Summarization in a multi-domain network

A method of operating a routing control entity of a first network domain in a multi-domain network, the first network domain comprising a plurality of network nodes connected by links and comprising border nodes which connect with other network domains, the network domain comprising apparatus of a first network technology type, the method comprising:

• receiving a request for an intra-domain routing between the border nodes of the first network domain as part of an inter-domain routing between end nodes, the request specifying an advertised value, or value range, of a summarised network topology parameter for a virtual link between the border nodes for the routing, wherein the summarised network topology parameter is part of a common set of network topology parameters used by domains of different technology types, wherein the different technology types comprise packet-switched network technology and wavelength-switched optical network technology and wherein a summarized network topology of paths comprises a plurality of virtual links between a pair of border nodes, each virtual link representing a plurality of possible intra-domain paths between the pair of border nodes, each virtual link being described by a different value or value range of the summarized network topology parameter;
• and
• determining an intra-domain path between the border nodes which meets the requested value, or value range, of the summarised network topology parameter,
• wherein the common set of network topology parameters are expressed in units that are the same irrespective of technology type.

A non-transitory machine readable storage medium having stored therein instructions which, when executed by a processor, cause the processor to perform a method of generating network topology parameters for a first network domain in a multi-domain network, the first network domain comprising a plurality of network nodes connected by links and comprising border nodes which connect with other network domains, the first network domain comprising apparatus of a first network technology type, the method comprising, at a control entity of the first network domain:

• determining an intra-domain topology of the nodes and links of the first network domain by collecting values of at least one network topology parameter of the first technology type;
• and
• determining a summarised intra-domain topology of paths between border nodes of the first network domain which is described using values of at least one summarised network topology parameter, wherein values of the summarised network topology parameter are derived from the values of the network topology parameter of the intra-domain topology of the first technology type and wherein the summarised network topology parameter is part of a common set of network topology parameters for advertising between domains comprising apparatus of different technology types, wherein the different technology types comprise packet-switched network technology and wavelength-switched optical network technology,
• wherein the summarized intra-domain topology of paths comprises a plurality of virtual links between a pair of border nodes, each virtual link representing a plurality of possible intra-domain paths between the pair of border nodes, each virtual link being described by a different value or value range of the summarized network topology parameter, and
• wherein the common set of network topology parameters are expressed in units that are the same irrespective of technology type.

Apparatus for generating network topology parameters for a first network domain in a multi-domain network, the first network domain comprising a plurality of network nodes connected by links and comprising border nodes which connect with other network domains, the first network domain comprising apparatus of a first network technology type, the apparatus comprising a processing apparatus and memory which is arranged to:

• determine an intra-domain topology of the nodes and links of the first network domain by collecting values of at least one network topology parameter of the first technology type;
• and
• determine a summarised intra-domain topology of paths between border nodes of the first network domain which is described using values of at least one summarised network topology parameter, wherein values of the summarised network topology parameter are derived from the values of the network topology parameter of the intra-domain topology of the first technology type and wherein the summarised network topology parameter is part of a common set of network topology parameters for advertising between domains comprising apparatus of different technology types, wherein the different technology types comprise packet-switched network technology and wavelength-switched optical network technology,
• wherein the summarized intra-domain topology of paths comprises a plurality of virtual links between a pair of border nodes, each virtual link representing a plurality of possible intra-domain paths between the pair of border nodes, each virtual link being described by a different value or value range of the summarized network topology parameter, and
• wherein the common set of network topology parameters are expressed in units that are the same irrespective of technology type.

A routing control entity of a first network domain in a multi-domain network, the first network domain comprising a plurality of network nodes connected by links and comprising border nodes which connect with other network domains, the network domain comprising apparatus of a first network technology type, the routing control entity comprising a processing apparatus and memory which is arranged to:

• receive a request for an intra-domain routing between the border nodes of the first network domain as part of an inter-domain routing between end nodes, the request specifying an advertised value, or value range, of a summarised network topology parameter for a virtual link between the border nodes for the routing, wherein the summarised network topology parameter is part of a common set of network topology parameters used by domains of different technology types, wherein the different technology types comprise packet-switched network technology and wavelength-switched optical network technology and wherein a summarized network topology of paths comprises a plurality of virtual links between a pair of border nodes, each virtual link representing a plurality of possible intra-domain paths between the pair of border nodes, each virtual link being described by a different value or value range of the summarized network topology parameter;
• and
• determine an intra-domain path between the border nodes which meets the requested value, or value range, of the summarised network topology parameter,
• wherein the common set of network topology parameters are expressed in units that are the same irrespective of technology type.