SDN and NFV are going to change infrastructure policy, if they succeed. I’ve blogged about that before. They’ll also likely change the services offered by operators. The notion of service agility as a benefit demands something to jump from (which we have; the present) and to (what we’d have to define). I’d like to think about that future service set today.
We have three broad classes of services today. First, we have connection services that allow us to communicate with someone (or multiple parties). Second, we have access services that let us get to something, like the Internet. Finally, we have private network services in the form of VPNs or VLANs. These categories are fairly broad, and I think it’s reasonable to assume that future services will tend to work within or among the current classes of service rather than to invent new classes.
As a class of service, connection services are becoming a subset of access services, meaning that we are transforming “connection services” into “connection as a service”. That shift is inevitable given the fact that the Internet is a connection fabric and most connection services can fit easily within it. Traditional connection services are the least-likely to be profitable in the long term, and so one change we can expect to see is for operators themselves to under-invest in these services and accept that they’ll lose some of each (or all of some) to OTT over time.
Voice calling and SMS/IM are examples of things that just don’t make a lot of sense to spend money on as an operator. That doesn’t mean that they’ll disappear from wireless and wireline operator inventories tomorrow, but rather that more and more of them will get subsumed into social-media and other applications.
Service-specific access is also going to slip. I am of the view that IPTV in the U-verse sense is doomed and I think you can see that in AT&T’s quarterly report. The whole notion of service agility demands users be prepped with enough access capacity to accept delivery of their services without physical changes being made to the demarcation. Thus, you don’t necessarily have to give a user the fattest pipe their media can support, but you do have to give them media to support more services than they initially buy, and provide a ready means to upspeed it.
Where this trend takes is to the notion of an agile demarcation (dmark) point, a place where services can be connected for presentation to the user on demand. The first question that SDN and NFV would have to answer is how their use would facilitate this on-demand connection/presentation.
An futuristic IP dmark could be a more sophisticated version of a gateway router (virtual or real). A user sees an IP network as a series of accessible subnetworks, which means that it’s fairly easy to present all manner of services as simply a piece of an address space. You’d have to make sure that you didn’t allow routing between the services for security and stability control, but that problem exists today where VPNs and Internet are provided to the same site.
One possibility here is to presume that a user has a series of IP services that are mapped to a public IP address (the popular Class A address of IPv4 RFC 1918, 10.x.x.x, is an example), which would mean that every IP connection would “see” both public Internet and a series of private services in the same connection. Another idea would be to create tunnels with SDN that would partition the services in a way similar to that used to deliver IPTV, packet voice, and Internet over fiber.
Carrier Ethernet could be changed by this model. Ethernet is based on Level 2 addressing, and it would be possible to give each service a Level 2 address through which it would connect. If the service is something like VLAN that address could represent a “bridge” to an Ethernet LAN, and if the service were Level 3 (IP) the address could look like a router that’s an on-ramp to the IP subnet(s) the service uses. You could map the same kind of service model to carrier Ethernet as to IP, which means that you could evolve both residential and business customers to the service model.
In the long run, the smart thing to do in both cases would be to give the users a fiber path that could be metered to a range of speeds, and then let the user set the total capacity of their access connection using an operations tool. That would then set the maximum capacity of agile service connections that could be terminated on that site.
Introducing NFV into the picture changes things a bit in my view. NFV is about hosting features not hosting connectivity, and in order to give users a feature you need to present what I’ll call a “logical service”, not a series of tunnels. Features are either embedded in a data path, in which case they are somewhat transparent to the user except in behavior terms, or they look like something the user can address (which implies they have an address and are part of a service address space).
It’s possible to see a service set as a series of tunnels, but it’s not an easy model to manage at the user level. Given that, I think it’s fair to presume that the future services will be presented as addresses, which means that the service dmark will be either a L2 or L3 virtual window on a world of routers and switches that are gateways to useful stuff.
Connection services in this model are simply addresses through which a connection can be created. Private network services are the same, and access services are address windows into hosted features of any sort. This is a kind of compositional dmark model for service evolution. Every user gets one (or two, for redundancy) access pipes that offer an address-space (or even two—one at L2 and one at L3) window into a service spectrum.
SDN and NFV are interior technologies in this model, obviously. The biggest change is in the service dmark device that does the composing. It doesn’t have to be on premises (you could just terminate an access path to an interior element) and it doesn’t have to be an appliance (software virtual routers and switches would work fine). The point is that whatever the technology, it has to be service-elastic. Otherwise we have all this wonderful capability to turn on Service A from a portal in 20 seconds, and then watch users wait three weeks for a new access pipe to use it.
There are profound implications to all of this. Regulators have to address the question of whether providing IP services through virtual address windows links them to the Internet and makes them a neutrality issue. Operators have to figure out how (based in part on the regulatory issue’s resolution) how “premium” services might be offered—as Internet/OTT services or as part of a private special-service address space. Everyone will have to figure out how to make all this stuff seem plug-and-play to the buyer.
I think it can be. I think that the address-space windowed compositional dmark model is the logical vision for the SDN/NFV future if you look at infrastructure from the user’s perspective; if you look (virtually) down the access pipe that connects you to your carrier. I think this is the vision that everyone has to work to, or new services are going to underperform.
