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More DASH7 with MQTT

Patrick Burns
pat@haystacktechnologies.com
DASH7istheOppositeofTCP
DASH7’s networking technology is different than TCP/IP.

DASH7 is designed to handle small data, b...
MQTT Handles Connections “One at a Time”
3
• Client connects to MQTT server
(called a “Broker”)
• Client subscribes to som...
DASH7 Handles Connections in Groups
4
• DASH7 devices can do peer-to-
peer, multicast publishing
without a broker.
• QoS i...
DASH7 is Like Peer-to-Peer MQTT on a LAN
5
Broker
Unsubscribed

Client(s) Subscribed

Client(s)
1. Client publishes on

to...
A Proxy Can Integrate it with Cloud MQTT
6
Broker
Unsubscribed

Client(s) Subscribed

Client(s)
1. Client publishes on

to...
DASH7+MQTT Topic Naming Best Practices
7
Keep topic names below 16 chars.
‣ e.g. topic/this_is_too_long
‣ e.g. topic/titl ...
Example of MQTT-Tunneled DASH7 Query
8
1. Define topic that will address all the
endpoints you want to query. This example
...
UDP Data Exchange Within MQTT
9
• DASH7 can Publish (and receive) data
over MQTT in a variety of formats.
‣ ALP/NDEF
‣ CBO...
UDP Data Exchange Within MQTT
10
• Some common UDP Apps
‣ Trivial File Transfer Protocol (TFTP)
‣ Network Time Protocol (N...
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More on Using Haystack + DASH7 with MQTT

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More details on implementing broadcast/multicast messaging in IoT networking running Haystack + DASH7 networking software. Also implementing CBOR to enable queries over MQTT.

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More on Using Haystack + DASH7 with MQTT

  1. 1. More DASH7 with MQTT
 Patrick Burns pat@haystacktechnologies.com
  2. 2. DASH7istheOppositeofTCP DASH7’s networking technology is different than TCP/IP.
 DASH7 is designed to handle small data, but lots of devices at the same time. 
 TCP/IP handles large data, but only between two devices. 2
  3. 3. MQTT Handles Connections “One at a Time” 3 • Client connects to MQTT server (called a “Broker”) • Client subscribes to some MQTT “Topics” (these are like feeds). • When Broker is supplied new data on a given Topic, it forwards to all subscribers, one at a time. Broker Unsubscribed
 Client(s) Subscribed
 Client(s) 1. Client publishes on
 topic “X” to broker 1 2 3 4 2, 3, 4. Broker forwards Pub (1)
 to all clients subscribed to “X”, … one at a time.
  4. 4. DASH7 Handles Connections in Groups 4 • DASH7 devices can do peer-to- peer, multicast publishing without a broker. • QoS is dictated by the manner in which devices acknowledge (ACK) the Publisher. • It’s a lot like peer-to-peer MQTT. 1. Multicast 
 Publish 2, 3, 4. Synchronized ACKs 2 3 4
  5. 5. DASH7 is Like Peer-to-Peer MQTT on a LAN 5 Broker Unsubscribed
 Client(s) Subscribed
 Client(s) 1. Client publishes on
 topic “X” to broker 1 2 3 4 2, 3, 4. Broker forwards Pub (1)
 to all clients subscribed to “X”, … one at a time. 1. Multicast 
 Publish 2, 3, 4. Synchronized ACKs 2 3 4
  6. 6. A Proxy Can Integrate it with Cloud MQTT 6 Broker Unsubscribed
 Client(s) Subscribed
 Client(s) 1. Client publishes on
 topic “X” to broker 1 2 3 4 2, 3, 4. Broker forwards Pub (1)
 to all clients subscribed to “X”, … one at a time. DASH7 WAN/LAN Prox • A DASH7-MQTT Proxy can be just an MQTT Client that has a second interface on a DASH7 WAN or LAN. • It forwards pub and sub messages. • Additional sophistication can make it more efficient, although Topic naming best practices makes a big improvement with minimal sophistication.
  7. 7. DASH7+MQTT Topic Naming Best Practices 7 Keep topic names below 16 chars. ‣ e.g. topic/this_is_too_long ‣ e.g. topic/titl — (ok) DASH7 devices have limited communication bandwidth and memory. Queries work fastest on strings 16 characters or less. Use Path separators to define hierarchies based on data latency requirements. ‣ e.g. rt/temp ‣ e.g. noncrit/temp Here, we have real-time and “non-critical” groups of temperature sensors. This structure allows the proxy to be more intelligent. Wildcards are cool. ‣ e.g. rt/# ‣ e.g. #/temp — (not advisable for std MQTT) DASH7 querying supports wildcards and other search features. The second topic will bog down a normal MQTT network, but a DASH7-MQTT proxy can actually handle it without problems. The “ID/“ topic can be used for addressing ‣ e.g. ID/# — (broadcast) ‣ e.g. ID/0790 — (16bit LAN address) ‣ e.g. ID/DA5701A976B31F54 — (MAC) This is a way to tunnel direct device addressing through an MQTT proxy. (And yes, wildcards can be used with partial addressing)
  8. 8. Example of MQTT-Tunneled DASH7 Query 8 1. Define topic that will address all the endpoints you want to query. This example looks for devices containing real-time temperature data.
 (note: we can set topics any way we want when we write the system specification). 2. Put a MQTT response params in the payload, with JSON or CBOR. The endpoints will publish-back their data on this topic & QoS. 3. Endpoints with rt/temp data available will publish it back. Data format is CBOR. rt/temp { “topic”:”hub/rt/temp”, “qos”:1 } CBOR examples:
 http://cbor.io/tools.html
  9. 9. UDP Data Exchange Within MQTT 9 • DASH7 can Publish (and receive) data over MQTT in a variety of formats. ‣ ALP/NDEF ‣ CBOR ‣ Proprietary Application data • In all cases, data is binary format. • ALP is the normal way to frame data. ‣ An ALP frame is shown to the right ‣ More info on specifics: 
 http://www.indigresso.com/wiki/doku.php? id=opentag:alpapi ALP frames are very simple: ‣ Flags (for message fragmentation) ‣ Payload Length (size of data in bytes) ‣ ALP-ID (maps to a UDP destination port) ‣ ALP-CMD (application dependent usage) ‣ Payload is UDP application data DASH7 supports UDP applications as well as some UDP-like applications optimized for DASH7. DASH7-optimized UDP protocols use ALP-CMD to define protocol functions. Native UDP protocols use ALP-CMD as the UDP source port number.
  10. 10. UDP Data Exchange Within MQTT 10 • Some common UDP Apps ‣ Trivial File Transfer Protocol (TFTP) ‣ Network Time Protocol (NTP) ‣ Lightweight Directory Services Protocol (LDAP) ‣ Constrained Application Protocol (CoAP) ‣ MQTT itself also can work on UDP • UDP Apps Unique to DASH7 ‣ Mode 2 Batch File Protocol
 Point-to-Point and Point-to-Multipoint protocol for reading, writing, or querying data from the filesystem. 
 (similar to cat & < / > operators in UNIX) ‣ Confit (i.e. “Configure It”)
 Point-to-Point and Point-to-Multipoint protocol for transferring bulk updates, such as Firmware Updates. Almost identical to TFTP, except it works at very low power on the device endpoint. • All of these applications can be tunneled over MQTT, to DASH7! • You can use MQTT topics to achieve multicast addressing! • There is a file on the device for storing dynamic CBOR CDDL!

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