The Internet of Things (IoT) at its most basic level is about connecting potentially billions of different devices to a network so that devices can communicate with each other and share data. Most of the early solutions, which were called machine-to-machine (M2M) communications, used closed, private networks making it impossible to share and transmit the data to other networks or other industries.

But that isn’t the case today. IoT now involves many different layers in the platform stack including the cloud, the management of the data, the enabling of the applications, the management of the devices or hardware, and the connectivity.

Delving into the connectivity layer alone can be confusing because there are already a number of competing technologies being used to connect devices to the network. Some of the options include cellular networks (2G, 3G, and LTE), WiFi networks, low-power wide area (LPWA) networks, proprietary networks like Ingenu or SigFox, or even some sort of short-range communication network like Zwave.

But the connectivity layer is a big part of the IoT ecosystem. Gartner estimates the connectivity market for IoT was a $10 billion market in 2015 and will grow more than threefold to $31 billion in 2020.

Because of the size of the market, some experts believe that, at least in the short-term, there will be plenty of opportunity for these differing connectivity options. “In the long term, I believe standards will win and interoperability will win,” says Christian Renaud, research director for the Internet of Things at 451 Research. “But in the short-term, many of these proprietary solutions will make headway. Customers are not waiting.”

The options right now are numerous and can be confusing. Here’s a breakdown of the different IoT connectivity technologies and some of the companies providing this service.

Ingenu: Ingenu uses a proprietary technology called random phase multiple access (RPMA) that the company says is built specifically for IoT connectivity. The company says it operates 38 private networks around the globe and is expanding to 30 major markets in the U.S. by year-end.

LPWA: Low power wide area (LPWA) is a generic term for a group of technologies that have long battery life, connect to the wide-area network and have limited throughput. The LoRaWAN protocol (LoRa) is an example of a LPWA network. KPN has launched a LoRa network in the Netherlands and SK Telecom and Orange have both said they will build nationwide LoRa networks. Cisco supports LoRa and has built an industrial IoT product line around the protocol.

LTE-M: This technology is also known a LTE CAT-M and is part of the 3GPP LTE Release 13 Advanced Pro standard. It is intended for narrowband LTE applications such as IoT sensors and wearables. AT&T has said it will launch a CAT-M trial later this year.

NB-IoT: This is a standardized cellular technology that is part of the 3rd Generation Partnership Project’s (3GPP) LTE Release 13. Momentum is gathering around this standard. Vodafone has said it will commercially launch an NB-IoT network next year. Singapore’s Mobile One cellular operator has said it will launch an NB-IoT network in the first half of 2017.

SigFox: This French company is deploying a narrowband (or ultra-narrowband) technology that uses a standard radio transmission method called binary phase-shift keying (BPSK). SigFox’s technology, which includes the backend data and cloud server to the endpoints software, is proprietary. Large manufacturers like STMicroelectronics, Atmel, and Texas Instruments make SigFox radios. SigFox has said it will have its network deployed in 100 markets in the U.S. by year-end.

Z-Wave: Z-Wave is an RF-based communications technology designed specifically for control, monitoring, and status reading applications in residential and light commercial environments.

Although Renaud believes that ultimately some of these technologies will go away and some providers of IoT connectivity will be acquired by others, at this point there are plenty of use cases to keep all of them in business. “The market is so big and customers are not waiting,” he says.