The two dynamic routing protocols supported when using Cisco ACI to connect to an external Layer 3 network are iBGP (Option A) and eBGP (Option E)78. These protocols are included in the routing protocol options for a Layer 3 external outside network configuration in ACI

ACI Multi-Site architecture is designed to interconnect geographically dispersed data centers and extend Layer 2 and Layer 3 connectivity between those locations with consistent policy enforcement. It allows for either a single APIC cluster to manage multiple ACI sites or supports a dedicated APIC cluster per site. This architecture ensures a scalable and flexible approach to managing multiple data center sites, providing a unified policy framework and operational model across the sites34.

References :=

Cisco Multi-Site Deployment Guide for ACI Fabrics3

Cisco ACI Multi-Site Architecture White Paper4

To move the gateway address for VLAN 1001 from the core outside the Cisco ACI fabric into the Cisco ACI fabric and ensure that endpoints in EPG-1001 route traffic to endpoints in other EPGs while minimizing flooded traffic in the fabric, the following configuration set is needed on the bridge domain:

Enable Hardware Proxy: This step involves enabling the hardware proxy feature, which allows the fabric to learn and maintain endpoint information more efficiently7.

Enable Unicast Routing: This step involves enabling unicast routing within the bridge domain, which allows for the routing of traffic between different EPGs and minimizes flooded traffic

To break the STP loop between switch1 and switch2 in a Cisco ACI environment, enabling BPDU filtering on the interfaces facing the MST (Multiple Spanning Tree) switches is the necessary step. BPDU filtering prevents BPDUs from being sent or received through a port, which effectively stops the STP process on those ports and breaks the loop1.

When BPDU filtering is enabled on an interface, the switch does not send any BPDUs and ignores any BPDUs it receives on that interface. This can be used to prevent unwanted STP negotiations on ports where loops are not expected to happen or where STP is not desired1.

References :=

Use of ACI Operation with L2 Switches and Spanning Tree Link Types - Cisco1

 In a Cisco ACI fabric, the spine switches are typically configured as route reflectors. This is because spine switches are central to the fabric’s architecture and are responsible for interconnecting all the leaf switches, making them ideal for reflecting BGP routes within the fabric. Therefore, the components that should be configured as route reflectors are:

Spine1 (Option A)

Spine2 (Option C)

To deploy a leaf access port policy group in ACI Fabric that controls the amount of application data flowing into the system and allows auto-negotiation of link speed, the two ACI policies that must be configured are:

Link level policy2.

Ingress data plane policing policy2.

Slow Drain handles FCoE packets that are causing traffic congestion on ACI fabric. So, it is wrong.

Ingress control plane is wrong, because the request is for “application data flowing”.

L2 interface policy is concerned about QinQ and VLAN scope.

The feature that allows firewall ACLs to be configured automatically when new endpoints are attached to an EPG is ARP gleaning. This feature helps in identifying the endpoints and applying the necessary ACLs to them as they are discovered

o protect the ACI fabric from spanning-tree loops, the feature that must be enabled on the ACI leaf ports is BPDU Guard 

To clear the fault raised by the Cisco APIC when the EPG must accept endpoints from a VMM domain, the EPG should be associated with the VMM domain. This association is necessary for the APIC to recognize the endpoints within the VMM domain as part of the EPG. Without this association, the APIC cannot apply the policies defined in the EPG to the endpoints, which can result in errors1.

References :=

APIC Policy Deployment and Resolution Immediacy For AVS VMM Domain - Cisco Community

To reduce instability during the migration of a legacy environment to Cisco ACI, the feature that should be enabled in the bridge domain is to Set Multi-Destination Flooding to Flood in BD (Option A). This setting allows unknown multicast, broadcast, and unknown unicast traffic to be flooded within the bridge domain, which can help prevent traffic loss during the migration process.

On the egress leaf switch, when traffic is received from an L3Out, no source MAC or IP address of the traffic is learned as a remote endpoint1. The Cisco ACI fabric does not learn the IP addresses from the data plane in an L3Out domain; instead, it uses ARP to resolve next-hop IP and MAC relationships to reach the prefixes behind external routers1.

To connect Cisco ACI fabric using Layer 2 with external third-party switches configured using 802.1s protocol, the two constructs required are:

Spanning tree policy for mapping MST Instances to VLANs (Option A): This policy will ensure that the Multiple Spanning Tree (MST) instances on the third-party switches are correctly mapped to the VLANs in the ACI fabric.

Static binding of native VLAN in all existing EPGs (Option E): This construct is necessary to maintain the native VLAN across all EPGs when integrating with third-party switches that use 802.1s protocol.

https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2019/pdf/BRKACI-3101.pdf

https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-in frastructure/white-paper-c07-732033.html

 For a blade server that lacks support of bonding, the port channel mode that results in “route based on originating virtual port” on the VMware VDS is MAC Pinning-Physical-NIC-load (Option B). This mode ensures that the virtual machine traffic is distributed across the available uplinks based on the MAC address of the originating virtual port1.

https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/6x/virtualization/cisco-aci-virtualization-guide-60x/ACI-Virtualization-Guide-60x-aci-with-vmware-vds.pdf

For external connections to the fabric that only require a default route, there is support for originating a default route for OSPF, EIGRP, and BGP L3Out connections. If a default route is received from an external peer, this route can be redistributed out to another peer following the transit export route control as described earlier in this article. A default route can also be advertised out using a Default Route Leak policy. This policy supports advertising a default route if it is present in the routing table or it always supports advertising a default route. The Default Route Leak policy is configured in the L3Out connection. https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/2-x/L3_config/b_Cisco_APIC_Layer_3_Configuration_Guide/b_Cisco_APIC_Layer_3_Configuration_Guide_chapter_010100.html

 The statement about the MTU value of MP-BGP EVPN control plane packets in Cisco ACI that is true for communication between spine nodes in different sites is that by default, spine nodes generate 9000-bytes packets to exchange endpoints routing information. As a result, the Inter-Site network should be able to carry 9000-bytes packets2. This ensures that the control plane traffic, which is not VXLAN encapsulated, can be properly handled across the sites2.

To ensure that servers supporting only Cisco Discovery Protocol are discovered automatically by the Cisco ACI fabric when connected, the action that must be taken is to Create an override policy that enables Cisco Discovery Protocol after LLDP is enabled in the default policy group

When extending EPG connectivity to an external network that houses the Layer 3 gateway and other end hosts, the ACI bridge domain configuration should use Forwarding: Custom, L2 Unknown Unicast: Hardware Proxy, L3 Unknown Multicast Flooding: Flood, Multi Destination Flooding: Flood in BD, and ARP Flooding: Enabled23. This configuration ensures that unknown unicast traffic is handled efficiently while still allowing ARP flooding, which is necessary for the ACI fabric to learn about endpoints on the external network23.

To deploy an access port policy group within Cisco ACI, an attachable entity profile (AEP) needs to be created. An AEP is a policy construct that groups together various domains and allows them to be attached to the fabric access layer

To set Layer 2 loop migration in an ACI Fabric with a Layer 2 Out configured, MCP (Misconfiguration Protocol) must be enabled on the ACI fabric56. MCP helps to prevent Layer 2 loops by detecting misconfigurations that could potentially cause loops56.

In a Cisco ACI environment with multiple silent hosts that are often relocated between leaf switches, configuring IP Data-Plane Learning to ‘No’ will minimize the relocation impact and make the ACI fabric relearn the new location of the host faster. Disabling IP Data-Plane Learning prevents the fabric from learning IP addresses from the data plane, which can speed up the process of relearning host locations when they move3.

 In the context of ACI Multi-Site, the information of an endpoint (MAC/IP) that belongs to site 1 is advertised to site 2 using the EVPN control plane as soon as the endpoint is discovered in one site. This allows for immediate visibility of the endpoint across sites.

https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/6x/l4-l7-configuration/cisco-apic-layer-4-to-layer-7-services-deployment-guide-60x/defining-a-logical-device-60x.html

To allow IP mobility between Site1 and Site2 in a Cisco ACI Multi-Site orchestrator while meeting the disaster recovery (DR) requirements and avoiding broadcast storms, the following actions should be taken:

Disable Inter-site BUM Traffic: Disabling Broadcast, Unknown unicast, and Multicast (BUM) traffic between sites helps to avoid broadcast storms that can occur when extending Layer 2 domains across multiple sites1.

Apply the L2 Stretch feature: The Layer 2 Stretch feature allows subnets to be extended across multiple sites without the need to re-IP the application servers. This supports IP mobility and enables applications to be started at a DR site using the same IP address space1.

These actions ensure that the design supports a DR solution without requiring vMotion support, allows applications to be started at a DR site without re-IPing servers, and avoids broadcast storms between the sites.

References :=

Cisco ACI Multi-Site Architecture White Paper1

Cisco Nexus Dashboard Orchestrator Overview2

In Cisco ACI, a leaf switch learns a source IP or MAC as a remote endpoint when VXLAN traffic arrives on a leaf fabric port from the spine, and the inner source IP is within the range of the bridge domain subnets associated with the leaf. This process is part of the ACI’s COOP (Council Of Oracles Protocol), which ensures that endpoint information is accurately disseminated across the fabric for efficient traffic forwarding.

The scenario involves deploying a WAN with Cisco ACI, where Routers 1 and 2 (connected via an L3Out with OSPF Area 0) must receive specific routes (192.168.11.0/24 and 192.168.21.0/24) from the ACI fabric, and reachability to WAN users must be permitted only for servers in vrf_prod. The diagram shows three bridge domains (bd_vlan11, bd_vlan21, bd_vlan31) with their respective subnets and EPGs, all under vrf_prod, along with an L3Out (epg_l3out) for WAN connectivity.

Requirement Analysis

Routers 1 and 2 must receive only routes 192.168.11.0/24 and 192.168.21.0/24:

These subnets belong to bd_vlan11 and bd_vlan21, respectively. To advertise these routes to Routers 1 and 2 via the L3Out, they must be marked with the appropriate scope in the bridge domain configuration.

In ACI, the "Advertised Externally" scope on a subnet ensures that it is advertised to external routers via the L3Out routing protocol (OSPF in this case).

Reachability to WAN users must be permitted only for servers in vrf_prod:

This implies that only the subnets in vrf_prod (192.168.11.0/24, 192.168.21.0/24, and 192.168.31.0/24) should be accessible, but WAN users should only reach specific subnets based on policy.

The external EPG (epg_l3out) represents the WAN users (10.171.0.0/16), and its subnet scope must control inbound reachability.

The subnet 192.168.31.0/24 (bd_vlan31) should not be advertised to the WAN, as it is not listed in the routes Routers 1 and 2 should receive.

Option Evaluation

A. Configure the subnets 192.168.11.0/24 and 192.168.21.0/24 as Private to VRF. Configure the subnet 192.168.31.0/24 as Advertised Externally. Configure an EPG subnet 0.0.0.0/0 as External Subnets for External EPG:

Setting 192.168.11.0/24 and 192.168.21.0/24 as "Private to VRF" means they are not advertised externally, which fails the requirement for Routers 1 and 2 to receive these routes.

Setting 192.168.31.0/24 as "Advertised Externally" incorrectly advertises this subnet to the WAN, which is not desired.

The "External Subnets for External EPG" scope on 0.0.0.0/0 allows WAN users to reach all subnets in vrf_prod, which is correct for reachability.

Conclusion: Fails the first requirement (route advertisement).

 In the Cisco ACI Active-Active Across Pods deployment mode, one of the key characteristics of Policy-Based Redirect (PBR) is that traffic is dynamically redirected to the firewall that owns the connection. This allows for load distribution across multiple Layer 4 to Layer 7 devices, also known as symmetric PBR. Additionally, deployment in this mode occurs in go-to mode only, which means that traffic is explicitly directed to a service node or firewall for processing

The scenario involves a Cisco ACI fabric with 10 standalone leaf switches, and the engineer must configure only the first two leaf switches (e.g., Leaf-1 and Leaf-2) in a Virtual Port Channel (vPC) configuration. The goal is to select the appropriate vPC protection type to achieve this specific pairing while leaving the other eight leaf switches standalone.

Requirement Analysis

In Cisco ACI, vPC is used to provide active-active link redundancy and load balancing between two leaf switches connected to the same set of endpoints (e.g., servers or external devices).

The fabric contains 10 standalone leaf switches, meaning no pre-existing vPC pairs are configured, and the task is to form a vPC specifically between the first two leaf switches.

The vPC protection type determines how the pair is defined and protected within the ACI fabric, ensuring the configuration is limited to the intended switches.

Option Evaluation

A. serial:

The "serial" protection type is not a valid vPC protection option in Cisco ACI. This term might be confused with serial link configurations or other networking contexts, but it does not apply to vPC in ACI.

 In Cisco Application Centric Infrastructure (ACI), when a subnet is configured on a bridge domain, the gateway IP address is configured on the leaf switches where the bridge domain of the tenant is present. This configuration allows for localized routing within the fabric, providing efficient east-west traffic handling without requiring traffic to traverse up to the spine nodes unless necessary for north-south routing or policy enforcement.

In a two-pod Cisco ACI Multi-Pod environment, it is recommended to deploy no more than two Cisco APIC controllers in the same pod to avoid losing all replicas of a shard if a pod fails. The APIC cluster is a distributed system where each APIC contains a replica of the configuration database, referred to as a shard. If all replicas of a shard were located in the same pod and that pod were to fail, it would result in the loss of the shard and potentially impact the entire fabric’s operation. By distributing the APIC controllers across pods, the risk of losing all replicas due to a single point of failure is mitigated, enhancing the overall resiliency of the system1.

References :=

ACI Multi-Pod White Paper - Cisco1

The two IP address types that are available for transport over the Inter-Site Network (ISN) when they are configured from Cisco ACI Multi-Site Orchestrator (MSO) are the Anycast Overlay Multicast Tunnel Endpoint (TEP) and the MP-BGP EVPN Router-ID. These IP addresses are used for inter-site communication and routing in a Multi-Site deployment.

To enable communication between EPGs and BDs from any tenant without the need for contracts or VRF route leaking, the best approach is to implement an unenforced VRF within the common tenant. By doing so, all bridge domains that are associated with this VRF will be able to communicate with each other without additional configurations. This method simplifies the network architecture and reduces the complexity associated with contract management and VRF route leaking1.

References :=

Cisco ACI Contract Guide White Paper1

 After ARP flooding is enabled in Cisco ACI Multi-Pod, broadcast frames are forwarded within the pod and across the Inter-Pod Network (IPN) using the multicast address associated with the bridge domain. If the setting is ‘Flood’, the leaf switch floods to the Group IP (GIPo) multicast group allocated for the bridge domain, ensuring that both local and remote pods receive a flooded copy

The engineer is implementing out-of-band (OOB) management access for the Cisco ACI fabric with the following requirements:

Only GUI (HTTPS) and Secure Shell (SSH) must be allowed to access the management interfaces.

Only IP ranges 10.10.10.0/24 and 192.168.15.0/24 must be permitted to connect.

This requires configuring access control and restricting IP ranges for OOB management.

Requirement Analysis

OOB management in ACI is typically handled via the Management Tenant (mgmt) and an OOB contract to define allowed protocols and sources.

The external network instance profile defines the permitted IP ranges for external access.

Option Evaluation

A. Implement HTTPS and SSH protocol filters in the OOB contract. Add the required subnets to the external network instance profile:

An OOB contract can specify allowed protocols (HTTPS on port 443 and SSH on port 22) to restrict access to GUI and SSH only. Adding the subnets 10.10.10.0/24 and 192.168.15.0/24 to the external network instance profile limits the source IP ranges, meeting both requirements.

To meet the requirements for the new e-commerce software deployed on the Cisco ACI fabric, the scope of the contracts should be set to “Application Profile”. This scope ensures that the contracts are applied within the same Application Network Profile (ANP), allowing the e-commerce software to communicate only with software Endpoint Groups (EPGs) that are part of the same ANP. It also prevents communication with applications in different ANPs, thus maintaining the necessary isolation and reducing the overall number of contracts by reusing existing ones within a VRF.

References :=

Cisco ACI Contracts and Scopes Documentation

Cisco ACI Best Practices Guide

The correct statement about ACI syslog is that all syslog messages are sent to the destination through APIC1. This centralized approach allows for consistent logging and monitoring across the ACI fabric1.

To set up a Cisco ACI fabric to send Syslog messages related to hardware events to a dedicated Syslog server, the policy should be configured at uni/fabric/monfab-default4. This location in the Cisco APIC allows for the configuration of Syslog policies that can be applied to the entire fabric4.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/4-x/aci -fundamentals/Cisco-ACI-Fundamentals-401/Cisco-ACI-Fundamentals-401_chapter_01100.html

To migrate the gateway address out of the ACI fabric for an endpoint group (EPG), the bridge domain configuration must ensure that routing is contained within the ACI fabric and that ARP requests are managed efficiently. The correct configuration set is:

L2 Unknown Unicast: Set to Hardware Proxy. This setting allows the ACI fabric to use the spine proxy function to handle unknown unicast traffic, which helps to reduce flooding within the fabric.

Unicast Routing: Set to Disabled. Since the gateway is being migrated out of the ACI fabric, unicast routing should be disabled to prevent the ACI fabric from attempting to route traffic for the EPG.

ARP Flooding: Set to Enabled. This allows ARP requests to be flooded within the bridge domain, which is necessary when the unicast routing is disabled, to ensure that ARP requests can still be resolved.

References :=

Cisco ACI Bridge Domain Configuration Guide

Cisco ACI Best Practices Guide

To ensure that users can access the Cisco APIC GUI with a local account if the RADIUS server is unreachable, the network administrator must enable the fallback check with the default authentication domain. This allows for local authentication as a backup method when RADIUS is not available. The fallback mechanism is crucial for maintaining access to the APIC GUI in case of RADIUS server issues1.

References :=

Cisco Community Discussion on Auth Radius fallback to Local1

Cisco APIC Security Configuration Guide

The XML configuration snippet provided in the exhibit results in the creation of two objects within the Cisco ACI environment:

Bridge Domain (Option C): This is indicated by the XML element , which defines a bridge domain with the name “bd1”.

VRF (Option E): This is shown by the XML element , which defines a Virtual Routing and Forwarding instance named “pvn1”.

These objects are essential for network segmentation and routing within the ACI fabric, where the bridge domain represents a Layer 2 broadcast domain and the VRF is used for Layer 3 routing separation.

 The table that holds IP address, MAC address, and VXLAN/VLAN information on a Cisco ACI leaf is the endpoint table6. This table is essential for the ACI fabric’s ability to track and apply policies to endpoints.

To create an exit point from all tenants using the common tenant and decrease the routing footprint, the following configuration tasks must be completed:

Update the L3Out ExtEPG subnet in the common tenant with flag Shared Route Control Subnet and Aggregate Shared Routes: This configuration allows the subnets to be shared across different VRFs within the common tenant, enabling communication between EPGs that are in different tenants1.

Change contract Ctr-3 scope to Global, consume it by all EPGs, and flag all subnets with flag Shared between VRFs: By changing the scope of contract Ctr-3 to Global, it can be consumed by all EPGs across the fabric. Additionally, flagging all subnets with Shared between VRFs ensures that the subnets can be used by multiple tenants1.

References :=

Cisco Community Discussion on Common Tenant1

Cisco ACI Basic Configuration Guide2

Cisco ACI Configuring Shared L3Outs Documentation

To support cross-site connectivity in a production Multi-Site solution, where connectivity from EPGs from a specific site to networks reachable through a remote site L3OUT is required, the additional configuration that must be implemented in the Multi-Site Orchestrator is to add a new stretched external EPG to the existing L3OUT1. This allows the EPGs from one site to communicate with the networks defined in the L3OUT at the remote site, facilitating the required connectivity across sites.

References :=

Cisco ACI Multi-Site Configuration Guide1

To allow SNMP traffic on the APIC controller, a contract under tenant mgmt must be configured3.

To ensure that destination updates from a newly created L3Out are propagated to all Cisco ACI leaf switches, a BGP route reflector policy should be applied. This policy allows the border leaf switches, which act as BGP route reflectors, to redistribute the learned routes to other leaf switches within the fabric1.

When Cisco ACI connects to an outside Layer 2 network, the ACI fabric floods the STP BPDU frame within the bridge domain (Option A)5. This ensures that BPDUs are properly propagated within the relevant VLAN encapsulation associated with the bridge domain5.

To configure communication between the EPGs in different tenants, the subnet scope should be set to “Shared between VRFs”. This allows the subnet to be shared across different VRFs, enabling communication between EPGs that are in different tenants but within the same VRF. By marking the subnet as shared, it becomes visible to other VRFs, which is necessary for inter-tenant communication1.

References :=

Learning ACI - Part 12: Inter-VRF and Inter-Tenant Communication

The scenario involves a tenant configured with a single L3Out and a single-homed link from the ACI fabric (via border leaf BL-1001) to a core router (Core-1). The engineer must add a second link to the L3Out, connecting to Core-2 via BL-1002, ensuring that traffic from Core-2 to BL-1002 has the same connectivity as traffic from Core-1 to BL-1001. The exhibit shows a single-homed setup with BL-1001 and BL-1002 as potential border leaves, with a dashed line indicating a planned second link.

Requirement Analysis

The existing L3Out is single-homed to Core-1 via BL-1001, and the goal is to extend it to a multi-homed configuration with Core-2 via BL-1002.

"Same connectivity" implies that the second link must be integrated into the existing L3Out configuration, sharing the same routing policies, external EPG, and subnet reachability.

The solution must leverage ACI’s L3Out framework to add the new path without creating a separate L3Out or altering the current routing setup unnecessarily.

Option Evaluation

A. Add a second path to the logical interface profile of the existing L3Out:

The logical interface profile in an L3Out defines the interfaces (e.g., routed ports or sub-interfaces) and their associations with nodes (border leaves). Adding a second path to this profile allows the inclusion of the new link from BL-1002 to Core-2, ensuring it operates under the same L3Out configuration (e.g., routing protocol, external EPG). This maintains consistent connectivity and leverages ACI’s multi-homing support.

 In the scenario where Server A is connected to the Cisco ACI fabric using teamed interfaces with one active and one standby, enabling ARP flooding in the bridge domain configuration is necessary to resolve the issue that occurs when the standby interface becomes active and uses its built-in MAC address to send traffic. Enabling ARP flooding allows the fabric to learn the new MAC address without waiting for the ARP timeout, which helps to ensure that traffic continues to flow to the correct destination after a failover event1.

References :=

Discuss Cisco 300-620 Exam Topic 9 Question 71 | Pass4Success1

For the BGP Route Reflector policy to take effect, the components that must be configured are the leaf fabric interface overrides and profiles. These configurations are necessary to establish the route reflector relationships within the BGP protocol on the leaf switches

The setting that prevents the learning of Endpoint IP addresses whose subnet does not match the bridge domain subnet is the “Limit IP learning to subnet” setting within the bridge domain1. This setting ensures that only IP addresses belonging to the subnets configured on the bridge domain are learned, preventing mis-learning of IP addresses that may not belong to the fabric1.

 In the Cisco ACI VMM domain configuration, to generate port groups with names formatted as “Tenant=Application=EPG”, the configuration option used is delimiter. The delimiter is a character that separates the elements of the port-group name. By changing the delimiter setting to “=”, the port-group names will be generated with the desired format.

For the new nodes in a Cisco ACI Multi-Pod deployment to be discoverable by the existing Cisco APICs, DHCP relay should be enabled on all links that are connected to Cisco ACI spines on Inter-Pod Network (IPN) devices. This allows the APICs to dynamically assign IP addresses to the new nodes, facilitating their discovery and integration into the fabric.

References :=

Cisco ACI Multi-Pod Configuration Guide

Cisco ACI Best Practices Guide

To support the addition of new ESXi hosts to the existing VMM domain, the action that should be taken is to map the leaf interface selector to the AEP that is associated with the VMM domain (Option D). This ensures that the correct policies are applied to the interfaces where the new ESXi hosts are connected.

In the Cisco ACI fabric, Spanning Tree Protocol (STP) Bridge Protocol Data Units (BPDUs) are flooded within the bridge domain VLAN. This allows the BPDUs to be propagated throughout the bridge domain, enabling STP to function correctly for the associated VLAN.

To meet the criteria for configuring the Cisco ACI fabric to connect to vCenter, the following actions should be taken:

Create a dynamic VLAN pool with the VLAN range of 20-30: This step involves creating a VLAN pool that dynamically assigns VLANs within the specified range to the port groups as they are created1.

Create a VMM domain and associate it with the VLAN pool: The VMM domain is a representation of the VMware vSphere Distributed Switch (VDS) in ACI, and associating it with the VLAN pool allows for the automatic creation of port groups on the VDS1.

Create the EPG and associate the domain: An Endpoint Group (EPG) is a logical entity to which workloads are attached. Associating the EPG with the VMM domain ensures that the port groups are automatically created in vCenter when the EPG is associated with a VMM domain1.

Set the deployment immediacy to On Demand: Setting the deployment immediacy to ‘On Demand’ optimizes the CAM space on the leaf switches by deploying policies to leaf nodes only when endpoints assigned to this EPG are connected, rather than immediately upon configuration12.

By following these steps, the network engineer can ensure that the Cisco ACI fabric is correctly configured to connect to vCenter, with port groups being automatically created on the distributed virtual switch, using the VLAN allocation in the range between 20-30, and optimizing the CAM space on the leaf switches.

To configure an L3Out peering with the backbone network that must forward both unicast and multicast traffic, the two methods that should be used are:

Layer 3 routed port (Option A): This method involves configuring a physical port on the Cisco ACI leaf switch as a Layer 3 interface, which is suitable for routing unicast and multicast traffic.

Layer 3 routed subinterface (Option D): This method involves configuring a subinterface under a physical port, which allows for traffic segregation and routing over the same physical link, supporting both unicast and multicast traffic.

These methods ensure that the L3Out can handle the required traffic types and maintain proper routing with the backbone network.

https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centricinfrastructure/

guide-c07-743150.html#_L3Out_sStatic_rRoutes

https://www.cisco.com/ c/en/us/td/docs/switches/datacenter/aci/apic/sw/4-x/L3-configuration/Cisco-APIC-Layer-3-Networking-Configuration-Guide-401/Cisco-APIC-Layer-3-Networking-Configuration-Guide-401_chapter_010010.html

The group of settings required to meet the requirements for workload migration where servers will physically terminate at the Cisco ACI, but their gateway must stay in the existing network, is:

L2 Unknown Unicast: Flood

L3 Unknown Multicast Flooding: Flood

Multi Destination Flooding: Flood in BD

ARP Flooding: Enable5

These settings ensure that the bridge domain is configured to handle unknown unicast and multicast traffic appropriately, and ARP flooding is enabled to allow for the resolution of IP addresses when the gateway is outside the fabric5.

https://www.cisco.com/c/en/us/td/docs/switches/datac enter/aci/apic/sw/migration_guides/migrating_existing_networks_to_aci.html

When configuring Cisco ACI VMM domain integration with VMware vCenter, the object that is created in vCenter is a VMware vSphere Distributed Switch (VDS)12. The VDS is a virtual switch that extends across all esxi hosts in the cluster and provides a centralized interface from which network configurations can be managed12. This switch allows network administrators to manage networking for multiple hosts and virtual machines from a single interface within vCenter12.

To ensure that application EPGs communicate only with their respective database EPGs, the app-to-db contract should be configured with a scope set to the Application Profile. This scope ensures that the contract is applied only within the specific application profile, allowing for granular control over the communication between the application and database tiers. By setting the scope to Application Profile, the contract will not apply to other application profiles, thus preventing unwanted traffic between EPGs of different applications1.

References :=

Cisco ACI Contract Guide White Paper1

To support a new application that is sensitive to latency and jitter and sets the DSCP values of packets to AF31 and CS6, it is necessary to align the ACI Quality of Service (QoS) levels and Inter-Pod Network (IPN) QoS policies. This alignment ensures that the DSCP values are preserved and respected across the ACI fabric and the IPN, preventing packets from being delayed or dropped between pods.

References :=

Cisco ACI Multi-Site Architecture White Paper

Cisco ACI Best Practices Guide

Cisco ACI Quality of Service Configuration Guide

When configuring an L3Out in Cisco ACI and encountering a QoS-related error, creating a custom QoS policy is often necessary to clear the fault. This involves defining a QoS policy that meets the specific requirements of the L3Out configuration and applying it to the relevant interfaces or globally within the fabric. The custom QoS policy should be designed to prioritize traffic appropriately and ensure that the necessary QoS settings are in place for the L3Out connections1.

References :=

Cisco ACI L3Out Configuration Examples1

The engineer configures port 1/2 on Leaf-101 and Leaf-102 to connect to a new server (SVR-12), which belongs to EPG-12 using VLAN-1212 encapsulation. The server is configured as a vPC member port and statically bound to EPG-12. The task is to ensure connectivity, indicating a missing configuration step.

Requirement Analysis

Static binding of a vPC member port to an EPG requires proper VLAN association and domain mapping.

vPC ensures redundancy, and the VLAN (1212) must be allocated and associated with the EPG via a domain (e.g., VMM or physical domain).

Option Evaluation

A. Create a VPC Explicit Protection Group for EPG-12 and VLAN-1212:

vPC Explicit Protection Groups are used for specific vPC configurations, but this is not a standard requirement for EPG binding and VLAN association.

 In a Cisco ACI Multi-Site fabric, when the Inter-Site BUM Traffic Allow option is enabled for a stretched bridge domain, ingress replication on the spines in the source site is used to forward Broadcast, Unknown unicast, and Multicast (BUM) traffic to all endpoints in the same broadcast domain. This method ensures that BUM traffic is replicated and sent out through the spines to the destination sites.