Patent Description:
For the purposes of this application European Telecommunications Standards Institute (ETSI) terminology will be used. It will however, be appreciated that equivalent virtual components and procedures may be used. In a virtual environment, a virtual network functions manager (VNFM), or a Lifecycle Management (LCM) component, may provide a virtual network function (VNF) lifecycle management interface to a network function virtualization orchestrator (NFVO). VNF lifecycle management operations may include VNF instantiation, scaling and termination.

A Virtual Infrastructure Manager (VIM) may provide a resource orchestration interface to an NFVO. The resource orchestration interface may allow for operation such as allocating, updating and terminating VNFs. In indirect mode, the VNFM may use the resource orchestration interface provided by the NFVO. In direct mode, the VNFM may talk directly to the VIM instead of the NFVO.

A VNFM (both in direct and indirect mode) may use several VIMs, but it may not be possible to instantiate a VNF whose components are distributed to several VIMs.

NFVOs provide Network Services to the NFVO customers. An orchestration hierarchy may be formed by NFVOs connected in a hierarchical fashion. An NFVO may be split into a Network Service Orchestrator (NSO) and a Resource Orchestrator (RO) component corresponding to lifecycle and resource management respectively.

<CIT> relates to a method and an apparatus for deploying a network service, and resolves, by means of information exchange between orchestrators, a problem of deploying an NS in different domains.

The project leading to this application has received funding from the European Union's Horizon <NUM> research and innovation programme under grant agreement No. <NUM>.

According to embodiments described herein there is provided a method, in a Life Cycle Management, LCM, component in a virtual network. The virtual network comprises a first orchestration layer comprising a first network function virtualisation orchestrator, NFVO, and a second orchestration layer, subordinate to the first orchestration layer, comprising a second NFVO. The method comprises receiving a first request, from the first NFVO, to determine a first substitution for a first VNF. A first network service request received by the first NFVO requests instantiation of a first network service comprising the first VNF. The first substitution maps the first network service request onto the second orchestration layer. The method further comprises, responsive to receiving the first request, determining the first substitution. The method further comprises, responsive to a determination, based on a topology of the second orchestration layer, that the first substitution comprises a second VNF associated with the second NFVO, receiving a second request from the second NFVO to provide a second substitution for the second VNF in a second network service request transmitted by the first NFVO to the second NFVO, the second network service request requesting instantiation of a second network service comprising the second VNF, wherein the second substitution maps the second network service onto a third network layer, and the second network service implements at least part of the first network service. The method further comprises, responsive to receiving the second request, determining the second substitution.

According to some embodiments there is provided a method in a first network function virtualisation orchestrator, NFVO. The first NFVO is in a first orchestration layer superior to a second orchestration layer comprising a second NFVO in a virtual network. The method comprises receiving a first network service request to instantiate a first network service comprising a first VNF; and transmitting a first request to a Lifecycle manager, LCM, component to determine a first substitution for the first VNF, wherein the first substitution maps the first network service onto a topology of the second orchestration layer. The method further comprises responsive to transmitting the first request to the LCM component, receiving the first substitution for the first VNF from the LCM component, wherein the first substitution comprises a second VNF associated with the second NFVO; transmitting an indication of the second VNF to the second NFVO; and responsive to receiving an indication that the second NFVO is capable of supporting the second VNF, transmitting a second network service request to the second NFVO to instantiate a second network service comprising the second VNF, wherein the second network service implements at least part of the first network service.

According to some embodiments there is provided a Life Cycle Management, LCM, component in a virtual network. The virtual network comprises a first orchestration layer comprising a first network function virtualisation orchestrator, NFVO, and a second orchestration layer, subordinate to the first orchestration layer, comprising a second NFVO. The LCM component comprises processing circuitry configured to: receive a first request, from the first NFVO, to determine a first substitution for a first VNF, wherein a first network service request received by the first NFVO requests instantiation of a first network service comprising the first VNF, and wherein the first substitution maps the first network service onto the second orchestration layer; responsive to receiving the first request, determine the first substitution, responsive to a determination, based on a topology of the second orchestration layer, that the first substitution comprises a second VNF associated with the second NFVO, receive a second request from the second NFVO to provide a second substitution for the second VNF in a second network service request transmitted by the first NFVO to the second NFVO, the second network service request requesting instantiation of a second network service comprising the second VNF, wherein the second substitution maps the second network service onto a third network layer, and the second network service implements at least part of the first network service, and responsive to receiving the second request, determine the second substitution.

According to some embodiments there is provided a first network function virtualisation orchestrator, NFVO, in a first orchestration layer superior to a second orchestration layer comprising a second NFVO in a virtual network. The first NFVO comprises processing circuitry configured to receive a first network service request to instantiate a first network service comprising a first VNF; and transmit a first request to a Lifecycle manager, LCM, component to determine a first substitution for the first VNF, wherein the first substitution maps the first network service onto a topology of the second orchestration layer. The processing circuitry is further configured to: responsive to transmitting the first request to the LCM component, receive the first substitution for the first VNF from the LCM component, wherein the first substitution comprises a second VNF associated with the second NFVO; transmit an indication of the second VNF to the second NFVO; and responsive to receiving an indication that the second NFVO is capable of supporting the second VNF, transmit a second network service request to the second NFVO to instantiate a second network service comprising the second VNF, wherein the second network service implements at least part of the first network service.

According to some embodiments there is provided a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method as described above.

According to some embodiments there is provided a computer program product comprising a computer-readable medium with the computer program as described above.

The aforementioned embodiments therefore provide methods and apparatus which allow the LCM component by delegated to the subordinate second orchestration layer in order to decompose the virtual network functions onto the topology of the lower network layers. This delegation of the LCM component may ensure that an optimal placement of virtual network functions in the physical infrastructure layer is provided.

<FIG> illustrates an example of a virtualisation network comprising a multi-provider orchestration layer and the corresponding topology of the network layers. Please note that throughout the application the terms Orchestrator and Network Functions Virtualization Orchestrator (NFVO) are used interchangeably. Similarly the terms Life Cycle Management (LCM) component and Virtual Network Functions Manager (VNFM) are used interchangeably.

Lifecycle Management (LCM) components are registered to an NFVO corresponding to an orchestration layer. For example, a first orchestration layer may comprise a first NFVO (Orchestrator Black) <NUM>. A LCM component <NUM> may be registered to the first NFVO <NUM>.

In this example, a subordinate network layer to the first orchestration layer comprises a second orchestration layer. The second orchestration layer comprises a second NFVO, (Orchestrator Blue) <NUM> and a third NFVO (Orchestrator Green) <NUM>. The second and third NFVOs are part of separate autonomous systems (AS) or domains, namely a Blue domain and a Green domain. These domains may be managed by separate network service providers.

In this example, a third network layer, subordinate to the second orchestration layer, comprises a plurality of Virtual Infrastructure Managers (VIMs). Specifically three VIMs <NUM> are connected to the second NFVO <NUM> in the Blue domain, and four VIMs <NUM> are connected to the third NFVO <NUM> in the Green domain. These VIMs may correspond to a physical infrastructure layer.

The left hand side of <FIG> illustrates the topology of each layer as understood by the network layer above. It will be appreciated that, in hierarchies such as the one illustrated in <FIG>, domain abstractions, for example, hiding the topology, resources and capability details of a network layer below from a network layer above, may be common due to the domain boundaries, scalability and split of concerns.

In this example, each domain has external connection points denoted by stars. A, B, C, D, E are customer endpoints while stars x, y represent inter-domain connection points.

The box <NUM> illustrates the topology of the first orchestration layer as viewed by a customer requesting a network service from the first NFVO <NUM>. The topology of the first orchestration layer comprises only the first NFVO <NUM> with the customer A, B, C, D, E connected to the first NFVO <NUM>. In box <NUM>, the endpoints may not necessarily be connected to the distributed router offered at the first NFVO, and it may be a decision of the customer how exactly to use the offered virtual function. In some embodiments, the end points A, B, C, D and E may comprise other VNFs, for example other NFVOs or service provider domains.

A distributed router VNF may comprise a virtual function which is capable of routing communications between end points by using a plurality of router VNFs associated with points of presence in a subordinate network layer.

From the point of view of the customers, also named tenants, the first NFVO may also be regarded as a so-called VNFaaS (Virtual Network Function as a Service).

The topology of the second orchestration layer as seen from the first NFVO <NUM> is illustrated in box <NUM>. In this topology the first NFVO <NUM> does not have knowledge of the third network layer and therefore can see a single node <NUM> representing the second NFVO <NUM>, and a single node <NUM> representing the third NFVO <NUM>. The topology of the second orchestration layer also comprises the customer end points A and B connected to the second NFVO <NUM> in the Blue domain, and the customer end points C, D and E connected to the third NFVO <NUM> in the Green domain.

The topology of the third orchestration layer, as seen from the second NFVO <NUM> and the third NFVO <NUM>, is illustrated in box <NUM>. In this topology the virtualization domains managed by each of the VIMs in the third network layer are visible. Specifically, the second NFVO <NUM> can see the topology of the third network layer in the Blue domain. In other words, the second NFVO <NUM> may see the VIMs 110a, 110b, and 110c and their interconnections with each other and the customer end points A and B. The second NFVO <NUM> may also see that the topology of the third network layer comprises the inter-domain connection points x and y. Similarly, the third NFVO <NUM> can see the topology of the third network layer in the Green domain. In other words, the third NFVO <NUM> can see the VIMs 112a, 112b, 112c and 112d and their interconnections with each other and the customer end points C, D and E. The third NFVO <NUM> may also see the inter-domain connection points x and y.

Each NFVO may embed network service requests, received from the network layer above, into the topology of the network layer below. In other words, if for example, the second NFVO <NUM> receives a request from the first NFVO <NUM> to provide a network service comprising a virtual network function (VNF), the second NFVO must map this VNF onto one of the three available VIMs in the topology of the third network layer.

As described above the LCM component <NUM> is registered to the first NFVO <NUM>. This LCM component <NUM> may be able to resolve topological dependencies corresponding to the details regarding the topology of the subordinate layers which are available at the first NFVO <NUM>. In other words, the LCM component <NUM> may receive information relating to the topology of the second orchestration layer, and may be able to decompose virtual network functions (VNFs) requested in a network service in order to implement the network service in the topology of the second orchestration layer.

However, the LCM component <NUM> is only aware of the topology of the second orchestration layer as it is connected to the first NFVO. It may therefore not be able to decompose the virtual network function sufficiently for the network function to be optimally implemented in the third orchestration layer.

<FIG> illustrates an example where the decomposition provided by the LCM component <NUM> for the first NFVO does not result in an optimal implementation of the network service request in the third network layer.

For example, box <NUM> illustrates a VNF forwarding graph (VNF-FG) of a first network service request for a distributed router (dR) VNF between the customer end points A, B, C, D and E. The first NFVO <NUM> may, with the help of the LCM component <NUM>, provide a first substitution for the VNF dR, wherein the first substitution maps the first network service request onto the second orchestration layer. In other words, the LCM component <NUM>, based on the topology of the second orchestration layer, and the request to provide a VNF dR between the customer end points A, B, C, D and E, may determine that the first substitution comprises two separate router VNFs, R1 and R2, as illustrated in box <NUM>. The first substitution may therefore be implemented by as a second service request to the second NFVO <NUM> for a router VNF, and a third service request to the third NFVO <NUM> for a router VNF.

Even though the second orchestration layer comprises two NFVOs, as the first NFVO <NUM> is not aware of the topology of any subordinate layers to the second orchestration layer, it may not provide a first substitution which may require any further decomposition as, in this embodiment, the third NFVO <NUM> and second NFVO <NUM> do not have the capability to provide any further VNF substitution.

The second NFVO <NUM> may therefore receive a second network service request from the first NFVO <NUM> to provide a router VNF between the customer end points A and B and the Green domain. The second NFVO <NUM> may therefore embed the router VNF R1 at one of the three VIMs in the Blue domain. Given that the second NFVO <NUM> has knowledge of the topology of the third network layer, the second NFVO <NUM> may embed the router VNF R1 at the VIM 110a, as illustrated by the VNF-FG in box <NUM>.

Similarly, the third NFVO <NUM>, may receive a third network service request from the first NFVO <NUM> to provide a router VNF R2 between the customer end points C, D, and E, and the Blue domain. The third NFVO <NUM> may therefore embed the router VNF R2 at one of the four VIMs in the Green domain. Given that the third NFVO <NUM> has knowledge of the topology of the third network layer, the third NFVO <NUM> may embed the router VNF R2 at the VIM 112d, as illustrated by the VNF-FG in box <NUM>.

However, given the specific topology of the third network layer in this example, this embedding of the router VNF R2 at VIM 112d results in a sub-optimal mapping of the original service request from the customer to the first NFVO <NUM>, as the lack of router VNF at the VIM 112a may prevent traffic from the customer end point E from travelling between the VIMs 112a and 112d. Therefore, the resulting services provided by embedding R1 and R2 may not truly implement a distributed router VNF between the customer end points A, B, C, D and E.

According to some embodiments therefore, the LCM component <NUM> may be delegated to subordinate orchestration layers of the virtual network, such that decomposition of VNFs may occur in subordinate orchestration layers. The LCM component <NUM> may therefore oversee the topology aware service (component) decomposition in its local scope, and recursively delegate itself to subordinate orchestrators until the physical infrastructure layer is reached or until no LCM delegation is supported.

<FIG> illustrates a method, in a Life Cycle Management, LCM, component in a virtual network according to some embodiments. The virtual network comprises a first orchestration layer comprising a first NFVO <NUM>, and a second orchestration layer, subordinate to the first orchestration layer, comprising a second NFVO <NUM>.

In step <NUM>, the LCM component receives a first request, from the first NFVO, to determine a first substitution for a first VNF in a first network service request, wherein the first substitution maps the first network service request onto the second orchestration layer.

In step <NUM>, the LCM component determines the first substitution. As described previously, the first substitution may be determined based on a topology of the second orchestration layer. However, conversely to as described above with reference to <FIG>, this first substitution may associate VNFs with the NFVOs in the second orchestration layer that may require further decomposition. For example, the first substitution may associate a distributed router VNF with an NFVO in the second orchestration layer.

In step <NUM>, the LCM component may determine whether the first substitution comprises a second VNF associated with a second NFVO in a second orchestration layer. For example, the first network service request may comprise a distributed router VNF associated with a first NFVO, and a first substitution may comprise a distributed router VNF associated with the second NFVO.

Responsive to a determination in step <NUM> that the first substitution comprises a second VNF associated with the second NFVO, the method passes to step <NUM> in which the LCM component receives a second request from the second NFVO to provide a second substitution for the second VNF in a second network service request. The second network service request may be a subclass or reclassification of the first network service request.

The second substitution maps the second network service request onto a third network layer, and the second network service request implements at least part of the first network service request. For example, the first network service request may comprise a first VNF-FG linking a plurality of network end points to the first VNF. The second network service request may therefore comprise a second VNF-FG linking at least two of the plurality of network end points to the second VNF.

Responsive to a determination in step <NUM> that the first substitution does not comprise a second VNF associated with the second NFVO, the method may end in step <NUM> as the LCM component may not be required to delegate to any further NFVOs.

<FIG> illustrates a method, in a first NFVO according to some embodiments. The first NFVO may be in a first orchestration layer superior to a second orchestration layer comprising a second NFVO in a virtual network.

In step <NUM>, the first NFVO receives a request to instantiate a first network service comprising a first VNF. For example, the first NFVO may be requested to instantiate a first network service comprising a distributed router VNF.

In step <NUM> the first NFVO transmits a first request to a Lifecycle manager, LCM, component to determine a first substitution for the first VNF, wherein the first substitution maps the first network service onto a topology of the second orchestration layer.

In some embodiments, the first NFVO maps the first VNF to the topology of the second orchestration layer and transmits this as a VNF forwarding graph (VNF-FG) to the LCM component as the first request. The LCM component may then determine the first substitution based on the received VNF-FG. In some embodiments, the LCM component receives the first VNF separately from the topology of the second orchestration layer, and determines the first substitution based on the first VNF and the topology of the second orchestration layer.

In step <NUM> the first NFVO receives the first substitution from the LCM component.

In step <NUM>, the first NFVO may determine whether the first substitution comprises a second VNF associated with a second NFVO.

If the first substitution does not comprise a second VNF associated with a second NFVO, the method passes to step <NUM> in which the first NFVO may implement the first network service request using the first substitution.

If the first substitution comprises a second VNF associated with a second NFVO, the method passes to step <NUM> in which the first NFVO transmits an indication of the second VNF to the second NFVO. This may allow the second NFVO to attempt to register with an LCM component, and to determine whether the second VNF is supported by the NFVO.

The first NFVO may then in step <NUM> receive an indication of whether the second NFVO is capable of supporting the second VNF. The first NFVO may then determine, based on the indication, whether the second NFVO is capable of supporting the second VNF.

If the second NFVO is capable of supporting the second VNF, the method passes to step <NUM> in which the first NFVO implements the first network service request using the first substitution. For example, the first NFVO may transmit a second network service request to the second NFVO to instantiate a second network service comprising the second VNF. The second network service may implement at least part of the first network service.

If the second NFVO is not capable of supporting the second VNF, the method passes to step <NUM> in which the first NFVO may transmit a request to the LCM component to update the first substitution based on the determination that the second NFVO is not capable of supporting the second VNF. The LCM may then be able to update the first substitution based on the reduced capabilities of the second NFVO, and may transmit an updated first substitution to the first NFVO. This updated first substitution may be received by the first NFVO in step <NUM>.

The method may then pass back to step <NUM>. In some embodiments, the method may pass back to step <NUM> if the updated first substitution comprises a new second VNF associated with a new second NFVO where the capability of the new second NFVO to support the new second VNF has not already be investigated.

Turning to <FIG> as an example implementation of the methods illustrated in <FIG> and <FIG>. This example utilises routers and distributed routers as example VNFs. However, it will be appreciated that any type of VNF may be used.

In <FIG>, a first NFVO <NUM> receives a request from a customer <NUM> to instantiate a network service according to the VNF-FG illustrated in box <NUM>. In other words, the first network service comprises a distributed router VNF between the customer end points A, B, C, D and E. As previously mentioned the end points A, B, C, D and E may also represent further VNFs which may for example be part of further service provider network domains. The first NFVO <NUM> therefore receives the request to instantiate the first network service as described in step <NUM> of <FIG>. The first NFVO <NUM> may then map the first VNF to the topology of the second orchestration layer, which, in this example may result in the VNF-FG illustrated in box <NUM>. In this example, the first NFVO <NUM> maps the VNF dR to the second NFVO <NUM> in the second orchestration layer. The first NFVO <NUM> may then transmit the VNF-FG illustrated in box <NUM> to the LCM component <NUM> as the first request to the LCM component <NUM> to determine the first substitution as in step <NUM> of <FIG>.

The LCM component <NUM> receives the first request from the first NFVO <NUM> as described in step <NUM> of <FIG>. The LCM component <NUM> may then determine, based on the received VNF-FG, for example as illustrated in box <NUM>, a first substitution (or decomposition) for the VNF dR, as described in step <NUM> of <FIG>. In other words, the LCM component <NUM> may perform a topology aware decomposition of the first VNF onto the topology of the second orchestration layer to provide the first substitution.

In this example, the LCM component <NUM>, may determine that the first substitution comprises a second distributed router VNF dR1 associated with the second NFVO <NUM>, and a third distributed router VNF dR2 associated with the third NFVO <NUM>, as illustrated in the VNF-FG in box <NUM>. It will however, be appreciated that the second orchestration layer may comprise only one orchestrator, and may comprise other components such as VIMs. In these circumstances, the decomposition of the dR onto the second orchestration layer may be different. For example, the first substitution may comprise a single dR VNF associated with an orchestrator in the second orchestration layer, and a router VNF associated with a VIM in the second orchestration layer.

The LCM component <NUM> may then transmit the first substitution to the first NFVO <NUM>, as described in step <NUM> of <FIG>. The first substitution may be transmitted by the LCM component <NUM> along with a request that the first NFVO <NUM> instantiate LCM registration at both the second NFVO <NUM>, and the third NFVO <NUM>.

The first NFVO <NUM> may therefore determine, as in step <NUM> of <FIG>, that the first substitution comprises a second VNF, VNF dR1 associated with a second NFVO <NUM>.

In this example, the first NFVO <NUM> determines that the first substitution comprises a third VNF, VNF dR2, associated with a third NFVO <NUM> in the second orchestration layer.

The first NFVO <NUM> may then transmit an indication of the second VNF to the second NFVO <NUM>. In other words, the first NFVO <NUM> may transmit a request to the second NFVO, instructing the second NFVO <NUM> to both attempt to register with the LCM component <NUM>, and request that the LCM component <NUM> determine a second substitution for the VNF dR1 in the third network layer. In other words, the first NFVO <NUM> may instruct the second NFVO <NUM> to instantiate a topology aware substitution request to LCM component <NUM>.

Similarly, in this example, the first NFVO <NUM> may transmit an indication of the third VNF dR2, to the third NFVO <NUM>. In other words, the first NFVO <NUM> may transmit a request to the third NFVO <NUM> instructing the third NFVO <NUM> to both attempt to register with the LCM component <NUM>, and to request that the LCM component <NUM> determine a third substitution for the VNF dR2 in the third network layer. In other words, the first NFVO <NUM> may instruct the third NFVO <NUM> to instantiate a topology aware substitution request to LCM component <NUM>.

The second NFVO <NUM> may therefore transmit a second request to the LCM component <NUM> to provide a second substitution for the second VNF dR1 in the third network layer, as described in step <NUM> of <FIG>. The LCM component <NUM> may then determine, from the topology of the third network layer, in particular the topology of the third network layer in the Blue domain, that the second substitution comprises the router VNF R1a associated with the VIM 110a. As this second substitution does not comprise a VNF associated with a NFVO, the LCM may not need to delegate to any further subordinate layers of the network. It will be appreciated however, that the third network layer may in some embodiments comprise a further orchestration layer comprising for example a fourth NFVO. In this example, the second substitution may comprise a fourth VNF associated with the fourth NFVO, and therefore the second NFVO <NUM> may transmit an indication of the fourth VNF to the fourth NFVO, instructing the fourth NFVO to attempt to register with the LCM component <NUM> similarly to above.

In this example, therefore, the LCM component may transmit the second substitution to the second NFVO <NUM>.

The third NFVO <NUM> may also transmit a request to the LCM component <NUM> to provide a third substitution for the third VNF dR2 in the third network layer. The LCM component <NUM> may then determine, from the topology of the third network layer, in particular the topology of the third network layer in the Green domain, that the third substitution comprises a router VNF R2a associated with the VIM 112a, and a router VNF R2b associated with the VIM 112d. Similarly to above, as this third substitution does not comprise a VNF associated with a NFVO, the LCM does not need to delegate to any further subordinate layers of the network.

The LCM component <NUM> may therefore transmit the third substitution to the third NFVO <NUM>.

The LCM component <NUM> may then alert the first NFVO <NUM> that the delegation through the network has been completed, and that the first substitution may be used to implement the network service request from the customer <NUM>. The first NFVO <NUM> may then transmit a second service request to the second NFVO <NUM> to provide the VNF dR1 between the customer end points A and B and the Green domain. The first NFVO <NUM> may also transmit a third service request to the third NFVO <NUM> to provide the VNF dR2 between the customer end points C, D and E and the Blue Domain.

The second NFVO <NUM> may then use the second substitution, received from the LCM component <NUM> to implement the second service request using the router VNF R1a at VIM 110a. The third NFVO <NUM> may then use the third substitution received from the LCM component <NUM>, to implement the third service request using the router VNFs R2a at VIM 112a, and R2ba at VIM 112d.

Therefore, by delegating the LCM component <NUM> to the subordinate second orchestration layer to decompose the requested VNFs onto the topology of the lower layers, the LCM component <NUM> may ensure that an optimal placement of VNFs in the physical infrastructure layer is provided.

In other words, in contrast to the example illustrated in <FIG>, the delegation of the LCM component <NUM> ensures that a second router is placed in the Green domain in the third network layer, thereby providing an optimal decomposition of the distributed router service request form the customer <NUM>.

<FIG> illustrates an example of signalling between the customer <NUM>, the first NFVO <NUM>, the LCM component <NUM>, the second NFVO <NUM>, and the third NFVO <NUM> to implement the VNFs at the VIMs associated with a physical infrastructure layer. This figure is split in <FIG> and <FIG> which form part of the same signalling diagram.

In step <NUM>, the customer <NUM> transmits a request to the first NFVO <NUM> to instantiate a first network service (NS). For example, the first network service request may be the network service request illustrated in box <NUM> of <FIG>. The first network service request may comprise a VNF at the first NFVO <NUM> which may require decomposing for implementation in the subordinate orchestration layer.

In step <NUM> the first NFVO <NUM> transmits a first request to a Lifecycle manager, LCM, component <NUM> to determine a first substitution for the first VNF. As previously described this first request may comprise an VNF-FG as illustrated in box <NUM> of <FIG>.

In particular, the first request shown to the LCM component <NUM> can be limited to expose only the topology related to the embedded service request and not any components of the subordinate network layer which do not form part of the network service request.

In step <NUM> the LCM component <NUM> determines the first substitution based on the topology of the second orchestration layer. In this example, the first substitution comprises the VNF-FG illustrates in box <NUM> of <FIG>.

In step <NUM>, the LCM component <NUM> transmits the first substitution to the first NFVO <NUM>. The first NFVO <NUM> may then instruct the second NFVO <NUM> to request a substitution for the second VNF dR1 from the LCM component <NUM> in step <NUM>. This may require the second NFVO <NUM> to register with the LCM component <NUM> in step <NUM>. In some embodiments however, for example where a particular network service request is used frequently, the second NFVO <NUM> may previously have registered with the LCM component <NUM>.

In step <NUM> the second NFVO <NUM> may indicate to the first NFVO <NUM> whether it is capable of supporting the second VNF. In some examples, as will be illustrated in <FIG>, an NFVO may not be capable of supporting a VNF. This may be due to missing resources or incompatibly in the capabilities show to the LCM component. Alternatively, the LCM registration may fail.

Steps <NUM> to <NUM> correspond to steps <NUM> to <NUM> but for the third NFVO <NUM> rather than the second NFVO <NUM>. In some examples, steps <NUM> to <NUM> may be performing concurrently with steps <NUM> to <NUM>. Once the first NFVO <NUM> has received confirmation from both the second NFVO <NUM> and the third NFVO <NUM> that they are capable of supporting the second VNF and third VNF respectively, the first NFVO <NUM> may report this capability to the LCM component <NUM> in step <NUM>. The above process may be repeated in <NUM> until all capabilities for the first substitution have been satisfied.

The LCM component <NUM> may then transmit an indication to the first NFVO <NUM> to implement the first network service request according to the first substitution in step <NUM>.

The first NFVO <NUM> may then implement the first network service request by transmitting a second network service request to the second NFVO <NUM> in step <NUM>, and by transmitting a third network service request to the third NFVO <NUM> in step <NUM>. The second network service request may comprise a request to implement the second VNF, and the third network service request may comprise a request to implement the third VNF.

In step <NUM>, the second NFVO <NUM> may then perform steps <NUM> to <NUM> with the LCM component <NUM>. For the example of <FIG>, the topology of the third network layer comprises no NFVOs, and therefore steps <NUM> to <NUM> may not occur. It will however, be appreciated, that in some embodiments, the third network layer may comprise at least one NFVO, and therefore these steps may occur.

At the end of step <NUM>, the second NFVO receives an indication from the LCM component <NUM> to implement the second network service request according to the second substitution. The second NFVO <NUM> may therefore implement the second network service request in step <NUM>. In this example, the second substitution comprises a router VNF R1a as illustrates in box <NUM> and therefore the second NFVO <NUM> creates the R1a VNF at the VIM 110a.

Similarly, in step <NUM>, the third NFVO <NUM> may perform steps <NUM> to <NUM> with the LCM component. For the example of <FIG>, the topology of the third network layer comprises no NFVOs, and therefore steps <NUM> to <NUM> may not occur. It will however, be appreciated, that in some embodiments, the third network layer may comprise at least one NFVO, and therefore these steps may occur.

At the end of step <NUM>, the third NFVO <NUM> receives an indication from the LCM component <NUM> to implement the third network service request according to the third substitution. The third NFVO <NUM> therefore implements the third network service request in step <NUM>. In this example, the third substitution comprises routers VNF R2a and VNF R2b as illustrated in box <NUM> of <FIG>, and therefore the second NFVO <NUM> creates the R2a VNF at VIM 112a and the R2b VNF at VIM 112d.

<FIG> illustrates an example of the signalling when a NFVO is not capable of supporting a VNF. This figure is split in <FIG> and <FIG> which form part of the same signalling diagram.

In this example, at step <NUM>, an error occurs in the registration with the LCM component <NUM>. For example, the third NFVO <NUM> may have missing resources or incompatibly with the capabilities shown to the LCM component <NUM>. Alternatively, the LCM registration may fail.

In response to this, the third NFVO <NUM> may indicate to the first NFVO <NUM> that it is not capable of supporting the third VNF, in step <NUM>.

The first NFVO, responsive to receiving the indication that the third NFVO <NUM> does not support the third VNF may transmit a request, in step <NUM>, to the LCM component <NUM> to update the first substitution based on the indication that the third NFVO <NUM> does not support the third VNF.

In this example, therefore, when the method reaches step <NUM>, the capabilities of the first substitution are not yet satisfied.

The LCM component <NUM> may therefore update the first substitution based on the determination that the third NFVO <NUM> does not support the third VNF; and transmit the updated first substitution to the first NFVO <NUM>.

In some examples, this may require the LCM component <NUM> to delegate to a new NFVO, or to re-delegate to the second NFVO <NUM>, to determine whether a VNF in the updated first substitution is supported.

In this example, the updated substitution does not require any further delegation and therefore the LCM component <NUM> transmits the updated first substitution to the first NFVO <NUM>. In this example, the updated substitution comprises a dR associated with the second NFVO <NUM> and a router R associated with the third NFVO <NUM>.

Therefore, when the first NFVO transmits a third network service request to the third NFVO <NUM> in step <NUM>, the third network service request may in this embodiment comprise a router VNF R, instead of a distributed router VNF dR as in <FIG>.

The third NFVO will then embed this router VNF R into the topology of the third network layer without requesting a substitution from the LCM component <NUM>, which may result in a sub-optimal embedding.

It will also be appreciated that in some embodiments, the first network service request is received at the first NFVO from a higher orchestration layer, rather than a customer end point, as illustrated in <FIG>. This figure is split in <FIG> and <FIG> which form part of the same signalling diagram. In this figure a fourth NFVO <NUM> occupies a fourth orchestration layer which is superior to the first orchestration layer in the network hierarchy. Regardless of this, the first NFVO performs the same method upon receiving the first network service request in step <NUM>. In this embodiment however, the first network service request may have resulted from a decomposition performed by the LCM component <NUM> in the further orchestration layer.

<FIG> illustrates an example of a registration process which may be performed in steps <NUM> and <NUM> of <FIG>, <FIG> and <FIG>. It will however, be appreciated that other LCM component registration mechanisms may be used.

The second NFVO <NUM> receives in step <NUM> an instruction from the first NFVO <NUM> to instantiate the LCM component <NUM>.

The second NFVO <NUM> may then embed the LCM component <NUM> into the topology of the third orchestration layer to find an appropriate VIM in the third network layer to host the LCM functionality, in step <NUM>.

The second NFVO may then create any appropriate VNFs including any VNFs for providing LCM functionality, in step <NUM>. In some embodiments, an Element Management interface to the LCM component <NUM> function could be added, which enables configuration of the LCM logic. For example, it may be that only a bare LCM engine is instantiated in the subordinate layer and the LCM "templates" are configured via the EM interface. An upper layer LCM component <NUM> may act as an EM for the subordinate domains.

In step <NUM> the second NFVO <NUM> and a Management and Orchestration (MANO) Monitor <NUM> associated with the second NFVO may check whether any VNFs comprise an LCM component to receive the delegated LCM component <NUM>, if not the registration to the LCM component <NUM> may fail. However, if a VNF does have the required LCM functionality, the method may pass to step <NUM> in which the MANO requests that the second NFVO <NUM> requests registration with the LCM component <NUM>.

To do this, the second NFVO <NUM> may therefore request information from the LCM component <NUM> in step <NUM>, and may receive the information in step <NUM>. The LCM component <NUM> may then be considered to be registered with the second NFVO <NUM> in step <NUM>. The second NFVO <NUM> may then confirm the registration of the LCM component <NUM> with the MANO <NUM> in step <NUM>.

As the registration in therefore complete, the second NFVO may confirm its capabilities to the first NFVO in step <NUM> as described in <FIG>, <FIG> and <FIG>.

<FIG> illustrates a network functions virtualisation orchestrator (NFVO) <NUM> comprising processing circuitry (or logic) <NUM>. The processing circuitry <NUM> controls the operation of the first network functions virtualisation orchestrator (NFVO) <NUM> and can implement the method described herein in relation to a network functions virtualisation orchestrator (NFVO) <NUM>. The processing circuitry <NUM> can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the network functions virtualisation orchestrator (NFVO) <NUM> in the manner described herein. In particular implementations, the processing circuitry <NUM> can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein in relation to the network functions virtualisation orchestrator (NFVO) <NUM>.

Briefly, the processing circuitry <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> is configured to receive a request to instantiate a first network service comprising a first VNF; transmit a first request to a Lifecycle manager, LCM, component to determine a first substitution for the first VNF, wherein the first substitution maps the first network service onto a topology of the second orchestrator layer; receive the first substitution for the first VNF, wherein the first substitution comprises a second VNF associated with the second NFVO; transmit an indication of the second VNF to the second NFVO; and responsive to receiving an indication that the second NFVO is capable of supporting the second VNF, transmit a second network service request to the second NFVO to instantiate a second network service comprising the second VNF, wherein the second network service implements at least part of the first network service.

In some embodiments, the network functions virtualisation orchestrator (NFVO) <NUM> may optionally comprise a communications interface <NUM>. The communications interface <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> can be for use in communicating with other nodes, such as other virtual nodes. For example, the communications interface <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> can be configured to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar. The processing circuitry <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> may be configured to control the communications interface <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar.

Optionally, the network functions virtualisation orchestrator (NFVO) <NUM> may comprise a memory <NUM>. In some embodiments, the memory <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> can be configured to store program code that can be executed by the processing circuitry <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> to perform the method described herein in relation to the network functions virtualisation orchestrator (NFVO) <NUM>. Alternatively or in addition, the memory <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM>, can be configured to store any requests, resources, information, data, signals, or similar that are described herein. The processing circuitry <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> may be configured to control the memory <NUM> of the network functions virtualisation orchestrator (NFVO) <NUM> to store any requests, resources, information, data, signals, or similar that are described herein.

<FIG> illustrates a Lifecycle Management (LCM) component <NUM> comprising processing circuitry (or logic) <NUM>. The processing circuitry <NUM> controls the operation of the Lifecycle Management (LCM) component <NUM> and can implement the method described herein in relation to a Lifecycle Management (LCM) component <NUM>. The processing circuitry <NUM> can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the Lifecycle Management (LCM) component <NUM> in the manner described herein. In particular implementations, the processing circuitry <NUM> can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein in relation to the Lifecycle Management (LCM) component <NUM>.

Briefly, the processing circuitry <NUM> of the Lifecycle Management (LCM) component <NUM> is configured to receiving a first request, from a first NFVO, to determine a first substitution for a first VNF in a first network service request, wherein the first substitution maps the first network service request onto the second orchestration layer; responsive to a determination, based on a topology of the second orchestration layer, that the first substitution comprises a second VNF associated with a second NFVO, receiving a second request from the second NFVO to provide a second substitution for the second VNF in a second network service request, wherein the second substitution maps the second network service request onto a third network layer, and the second network service request implements at least part of the first network service request.

In some embodiments, the Lifecycle Management (LCM) component <NUM> may optionally comprise a communications interface <NUM>. The communications interface <NUM> of the Lifecycle Management (LCM) component <NUM> can be for use in communicating with other nodes, such as other virtual nodes. For example, the communications interface <NUM> of the Lifecycle Management (LCM) component <NUM> can be configured to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar. The processing circuitry <NUM> of the Lifecycle Management (LCM) component <NUM> may be configured to control the communications interface <NUM> of the Lifecycle Management (LCM) component <NUM> to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar.

Optionally, the Lifecycle Management (LCM) component <NUM> may comprise a memory <NUM>. In some embodiments, the memory <NUM> of the Lifecycle Management (LCM) component <NUM> can be configured to store program code that can be executed by the processing circuitry <NUM> of the Lifecycle Management (LCM) component <NUM> to perform the method described herein in relation to the Lifecycle Management (LCM) component <NUM>. Alternatively or in addition, the memory <NUM> of the Lifecycle Management (LCM) component <NUM>, can be configured to store any requests, resources, information, data, signals, or similar that are described herein. The processing circuitry <NUM> of the Lifecycle Management (LCM) component <NUM> may be configured to control the memory <NUM> of the Lifecycle Management (LCM) component <NUM> to store any requests, resources, information, data, signals, or similar that are described herein.

There is therefore provided methods and apparatus for providing delegation of an LCM component <NUM> to subordinate layers of a network hierarchy, thereby ensuring that optimal implementations of network service requests received at the higher levels of the network are provided.

Claim 1:
A method, in a Life Cycle Management, LCM, component in a virtual network, wherein the virtual network comprises a first orchestration layer comprising a first network function virtualisation orchestrator, NFVO, and a second orchestration layer, subordinate to the first orchestration layer, comprising a second NFVO (<NUM>), the method comprising:
receiving a first request, from the first NFVO (<NUM>), to determine a first substitution for a first VNF, wherein a first network service request received by the first NFVO requests instantiation of a first network service comprising the first VNF, and wherein the first substitution maps the first network service onto the second orchestration layer;
responsive to receiving the first request, determining the first substitution;
responsive to a determination, based on a topology of the second orchestration layer, that the first substitution comprises a second VNF associated with the second NFVO (<NUM>), receiving a second request from the second NFVO (<NUM>) to provide a second substitution for the second VNF in a second network service request transmitted by the first NFVO to the second NFVO, the second network service request requesting instantiation of a second network service comprising the second VNF, wherein the second substitution maps the second network service onto a third network layer, and the second network service implements at least part of the first network service; and
responsive to receiving the second request, determining the second substitution.