iot

物联网是互联网、传统电信网等信息承载体，让所有能行使独立功能的普通物体实现互联互通的网络。在物联网上，每个人都可以应用电子标签将真实的物体上网联结，在物联网上都可以查出它们的具体位置。通过物联网可以用中心计算机对机器、设备、人员进行集中管理、控制，也可以对家庭设备、汽车进行遥控，以及搜索位置、防止物品被盗等，类似自动化操控系统，同时透过收集这些小事的数据，最后可以聚集成大数据，包含重新设计道路以减少车祸、都市更新、灾害预测与犯罪防治、流行病控制等等社会的重大改变，实现物和物相联。 物联网将现实世界数字化，应用范围十分广泛。物联网拉近分散的信息，统整物与物的数字信息，物联网的应用领域主要包括以下方面：运输和物流领域、工业制造、健康医疗领域范围、智能环境（家庭、办公、工厂）领域、个人和社会领域等，具有十分广阔的市场和应用前景。 物联网的基本构架由三层组成，分别是感知层、网络层和应用层。同时物联网也是基于目前的互联网OSI计算机网络体系结构，目前物联网面临的协议层威胁主要为，物理层、数据链路层、网络层、传输层，下边我们介绍一下各协议层易受到的攻击手段。 一、 物理层 1.拥塞攻击 通过发出无线干扰射频信号，实现破坏无线通信的目的，分为全频段拥塞干扰和瞄准式拥塞干扰。传感器网络可采用诸如跳频、调节节点占空比等技术防范拥塞攻击。 2.物理破坏 攻击者俘获一些节点，对它进行物理上的分析和修改

NB－IoT的全称是Narrow Band－Internet of Things，是基于蜂窝网络的窄带物联网技术，聚焦于低功耗广域网，支持物联网设备在广域网的蜂窝数据连接，可直接部署与LTE网络，可降低部署成本和实现平滑升级，是一种可在全球范围内广泛应用的一门物联网技术，他的特点可以概括为：广覆盖、低功耗、低成本、大连接等特性。 NB－IOT，是基于3GPP组织定义的国际标准，可在全球范围内部署，基于授权频谱的运营、NB－IOT技术来源于电信运营商，通信设备商以及芯片设计商的共同努力，早期，华为和沃达丰主导了NB－M2M技术，高通等联合主导的NB－CIOT技术，以及MTK等主导的NB－LTE技术，其中，NB－LTE以及NB－CIOT等之间存在着较大差异，终端无法平滑升级，相关非标准基站也存在退网风险。最后从大局出发，把NB－CIOT以及NB－LTE等相关技术融合，最终形成了NB－IOT国际标准。标准化工作的完成使全球运营商有了基于标准化的物联网专有协议，同时也标志着NB－IOT进入模块化商用阶段，在5G商用前的节点期以及未来5G商用后的低成本、低速率市场，NB－IOT将有很大的空间。 NB－IOT网络由以下单元组成： 1、核心网： 为了将物联网数据发送给应用，蜂窝物联网（CIoT）在EPS定义了两种优化方案：分别如下： CIoT EPS用户面功能优化（User Plane CIoT

IoT是Internet of Things的缩写，字面翻译是"物体组成的因特网"，准确的翻译应该为"物联网"。物联网(Internet of Things)又称传感网，简要讲就是互联网从人向物的延伸。 "物联网"(Internet of Things)指的是将各种信息传感设备，如射频识别装置、红外感应器、全球定位系统、激光扫描器等种种装置与互联网结合起来而形成的一个巨大网络。其目的是让所有的物品都与网络连接在一起，方便识别和管理。 具有代表意义的平台有PTC的Thingworx。 基本功能 IoT(Interoperability Test，互操作测试)是多厂商运营环境形成的技术基础。只有完成Iu接口的IoT，才能保证不同厂家的无线接入网与 核心网 互联互通，也只有完成Uu接口的IoT，才能保证每一款手机与无线接入系统之间的互联互通。从世界上已经完成的3G 设备选型 中可以看出，有一个非常明显的趋势就是，同一运营商大多选择二至三家厂商的设备，来组建自己的3G网络，形成多厂商设备的运营环境。所以，不同厂商之间的IoT(互操作测试)对3G时代就显得格外重要。IoT已经被摆在非常重要的战略地位，为此，信息产业部也特意组织所有参加信息产业部3G技术试验的系统厂家和手机厂家进行Uu/Iu接口的互操作IoT测试来验证各厂家系统之间和手机与系统之间的互通性。 IoT是一个持续的过程，众所周知

I am using Google IOT core with mongoose os. I wanted to update device connection status to firestore. But i am unable to find event which reports mqtt connection status to pub/sub like when device disconnects or reconnect i.e if device is offline or not. I am stuck on this problem for days.Any help will be appreciated Update As @devunwired mentioned in this response it is now possible to monitor Stackdriver logs for disconnect events. You must have at a minimum enabled INFO level logging on your project in IoT Core > Registries > [your registry] > Edit Registry > Select "Info" log level >

Could someone explain me what is going on within the Contiki-OS when it transmits an UDP packet? Here is the current consumption of my device in details running with the CC2538 chip: My question is: why it takes so long to transmit an UDP broadcast packet (about 250ms) knowing that theoretically at 250kbps the packet of 408 bits length should be transmitted in approximately 2ms? I'd understand if the transmission last lets say ten milliseconds but here the difference is huge. I use the example in contiki/examples/ipv6/simple-udp-rpl/broadcast-example.c Does anyone have an idea? By default,

I'm working on a CoAP app using Eclipse Californium that will declare explicitly only the root resource path, and the rest of the resources should be served and resolved through a wildcard /root/* just like on REST APIs or servlets. Is there any way to achieve that ? Ok I managed to do it. So after a few hours of digging on their Source code here is what ended up doing. Note that it works but it's only to show how it could be done, it's still a work on progress (I did this in 3h) as I removed some code like observer etc.. As soon as I have some time, I'll digg onto the Californium Api more and

When we are connecting to AWS IoT using wss protocol on ios version 12.1.1, we were able to connect to IoT successfully, but immediately we could see onError event being triggered from IoT and then the connection gets closed. It tries to reconnect again but without any luck. The error we are getting from IoT is "{IsTrusted : true}". We are not using any certificates, just using a profile access key and secret key. The same build is able to connect properly on ios 12.0.1, 12.1 IOS version:12.1.1(Not working version) AWS IOT SDK:2.0.0 iOS 12.1.1 introduced Apple's new Certificate Transparency

I have a C# desktop app. It connects to another PC on my network which is a UWP C# app. I am trying to send an image or 2 to my listening socket and to test this I get the listening socket to send me the image back. The trouble is that even though my server recieves all the bytes that were orginally sent the recieved image back to the client is not of the same size. To make this even more weird is sometimes the returned bytes are correct and I get the whole image and when I attempt to send 2 images the 1st one is OK and the 2nd one is not. Then it will/can revert back to no images being sent

I have been trying to connect my android application to AWS IoT portal. I have created an IAM account, which has a username and password. I have gone through the documentation but I could not see any proper guideline. I read somewhere that I can access the IoT devices through IAM/Cognito/using a certificate. Since I am an Android user I can't(I don't want to) use a device certificate. Can I use my IAM credentials to access my AWS IoT devices? I have downloaded all sample application and I could not find any working code. Or could someone explain how can I access AWS IoT portal from android app