Junos OS

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Junos OS
Junos sw logo.jpg
DeveloperJuniper Networks
OS familyFreeBSD
Working stateCurrent
Source modelClosed source and partly open source
Initial releaseJuly 7, 1998; 21 years ago (1998-07-07)
Latest release19.1R1[1] / June 4, 2019; 2 months ago (2019-06-04)
Available inEnglish
UserlandFreeBSD 10[2]
Default user interfaceCommand-line interface
LicenseProprietary,[3] FreeBSD License
Official websitewww.juniper.net/us/en/products-services/nos/junos/

Junos OS (more formally Juniper Network Operating System)[4] is the FreeBSD-based operating system used in Juniper Networks hardware routers.[5] It is an operating system that is used in Juniper's routing, switching and security devices. Juniper offers a Software Development Kit (SDK) to partners and customers to allow additional customization.[5][6] The biggest competitor of Junos is Cisco Systems' IOS.[7][needs update]

Junos OS was formerly branded as Juniper Junos, and is commonly referred to as simply Junos, though this is a general brand name of Juniper Networks, including other product lines such as Junos Fusion.[8]

Some of the key benefits Junos OS include:

  • Modular design: Every process and component in a Juniper network setup is shielded from every other. One module crashing will have no effect on the rest of the system.[9]
  • Single train compatibility: Every Juniper switch, router, or other product runs the same JUNOS system. The system is built for simple inter-operability across the system.[9]


Junos provides a single code base across most of Juniper's platforms. Juniper has issued a new release of Junos every 90 days since 1998.[6][10][needs update]


Junos supports a variety of routing protocols. With the introduction of the SRX and J-series (past version 9.3) platforms, it also supports "flow mode", which includes stateful firewalling, NAT, and IPsec. Its a flexible routing policy language that is used for controlling route advertisements and path selection.

Junos generally adheres to industry standards[citation needed] for routing and MPLS.

The operating system supports high availability mechanisms that are not standard to Unix, such as Graceful Restart.[citation needed]


Junos operating system is primarily based on Linux and FreeBSD[10], with Linux running as bare metal, and FreeBSD running in a QEMU Virtual machine. Because FreeBSD is a Unix implementation, customers can access a Unix shell and execute normal Unix commands. Junos runs on most or all Juniper hardware systems.[11] After Juniper acquired NetScreen, it integrated ScreenOS security functions into its own Junos network operating system.[12]

Junos Command Line Interface (CLI)[edit]

The Junos CLI is a text-based command interface for configuring, troubleshooting, and monitoring the Juniper device and network traffic associated with it. It supports two types of command modes.[13]

  • Operational Mode
  • Configuration Mode

The functions of Operational Mode include control of the CLI environment, monitoring of hardware status, and display of information about network data that passes though or into the hardware. The Configuration mode is used for configuring the Juniper router, switch, or security device, by adding, deleting, or modifying statements in the configuration hierarchy.

Junos SDK[edit]

Through the Juniper Developer Network (JDN)[14] Juniper Networks provides the Junos SDK[15] to its customers and 3rd-party developers who want to develop applications for Junos-powered devices such as Juniper Networks routers, switches, and service gateway systems.[16][17][18][19][20] It provides a set of tools and application programming interfaces (APIs), including interfaces to Junos routing, firewall filter, UI and traffic services functions. Juniper Networks also employs the Junos SDK internally to develop parts of Junos and many Junos applications such as OpenFlow for Junos, and other traffic services.

Market share[edit]

As of 2016, Juniper maintains a market share in Ethernet Switching of 16.9% and a market share in Enterprise Routing of 16.1%.[21] Juniper generated a $2,353 million revenue in Routing, $858 million in Switching, and $318 million in Security during 2016.[22]

Most of Juniper's revenue stems from The Americas ($2,969 million), with Europe, Middle East, and Africa ($1,238 million), and Asia ($783 million) combining for the rest of their annual revenue as of 2016.[23]


  1. ^ "Junos OS - Technical Documentation - Support - Juniper Networks". Retrieved 2019-02-11.
  2. ^ "Junos OS Release 15.1R2 Migration, Upgrade, and Downgrade Instructions". 2015-11-19. Retrieved 2016-01-12.
  3. ^ "JunOS 9.5 Licensing". Juniper Networks. Retrieved 2013-04-17.
  4. ^ https://www.juniper.net/us/en/products-services/nos/junos/
  5. ^ a b "JUNOS Software: Network Operating System". Retrieved 2008-11-10.
  6. ^ a b Kerner, Sean Michael. "JUNOS: Open, But Not Open Source". Retrieved 2008-11-10.
  7. ^ Duffy, Jim (2008-04-17). "Cisco's IOS vs. Juniper's JUNOS". Network World. Archived from the original on 2008-09-27. Retrieved 2008-11-10.
  8. ^ https://www.juniper.net/assets/us/en/local/pdf/datasheets/1000523-en.pdf
  9. ^ a b "Junos OS: The Power of One Operating System" (PDF). Juniper.
  10. ^ a b iXsystems. "Juniper's JUNOS FreeBSD based router operating system". FreeBSDNews.com. Archived from the original on 2008-08-28. Retrieved 2008-11-12. The first version of Junos was available on 7 July 1998 and since then Juniper has been updating it with new features every quarter. The release of JUNOS 9.1 in May this year was the 38th consecutive release.
  11. ^ "Junos Software Features :". Retrieved 2008-11-10.
  12. ^ Musich, Paula (2008-03-17). "Juniper at Last Integrates NetScreenOS into JUNOS". eWeek. Quinstreet Enterprise. Retrieved 2008-11-10.
  13. ^ "CLI User Guide" (PDF). Juniper. 2012-07-06.
  14. ^ "Juniper Developer Network". Juniper Networks. Retrieved 2012-05-30.
  15. ^ "Junos SDK". Juniper Networks. Retrieved 2012-05-30.
  16. ^ Kelly, James; Araujo, Wladimir; Banerjee, Kallol. "Rapid Service Creation Using the Junos SDK" (PDF). Juniper Networks. Retrieved 2012-05-30.
  17. ^ Bernier, Paula (2007-12-10). "Juniper Opens Router OS to Third-Party Developers". Archived from the original on 25 May 2010. Retrieved 2008-11-10.CS1 maint: Unfit url (link)
  18. ^ Hicket, Andrew R. "Juniper Opens OS To Third-Party Developers, Taking Stab At Cisco". CRN. The Channel Company. Retrieved 2008-11-10.
  19. ^ "Juniper Accelerates Innovation with the Partner Solution Development Platform (PSDP)" (PDF). Retrieved 2008-11-10.[dead link]
  20. ^ "Executive Essays on Innovation and the Partner Solution" (PDF). Juniper Networks. Archived from the original (PDF) on 2008-07-27. Retrieved 2008-11-10.
  21. ^ "IDC's Worldwide Quarterly Ethernet Switch and Router Trackers Show Slight Yet Continuous Growth for 4Q2016 and Full-Year 2016". www.idc.com. Retrieved 2017-06-30.
  22. ^ "Juniper Networks Reports Preliminary Fourth Quarter and Fiscal Year 2016 Financial Results". investor.juniper.net. Retrieved 2017-06-30.
  23. ^ "Juniper Networks Reports Preliminary Fourth Quarter and Fiscal Year 2016 Financial Results". investor.juniper.net. Retrieved 2017-06-30.

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