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Complete Steps to Create vPC in Cisco ACI (via APIC GUI)

 Understanding vPC in
Cisco ACI: A Modern Approach to High Availability

In the evolving
landscape of data center networking, Virtual Port Channel (vPC) stands
out as a cornerstone of high availability and link redundancy. While
traditional NX-OS environments rely on CLI-driven configurations, Cisco
ACI reimagines vPC through a policy-driven, intent-based model that aligns
with the fabric’s overarching design philosophy.
Unlike legacy setups,
ACI abstracts physical connectivity into logical constructs, allowing
administrators to define vPC behavior through interface policy groups, switch
profiles, and attachable access entity profiles (AAEPs). This not only
simplifies deployment but also ensures consistency across the fabric.
At its core, a vPC in
ACI enables two leaf switches to present a unified uplink to a downstream
device—be it a server, firewall, or load balancer—without relying on spanning
tree protocols. The result is active-active forwarding, improved bandwidth
utilization, and seamless failover.
In this guide, we’ll
walk through the step-by-step configuration of vPC in Cisco ACI,
demystifying each component and highlighting best practices to ensure a robust
and scalable deployment.
Note:- In Cisco ACI, a Fabric Extender (FEX) can be integrated using a port channel in a straight-through topology, where each FEX connects directly to a leaf switch. While vPCs can be established between hosts and the FEX for redundancy and load balancing, the FEX itself does not support vPC connectivity to multiple leaf switches.

 Complete
Steps to Create vPC in Cisco ACI (via APIC GUI)

Step 1: Leaf
Onboarding (One-by-One)

🔍 Monitor Discovery in APIC

  1. Log in to the APIC GUI
  2. Navigate to:
    Fabric → Inventory → Fabric Membership → Nodes Pending Registration
  3. Wait for Leaf101 to
    appear
    • You’ll see its Serial Number
    • Node Role: Leaf
    • Status: Blank / Not Registered

📝 Register Leaf101

  1. Right-click on Leaf101’s serial number
  2. Click Register
  3. In the registration window, enter:
    • Node ID: 101
    • Node Name: Leaf101
    • Click Register
    • Wait for it to appear in Registered
      Nodes

📝 Register Leaf102

  1. Repeat the same steps for Leaf102:
    • Wait for it to appear in Nodes
      Pending Registration
    • Right-click → Register
    • Enter:
      • Node ID: 102
      • Node Name: Leaf102
    • Click Register
    • Wait for it to appear in Registered
      Nodes

🔢 Step-by-Step ACI Configuration Flow

2. VLAN Pool (VLAN
113)

  • Navigate to:
    Fabric → Access Policies → Pools → Right Click on VLAN and click
    Create Vlan Pool
  • Create VLAN Pool:
    • Name: VLAN_113_Pool
    • Mode: Static
    • Click + under Encap Blocks

Ø  Range:  113 – 113

Ø  Allocation mode: Static

    • Click Ok – >Submit

3. Domain (Physical
Domain)

  • Go to:
    Fabric → Access Policies → Physical and External Domains ->Right Click
    on Physical domain ->
  • Create Physical Domain:
    • Name: PhysDom_VLAN113
    • VLAN Pool: VLAN_113_Pool
    • Click Submit

4. AEP (Attachable
Access Entity Profile)

  • Navigate to:
    Fabric → Access Policies → Policies-> Global → Right Click on Attachable
    Access Entity Profiles -> Click Create Attachable Access Entity
    Profiles
  • Create AEP:
    • Name: AEP_VLAN113
    • Click + under Domains and Associated
      Domain      : PhysDom_VLAN113
    • Click Update ->Next -> Finish

5. Interface Policy
Group (vPC)

  • Go to:
    Fabric → Access Policies → Interface → Leaf Interfaces – >Policy Groups->Right
    click on VPC Interfaces – >Create VPC Interfaces
  • Create VPC Interface Policy Group:
    • Name:  vPC_LF101_LF102_1_1
    • AEP: AEP_VLAN113
    • Port Channel Policy: system-lacp-Active
    • Link Level Policy: system-link-level-XG-Auto
  • Click Next > Finish

6. Create vPC
Policy (Your Mentioned Step)

  • Go to:
    Fabric → Access Policies → Policies → Switch
  • Right-click on Virtual Port
    Channel Default

Name:VPC_101_102

ID:10

VPC Domain Policy: Default

Switch1: Leaf101

Switch2: Leaf102

This step ensures the
vPC behavior is defined at the switch policy level.

7. Interface
Profile

  • Navigate to:
    Fabric → Access Policies → Interface → Leaf Interface -> Profiles
  • Right click on the interface profile and
    click Create Interface Profile:
    • Name: IntProf_Leaf101_102
  • Click + under Interface Selector:
    • Name: Eth1_4
    • Interface ID: 1/4
    • Policy Group: vPC_LF101_LF102_1_1
  • Click Ok – > Submit

 

8. Switch Profile

  • Go to:
    Fabric → Access Policies → Switches → Profiles
  • Right Click on Profile and click Create
    Leaf Profile:
    • Name: LeafProf_101_102
  • Click + under Leaf Selector:
    • Name: Leaf101_102
    • Node Block: From 101 to 102
  • Click Update -> Next
  • Attach Interface Profile:
    • IntProf_Leaf101_102

9. Create Tenant

  • Navigate to:
    Tenants
  • Click Add Tenant
    • Name: Tenant_WebApp
  • Click Submit

10. Create VRF

  • Navigate to:
    Tenants
  • Click Networking -> VRF -> Right
    click on VRF -> click Create VRF
    • Name: WebApp_VRF
    • Uncheck Create A Bridge Domain
  • Click Finish

11 Create BD

  • Navigate to:
    Tenants
  • Click Networking -> Bridge
    Domain -> Right click on Bridge Domain-> click Create Bridge Domain
    • Name: WebApp_BD
    • VRF: WebApp_VRF
    • Click Next
    • Click + under Subnet

Ø  Gateway IP: 10.1.1.1/24

Ø  Check “Make this IP address Primary”

Ø  Scope: check “Advertised Externally”

  • Click OK -> Next->
    Finish

 

12. Create
Application Profile (AP)

  • Inside Tenant_WebApp, go to:
    Application Profiles
  • Right Click on Application Profile  and Create Application Profile:
    • Name: WebApp_AP
  • Click Submit

13. Create Endpoint
Group (EPG)

  • Inside WebApp_AP, go to:
    EPGs
  • Right Click on Application EPG and click
    Create Application EPG:
    • Name: WebApp_EPG
    • Bridge Domain: WebApp_BD
    • Click Finish
  • Right Click on WebApp_EPG and click
    ADD Physical Domain Association:
    • Domain Association: PhysDom_VLAN113
    • Click Submit

14. Create Contract
(Allow TCP Port 80)

  • Go to:
    Tenant_WebApp → Contracts -> Standard
  • Right Click on Standard -> Click Create
    Contract:
    • Name: Allow_HTTP
  • Click + under Subject:
    • Name: HTTP_Subject
    • Filter: Click + under Filter
      • Click + Under Name
      • Name: HTTP_Filter
      • Click + under Entries
      • Name: HTTP_Entry
      • EtherType: IP
      • IP Protocol: TCP
      • Destination Port: From http – To http
      • Click Update-> Submit
      • Click Update -> Ok -> Submit
  • Provide contract to/from EPG as needed

15. Static Binding
of EPG to Port

  • Go to Tenant WebApp_EPG->
    Application Profiles -> WebApp_AP -> 
    Application EPGs -> WebApp_EPGs
  • Right Click on WebApp_EPGs -> Click Deploy
    Static EPG on PC,VPC, or Interface
    • Path Type: Virtual Port Channel
    •  Path: Leaf101/eth1/4 and Leaf102/eth1/4
    • Mode: Trunk
    • Encapsulation: vlan-113