Cisco Application Centric Infrastructure (ACI) and VMware use different terms to describe the same constructs. This section provides a table for mapping Cisco ACI and VMware terminology; the information is relevant to VMware vSphere Distributed Switch (VDS) and Cisco ACI Virtual Edge.

ACI fabric virtual machine manager (VMM) domains enable an administrator to configure connectivity policies for virtual machine controllers. The essential components of an ACI VMM domain policy include the following:

• Virtual Machine Manager Domain Profile—Groups VM controllers with similar networking policy requirements. For example, VM controllers can share VLAN pools and application endpoint groups (EPGs). The APIC communicates with the controller to publish network configurations such as port groups that are then applied to the virtual workloads. The VMM domain profile includes the following essential components:

  • Credential—Associates a valid VM controller user credential with an APIC VMM domain.

  • Controller—Specifes how to connect to a VM controller that is part of a policy enforcement domain. For example, the controller specifies the connection to a VMware vCenter that is part a VMM domain.

  Note	A single VMM domain can contain multiple instances of VM controllers, but they must be from the same vendor (for example, from VMware or from Microsoft.

• EPG Association—Endpoint groups regulate connectivity and visibility among the endpoints within the scope of the VMM domain policy. VMM domain EPGs behave as follows:

  • The APIC pushes these EPGs as port groups into the VM controller.

  • An EPG can span multiple VMM domains, and a VMM domain can contain multiple EPGs.

• Attachable Entity Profile Association—Associates a VMM domain with the physical network infrastructure. An attachable entity profile (AEP) is a network interface template that enables deploying VM controller policies on a large set of leaf switch ports. An AEP specifies which switches and ports are available, and how they are configured.

• VLAN Pool Association—A VLAN pool specifies the VLAN IDs or ranges used for VLAN encapsulation that the VMM domain consumes.

An APIC VMM domain profile is a policy that defines a VMM domain. The VMM domain policy is created in APIC and pushed into the leaf switches.

VMM domains provide the following:

• A common layer in the ACI fabric that enables scalable fault-tolerant support for multiple VM controller platforms.

• VMM support for multiple tenants within the ACI fabric.

VMM domains contain VM controllers such as VMware vCenter or Microsoft SCVMM Manager and the credential(s) required for the ACI API to interact with the VM controller. A VMM domain enables VM mobility within the domain but not across domains. A single VMM domain can contain multiple instances of VM controllers but they must be the same kind. For example, a VMM domain can contain many VMware vCenters managing multiple controllers each running multiple VMs but it may not also contain SCVMM Managers. A VMM domain inventories controller elements (such as pNICs, vNICs, VM names, and so forth) and pushes policies into the controller(s), creating port groups, and other necessary elements. The ACI VMM domain listens for controller events such as VM mobility and responds accordingly.

VLAN pools represent blocks of traffic VLAN identifiers. A VLAN pool is a shared resource and can be consumed by multiple domains such as VMM domains and Layer 4 to Layer 7 services.

Each pool has an allocation type (static or dynamic), defined at the time of its creation. The allocation type determines whether the identifiers contained in it will be used for automatic assignment by the Cisco APIC (dynamic) or set explicitly by the administrator (static). By default, all blocks contained within a VLAN pool have the same allocation type as the pool but users can change the allocation type for encapsulation blocks contained in dynamic pools to static. Doing so excludes them from dynamic allocation.

A VMM domain can associate with only one dynamic VLAN pool. By default, the assignment of VLAN identifiers to EPGs that are associated with VMM domains is done dynamically by the Cisco APIC. While dynamic allocation is the default and preferred configuration, an administrator can statically assign a VLAN identifier to an endpoint group (EPG) instead. In that case, the identifiers used must be selected from encapsulation blocks in the VLAN pool associated with the VMM domain, and their allocation type must be changed to static.

The Cisco APIC provisions VMM domain VLAN on leaf ports based on EPG events, either statically binding on leaf ports or based on VM events from controllers such as VMware vCenter or Microsoft SCVMM.

Note	In dynamic VLAN pools, if a VLAN is disassociated from an EPG, it is automatically reassociated with the EPG in five minutes.

Note	Dynamic VLAN association is not a part of configuration rollback, that is, in case an EPG or tenant was initially removed and then restored from the backup, a new VLAN is automatically allocated from the dynamic VLAN pools.

The Cisco Application Centric Infrastructure (ACI) fabric associates tenant application profile endpoint groups (EPGs) to virtual machine manager (VMM) domains, The Cisco ACI does so either automatically by an orchestration component such as Microsoft Azure, or by a Cisco Application Policy Infrastructure Controller (APIC) administrator creating such configurations. An EPG can span multiple VMM domains, and a VMM domain can contain multiple EPGs.

In the preceding illustration, end points (EPs) of the same color are part of the same EPG. For example, all the green EPs are in the same EPG although they are in two different VMM domains.

See the latest Verified Scalability Guide for Cisco ACI for virtual network and VMM domain EPG capacity information.

Note

When multiple VMM domains with an overlapping VLAN ID range are connected to the same leaf switch, those domains should use the same VLAN pool. With the same VLAN pool, Cisco APIC can make sure to pick a different VLAN ID for each domain-to-EPG association. Otherwise, Cisco APIC might pick a VLAN ID that is already used on the switch for another domain-to-EPG association, which causes the VLAN deployment fail. When multiple VMM domains with an overlapping VLAN ID range are connected to the same leaf switch and those domains use the same VLAN pool, you can have multiple VMM domains associated with the same EPG. However, each domain-to-EPG association deploys a different VLAN ID, respectively, even though the VLANs are for the same EPG and potentially are on the same port. If using VLAN IDs in this manner is suboptimal to your requirements, you can use the same VMM domain with multiple VMM controllers instead of having multiple VMM domains.

EPGs can use multiple VMM domains in the following ways:

• An EPG within a VMM domain is identified by using an encapsulation identifier. Cisco APIC can manage the identifier automatically, or the administrator can statically select it. An example is a VLAN, a Virtual Network ID (VNID).

• An EPG can be mapped to multiple physical (for baremetal servers) or virtual domains. It can use different VLAN or VNID encapsulations in each domain.

Note	By default, the Cisco APIC dynamically manages the allocatiion of a VLAN for an EPG. VMware DVS administrators have the option to configure a specific VLAN for an EPG. In that case, the VLAN is chosen from a static allocation block within the pool that is associated with the VMM domain.

Applications can be deployed across VMM domains.

While live migration of VMs within a VMM domain is supported, live migration of VMs across VMM domains is not supported.

Note	When you change the VRF on a bridge domain that is linked to an EPG with an associated VMM domain, the port-group is deleted and then added back on vCenter. This results in the EPG being undeployed from the VMM domain. This is expected behavior.

The ACI fabric provides multiple attachment points that connect through leaf ports to various external entities such as bare metal servers, virtual machine hypervisors, Layer 2 switches (for example, the Cisco UCS fabric interconnect), or Layer 3 routers (for example Cisco Nexus 7000 Series switches). These attachment points can be physical ports, FEX ports, port channels, or a virtual port channel (vPC) on leaf switches.

Note

When creating a VPC domain between two leaf switches, both switches must be in the same switch generation, one of the following: Generation 1 - Cisco Nexus N9K switches without “EX” or "FX" on the end of the switch name; for example, N9K-9312TX Generation 2 – Cisco Nexus N9K switches with “EX” or "FX" on the end of the switch model name; for example, N9K-93108TC-EX Switches such as these two are not compatible VPC peers. Instead, use switches of the same generation.

An Attachable Entity Profile (AEP) represents a group of external entities with similar infrastructure policy requirements. The infrastructure policies consist of physical interface policies that configure various protocol options, such as Cisco Discovery Protocol (CDP), Link Layer Discovery Protocol (LLDP), or Link Aggregation Control Protocol (LACP).

An AEP is required to deploy VLAN pools on leaf switches. Encapsulation blocks (and associated VLANs) are reusable across leaf switches. An AEP implicitly provides the scope of the VLAN pool to the physical infrastructure.

The following AEP requirements and dependencies must be accounted for in various configuration scenarios, including network connectivity, VMM domains, and multipod configuration:

• The AEP defines the range of allowed VLANS but it does not provision them. No traffic flows unless an EPG is deployed on the port. Without defining a VLAN pool in an AEP, a VLAN is not enabled on the leaf port even if an EPG is provisioned.

• A particular VLAN is provisioned or enabled on the leaf port that is based on EPG events either statically binding on a leaf port or based on VM events from external controllers such as VMware vCenter or Microsoft Azure Service Center Virtual Machine Manager (SCVMM).

• Attached entity profiles can be associated directly with application EPGs, which deploy the associated application EPGs to all those ports associated with the attached entity profile. The AEP has a configurable generic function (infraGeneric), which contains a relation to an EPG (infraRsFuncToEpg) that is deployed on all interfaces that are part of the selectors that are associated with the attachable entity profile.

A virtual machine manager (VMM) domain automatically derives physical interface policies from the interface policy groups of an AEP.

An override policy at the AEP can be used to specify a different physical interface policy for a VMM domain. This policy is useful in scenarios where a VM controller is connected to the leaf switch through an intermediate Layer 2 node, and a different policy is desired at the leaf switch and VM controller physical ports. For example, you can configure LACP between a leaf switch and a Layer 2 node. At the same time, you can disable LACP between the VM controller and the Layer 2 switch by disabling LACP under the AEP override policy.

Whenever an endpoint group (EPG) associates to a virtual machine manager (VMM) domain, the administrator can choose the resolution and deployment preferences to specify when a policy should be pushed into leaf switches.

Deployment Immediacy

Once the policies are downloaded to the leaf software, deployment immediacy can specify when the policy is pushed into the hardware policy content-addressable memory (CAM).

• Immediate: Specifies that the policy is programmed in the hardware policy CAM as soon as the policy is downloaded in the leaf software.

• On demand: Specifies that the policy is programmed in the hardware policy CAM only when the first packet is received through the data path. This process helps to optimize the hardware space.

Note

When you use on demand deployment immediacy with MAC-pinned VPCs, the EPG contracts are not pushed to the leaf ternary content-addressble memory (TCAM) until the first endpoint is learned in the EPG on each leaf. This can cause uneven TCAM utilization across VPC peers. (Normally, the contract would be pushed to both peers.)

Follow the sequence below to assure that the Cisco Application Policy Infrastructure Controller (APIC) request to delete a VMM domain automatically triggers the associated VM controller (for example VMware vCenter or Microsoft SCVMM) to complete the process normally, and that no orphan EPGs are stranded in the Cisco Application Centric Infrastructure (ACI) fabric.

1. The VM administrator must detach all the VMs from the port groups (in the case of VMware vCenter) or VM networks (in the case of SCVMM), created by the Cisco APIC.

2. The Cisco ACI administrator deletes the VMM domain in the Cisco APIC. The Cisco APIC triggers deletion of VMware VDS or SCVMM logical switch and associated objects.

   Note

   The VM administrator should not delete the virtual switch or associated objects (such as port groups or VM networks); allow the Cisco APIC to trigger the virtual switch deletion upon completion of step 2 above. EPGs could be orphaned in the Cisco APIC if the VM administrator deletes the virtual switch from the VM controller before the VMM domain is deleted in the Cisco APIC.

If this sequence is not followed, the VM controller does delete the virtual switch associated with the Cisco APIC VMM domain. In this scenario, the VM administrator must manually remove the VM and vtep associations from the VM controller, then delete the virtual switch(es) previously associated with the Cisco APIC VMM domain.

The NetFlow technology provides the metering base for a key set of applications, including network traffic accounting, usage-based network billing, network planning, as well as denial of services monitoring, network monitoring, outbound marketing, and data mining for both service providers and enterprise customers. Cisco provides a set of NetFlow applications to collect NetFlow export data, perform data volume reduction, perform post-processing, and provide end-user applications with easy access to NetFlow data. If you have enabled NetFlow monitoring of the traffic flowing through your datacenters, this feature enables you to perform the same level of monitoring of the traffic flowing through the Cisco Application Centric Infrastructure (Cisco ACI) fabric.

Instead of hardware directly exporting the records to a collector, the records are processed in the supervisor engine and are exported to standard NetFlow collectors in the required format.

For more information about NetFlow, see the Cisco APIC and NetFlow knowledge base article.

A virtual machine manager exporter policy (netflowVmmExporterPol) describes information about the data collected for a flow that is sent to the reporting server or NetFlow collector. A NetFlow collector is an external entity that supports the standard NetFlow protocol and accepts packets marked with valid NetFlow headers.

An exporter policy has the following properties:

• VmmExporterPol.dstAddr—This mandatory property specifies the IPv4 or IPv6 address of the NetFlow collector that accepts the NetFlow flow packets. This must be in the host format (that is, "/32" or "/128"). An IPv6 address is supported in vSphere Distributed Switch (vDS) version 6.0 and later.

• VmmExporterPol.dstPort—This mandatory property specifies the port on which the NetFlow collector application is listening on, which enables the collector to accept incoming connections.

• VmmExporterPol.srcAddr—This optional property specifies the IPv4 address that is used as the source address in the exported NetFlow flow packets.

The VMware vSphere Distributed Switch (VDS) supports NetFlow with the following caveats:

• The external collector must be reachable through the ESX. ESX does not support virtual routing and forwardings (VRFs).

• A port group can enable or disable NetFlow.

• VDS does not support flow-level filtering.

Configure the following VDS parameters in VMware vCenter:

• Collector IP address and port. IPv6 is supported on VDS version 6.0 or later. These are mandatory.

• Source IP address. This is optional.

• Active flow timeout, idle flow timeout, and sampling rate. These are optional.