The new SNEP specification employs the same NDEF commands used in tag reading and writing applications, allowing information stored on an NFC tag to be read by a phone and then passed on to other NFC phones or exchanged with a wide range of other types of NFC-enabled device.
The NFC Forum has published the Simple NDEF Exchange Protocol (SNEP) specification, setting out a common data format that can be used across all NFC devices for both peer-to-peer and read/write NFC applications.
"Previously, NDEF was applicable only to NFC tags in reader/writer mode," the NFC Forum explains. "Now, SNEP enables the use of the openly standardised NDEF in peer-to-peer mode, making seamless interchange of data a reality."
"Application developers no longer need to concern themselves with how their NDEF data gets transferred between NFC-enabled devices," the forum adds. "By providing this capability, the SNEP specification makes the difference between reader-writer and peer-to-peer operation modes disappear — a major step towards global interoperability of NFC applications."
SNEP extends the capabilities of NFC in three key ways:
- Standardised, simplified transfer of contact information. For example, a phone can be configured to automatically send business card information when an NFC peer-to-peer connection is established. The recipient doesn't have to do anything other than to accept the business card and allow it to be entered into his phone book.
- Collecting information and promotional coupons for later use. A consumer could get a link to a movie trailer from an NFC tag on, say, a smart poster. When they get home, they could watch the trailer on their TV by simply tapping their phone to an NFC-enabled TV remote control.
- Viral transfer of information. Because the same format is used for both tag reading/writing and peer-to-peer, information collected from an NFC tag can also be exchanged with other NFC phones. A coupon, special offer, or links to promotional trailers, games or other marketing material stored on a smart poster could therefore be passed virally from one consumer to another by simply touching their two phones together.
SNEP is a request/response protocol which allows an application on an NFC-enabled device to exchange NDEF messages with any other NFC-enabled device operating in NFC Forum peer-to-peer mode. The protocol makes use of the forum's existing Logical Link Control Protocol (LLCP) to provide a reliable data exchange.
In operation, a SNEP client application sends a request to a SNEP server application to either retrieve data from the server with a GET method or push data to the server using the PUT method. The protocol handles segmentation and reassembly of large messages as well as early cancellation of transfers that would exhaust receiving capabilities.
Beyond the protocol definition, the SNEP specification also defines a default server that is available as a well-known service on an NFC-enabled device. This default server functions as a simple inbox that applies locally defined processing to received NDEF messages. An NFC-enabled personal computer could, for example, open the web page that is provided in a Smart Poster NDEF message sent from an NFC-enabled mobile phone.
"By extending NDEF to peer-to-peer communications, our SNEP specification adds to the usability of NFC technology and broadens its possibilities, enabling enterprises to offer new, creative, and appealing applications to businesses and consumers," said Koichi Tagawa, chairman of the NFC Forum.
The SNEP specification is available to download free of charge from the NFC Forum's website.