Cisco NX-OS

NX-OS is a network operating system for the Nexus-series Ethernet switches and MDS-series Fibre Channel storage area network switches made by Cisco Systems. It evolved from the Cisco operating system SAN-OS, originally developed for its MDS switches.

It is based on Wind River Linux and is inter-operable with other Cisco operating systems. The command-line interface of NX-OS is similar to that of Cisco IOS.

Recent NX-OS has both Cisco-style CLI and Bash shell available. On NX-OS 7.0(3)I3, the output from  with the   command line argument might look like the text below:

Core features

 * System Manager
 * Persistent Storage Service (PSS)
 * Message & Transaction Services (MTS)

Additional features

 * Fibre Channel and FICON
 * FCIP
 * FCoE (Nexus 5000/7000 linecards)
 * iSCSI
 * IPsec
 * Scheduling
 * NPIV NX Port ID Virtualization
 * Inter–VSAN Routing
 * VSAN
 * Zoning (Hard zoning)
 * Callhome
 * Cisco Fabric Services (distributed configuration)
 * SSH and Telnet
 * Storage Media Encryption
 * Port Channels
 * Cisco Data Mobility Manager
 * Fibre Channel Write Acceleration

Switches running NX-OS

 * Nexus B22 (HP, Dell, Fujitsu)
 * Nexus 9000 series
 * Nexus 7700 series
 * Nexus 7000 series
 * Nexus 6000 series
 * Nexus 5000 series
 * Nexus 4000 (for IBM BladeCenter)
 * Nexus 2000 series
 * Nexus 3000
 * Nexus 1000V
 * MDS 9700 FC Directors
 * MDS 9500 FC Directors
 * MDS 9250i FC Switch
 * MDS 9222i FC Switch
 * MDS 9100 FC Switches

Differences between IOS and NX-OS

 * NX-OS does not support the login command to switch users.
 * NX-OS does not distinguish between standard or extended access lists, all lists are named and "extended" in functionality.
 * NX-OS did not support scp server prior to 5.1(1) release.
 * In NX-OS, there is no "write" command to save the configuration like on IOS (one uses the "copy" command, instead). Instead, command aliases can be created to provide the "write" command.
 * When accessing NX-OS, users authenticate directly to their assigned privilege level.
 * SSH server is enabled while Telnet server is disabled by default in NX-OS.

Releases
4.1, 4.2, 5.0, 5.1, 5.2, 6.0, 6.1, 6.2, 7.0, 9.2, 9.3, 10.1