vxlanGlobal Config

interface nve1

Enters NVE (Network Virtualization Edge) interface configuration mode to configure VXLAN tunnel endpoints.

Overview

The 'interface nve1' command is used to enter the configuration mode for the Network Virtualization Edge (NVE) interface on Cisco Nexus switches running NX-OS. The NVE interface is a logical tunnel interface that serves as the termination point for VXLAN (Virtual Extensible LAN) tunnels. VXLAN is an overlay network technology that extends Layer 2 segments over a Layer 3 underlay network, enabling network virtualization in data centers. The NVE interface encapsulates Ethernet frames in UDP packets and sends them to remote VXLAN tunnel endpoints (VTEPs).

This command is essential when deploying VXLAN-based fabrics, such as in Cisco ACI or VXLAN EVPN designs. It is typically the first step in configuring VXLAN on a Nexus switch. After entering NVE interface configuration mode, you can configure the source IP address (using 'source-interface' or 'source-ip'), associate VNIs (using 'member vni'), and enable features like ARP suppression or multicast replication.

On Cisco NX-OS, the NVE interface is always numbered 1 (nve1). There is no support for multiple NVE interfaces. The interface must be configured with a source IP that is reachable from other VTEPs. The NVE interface does not have a MAC address; it uses the MAC address of the source interface. Troubleshooting often involves checking the NVE interface status with 'show interface nve1' and verifying VXLAN tunnel endpoints with 'show nve peers'.

Syntax·Global Config

interface nve1

When to Use This Command

Configuring VXLAN overlay networks for data center virtualization
Setting up VXLAN tunnel endpoints for network segmentation
Enabling VXLAN features like ARP suppression and multicast replication
Integrating with Cisco ACI or VXLAN EVPN fabrics

Parameters

Parameter	Syntax	Required	Description
interface nve1	interface nve1	Required	The command to enter NVE interface configuration mode. The number must be 1. No other parameters are needed.

Command Examples

Basic NVE interface configuration

interface nve1

Enters NVE interface configuration mode for interface 1. No output is shown; the prompt changes to (config-if-nve)#.

Verifying NVE interface status

show interface nve1

nve1 is up, line protocol is up
  Hardware is NVE
  Internet address is 10.1.1.1/24
  MTU 9216 bytes, BW 10000000 Kbit
  Encapsulation VXLAN

Shows NVE interface is up, IP address assigned, MTU set for jumbo frames, and encapsulation type is VXLAN.

Understanding the Output

The 'show interface nve1' command displays the operational status of the NVE interface. The first line indicates whether the interface is administratively up/down and the line protocol status. 'Hardware is NVE' confirms it's a virtual NVE interface. The Internet address shows the source IP used for VXLAN encapsulation. MTU should be set to at least 1550 for VXLAN overhead; 9216 is typical for jumbo frames. Bandwidth is a virtual value. Encapsulation VXLAN confirms the tunnel type. A healthy interface shows 'up' for both status and protocol. If down, check source interface or NVE configuration.

Configuration Scenarios

Basic VXLAN configuration with NVE

Two Nexus switches acting as VTEPs in a VXLAN fabric.

Topology

SwitchA (10.1.1.1) --- IP Network --- SwitchB (10.1.1.2)

Steps

1.Configure loopback interface for source IP.
2.Enter NVE interface configuration mode.
3.Set source-interface to loopback.
4.Associate a VNI to the NVE.

Configuration

! On SwitchA
interface loopback0
 ip address 10.1.1.1/32
interface nve1
 source-interface loopback0
 member vni 10000
!

Verify: Use 'show interface nve1' to verify status. Use 'show nve peers' to see remote VTEPs.

Watch out: Ensure the source interface IP is reachable from remote VTEPs. Also, VNI must be created under 'vlan' configuration first.

Troubleshooting with This Command

When troubleshooting NVE interface issues on Cisco NX-OS, start with 'show interface nve1' to check if the interface is up. If the interface is down, verify that a source-interface or source-ip is configured. Use 'show running-config interface nve1' to confirm the configuration. Check that the source interface (e.g., loopback) is up and has an IP address. If the NVE interface is up but VXLAN traffic is not working, use 'show nve peers' to see if remote VTEPs are learned. For EVPN, check BGP sessions. Common issues include MTU mismatch (VXLAN adds 50 bytes overhead), incorrect VNI mapping, or firewall blocking UDP port 4789. Use 'show nve vni' to verify VNI associations. Debug commands like 'debug nve packets' can help but should be used cautiously in production.

CCNA Exam Tips

Remember that NVE interface number must match the VNI configuration.

Know that 'interface nve1' is the only NVE interface supported on Nexus 9000.

Understand that NVE interface must have a source IP configured under it.

Common Mistakes

Forgetting to configure a source-interface under the NVE, causing the interface to stay down.

Using 'interface nve' without a number; the correct syntax is 'interface nve1'.

Assuming NVE interface supports routing; it is a Layer 2 tunnel interface only.

Platform Notes

On Cisco NX-OS (Nexus), the NVE interface is a virtual interface specific to VXLAN. Unlike Cisco IOS, which uses 'tunnel mode vxlan' on a tunnel interface, NX-OS uses the dedicated NVE interface. The NVE interface does not support IPv6 or routing; it is purely a Layer 2 tunnel endpoint. In NX-OS, the NVE interface number is always 1. For Cisco IOS XE, VXLAN configuration uses 'interface Tunnel' with 'tunnel mode vxlan'. On Arista EOS, the equivalent is 'interface Vxlan1'. On Juniper Junos, it is 'interfaces vtep'. Version differences: NX-OS 7.0(3)I7(1) introduced VXLAN EVPN support. Always check the specific NX-OS version for feature support.

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