The second of the three 2019 trends I blogged about a couple weeks ago is the subduction of IP network features. IP, largely because of the Internet, has become the “service protocol of choice” globally, meaning that applications and devices are built to presume IP connectivity. The IP model has a lot of issues associated with it, and many vendors and organizations have at various times proposed a different approach. In fact, in the ‘80s and earlier, we had a different approach; networks were built on protocol-independent transport. A more protocol-neutral approach to networking may now be emerging.
Fundamental to any new network model is the reality that IP is the service protocol of choice, and that any attempt to replace it is surely doomed to failure. Thus, a new network model has to focus on creating something different below the IP service layer. The OSI model, which is more recent than IP but still ancient by today’s standards, allowed for and even mandated multiple layers of protocol functionality, with each layer having a role of supporting the layers above. IP doesn’t really break neatly into OSI layers (as I said, it predates it), but if we could map some basic transport-like IP features downward to something else, we might emerge with a simple IP service layer and a better framework for security and service management.
Optical networking, typically based on Ethernet as an electrical protocol riding on fiber or on wavelengths (lambdas) within a fiber. This is Level/Layer 1 of the OSI model, the physical layer. Fiber is the most critical transport element; it’s the fabric on which virtually all wide-area networking is built, but fiber capacity improvements mean that few sites can justify dedicated fiber connections. Residential fiber (fiber to the home or FTTH) is based on passive optical network sharing, and even that doesn’t lower costs enough to enable direct fiber connection of most homes, or even most small business sites.
Even where fiber is justified, additional subdivision of fiber capacity (called “grooming”) is essential if you want to support multiple higher-level connections on a single fiber. There have been a number of approaches offered to fiber grooming, ranging from some form of Ethernet (the preferred approach, obviously, of the MEF) to SDN. Since most fiber uses an Ethernet overlay, Ethernet is a logical choice, and if all we wanted to do was to subdivide fiber into electrically generated subchannels, that would likely be the choice.
What complicates that model is the fact that if you’re going to do electrical-layer handling it would be nice to be able to cross-connect the electrical tunnels to create end-to-end pipes. In effect, this creates a virtual physical layer that can be much more connective than optics, and in addition that layer can provide routing and rerouting. That means that the IP service layer can reduce or eliminate its own features in that area. The electrical layer subnetworks also can separate IP networks to improve security.
Ciena is a logical kingpin player in this expanded optical/electrical hybrid space. They’ve been doing M&A to supplement their own optical products, including a vendor who supplies SDN and service automation and orchestration (Blue Planet) and one that adds in sophisticated device discovery and inventory (DonRiver) and custom skills in operations integration. They’ve quietly assembled the pieces they need to present a logical subnetwork to the IP service layer, and to operationalize that layer fully.
The problem Ciena has is typical of vendors these days. They have an axel and want someone else to conceptualize the car. The problem with the subduction of IP features is that it’s necessarily an ecosystemic shift. You add stuff to layers that never had it, and remove that same stuff from where it traditionally lived. Both change equally, and so you have to be prepared to present a vision of how the new balance of features would work overall. Ciena is not doing that.
Google, in Andromeda and related stuff, has demonstrated how you use SDN open connectivity as the core of an IP network. A lot of the stuff used in that transformation is open source and available to Ciena and everyone else. It’s not rocket science. Route determination and advertising in IP is managed by control protocols. If you spoof them at the boundary between “real” IP and an IP subset based on agile physical-layer technology, you can make the IP network see what it expects, however much of it is displaced. Google creates this boundary at the BGP level, but you could do it everywhere from there out to the default gateway.
Control protocols in IP are a big part of the whole picture of feature subduction. Most of the IP features not directly related to passing packets are supported via one or more control protocols. These combine to create management, topology discovery, and endpoint visibility capabilities in IP. If you decide to subduct an IP feature, you need to then intervene in the control protocol handling associated with that feature. If you can do that correctly, then where and how the feature is provided isn’t relevant and your subduction is feasible.
This same level of attention is important in the creation of the IP service overlay network, and the hottest topic in the WAN today is an example of where we should see it. SD-WAN creates an overlay network that merges the IP VPN created through traditional MPLS VPN services with an overlay VPN created by SD-WAN nodes. Ideally, SD-WAN products should “look” like a gateway router, even perhaps a default gateway, and ideally they should participate in control exchanges that make SD-WAN-connected users and resources true partners in the VPN, just as if they were directly on it. Perhaps some or most do, but you don’t hear anything about that in the documentation, as users and prospective users have pointed out to me.
A holistic vision for an SD-WAN service layer would likely create what might be called “IP lite”, a stripped-down version of IP that eliminated the features that were to be subducted down to the transport level. It would also have to define how the control protocols for the features involved would be spoofed/emulated or transformed at the service layer boundary, the user interface, or both. This is what some people think the MEF is up to with its SD-WAN work, but insiders tell me that they’re not focusing on that at all, but on standardizing the interface between an SD-WAN node and the IP network providing transport service. A similar transformation might then be provided for the Ethernet (“Third Network”) transport model.
Does Ciena have to worry about the electrical-layer players? After all, you can create a grooming layer from above as easily as from below, right? Perhaps not. Optical-layer technology is mandatory in any realistic scenario for metro transformation, and there’s not much white-box optics rearing its head. At the electrical layer, everything above a hundred gig is very likely to move to white-box, and perhaps to SDN, and so the major switch vendors are less likely to have an incentive to drive the market.
That’s Ciena’s real worry, because they’ve been anemic at driving the market themselves. Like many vendors who offer something essential, Ciena has been focused more on fulfillment than on sales/marketing, and as I noted earlier, they’ve followed the normal vendor pattern of kissing off the future in the name of performing in the next quarter. If they want to leverage the enormous benefit their optical position gives them, they’ll have to do better.
