Network followed by compute load balancing procedure for embedding cloud services in software-defined flexible-grid optical transport networks
A method for solving a cloud embedding problem includes first mapping virtual links over physical links followed by virtual nodes over physical nodes. The inventive method entails an efficient procedure, namely network followed by compute load balancing (NCLB), that first maps virtual links over physical links while balancing network resources, and finally, maps virtual nodes over physical nodes while balancing different types of computational resources.
1. A method comprising the steps of:
implementing by a computer an embedding of cloud demands over a software defined flexible grid optical transport network, the implementing comprising:
initially mapping virtual links over physical links in the network;
finding potential modulation formats and routing solutions for a virtual link mapping;
selecting a modulation format and a physical routing solution for a virtual link based on a probability of mapping the virtual link over the route using the modulation format;
assigning a wavelength and allocation spectrum to a virtual link such that spectral fragmentation is minimized thereby improving likelihood of mapping virtual links over physical routes; and
mapping virtual nodes over physical nodes which includes assigning virtual nodes associated with the mapped virtual link to the end of physical nodes of a selected route on which the virtual link is mapped;
wherein the step of assigning a wavelength comprises finding a lowest wavelength slot starting from which consecutive wavelength slots are available and provisioning the virtual link VL at found wavelength slots on a selected route between physical nodes PNs.
2. The method of claim 1 , wherein the selecting step comprises selecting a virtual link VL from a list of virtual links, and finding a set of physical nodes PNs for each unmapped virtual node VN of the VL such that all PNs within a set have at least the required number of each type of resources.
3. The method of claim 2 , wherein the step of finding comprises checking whether both virtual nodes VNs of the virtual VL are not yet mapped, and if both the VNs of the VL are not yet mapped, then for each of k-shortest routes between each combination of nodes there is a determination of a set of feasible modulation formats based on a reachability constraint, on the other hand, if at least one of the VNs is already mapped, then there is a checking of whether one of the VNs is already mapped while the other is not yet mapped and if this is true, then for each of the k-shortest routes between each combination of nodes where the VN is already mapped to the PN there is a determination of a set of feasible modulation formats based on the reachability constraint, otherwise, for each of the k-shortest routes between nodes where VNs are already mapped to PNs, there is a determination of a set of feasible modulation formats based on the reachability constraint.
4. A method comprising the steps of:
implementing by a computer an embedding of cloud demands over a software defined flexible grid optical transport network, the implementing comprising:
initially mapping virtual links over physical links in the network;
finding potential modulation formats and routing solutions for a virtual link mapping;
selecting a modulation format and a physical routing solution for a virtual link based on a probability of mapping the virtual link over the route using the modulation format;
assigning a wavelength and allocation spectrum to a virtual link such that spectral fragmentation is minimized thereby improving likelihood of mapping virtual links over physical routes; and
mapping virtual nodes over physical nodes which includes assigning virtual nodes associated with the mapped virtual link to the end of physical nodes of a selected route on which the virtual link is mapped;
wherein the step of selecting a modulation format comprises finding a bit-map of each of k-shortest routes connecting each combination of nodes, with a bit-map of a route being determined by performing bit-wise logical end operations on bit-maps of all physical links along the route.
5. The method of claim 4 , wherein the step of selecting further comprises determining a total required spectrum for each modulation format and determining a probability of mapping the virtual link on a route connecting physical nodes PNs using a modulation format taking into account a ratio of a number of wavelength slots starting from where consecutive wavelength slots are available for a modulation format on a bit-map of a route to a total number of possible wavelength slots starting from which consecutive wavelength slots can be mapped.
6. A system comprising:
implementation by a computer an embedding of cloud demands over a software defined flexible grid optical transport network, the implementation comprising:
initially mapping virtual links over physical links in the network;
finding potential modulation formats and routing solutions for a virtual link mapping;
selecting a modulation format and a physical routing solution for a virtual link based on a probability of mapping the virtual link over the route using the modulation format;
assigning a wavelength and allocation spectrum to a virtual link such that spectral fragmentation is minimized thereby improving likelihood of mapping virtual links over physical routes; and
mapping virtual nodes over physical nodes which includes assigning virtual nodes associated with the mapped virtual link to the end of physical nodes of a selected route on which the virtual link is mapped;
wherein the selecting step comprises selecting a virtual link VL from a list of virtual links, and finding a set of physical nodes PNs for each unmapped virtual node VN of the VL such that all PNs within a set have at least the required number of each type of resources;
wherein the step of finding comprises checking whether both virtual nodes VNs of the virtual VL are not yet mapped, and if both the VNs of the VL are not yet mapped, then for each of k-shortest routes between each combination of nodes there is a determination of a set of feasible modulation formats based on a reachability constraint, on the other hand, if at least one of the VNs is already mapped, then there is a checking of whether one of the VNs is already mapped while the other is not yet mapped and if this is true, then for each of the k-shortest routes between each combination of nodes where the VN is already mapped to the PN there is a determination of a set of feasible modulation formats based on the reachability constraint, otherwise, for each of the k-shortest routes between nodes where VNs are already mapped to PNs, there is a determination of a set of feasible modulation formats based on the reachability constraint.
7. The system of claim 6 , wherein the step of selecting a modulation format comprises finding a bit-map of each of k-shortest routes connecting each combination of nodes, with a bit-map of a route being determined by performing bit-wise logical end operations on bit-maps of all physical links along the route.
8. The system of claim 7 , wherein the step of selecting further comprises determining a total required spectrum for each modulation format and determining a probability of mapping the virtual link on a route connecting physical nodes PNs using a modulation format taking into account a ratio of a number of wavelength slots starting from where consecutive wavelength slots are available for a modulation format on a bit-map of a route to a total number of possible wavelength slots starting from which consecutive wavelength slots can be mapped.
9. The system of claim 6 , wherein the step of assigning a wavelength comprises finding a lowest wavelength slot starting from which consecutive wavelength slots are available and provisioning the virtual link VL at found wavelength slots on a selected route between physical nodes PNs.