Cisco NX-OS/IOS Interface Comparison

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Objective

This tech note outlines the main differences in interface support between Cisco® NX-OS Software and Cisco IOS® Software. Sample configurations are included for Cisco NX-OS and Cisco IOS Software for some common features to demonstrate the similarities and differences. Please refer to the NX-OS documentation on Cisco.com for a complete list of supported features.


Interface Configuration Overview

The NX-OS supports different physical and virtual interface types to meet various network connectivity requirements. The different interface types include: layer-2 switched (access or trunk), layer-3 routed, layer-3 routed (sub-interface trunk), switched virtual interface (SVI), port-channel, loopback, and tunnel interfaces. Port-channel interfaces are documented in the Cisco NX-OS/IOS Port-Channel ComparisonTech-Note.


Important Cisco NX-OS and Cisco IOS Software Differences

In Cisco NX-OS:

  • SVI command-line interface (CLI) configuration and verification commands are not available until you enable the SVI feature with the feature interface-vlan command.
  • Tunnel interface command-line interface (CLI) configuration and verification commands are not available until you enable the Tunnel feature with the feature tunnel command.
  • Interfaces support stateful and stateless restarts after a supervisor switchover for high availability.
  • Only 802.1q trunks are supported, so the encapsulation command isn't necessary when configuring a layer-2 switched trunk interface. (Cisco ISL is not supported)
  • An IP subnet mask can be applied using /xx or xxx.xxx.xxx.xxx notation when configuring an IP address on a layer-3 interface.
  • The CLI syntax for specifying multiple interfaces is different in Cisco NX-OS Software. The range keyword has been omitted from the syntax (IE: interface ethernet 1/1-2)
  • The out-of-band management ethernet port located on the supervisor module is configured with the interface mgmt 0 CLI command.


Things You Should Know

The following list provides some additional facts about the Cisco NX-OS that should be helpful when configuring interfaces.


  • An interface can only be configured in 1 VDC at a time.
  • All 4 interfaces in a port group must be assigned to the same VDC when assigning interfaces on the 32 port 10GE module. There are not any restrictions for the 48 port 1GE modules.
  • 10 GE interfaces can be configured in dedicated mode using the rate-mode dedicated interface CLI command.
  • The default port type is configurable for L3 routed or L2 switched in the setup startup script. (L3 is the default port type prior to running the script)
  • A layer-2 switched trunk port sends and receives traffic for all VLANs by default (This is the same as Cisco IOS Software). Use the switchport trunk allowed vlan interface CLI command to specify the VLANs allowed on the trunk.
  • The clear counters interface ethernet x/x CLI command resets the counters for a specific interface.



Configuration Comparison

The following sample code shows configuration similarities and differences between the Cisco NX-OS and Cisco IOS Software CLIs. The CLI is very similar between Cisco IOS and Cisco NX-OS Software.


Cisco IOS CLI Cisco NX-OS CLI
Configuring a Routed Interface
interface gigabitethernet 1/1

ip address 192.168.1.1 255.255.255.0

no shutdown

interface ethernet 1/1

ip address 192.168.1.1/24

no shutdown

Configuring a Switched Interface (VLAN 10)
vlan 10


interface gigabitethernet 1/1

switchport

switchport mode access

switchport access vlan 10

no shutdown

vlan 10


interface ethernet 1/1

switchport

switchport mode access

switchport access vlan 10

no shutdown

Configuring a Switched Virtual Interface (SVI)
Cisco IOS Software does not have the ability to enable or disable SVI interfaces using the feature command.


interface vlan 10

ip address 192.168.1.1 255.255.255.0

no shutdown

feature interface-vlan


interface vlan 10

ip address 192.168.1.1./24

no shutdown

Configuring a Switched Trunk Interface
interface GigabitEthernet 1/1

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 2

switchport trunk allowed vlan 10,20

switchport mode trunk

no shutdown

interface ethernet 1/1

switchport mode trunk

switchport trunk allowed vlan 10,20

switchport trunk native vlan 2

no shutdown

Configuring a Routed Trunk Sub-Interface
interface gigabitethernet 1/1

no switchport

no shutdown


interface gigabitethernet1/1.10

encapsulation dot1Q 10

ip address 192.168.1.1 255.255.255.0

no shutdown

interface ethernet 1/1

no switchport

no shutdown


interface ethernet 1/1.10

encapsulation dot1q 10

ip address 192.168.1.1/24

no shutdown

Configuring a Loopback Interface
interface loopback 1

ip address 192.168.1.1 255.255.255.255

no shutdown

interface loopback 1

ip address 192.168.1.1/32

no shutdown

Configuring a Tunnel Interface
Cisco IOS Software does not have the ability to enable or disable Tunnel interfaces using the feature command.


interface Tunnel 1

ip address 192.168.1.1 255.255.255.0

tunnel source 172.16.1.1

tunnel destination 172.16.2.1

no shutdown

feature tunnel


interface tunnel 1

ip address 192.168.1.1/24

tunnel source 172.16.1.1

tunnel destination 172.16.2.1

no shutdown

Configuring an Interface Description
interface gigabitethernet 1/1

description Test Interface

interface ethernet 1/1

description Test Interface

Configuring Jumbo Frames
interface gigabitethernet 1/1

mtu 9216

interface ethernet 1/1

mtu 9216

Configuring Multiple Interfaces (Examples)
interface range gigabitethernet 1/1-2

or

interface range gigabitethernet 1/1, gigabitethernet 2/1

interface ethernet 1/1-1

or

interface ethernet 1/1, ethernet 2/1



Verification Command Comparison

The following table lists some useful show commands for verifying the status and troubleshooting an interface.


Cisco NX-OS Interface Cisco IOS Software Interface Command Description
show interface show interface Displays the status and statistics for all interfaces or a specific interface
show interface brief - Displays a brief list of the interfaces (type, mode, status, speed, MTU)
show interface capabilities show interface capabilities Displays interface capabilities
show interface counters show interface counters Displays interface counters (input/output unicast, multicast & broadcast)
show interface debounce - Displays the de-bounce status and time in ms for all interfaces
show interface description - Displays all interfaces with configured descriptions
show interface ethernet show interface interface-type Displays status and statistics for a specific interface
show interface flowcontrol show interface flowcontrol Displays Flow Control (802.1p) status and state for all interfaces
show interface loopback show interface loopback Displays status and statistics for a specific loopback interface
show interface mac-address - Displays all interfaces and their associated MAC Addresses
show interface mgmt - Displays status and statistics for the management interface located on the supervisor
show interface port-channel show interface port-channel Displays status and statistics for a specific port-channel
show interface status show interface status Displays all interfaces and their current status
show interface switchport show interface switchport Displays a list of all interfaces that are configured as switchports
show interface transceiver show interface transceiver Displays a list of all interfaces and optic information (calibrations, details)
show interface trunk show interface trunk Displays a list of all interfaces configured as trunks
show interface tunnel # show interface tunnel # Displays status and statistics for a specific tunnel interface
show interface vlan # show interface vlan # Displays status and statistics for a specific VLAN interface

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