Everyone accepts that network operators would love to eliminate proprietary network devices. NFV was aimed at eliminating at least some of them, but using a cloud to host a data-plane function has its issues. AT&T recognized this and decided to frame an open (later released as open-source) operating system to run in an appliance and perform Level 2 and 3 processing, defined by an existing chip-control forwarding language called “P4”. We also have commercial initiatives aimed at the “white box” virtual router opportunity, including one that just got a win in Europe. What does this portend? Let’s see.
I blogged about the dNOS and P4 approach last year. In brief, what AT&T has done is create an embedded operating system (dNOS, now Linux Foundation DANOS), and a general architecture that includes the use of programmable chips, which is where P4 comes in. The combination is aimed at creating open switches and routers that perform almost as well as their proprietary, custom-chipped, equivalents.
dNOS is an open framework for building disaggregated routers and switches. As I noted, it’s been released open-source via the Linux Foundation (DANOS), but there’s no material available from that source at this point. AT&T based dNOS largely on the Vyatta software router from Brocade, and dNOS/DANOS has native ability to handle the traditional IP protocol suite. It also has facilities to be extended to incorporate semiconductor packet processors through P4. P4 came out of an ACM article, but it’s also been adopted by the ONF. Complicated, huh?
DANOS is a part of AT&T’s 5G cell-site white-box router strategy, large-scale testing for which was announced in December 2018. This implementation doesn’t include P4, and I’m seeing a lot of interest in the DANOS concept from other operators (especially in the EU) but not a wave of commitment. Part of that may be the slow start in the Linux Foundation project, which as I’ve noted doesn’t have anything on its website yet. Part may also be that some operators may be reluctant to jump in on what was initially a competitor’s approach, and part that introducing something like DANOS is difficult unless you have a greenfield buildout like 5G.
On the commercial side, deep packet inspection vendor 6WIND has a virtual router offering that, perhaps ironically, is positioned as an alternative to the Vyatta stuff from now-broken-up Brocade. It recently got a win in Europe where it runs on the same boxes that Vyatta used.
Operators had a lot of interest in Vyatta when it came out. One Tier One talked extensively to me about it, and ran a fairly large-scale trial. Brocade, riding a combination of Vyatta and a positioning that transformation was mostly a data center technology task, managed to get the largest gain in strategic influence within a 6-month period that my surveys had ever recorded (this was in the spring of 2013). Brocade, of course, didn’t manage to get its act together in strategy, and subsequently got sold in pieces.
6WIND started with a deep packet inspection story, and in that same period was pushing that more than virtual routing. Virtual routing turned out to be a better approach, and so 6WIND applied its packet inspection thinking to the forwarding mission, doing a rather nice job. Their virtual router is designed to run on a commercial off-the-shelf server, and to take the place of a physical device. That means that it’s generally expected that, absent a failure, the virtual routers would stay where you put them. You can get source code on this, and roll your own implementation.
You can save a lot of money with a 6WIND virtual router, versus proprietary router hardware. Some operators have told me the savings could easily be 70%, in fact. The virtual routers will work in nearly any mission a real router could be used, except the very high-traffic cord devices. Operators have already deployed the 6WIND solution; the company lists half-a-dozen successes, but obviously we’re not seeing a tectonic shift with 6WIND either, and since they’re not a network operator (AT&T obviously is) they don’t have a captive deployment to leverage.
These two examples illustrate two slightly different approaches to the “get-rid-of-routers” job. DANOS and P4 offer an open-source model, which has the advantage of cheapness and the risk of having little or no real support. 6WIND has a commercial virtual router of the kind that operators have been pretty interested in for about 6 years. DANOS is an optimized appliance operating system, where 6WIND’s approach is designed to work on those open servers. Is one strategy better a clear winner?
To me, the issue with either approach is a realistic deployment scenario. Nobody wants to stick a virtual router in the middle of a vendor-router network; you can imagine how much finger-pointing that would generate! Every network failure that happened from the deployment to the end of the world would be blamed on that hypothetical single virtual device. A more likely model would be a greenfield deployment. The most likely greenfield place, of course, would be 5G, which of course is what AT&T had in mind for dNOS in the first place.
Greenfield deployments pose their own risks. AT&T might be willing to bet their 5G edge on the DANOS successor to dNOS, but would other operators? However, would they be more likely to bet on something like 6WIND, who after all isn’t exactly a household word in networking? I know the 6WIND people and have worked with them, but that’s not true of everybody.
To compare the approaches in more detail, I think you have to look at the concept of P4. The DANOS model was designed to support packet-processing chips using a kind of stub interface and the P4 programming language to create the forwarding rules. This approach, which is still based on open concepts, could result in some very useful capabilities. Vendors like 6WIND, of course, can customize their own stuff to accommodate specialized semiconductor support too, so the question may come down to how fast it happens. Part of that depends on how fast P4 happens.
Right now, DANOS and P4 are embodied almost totally in open consortium activities, each of which tend to move at the pace of a turtle. Since we have at least two such activities involved in DANOS/P4, we have what’s analogous to a turtle race where your entrant is two turtles tied together. That image doesn’t need to be expanded on very much to make the point that process is far from lightning fast. 6WIND, on the other hand, has shown the ability to transform its mission and be quickly credible, but if they’re a rabbit in our race, they may be one that’s not yet accepting where the finish line is. Do we need an architecture like DANOS/P4? If so, then 6WIND either has to adopt the model or offer an alternative.
I like the virtual-router 6WIND approach for its simplicity of message—replace routers with virtual routers. It’s easy to understand and to sell. I like the open model of DANOS and P4; in the reliance of open-source software, the vision of an open mechanism for incorporating packet processing chips, and the agility of a forwarding language to help navigate the evolution of network services. I think both approaches have a challenge in meeting the varied expectations of today’s market.
These aren’t the only initiatives in transforming networking for the age of the cloud. Next week I’ll talk about two others, and how they combine with these two to frame a lot of questions about how networks will look in ten, or even in five, years.
