Multi-tenant aware dynamic host configuration protocol (DHCP) mechanism for cloud networking

An approach includes providing support multi-tenancy support on a DHCP protocol. The approach includes receiving a dynamic host configuration protocol (DHCP) packet, inserting a tenant-specific option information within the DHCP packet, and transmitting the DHCP packet with the tenant-specific option information.

TECHNICAL FIELD

The technical character of the present invention generally relates to a Dynamic Host Configuration Protocol (DHCP) mechanism for a cloud networking, and more particularly, to a DHCP mechanism for multi-tenant cloud networking.

BACKGROUND

Multi-tenant support is a basic demand for cloud data center networks, which requires service isolations between different tenants. One type of service isolation is address isolation which provides overlapping addresses to different tenants. In current standards, such as Internet Engineering Task Force Network Virtualization Overlays (IETF NVO3) standards, a virtual network identifier (VNID) is provided to support the separation of virtual networks of different tenants in overlay virtual networks. Addressing and host configuration can be provided through Dynamic Host Configuration Protocol (DHCP), which provides configuration parameters to hosts.

DHCP has two components, including a protocol for delivering host-specific configuration parameters from a DHCP server to a host and a mechanism for allocation of network addresses to hosts. In DHCP, the protocol only supports a configuration in a single address space. Therefore, each DHCP server can only be configured with configuration parameters of a single address space (i.e., the protocol cannot support overlapped address spaces). Thus, the client of the DHCP server can only obtain an address from this single address space.

In order to provide overlapping addresses to different tenants in cloud data center networks, separate DHCP servers must be set up for each tenant. This is usually implemented by setting up a unique DHCP server in a separate LINUX namespace (i.e., operating system level virtualization) or running multiple DHCP servers in different hosts. In these implementations, there is one DHCP server for a tenant, and the addresses provided to different tenants can be overlapped.

However, configuring multiple Linux namespaces is complex and resource/computation intensive since there is usually only one physical network interface card used to connect to the data network. Further, multiple Linux namespaces requires multiple virtual network interfaces to be created and connected to an Ethernet bridge to serve those namespaces and multiple DHCP server instances to be run in which each one of them only serves a single tenant or even a single network segment. Also, there is a lack of scalability when a number of tenants grow into the thousands. Further, many legacy operating systems (e.g., WINDOWS SERVER and legacy LINUX kernels before 2.6.32.xx) do not support LINUX namespaces.

Moreover, there is no inter-operability between overlay networks, even when using overlay encapsulation protocols for multi-tenant support, such as virtual local area network (VLAN), virtual extensible local area network (VXLAN), distributed overlay virtual Ethernet (DOVE), network virtualization using generic routing encapsulation (NVGRE), stateless transport tunneling (STT), generic network virtualization encapsulation (GENEVE), etc. Therefore, such systems do not provide the flexibility required for multi-tenant support.

SUMMARY

In a first aspect of the invention, a method is provided for that includes receiving a dynamic host configuration protocol (DHCP) packet. The method further includes inserting a tenant-specific option information within the DHCP packet. The method further includes transmitting the DHCP packet with the tenant-specific option information.

In another aspect of the invention, there is a computer program product that includes a computer readable storage medium having program code embodied in the storage medium. The program code is not a transitory signal per se, and the program instructions are readable by a computing device to cause the computing device to perform a method that includes receiving a dynamic host configuration protocol (DHCP) packet. The method further includes determining that the DHCP packet comprises tenant-specific option information. The method further includes selecting an address space based on the tenant-specific option information.

In a further aspect of the invention, there is a computer program that includes a computer readable storage medium having program code embodied in the storage medium. The program code is not a transitory signal per se, and the program instructions are readable by a computing device to cause the computing device to perform a method that includes receiving a dynamic host configuration protocol (DHCP) packet which comprises a tenant-specific option information. The method further includes locating a tenant address space based on the tenant-specific option information. The method further includes obtaining a virtual network identifier from a virtual access point (VAP). The method further includes obtaining a subnet configuration corresponding to the obtained virtual network identifier. The method further includes allocating an internet protocol (IP) address which corresponds to the obtained subnet configuration.

In another aspect of the invention, a system is provided that includes a CPU, a computer readable memory, and a computer readable storage medium. Additionally, the system includes one or more program instructions. The system includes program instructions to insert multi-tenancy information within a dynamic host configuration protocol (DHCP) packet. The system further includes program instructions to transmit the DHCP packet with the multi-tenancy information. The program instructions are stored on the computer readable storage medium for execution by the CPU via the computer readable memory.

In another aspect of the invention, a method is provided for configuring a tenant-specific DHCP option frame format that includes configuring a first field of the tenant-specific DHCP option frame format to denote an overlay protocol type that is used for tenant isolation. The method further includes configuring a second field of the tenant-specific DHCP option frame format to uniquely identify a tenant. The method further includes configuring a third field of the tenant-specific DHCP option frame format to denote a virtual network.

Embodiments of the present invention provide systems and methods that implement technical features such as a novel DHCP mechanism for multi-tenant cloud networking, which addresses the issue of address isolation for different tenants in a more efficient manner than current systems. For example, in embodiments of the DHCP mechanism, tenant-specific information is included in a DHCP packet for a scoping of address space. The advantage of the aforementioned technical solution for embodiments of the DHCP mechanism is that it is backwards-compatible, and does not adversely affect currently implemented systems of DHCP processing. Further, if the tenant-specific information is not provided in the DHCP packet, DHCP processing can occur in a manner as current systems. Moreover, in comparison to an address range in the DHCP packet which has a global scope, in the technical features of embodiments of the DHCP mechanism, the address range in the DHCP packet is scoped locally to a tenant's address space when using the DHCP tenant-specific information.

Also, when using the DHCP mechanism of embodiments of the present invention, a single DHCP server is capable of providing DHCP services for multiple tenants, even though their address range may overlap with each other. Thus, in contrast to current systems, there is no need for operating system (OS) level isolation (e.g., LINUX namespace). Further, embodiments of the DHCP mechanism simplify the DHCP service provisioning in multi-tenant cloud data centers. The technical features of embodiments of the DHCP mechanism also address the interoperability issue when a data center network comprises heterogeneous virtual environments offered by different vendors.

DETAILED DESCRIPTION

The technical character of the present invention generally relates to a Dynamic Host Configuration Protocol (DHCP) mechanism for a cloud networking, and more particularly, to a DHCP mechanism for multi-tenant cloud networking. More specifically, embodiments of the present invention provide systems and methods that implement technical features such as a novel DHCP mechanism for multi-tenant cloud networking, which addresses the issue of address isolation for different tenants in a more efficient manner than current systems. For example, in embodiments of the DHCP mechanism, tenant-specific information is included in a DHCP packet for a scoping of address space.

The advantage of the aforementioned technical solution for embodiments of the DHCP mechanism is that it is backwards-compatible, and does not adversely affect currently implemented systems of DHCP processing. Further, if the tenant-specific information is not provided in the DHCP packet, DHCP processing can occur in a manner as current systems. Moreover, in comparison to an address range in the DHCP packet which has a global scope, in the technical features of embodiments of the DHCP mechanism, the address range in the DHCP packet is scoped locally to a tenant's address space when using the DHCP tenant-specific information.

Also, when using the DHCP mechanism of embodiments of the present invention, a single DHCP server is capable of providing DHCP services for multiple tenants, even though their address range may overlap with each other. Thus, in contrast to current systems, there is no need for operating system (OS) level isolation (e.g., LINUX namespace). Further, embodiments of the DHCP mechanism simplify the DHCP service provisioning in multi-tenant cloud data centers. The technical features of embodiments of the DHCP mechanism also address the interoperability issue when a data center network comprises heterogeneous virtual environments offered by different vendors.

In further embodiments of the DHCP mechanism, a single DHCP server providing addressing service is used for multiple tenants in a cloud data center based on overlay networks. Embodiments of the DHCP mechanism help to solve the following technical issues in DHCP systems:

(i) Address space isolation for different tenants in the presence of a DHCP relay agent;

(ii) Address subnet selection for tenant virtual networks with the aid of Network Virtualization Authority (NVA); and

(iii) General DHCP service provisioning for heterogeneous virtual environments that comprise a legacy physical infrastructure network and overlay networks with different encapsulation protocols (VLAN, VXLAN, NVGRE, STT, or GENEVE).

Further, embodiments of the DHCP mechanism do not disrupt current DHCP interactions between clients and a server, such as DHCP DISCOVER, OFFER, REQUEST, ACKNOWLEDGMENT, RELEASE, etc. In fact, the DHCP interactions also work in embodiments of the DHCP mechanism of the present invention.

In additional technical features of embodiments of the DHCP mechanism, the tenant-specific option is used as an indicator for a DHCP server to allocate an internet protocol (IP) address on an associated address space specific to that tenant. Hence, a single DHCP server can serve a plurality of tenants, and each tenant can have its own IP address pool for allocation. Moreover, each pool in a tenant is totally independent and can be overlapped (i.e., same IP address pool) with another pool for a different tenant. The tenant-specific option is added to a DHCP header by a DHCP relay agent.

In the technical solutions of the present invention, the tenant-specific option comprises the following fields:

(i) option: should have a unique value, used in known DHCP systems;

(ii) length: total number of bytes of remaining fields;

(iii) transport agent: encoding value to denote the overlay protocol type that is used for tenant isolation (e.g., VLAN, VXLAN, DOVE, NVGRE, STT, etc.);

(iv) tenant ID: a universally unique identifier (UUID) used to identify a tenant; and

(v) virtual network ID (VNID): denotes a virtual network, which is an abstract of a L2 segment or broadcast domain. A tenant may have multiple virtual networks.

In further embodiments, the tenant specific option is implemented as a sub-option in a DHCP relay agent information option (option 82, RFC 3046). In embodiments, the implementation adds a sub-option in the option 82 standard to include the proposed tenant-specific option. The tenant-specific option is added to the DHCP header by a DHCP relay agent, which runs on a network virtualization edge (NVE). Since the NVE is on an edge of the overlay network, it is easy to derive the encoding value of a transport agent in the tenant specific option. For example, the VNID can be derived from a virtual access point (VAP) on which the DHCP client connects.

In order to enable multi-tenant support in embodiments of the DHCP mechanism, the DHCP server supports two types of address spaces: global address space and tenant address space. The global address space is compatible with a known DHCP mechanism in which a tenant-specific option is not present in the DHCP packet. In the global address space of a current DHCP mechanism, the IP address ranges cannot be overlapped; whereas, in the technical solution using embodiments of the DHCP mechanism of the present invention, each tenant has a specific address pool in the tenant address space, and the address range in the DHCP mechanism can be overlapped across different tenant's address pool.

In embodiments of the DHCP mechanism, if the DHCP_DISCOVER message does not include the tenant specific option, a DHCP server performs a known DHCP processing. Otherwise, if the DHCP_DISCOVER message includes the tenant specific option, the tenant specific option is used to locate the tenant address space and IP range. The DHCP server locates the address space corresponding to the tenant ID in the tenant-specific option. If the DHCP_DISCOVER message has a subnet selection option (option 118) or a link selection sub-option (sub-option 5 in option 82), the DHCP server will allocate an address from that subnet. Otherwise, if the DHCP_DISCOVER message does not have a subnet selection option or a link selection sub-option, an IP range is associated to a VNID, and the DHCP server will find the IP range according to the VNID in the tenant specific option. Further, embodiments of the DHCP mechanism of the present invention can include a DHCP server which uses a matching criteria or access control list (ACL) rules on the tenant-specific option in the configuration to locate the tenant address space.

In embodiments of the DHCP mechanism of the present invention, a cloud service provider (CSP) may employ various overlay network solutions from different vendors to achieve a multi-tenant cloud data center. Therefore, embodiments of the DHCP mechanism can be utilized when the network size is expanded. In an example, the CSP may have two overlay networks, and these overlay networks may be built on top of a common physical network. A tenant may have virtual machines in both overlay networks. Therefore, in embodiments of the novel DHCP mechanism, there is a convenient way to provision the DHCP server in the physical network in case of a tenant having virtual machines spanning across heterogeneous overlay networks. The transport agent field in a tenant specific option is used to provision the DHCP server.

As the scope of VNID is limited to a single overlay network, in such heterogeneous networks, the DHCP server in embodiments of the DHCP mechanism can use the transport agent, together with VNID, in the tenant specific option, as the classification fields to derive the IP range from which IP addresses are allocated. Thus, to achieve IP address management service for heterogeneous virtual overlay networks with a single DHCP server in a cloud data center, a transport agent may be added as a dimension in the classification criteria to locate the IP address range in the tenant address space.

It is understood in advance that although this disclosure includes a detailed description on cloud computing, implementation of the techniques recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed.

Characteristics are as follows:

Service Models are as follows:

Deployment Models are as follows:

Program modules42generally carry out the functions and/or methodologies of embodiments of the invention as described herein. For example, some or all of the functions of a DHCP client80can be implemented as one or more of the program modules42. Additionally, the DHCP client80may be implemented as separate dedicated processors or a single or several processors to provide the functionality described herein. In embodiments, the DHCP client80performs one or more of the processes described herein.

Workloads layer90provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation91; software development and lifecycle management92; virtual classroom education delivery93; data analytics processing94; transaction processing95; and DHCP processes96described herein. In accordance with aspects of the invention, the DHCP processes96workload/function operates to perform one or more of the processes described herein.

FIG. 4depicts a cloud computing node according to another embodiment of the present invention. In particular,FIG. 4is another cloud computing node which comprises a same cloud computing node10asFIG. 1. InFIG. 4, the computer system/server12also comprises or communicates with a DHCP client170, a DHCP server160, and a DHCP relay agent180, as described in greater detail herein.

In accordance with aspects of the invention, the DHCP client170, the DHCP server160, and the DHCP relay agent180can be implemented as one or more program code in program modules42stored in memory as separate or combined modules. Additionally, the DHCP client170, the DHCP server160, and the DHCP relay agent180may be implemented as separate dedicated processors or a single or several processors to provide the function of these tools. While executing the computer program code, the processing unit16can read and/or write data to/from memory, storage system, and/or I/O interface22. The program code executes the processes of the invention.

By way of example, DHCP client170may be configured to send a DHCP request packet to a DHCP server160via a cloud computing environment50. As discussed with reference toFIG. 2, for example, cloud computing environment50may be the Internet, a local area network, a wide area network, and/or a wireless network. In response to the DHCP server160receiving the DHCP request packet, the DHCP server160allocates an IP address for the DHCP client170. In embodiments of the DHCP mechanism, DHCP server160may provide direct support for multi-tenancy on the DHCP protocol using a tenant-specific DHCP option to carry tenant information. Therefore, unlike current systems which require operating system virtualization (e.g., each tenant having a DHCP server running in a separate LINUX namespace), the DHCP server160can support overlapped IP address spaces. In fact, the DHCP server160provides numerous advantages and technical solutions over known OS virtualization for multi-tenancy, including addressing inter-operability between different encapsulation protocols for multi-tenant isolation, high scalability (e.g., not as computationally intensive), and seamlessly supports the software defined networking (SDN) address allocation requirement. Further, inFIG. 4, a DHCP relay agent180may be used as an intermediary to relay messages between DHCP client170and DHCP server160via the cloud computing environment50. One of ordinary skill in the art would understand that in another embodiment, DHCP client170and DHCP server160may communicate directly with each other without use of the DHCP relay agent180.

FIG. 5is a frame format for a tenant-specific DHCP option in accordance with aspects of the present invention. More specifically,FIG. 5depicts a tenant-specific DHCP option frame format100for carrying tenant information. The tenant-specific DHCP option frame format100includes a variety of fields, including, but not limited to option110, length120, transport agent130, tenant ID140, and virtual network ID150. Option110is a unique value in DHCP options. Length120is a total number of bytes of remaining fields. Transport agent130is an encoding value used to denote the overlay protocol type that is used for tenant isolation, e.g., VLAN, VXLAN, DOVE, NVGRE, STT, etc. Tenant ID140is a universally unique identifier (UUID) used to identify a tenant. Finally, virtual network ID150denotes a virtual network, which is an abstract of a L2 segment or broadcast domain.

A tenant may be joined to multiple virtual networks. The tenant-specific DHCP option frame format100is an indicator for a DHCP server to allocate an IP address on associated address space to that tenant. Therefore, a single DHCP server can serve a plurality of tenants, and each tenant can have its own IP address pool for allocation. The pools in different tenants are totally independent, and can be overlapped. The tenant-specific option frame format100can be added to a DHCP header by a DHCP relay agent. In embodiments, the tenant-specific option is a sub-option in DHCP relay agent information option (option 82, RFC 3046). Therefore, implementation will add a sub-option in the option 82 to include the tenant-specific option frame format100.

Flow Diagram

FIG. 6depicts an exemplary flow (swim diagram) for a DHCP packet processing in accordance with aspects of the present invention. More specifically,FIG. 6shows a tenant-specific option added to the DHCP header by a DHCP relay agent. Since a network virtualization edge (NVE) is an edge of the overlay network, it is easy to derive the encoding value of the transport agent in the tenant specific option. A virtual network identifier (VNID) can be derived from a virtual access point (VAP) to which the DHCP client connects. The VAP is a logical connection point on the NVE for connecting a tenant system to a virtual network. VAPs can be physical ports or virtual ports identified through logical interface identifiers, such as VLAN ID or internal vSwitch Interface ID connected to a virtual machine (VM). The tenant ID in the tenant-specific option can be derived through the VNID by consulting the local cache or remote database in NVA that consists of the mapping between VNID and tenant ID.

In current DHCP relays, for each L2 segment it serves, a gateway IP interface is needed, on which DHCP client packets on that L2 segment will be received. Therefore, in current DHCP systems, upon receiving a DHCP message from a DHCP client, the IP address of the IP interface will be filled in the GIADDR field of the DHCP packet if it is zero, and the DHCP message is sent to the DHCP server. In other words, the GIADDR is added by the first DHCP relay agent. The DHCP server will use the GIADDR to allocate the IP address and other network parameter to the DHCP client. The DHCP server will send a corresponding DHCP relay message to a DHCP relay agent identified by the GIADDR. The DHCP relay agent is designed to send the DHCP reply message to the directly connected DHCP clients—the clients in the same L2 segment as the IP interface of the DHCP relay agent identified by the GIADDR.

In contrast, as shown inFIG. 6, DHCP clients are running in the overlay network, and the overlay networks of different tenants are isolated. The DHCP server is designed to serve all the DHCP clients in different tenant overlay networks. The DHCP server and DHCP relay agents will communicate through the underlay network. The GIADDR added by the DHCP relay agent will be an underlay IP address of the relay agent. The DHCP server will not use the GIADDR to allocate the IP address and other network parameters to DHCP client. The DHCP server will use the tenant-specific option and other options to allocate the IP address and other network parameters to the DHCP client. The DHCP server will send a corresponding DHCP reply message to a DHCP relay agent identified by the GIADDR. The relay agent will use the VNID in tenant-specific option to deliver the DHCP reply message to the DHCP client accordingly.

More specifically,FIG. 6depicts an exemplary flow or swim lane diagram for a DHCP packet processing in accordance with aspects of the present invention.FIG. 5includes the following actors: DHCP client210(an example of DHCP client170described with regard toFIG. 4), DHCP relay agent220(an example of DHCP relay agent180with regard toFIG. 4), and DHCP server230(an example of DHCP server160described with regard ofFIG. 4).

InFIG. 6, in the DHCP packet processing, at step231, a DHCP client210sends a DHCP_DISCOVER message to a DHCP relay agent220. Then, at step232, the DHCP relay agent220sends a DHCP_DISCOVER with tenant specific option message to DHCP server230. In step233, the DCHP server230then sends a DHCP_OFFER with tenant specific option message to DHCP relay agent220. At step234, DHCP relay agent220sends a DHCP_OFFER message to DHCP client210. Then, at step235, DHCP client210sends a DHCP_REQUEST message to the DHCP relay agent220. The DHCP relay agent220sends a DHCP_REQUEST with tenant specific option message to DHCP server230, at step236. At step237, DHCP server230sends a DHCP_ACK with tenant specific option message to DHCP relay agent220. Finally, at step238, DHCP relay agent220sends a DHCP_ACK message to DHCP client210.

FIG. 7depicts an exemplary flow for an address allocation processing in accordance with aspects of the present invention. InFIG. 7, to enable multi-tenant support in the novel DHCP mechanism of the depicted embodiment, the DHCP server supports two types of address spaces: global address space and tenant address space. The global address space is compatible with current DHCP methods in which a tenant-specific option is not present in the DHCP packet. In the global address space of current DHCP methods, the IP address ranges cannot be overlapped; whereas, in contrast, in the technical solutions of the DHCP mechanism of the depicted embodiment of the present invention, each tenant has a specific address pool in the tenant address space. The address range in the DHCP mechanism of the depicted embodiment can be overlapped across different tenant's address pool.

For example, in the DHCP mechanism shown inFIG. 7, if the DHCP_DISCOVER message does not include the tenant specific option, the DHCP server performs a known DHCP processing. Otherwise, if the DHCP_DISCOVER message includes the tenant specific option, the tenant specific option is used to locate the tenant address space and IP range. The DHCP server locates the address space corresponding to the tenant ID in the tenant-specific option. Also, inFIG. 7, if the DHCP_DISCOVER message has a subnet selection option (option 118) or a link selection sub-option (sub-option 5 in option 82), the DHCP server will allocate an address from that subnet. Otherwise, if the DHCP_DISCOVER message does not have a subnet selection option or a link selection sub-option, an IP range is associated to a VNID, and the DHCP server will find the IP range according to the VNID in the tenant specific option. Further, the novel DHCP mechanism of the depicted embodiment can include a DHCP server which uses a matching criteria or access control list (ACL) rules on the tenant-specific option in the configuration to locate the tenant address space.

More specifically, inFIG. 7, in the address allocation processing, at step305, a DHCP server receives a DHCP request packet. At step310, the processes and systems of the DHCP server determine whether the DHCP request (e.g., DHCP_DISCOVER) has a specific option. If the DHCP request does not have a tenant specific option (i.e., NO), at step315, the DHCP server uses a global address space. Then, at step320, known DHCP protocol processing is performed by the DHCP server and the DHCP client, since there is no tenant specific option.

Alternatively, at step310, if the DHCP request (e.g., DHCP_DISCOVER) does have a tenant specific option (i.e., YES), at step325, an address space is chosen by the DHCP server according to the tenant specific option field. Further, at step330, a determination is made by the DHCP server as to whether there is either a link selection (option 118) or a subnet selection option (opt 82 subopt 5) in the DHCP request. If there is no link (i.e., NO) at step345, an address is allocated for VNID by the DHCP server. Alternatively, at step330, if there is either a link selection (option 118) or a subnet selection option (opt 82 subopt 5) in the DHCP request (i.e., YES), then at step335, there is a check by the DHCP server whether an available address in a requesting subnet. At step335, if there is an available address in the requesting subnet (i.e., YES), at step340, an address is allocated in the subnet by the DHCP server. Alternatively, at step335, if there is not an available address in the requesting subnet (i.e., NO), at step345, an address is allocated for VNID by the DHCP server.

FIG. 8depicts an exemplary flow for a DHCP subnet selection support in accordance with aspects of the present invention. InFIG. 8, in the DHCP subnet selection support in accordance with aspects of the present invention, a DHCP client410sends a DHCP_DISCOVER message to a DHCP relay agent420in step441. When the DHCP relay agent420receives the DHCP_DISCOVER message, DHCP relay agent420locates the tenant address space according to the tenant ID in the tenant specific option and allocates an IP address in the intended subnet. As shown inFIG. 7, the DHCP relay agent420derives its VNID from an associated VAP. Then, inFIG. 8, at step442, the DHCP relay agent420sends a query subnet of VNIDx message to a network virtualization authority (NVA)440to inquire of the subnet configuration of that VNID. A reply for the subnet of VNIDx is sent by the NVA440to the DHCP relay agent in step443. Finally, at step444, the DHCP_DISCOVER with tenant specific option and subnet selection option 118 or option 82 with subopt 5 is sent to DHCP server430.

InFIG. 8, a DHCP subnet selection option (option 118, RFC3011) and a link selection in relay agent information option (option 82, suboption 5, RFC3527) are used to communicate to a DHCP server on a desired subnet from which the DHCP clients expect to obtain their IP address. Therefore, the novel DHCP mechanism of the depicted embodiment can be easily extended to these situations through NVA.

As shown inFIG. 8, a NVA can maintain the subnet configuration for each VNID. In response to receiving each DHCP_DISCOVER packet from DHCP client410, the DHCP relay agent420derives its VNID from the associated VAP. After that, the DHCP relay agent420sends a query to NVA440to inquire of the subnet configuration of that VNID. The subnet configuration, which is replied by NVA440, is then filled in the DHCP option 118 or option 82—suboption 5. The subnet information is then communicated to DHCP server430together with the tenant-specification option. When DHCP server430receives the DHCP_DISCOVER packet, DHCP server430locates the tenant address space according to tenant ID in the tenant specific option and allocates an IP address in the intended subnet which is carried in the DHCP option 118 or option 82—suboption 5.

As should now be understood by those of skill in the art, in embodiments of the present invention, the DHCP mechanism provides numerous advantages over current systems. These advantages include, but are not limited to, providing direct support for multi-tenancy on DHCP protocol and removing the need of LINUX namespace OS-level virtualization to support multi-tenancy. In embodiments of the present invention, this technical solution is accomplished by formulating a tenant-specific DHCP option to carry tenant information and improving an address allocation scheme on a DHCP server to prioritize IP address allocation on the tenant address space once tenant-specific option is detected in the DHCP packet.

Also, both the DHCP client and the DHCP relay agent can add tenant-specific option. Moreover, in embodiments, an interoperability issue between different encapsulation protocols for multi-tenant isolation (e.g., VLAN, VXLAN, DOVE, NVGRE, STT, etc.) is alleviated.

Moreover, embodiments of the DHCP mechanism provide high scalability as the number of tenants grows. For example, in current systems, OS-virtualization to support multi-tenancy increases computational burden because each instance of a LINUX namespace requires additional resources; whereas, in embodiments of the DHCP mechanism of the present invention, computational burden is reduced in comparison to OS-level virtualization. Further, in embodiments of the DHCP mechanism, a SDN address allocation requirement is seamlessly supported because each DHCP client gets correct addresses belonging to its tenant and its connected virtual network.

In still further advantages to a technical problem, the systems and processes described herein provide a computer-implemented method for multi-tenancy support on a DHCP protocol, on a network. In this case, a computer infrastructure, such as the computer system shown inFIGS. 1 and 4or the cloud environment shown inFIG. 2can be provided and one or more systems for performing the processes of the invention can be obtained (e.g., created, purchased, used, modified, etc.) and deployed to the computer infrastructure. To this extent, the deployment of a system can comprise one or more of:

(i) installing program code on a computing device, such as computer system shown inFIG. 1, from a computer-readable medium;

(ii) adding one or more computing devices to the computer infrastructure and more specifically the cloud environment; and

(iii) incorporating and/or modifying one or more existing systems of the computer infrastructure to enable the computer infrastructure to perform the processes of the invention.