Cisco's IOS vs. Juniper's JUNOS

Juniper says too many versions of IOS; Cisco questions JUNOS purity

Juniper Networks says Cisco has too many versions of IOS, the software brains of its routers and switches. Cisco counters that Juniper has way more than one version of JUNOS, too. In the end, will their different operating-system architectures make any difference in the market?

Juniper Networks makes lots of hay about its single-operating-system approach to high-performance networking — saying that using JUNOS across its routing, switching and other application-specific platforms lowers cost and eases operations and management.

Rival Cisco, on the other hand, seems to unveil a new operating system with each product launch, a practice that more and more makes the original version of IOS a distant memory. This year alone, Cisco has unveiled a new operating system for its data center switch and another for its latest generation of edge routers, almost four years after launching yet another for its core routers.

If Juniper is correct, it would seem that Cisco is playing right into its hands.

Not that it looks as if Cisco is in any imminent danger of losing its market dominance. Cisco in 2007 grabbed 82% of the $4.2 billion enterprise-router market, 54% of the $4.7 billion service-provider edge-router market and 55% of the $2.7 billion service-provider core-router market, according to Dell'Oro Group. Juniper ran second to Cisco in every category, with 5%, 18% and 30% shares, respectively. In LAN switching, Cisco had a 71.5% share of the $18 billion worldwide market in 2007, Dell'Oro says. Juniper isn't on the radar screen yet, because its EX line began shipping just last month.

So, in the end, do their operating systems' differences really matter, and could those systems ever really help tip the balance of power in networking? (View companion slideshow: "The battle between JUNOS and IOS")

Juniper thinks so.

"Our customers . . . do not like multiple operating systems, they do not like the fact that they have to . . . figure out what release of the operating system works with which particular product and products," said Juniper Founder and CTO Pradeep Sindhu at the company's analyst conference last month. "Much of this is reflected in operational cost increasing for the customer."

Cisco, meanwhile, claims its various operating system flavors — IOS, IOS XR, IOS XE and NX-OS — are intended to address customer requirements for more consistency across and optimization within product segments.

It also counters that Juniper's single-operating-system claims are misleading. (Read more about Cisco vs. Juniper and Networking's Greatest Arguments.)

"Cisco maintains a consistent user interface across Cisco IOS, IOS XE, IOS XR and NX-OS while addressing segment- or architecture-specific requirements," says Suraj Shetty, senior director of service provider marketing at Cisco. "Seeing Juniper claim only one OS across all products . . . was surprising. They have JUNOS, JUNOS ES, ScreenOS, JUNOSe, IVE OS, NetScreen-IDP, WXOS, CTP and even an OEM OS for their Security Threat Response Manager, and each of those has a different user interface. This places a much larger burden on customers than our approach, which is to address customers' stated needs while maintaining a consistent look-and-feel."

Analysts say users would prefer to work with one operating system but sometimes it's not feasible given their vendors' heritage and direction.


Read related story: "Cisco IOS vs. Juniper JUNOS: The technical differences"


Cisco's legacy

Cisco has a more-than-20-year legacy in enterprise and service provider networking, and IOS has been the company's operating system from the beginning. It was born in the enterprise network environment, where its support for multiprotocol routing helped launch Cisco from a start-up to the $40 billion behemoth it is today.

Technology and requirements have changed over that time, however, and Cisco has entered new markets and acquired more than 120 companies. The Internet era, for example, has forced Cisco to address a whole new set of requirements by service providers — managed service offerings such as VPNs, security, high availability, QoS, multicast and MPLS — previously foreign to IOS.

At the same time, the enterprise was becoming a market for converged voice, video and data, ushering in a completely new set of technology requirements — and forcing Cisco to become proficient at handling the sort of traffic that has been the bread-and-butter of its 100-year-old telecommunications brethren.

"Markets develop in strange ways, acquisitions are needed to fill gaps and sometimes integration work falls off the development priority list when compared to maintaining an existing customer base," says Mark Seery, vice president of switching and routing research at Ovum/RHK. "Are there times when departure from one software platform makes sense? Yes, there probably are, but they should be the exception rather than the rule."

Comparing IOS with JUNOS

Cisco late last year introduced the latest big change to IOS: a plan to allow third-party and customer-developed applications to access IOS services that were previously off limits. (Juniper aired similar plans for JUNOS around the same time.)

Juniper's approach

Juniper began business 12 years ago with a clean slate to develop an operating system for service-provider routers. Its routers and the JUNOS operating system that controlled them were "purpose built" for the service-provider market, a key differentiator for the company vis-à-vis Cisco and its enterprise-born IOS.

Since then, however, Juniper has broadened its target markets — most notably into the enterprise — and acquired several companies, including Unisphere in edge routing and NetScreen in enterprise VPNs. Despite its derisive rhetoric directed at multiple operating systems, Juniper acknowledges it's now facing some of the same challenges as Cisco.

"A lot of these products are the result of acquisitions," says RK Anand, Juniper senior vice president of foundation technologies, referring to the NetScreen, Unisphere and other inorganic gear in Juniper's portfolio.

"We have to be careful about an installed base, customer commitments and continued delivery on products we acquire," Anand says. "Our approach has been fairly deliberate and planned and scheduled in a systematic manner about incorporating and bringing technologies that come as a result of these acquisitions into JUNOS while at the same time, continuing to ship existing systems, he says.

Juniper last month released JUNOS 9.0, 20 million lines of code that incorporates security features obtained from its NetScreen acquisition four years ago. Juniper rolls out a new release of JUNOS every quarter, each one a "superset" of its predecessor, Anand says, while Cisco ships a major release of IOS — currently it is shipping IOS 12.4 — every two years.

JUNOS 9.0 runs on Juniper's MX-series Carrier Ethernet switches, M- and T-series routers, EX enterprise LAN switches, J-series branch office routers, and the new Juniper Control System 1200. The NetScreen ScreenOS operating system continues to be offered separately from JUNOS, however, as does the JUNOSe operating system for the company's E-series edge routers, obtained via the acquisition of Unisphere six years ago.

"The E-series does not run the same exact JUNOS that the rest of the core and edge and Carrier Ethernet routers run," says Glen Hunt, a carrier infrastructure analyst at Current Analysis. There are differences between the functions and feature sets of JUNOS and JUNOSe that lead to operational inconsistencies between the platforms, he says.

As Juniper continues to grow, broaden into new markets and acquire companies, it appears that its single-operating-system strategy will continue to be just that — more strategy than reality, a continually moving target.

"We will look at entering adjacencies in the marketplace," Anand says. "In which case, be it an acquisition or be it a product, we will make a decision. But our long-term discipline is to be focused on a single network-operating-system of choice, and that is JUNOS."

"It'll take time to get there — and in fact, I think they believe they'll be doing it for the rest of their life," says Ovum/RHK's Seery. "They should be careful about throwing too many stones, obviously. But I think it is true — they do have [fewer] software versions than Cisco does."

Customer view

Whether reality or theory, the single-operating-system approach seems to resonate with some Juniper users. Video- and teleconferencing vendor Polycom uses Juniper's internally developed J6350 and M7i routers and MX480 Carrier Ethernet switch/router, and is evaluating the new EX enterprise LAN switch line.

One reason for choosing Juniper was JUNOS and its ability to offer a consistent interface and set of features in support of voice, video and data availability, service quality and security across products, said Polycom CIO Glenn Noga at Juniper's analyst conference last month.

"We need to be able to [assure] three different constituencies — demo, production and engineering — that [converged voice, video and data] will work well across one environment," Noga said. "As we moved around [between departments], we continued to understand the operating system."

Understanding the operating system is key for Cisco shop FactSet Research Systems as well. The company is a provider of financial information and analytic applications for worldwide investors that is consolidating several older Cisco 7200- and 7300-series routers into Cisco's new ASR 1000 router, which runs an IOS variant called IOS XE.

FactSet CTO Jeff Young says IOS XE is a "significant change" to IOS that includes additional complexity and cost in learning the nuances of the new operating system; but the benefits outweigh the inconveniences.

IOS XE offers the ability to perform in-service upgrades of hardware and software, whereas the 7200s and 7300s with older versions of IOS had to be taken out of service for those modifications, Young says. But in the end, IOS XE still feels like IOS, he says.

"I guess you could call it learning a new operating system," Young says. "To my network engineering staff, IOS is IOS: You log into the thing, it feels like you're at home. Certainly the mechanics of it are different. But to the network engineer to provision services and do the normal course of business, you haven't changed his life very much."

Cisco says there's a good reason for that.

"Goal No. 1: It must look exactly like IOS," says Doug Gourlay, Cisco senior director of data center solutions, explaining the company's strategy when it develops an IOS variant. "If you look at what we’ve done in NX-OS, we took software developed in the IOS group, brought it over — common look-and-feel, common operational characteristics, common code, common command interpreter — and are running that natively on top of a Linux operating system. [Users] probably wouldn't be able to tell the difference. Except for where we've chosen not to implement a particular feature set or type . . . we've defaulted to putting it in the same way we've already done it before, so it was consistent from a customer perspective."

A Linux operating system kernel allows Cisco and its customers to add IOS services as modules, and facilitates virtualized operation of those services, Gourlay says. IOS traditionally has been a monolithic operating system, where services and operations were tightly linked to the kernel, necessitating a wholesale replacement of the software to access new features, critics say.

Gourlay says the new IOS variants — IOS XR, IOS XE and NX-OS — are designed to support specific applications in different areas of the network. IOS XR was developed for multi-chassis scaling in the core, IOS XE for the different requirements at the edge, and NX-OS for consolidating storage and Ethernet capabilities in the data center.

"We've had to apply different architectural approaches to maintaining software segmentation, keeping feature velocity up, being able to trace a defect . . . to fix it quickly," Gourlay says. Cisco will continue to consolidate its product-specific operating system platforms over the next six to 12 months, he says.

In the end, the significance of a single operating system vs. multiple operating systems will be up to the customer. For now, users are taking Juniper's ongoing JUNOS integration work in stride, just as they are taking in stride Cisco's approach to delivering a specific operating system dedicated to a specific networking task.

"The only time a user would get concerned about whether there are multiple operating systems is if it affected the way he dealt with the multiple products," says Current Analysis' Hunt. "There’s probably a certain type of customer out there that would prefer to have one. But I haven't seen where it's really hurt them."

Learn more about this topic

JUNOS vs. IOS: The technical differences

JUNOS vs. IOS: The slideshow

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