MQTT-SN works in a similar manor to MQTT and normally requires a connection to a broker/gateway before it can exchange messages. MQTT-SN uses UDP which is a connectionless protocol the connection is actually a virtual connection. However because MQTT-SN uses UDP , MQTT-SN also provides the ability to publish message without requiring a connection to a broker or gateway using a message with a QOS of 3 or -1.
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Internet related articles and tutorials
Publishing MQTT messages Using the Node.js Client
In this tutorial we look at publishing messages using the node.js MQTT client. When you publish a message in MQTT you need to specify the Topic Message Retain QOS (0,1,2) Properties (MQTT v5)
Continue readingIPv6 Explained for Beginners
IPV6 has been developed to replace IPV4 which is running out of addresses. Although it has been around almost 10 years it is still not widely deployed and supported. However adoption rates are increasing rapidly and IPv6 traffic crossed the 10% threshold in February 2016 (wiki) .
Continue readingDNS Zones and Zone Files Explained
DNS is comprised logically of Domains but physically of zones. A domain is a logical division of the DNS name space whereas a zone is physical, as the information is stored in a file called a zone file.
Continue readingHost Name Resolution Methods Explained
On computer and home networks when you type an Internet address into a web browser the web browser needs to convert that web address into an IP address. To do that it uses the the name resolution processes provided by the host machine. There are several ways that the host machine can resolve a domain name. The main ones are:
Continue readingDNS Lookups Explained
In this tutorial we will examine what happens when you use DNS to lookup or resolve a domain name to an IP address. We look at how DNS lookups work, and the exact process involved when looking up a domain name. We follow the client DNS query as it is processed by the various DNS servers in the response chain. Before we start it might be useful to compare DNS name resolution with a standard question and answer that takes place in everyday life.
Continue readingSSL and SSL Certificates Explained For Beginners
Secure Sockets Layer (SSL) and Transport Layer security (TLS ) are protocols that provide secure communications over a computer network or link. They are commonly used in web browsing and email. In this tutorial we will look: TLS and SSL Public and Private keys Why we need certificates and what they do How to get a digital certificate and understand the different common certificate types. What is TLS TLS is based on SSL and was developed as a replacement in response to known vulnerabilities in SSLv3.
Continue readingUnderstanding The Domain Name Structure
To understand the domain name structure you really need to understand the problem the structure was meant to solve. The Domain Name Structure and Domain Name System were developed to organise and find the IP addresses of Computers on large distributed networks.
Continue readingBeginners Guide to Bluetooth
Bluetooth is a wireless networking protocol (like WIFI) designed to quickly and automatically connect devices like printers, PDAs, Cameras etc to computers and to each other without wires. Common Bluetooth applications are: Connecting mobile phones to each other to exchange pictures,ring tones, music etc Connecting computer peripherals like mice, keyboards, printers etc to a computer. Connecting headsets to mobile phones for hands free operation (Bluetooth car kits)
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