Typically DTLS capable CoAP devices will support RSA and AES or ECC and AES q

Typically dtls capable coap devices will support rsa

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° Typically, DTLS capable CoAP devices will support RSA and AES or ECC and AES . q Drawback: NAT Issue ° In CoAP, a sensor node is typically a server , not a client (may be both). § The sensor (or actuator) provides resources which can be accessed by clients to read or alter the state of the sensor. ° As CoAP sensors are servers, they must be able to receive inbound packets . To function properly behind NAT, a device may first send a request out to the server allowing the router to associate the two.
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19 University of Pennsylvania, Computer and Information Science MQTT and CoAP, IoT Protocols: Comparison ° MQTT is a many-to-many communication protocol for passing messages between multiple clients through a central broker. ° It decouples producer and consumer by letting clients publish and having the broker decide where to route and copy messages . ° While MQTT has some support for persistence, it does best as a communications bus for live data. ° CoAP is, primarily, a one-to-one protocol for transferring state information between client and server. While it has support for observing resources, CoAP is best suited to a state transfer model, not purely event based. ° MQTT clients make a long-lived outgoing TCP connection to a broker. This usually presents no problem for devices behind NAT . ° CoAP clients and servers both send and receive UDP packets . In NAT environments, tunneling or port forwarding can be used to allow CoAP , or devices may first initiate a connection to the head-end. ° Both protocols have pros and cons, choosing the right one depends on your application.
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20 University of Pennsylvania, Computer and Information Science WPAN : Bluetooth and Bluetooth Smart (1/3) Technical specification Classic Bluetooth technology Bluetooth Low Energy technology Distance/range (theoretical max.) 100 m (330 ft) >100 m (>330 ft) Over the air data rate 1 3 Mbit/s 125 kbit/s 1 Mbit/s 2 Mbit/s Application throughput 0.7 2.1 Mbit/s 0.27 Mbit/s Security 56/128-bit and application layer user defined 128-bit AES with Counter Mode CBC- MAC and application layer user defined Robustness Adaptive fast frequency hopping, FEC , fast ACK Adaptive frequency hopping, Lazy Acknowledgement, 24-bit CRC, 32- bit Message Integrity Check Latency (from a non-connected state) Typically 100 ms 6 ms Minimum total time to send data (det. battery life) 100 ms 3 ms Voice capable Yes No Profile concept Yes Yes Primary use cases Mobile phones, gaming, headsets, stereo audio streaming, smart homes, wearables, automotive, PCs, security, proximity, healthcare, sports & fitness, etc. Mobile phones, gaming, smart homes, wearables, automotive, PCs, security, proximity, healthcare, sports & fitness, Industrial, etc. q Bluetooth LE (Low Energy): formally marketed as Bluetooth Smart q Bluetooth SIG predicts that by 2018 more than 90 percent of Bluetooth-enabled smartphones will support Bluetooth Low Energy Nokia, 2001 Bluetooth SIG, 2011
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21 University of Pennsylvania, Computer and Information Science WPAN : Bluetooth and Wi-Fi Coexistence (2/3) q Bluetooth frequency hops in 1 MHz carriers over 2402
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