Wi-Fi Moves Up to the Carrier Class

Carl Weinschenk

The explosion of demand for spectrum has been a boon for the Wi-Fi industry. Until the advent of LTE networks and smartphones and tablets, Wi-Fi was a grassroots tool that lacked the features that give cellular roaming, carrier-level security and other high-level capabilities. Hillol Roy, a fellow at IBB Consulting, told IT Business Edge blogger Carl Weinschenk that standards and approaches that make Wi-Fi the coequal to cellular are here.

Weinschenk: Doesn’t it seem that Wi-Fi has a strange lineage for a something that is ending up as carrier class?

Roy: The way I will phrase it, Wi-Fi started as a consumer-class technology with unlicensed spectrum and gradually proved its worth. It proved that it can provide service, and it can provide capacity at a time when we were running out of it.

Given it provided capacity and the radio interface — which is the most critical element — worked, now people said, “Why not build the backend and other carrier-class infrastructure?” Initially, when Wi-Fi started it was not worthwhile doing all that in the unlicensed band ... Now they really, really need capacity. They are saying, “It’s a proven technology, let’s add all the stuff to make it mainstream.”

In order to make it carrier-class, you need a very robust reporting mechanism so that you can report who is using the network, when it was used and how it was used. You need a very detailed network management matrix and usage matrix. That is one part.

The second part is around inter-carrier authentication and security. The goal is to make it more seamless like 3G and 4G, so users don’t need to enter a key or user name and password.

The third part is around the user experience. If you are on a 3G network, you don’t have to choose the carrier. The equipment will automatically select each network. If you go outside the network, it will select the roaming partners.

Weinschenk: Could these abilities be brought over from the cellular side?

Roy: When it comes to how to build all that in Wi-Fi, a lot of what is used in cellular can be applied here. The unlicensed spectrum, only the … radio air interface changed. The type of security protocol or the schemes used to secure the network isn’t impacted that much. Overall, it will be very similar to cellular. A lot of principles and learning from cellular network transfer over.

Weinschenk: But not all …

Roy: [There is] one key difference between cellular and Wi-Fi. Most of the devices are provided [or approved by] the carriers. Verizon devices come from Verizon, AT&T’s from AT&T. Wi-Fi is built around the bring-your-own-device idea, in which the network does not have control of the device. The mechanism for securing those devices is based on credentials. How do you store those? They have to cover a wider array of devices. For example, devices on the AT&T network all have SIM cards and the credentials all are there. A Wi-Fi or laptop may or may not have a SIM card.

There are several schemes. Seamless-less technology such as Hotspot 2.0 is one. It will put certificates in devices where there is no SIM card. What is embedded in the device will emulate many SIM-like capabilities for serving these functions.

Weinschenk: Does this handle roaming as well as authentication to the home network?

Roy: When you are roaming all you are doing is trying to find a way to get to another network. Hotspot 2.0, once you have backwards connectivity established, when you go outside your home network will have the intelligence to find which network can give you access. In the cellular world, the way roaming works is that when you are outside your home network — for instance, if you are traveling outside country — the networks you are trying to use talk to the home network to see if you are allowed to talk to it. The next-generation hotspot will have that capability of finding out if you are allowed to use the network and automatically give you access if you are.

Weinschenk: Where are we on Hotspot 2.0?

Roy: Right now, there are some early trials. The standards always are evolving. Hotspot 2.0 is in its early stages of commercialization. Expect to see more deployments in the next couple of years. Hotspot 2.0 [helps make] Wi-Fi carrier-class and connects authentication, authorization and accounting to other AAA services. There are three things that are done: Authentication decides whether to let someone use the network, authorization is deciding — if they are allowed to use certain capabilities — which services they can use. The third is accounting. This is recording what they have used and how long and where. If your customer goes to someone else’s network, you expect them to provide data on what and where and how much was used in your network. You want a very detailed rundown on all of those.

Weinschenk: Are these things all standardized?

Roy: When [a subscriber] is in your network only and not connecting to anyone else’s you can use proprietary enhancements. But if you start getting into roaming scenarios where your customer connects your AAA to another’s AAA you have to give them accounting data and have to make sense of what they are giving you. There is a higher need for standardization in that scenario.

Weinschenk: That sounds a bit confusing in the use of standards in some cases and proprietary enhancements in others.

Roy: Standards typically stop shy of defining everything. Additional enhancements start [systems toward] diverging in stand-alone usage scenarios, but when operators start working together that’s where WRIX D comes in to help with accounting data exchange. In wireless WRIX D defines what the template or format is of the data exchange.

Weinschenk: Why not just use the framework used by the cellular industry?

Roy: Wi-Fi developed differently. At the high level it is the same, but there are some differences at network layer. WRIX — the Wireless Roaming Intermediary Exchange — follows philosophically much of what cellular does but there are some differences in the records fields and other details.

I think in terms of basic standardization, what we need to do is pretty well defined now. Standards are close to being completed and some will be completed during the next two years. We are at the point of deployment and trials and refining the standards.

Weinschenk: So progress has been steady.

Roy: The Wi-Fi Alliance has been looking at mobility and security for a long time. In the last three or four years, the momentum was much higher because of the huge capacity demand on mobile network. The momentum has increased mainly because people have seen the value of Wi-Fi and how it can help solve the capacity crunch.

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