analysis substep, said asymptotic analysis substep not being included in said application of said steps of determining blocking probabilities and determining network performance sensitivity to said second portion of said network.

A method for determining virtual path routings and allocation of bandwidth thereto in a communications network, said communications network being characterized by a set of switching nodes and a set of connecting links, comprising the steps of:

• determining blocking probabilities and network performance sensitivities of a plurality of services for a subset of said set of connecting links based on offered loads for said plurality of services and a plurality of transmission rates and initial determination of said virtual path routings and bandwidth allocations;
• evaluating said network sensitivities with respect to a predetermined network performance criterion;
• iteratively applying said determining step using revised virtual path routings and bandwidth allocations until a network performance gradient is less than a selected threshold;
• and
• further including a dynamic bifurcation of said network into a first network portion and a second network portion, wherein an application of said step of determining blocking probabilities and network performance sensitivity to said first portion of said network includes an asymptotic analysis substep, said asymptotic analysis substep not being included in application of said step of determining blocking probabilities and network performance sensitivity to said second portion of said network.

An object-oriented software system for carrying out a network analysis methodology, and having as an output at least one network performance parameter, said software system comprising:

• a parser process for determining and compiling network topology data into an object file;
• a network solver process for determining network blocking probabilities in respect to a plurality of services and network performance sensitivities as a function of offered loads;
• and
• an optimizer process for evaluating a resultant of said network solver process and causing said network process to be iteratively repeated until said resultant satisfies a defined criterion;
• wherein a set of actions carried out in operation of said software system are as depicted in the flow diagram of FIG. 4.