bt 4.2 phone supports 4.0 devices. Technical data of various protocols
Bluetooth 5.0 became a reality. Compared to Bluetooth 4.0 a new version It has twice the capacity, four times the range and a number of other improvements. Let's look at the advantages of Bluetooth 5.0 over its predecessors, including an example CPU CC2640R2F from Texas Instruments.
The popularity of the Bluetooth 4 protocol version, as well as some of its limitations, became the reasons for the creation of the next Bluetooth 5 specification. The developers set themselves a number of goals: expanding the range, growth bandwidth when sending broadcast packets, improving noise immunity, and so on.
Now that the first devices with Bluetooth 5 have begun to appear, users and developers rightly have questions: which of the previously stated promises have become reality? How much have the range and data transfer speed increased? How did this affect consumption levels? How has the approach to generating broadcast packets changed? What improvements have been made to improve noise immunity? And of course, main question— is there backward compatibility between Bluetooth 5 and Bluetooth 4? Let's answer these and some other questions and consider the main advantages of Bluetooth 5.0 over its predecessors, including using the example of a real processor with Bluetooth 5.0 support produced by the company Texas Instruments.
Let's get started Bluetooth review 5.0 with an answer to the most frequently asked question about backward compatibility with Bluetooth 4.x
Is Bluetooth 5.0 backwards compatible with Bluetooth 4.x?
Yes, it does. Bluetooth 5 adopts most of the features and extensions of Bluetooth 4.1 and 4.2. For example, Bluetooth 5 devices retain all the data security improvements of Bluetooth 4.2 and support the LE Data Length Extension. It is worth recalling that thanks to the LE Data Length Extension, starting with Bluetooth 4.2, the packet data unit (PDU) size at established connection can be increased from 27 to 251 bytes, which allows you to increase the data exchange speed by 2.5 times.
Due to the large number of differences between protocol versions, the traditional mechanism for negotiating parameters between devices when establishing connections is retained. This means that before they start exchanging data, the devices “get to know each other” and determine the maximum frequency of data transmission, the length of messages, and so on. In this case, Bluetooth 4.0 parameters are used by default. The transition to Bluetooth 5 parameters occurs only if, during the pairing process, it turns out that both devices support a later version of the protocol.
Speaking about the tools that are already available to developers, it is worth noting new processor CC2640R2F and free BLE5-Stack from Texas Instruments. To the delight of developers, BLE5-Stack is based on previous version BLE-Stack, and changes in its use affected only the new features of Bluetooth 5.0.
How has the data transfer speed increased in Bluetooth 5?
Bluetooth 5 uses wireless connection with a physical data transfer rate of up to 2 Mbit/s, which is twice as high as Bluetooth 4.x. It is worth noting here that the effective data exchange rate depends not only on the physical capacity of the transmission channel, but also on the ratio of service and useful information in a package, as well as from associated “overhead” costs, for example, loss of time between packages (Table 1).
Table 1. Communication speed for different versionsBluetooth
In versions Bluetooth 4.0 and 4.1, the physical bandwidth of the channel was 1 Mbit/s, which, with a PDU data packet length of 27 bytes, made it possible to achieve exchange rates of up to 305 kbit/s. Bluetooth 4.2 introduced the LE Data Length Extension. Thanks to it, after establishing a connection between devices, it became possible to increase the packet length to 251 bytes, which led to an increase in data exchange speed by 2.5 times - up to 780 kbit/s.
Bluetooth version 5 retains support for LE Data Length Extension, which, together with an increase in physical throughput to 2 Mbit/s, allows data exchange speeds of up to 1.4 Mbit/s to be achieved.
As practice shows, such acceleration of data transfer is not the limit. For example, the CC2640R2F wireless microcontroller is capable of operating at speeds up to 5 Mbps.
It is worth mentioning the common misconception that the increase in throughput to 2 Mbit/s was achieved by reducing the range. Of course, physically the transceiver chip (PHY) when operating at a frequency of 2 Mbit/s has 5 dBm less sensitivity than when operating at a frequency of 1 Mbit/s. However, in addition to sensitivity, there are other factors that contribute to increasing the range, for example, the transition to data encoding. For this reason, all other things being equal, Bluetooth 5 turns out to be more reliable and has a longer range compared to Bluetooth 4.0. This is discussed in detail in one of the following sections of the article.
How to enable high speed data transfer mode in Bluetooth 5?
When establishing a connection between two Bluetooth devices, Bluetooth 4.0 settings are initially used. This means that at the first stage the devices exchange data at a speed of 1 Mbit/s. Once the connection is established, the Bluetooth 5.0-enabled master can begin the PHY Update Procedure, the purpose of which is to establish maximum speed 2 Mbit/s. This operation will only succeed if the slave also supports Bluetooth 5.0. Otherwise, the speed remains at 1 Mbit/s.
For developers who have previously used the Texas Instruments BLE-Stack, the good news is that the new BLE5-Stack provides a single function, HCI_LE_SetDefaultPhyCmd(), to perform this procedure. Thus, when switching to Bluetooth 5.0, users of TI products will not have problems with the initial initialization. Also useful for developers will be an example posted on the GitHub portal, which allows you to evaluate the operation of two CC2640R2F microcontrollers operating as part of CC2640R2 LaunchPads in High Speed and Long Range modes.
How has the range of Bluetooth 5 increased?
The Bluetooth 5.0 specification states that the range is four times greater than Bluetooth 4.0. This is a rather subtle issue that is worth dwelling on in more detail.
Firstly, the concept of “four times” is relative and is not tied to a specific range in meters or kilometers. The fact is that the radio transmission range strongly depends on a number of factors: the state of the environment, the level of interference, the number of simultaneously transmitting devices, and so on. As a result, not a single manufacturer, as well as the developer of the Bluetooth SIG standard itself, provides specific values. The increase in range is measured in comparison with Bluetooth 4.0.
For further analysis, it is necessary to perform some mathematical calculations and estimate the radio channel power budget. When using logarithmic values, the radio channel budget (dB) is equal to the difference between the transmitter power (dBm) and the receiver sensitivity (dBm):
Radio channel budget = powerT X(dBm) – sensitivityR X(dBm)
For Bluetooth 4.0, the standard receiver sensitivity is -93 dBm. If we assume the transmitter power is 0 dBm, then the budget is 93 dB.
Quadrupling the range would require a 12 dB increase in budget, resulting in a value of 105 dB. How is this value supposed to be achieved? There are two ways:
- increasing transmitter power;
- increasing the sensitivity of receivers.
If you follow the first path and increase the transmitter power, this will inevitably cause an increase in consumption. For example, for the CC2640R2F, switching to an output power of 5 dBm leads to an increase in current consumption to 9 mA (Figure 1). At 10 dBm the current will increase to 20 mA. This approach does not look attractive to most wireless devices battery-powered and not always suitable for IoT, which is precisely the area Bluetooth 5.0 was primarily aimed at. For this reason, the second solution seems preferable.
To increase the sensitivity of the receiver, two methods are proposed:
- reduction in transmission speed;
- use of Coded PHY data encoding.
Reducing the data rate by a factor of eight theoretically increases receiver sensitivity by 9 dB. Thus, the desired value is only 3 dB short.
The required 3 dB can be achieved using additional Coded PHY coding. Previously, in Bluetooth 4.x versions, the bit encoding was unambiguous 1:1. This means that the data stream was directly sent to the differential demodulator. In Bluetooth 5.0, when using Coded PHY, there are two additional transmission formats:
- with 1:2 encoding, in which each bit of data is associated with two bits in the radio data stream. For example, a logical "1" is represented as a sequence of "10". In this case, the physical speed remains equal to 1 Mbit/s, and the real data transfer speed drops to 500 kbit/s.
- With 1:4 encoding. For example, a logical "1" is represented by the sequence "1100". The data transfer rate is reduced to 125 kbit/s.
The described approach is called Forward Error Correction (FEC) and allows errors to be detected and corrected on the receiving side, rather than requiring packets to be retransmitted, as was the case in Bluetooth 4.0.
On paper everything looks good. It remains only to find out how these theoretical calculations correspond to reality. As an example, let's take the same microcontroller CC2640R2F. Thanks to various improvements and new Bluetooth 5.0 modulation modes, the transceiver of this processor has a sensitivity of -97 dBm at 1 Mbps and -103 dBm when using Coded PHY and 125 kbps. Thus, in the latter case, only 2 dBm is missing from the level of 105 dB.
To evaluate the range of the CC2640R2F, engineers from Texas Instruments conducted a field experiment in Oslo. However, from the point of view of noise level environment in this experience it could not be called “friendly”, since the business part of the city was in close proximity.
To obtain a power budget greater than 105 dB, it was decided to increase the transmitter power to 5 dBm. This allowed us to achieve an impressive final value of 108 dBm (Figure 2). When performing the experiment, the range was 1.6 km, which is a very impressive result, especially considering minimum level consumption of radio transmitters.
How has the approach to Bluetooth 5 broadcast messages changed?
Previously, Bluetooth 4.x used three dedicated data channels to establish connections between devices (37, 38, 39). With their help, devices found each other and exchanged service information. It was also possible to transmit broadcast data packets over them. This approach has disadvantages:
- at large quantities active transmitters, these channels can simply be overloaded;
- All more devices uses broadcast messages without establishing a point-to-point connection. This is especially important for the Internet of Things IoT;
- the new Coded PHY coding system will require eight times more time to establish a connection, which will additionally load broadcast channels.
To solve these problems in Bluetooth 5.0, it was decided to move to a scheme in which data is transmitted on all 37 data channels, and service channels 37, 38, 39 are used to transmit pointers. The pointer refers to the channel over which the broadcast message will be transmitted. In this case, the data is transmitted only once. As a result, it is possible to significantly relieve the load on service channels and eliminate this bottleneck.
It is also worth noting that now the data length of a broadcast packet can reach 255 bytes instead of 6...37 bytes PDU in Bluetooth 4.x. This is extremely important for IoT applications, as it allows minimizing transmission overhead and eliminating connections, thereby reducing consumption.
Does Bluetooth 5 support Mesh networks?
Texas Instruments Solutions for Bluetooth 5
One of the very first microcontrollers with Bluetooth 5.0 was the high-performance CC2640R2F processor manufactured by Texas Instruments.
The CC2640R2F is built on a modern 32-bit ARM Cortex-M3 core with operating frequency up to 48 MHz. The operation of the radio transmitter is controlled by the second 32-bit ARM Cortex-M0 core (Figure 3). In addition, the CC2640R2F features rich digital and analog peripherals.
The advantage of the CC2640R2F microcontroller is also its low consumption level (Table 2). This applies to all operating modes. For example, in active mode when receiving data over the radio channel, the consumption is 5.9 mA, and when transmitting - 6.1 mA (0 dBm) or 9.1 mA (5 dBm). When switching to sleep mode, the supply current drops completely to 1 µA.
The combination of three important qualities such as Bluetooth 5.0 support, low consumption and high peak performance makes the CC2640R2F a very interesting solution for the Internet of Things. At the same time, using this microcontroller, you can create the entire range of IoT devices: autonomous sensors that operate for several years on a single battery, bridges between an additional control processor and a Bluetooth 5.0 channel, complex applications that require high computing power.
Table 2. Wireless microcontroller consumptionCC2640 R2 Fwith the supportBluetooth 5
| Operating mode | Parameter | Value (at Vcc = 3 V) |
|---|---|---|
| Active Computing | µA/MHz ARM® Cortex®-M3 | 61 µA/MHz |
| Coremark/mA | 48,5 | |
| Coremark at 48 MHz | 142 | |
| Radio exchange | Peak receive current, mA | 5,9 |
| Peak current during transmission, mA | 6,1 | |
| Sleeping mode | Sensor controller, µA/MHz | 8,2 |
| Sleep mode with RTC enabled and memory retention, mA | 1 |
To quickly get started with the CC2640R2F, Texas Instruments has prepared a traditional development kit (Figure 4). Using a couple of such devices, you can evaluate the speed and range of radio transmission via Bluetooth 5.0. To do this, you can use ready-made examples or create own application based on the free BLE 5 stack 1.0 protocol (www.ti.com/ble).
Conclusion
The new version of the Bluetooth 5.0 protocol is focused on maximum compliance with the needs of the Internet of Things (IoT). Compared to the Bluetooth 4.0 version, it has a number of qualitative improvements:
- data transfer speed has doubled and reached 2 Mbit/s;
- transmission range has increased fourfold due to Coded PHY and Forward Error Correction (FEC) data encoding;
- throughput broadcast messages increased 8 times.
In addition, Bluetooth 5.0 provides backwards compatible with Bluetooth 4.x devices and also supports most extensions later versions protocol.
You can evaluate the capabilities of Bluetooth 5.0 now using tools produced by Texas Instruments. The company produces a high-performance and low-power microcontroller CC2640R2F, provides a free BLE 5 stack 1.0 and many ready-made examples for the LAUNCHXL-CC2640R2 debugging kit.
Literature
- Bluetooth Core Specification 5.0 FAQ. 2016. Bluetooth SIG.
Bluetooth logo
Bluetooth technology is a well-established communications standard for short-range wireless communications, connecting devices via a single, universal, short-range radio link. Initially, the range of the radio interface was set at 10 meters, but now the Bluetooth specifications have already defined a second zone - about 100 m. There is no need for the connected devices to be in line of sight to each other. In addition, devices interacting with each other can be in motion.
origin of name
The technology got its name in honor of the Scandinavian king Harald Bluetooth, who became famous for uniting the Danish and Norwegian lands. In 1994, Ericsson erected a monument to Harald in the Swedish city of Lund, refreshing the memory of descendants of episodes of world history and giving the name of the monarch to a new wireless technology for mobile communications.
Creation and development of technology
1994
2014: Bluetooth 4.2
In early December 2014, the Bluetooth Special Interest Group released technical specification wireless data transmission technology Bluetooth 4.2. The standard has been significantly improved in terms of speed characteristics and information security.
They promise to officially add the ability to directly connect to the Internet to the standard. That is, devices with Bluetooth 4.2 support will be able not only to directly interact with each other, but also to connect to the Internet (thanks to support for the IPv6/6LoWPAN protocol) through appropriate access points.
The key idea behind the development of the standard is to using Bluetooth it was possible to connect any devices with each other. That is, in essence, we're talking about about the so-called Internet of Things (IoT). Harvard Business Review and Goldman Sachs estimate that 28 billion “things” will be connected to the Internet of Things in 2020. Bluetooth developers are laying claim to a certain (apparently significant) share of this pie. Considering the fact that bluetooth technology quite energy efficient, the chances of success are high.
The Bluetooth specification has also become more secure. From now on, active Bluetooth devices will be more difficult to track or intercept the corresponding traffic until the user independently allows this in the settings. New Bluetooth gadgets will be able to transmit data at a speed 2.5 times faster than using the previous version of the protocol. This was achieved by increasing the size of the standard data packet.
The first devices supporting Bluetooth 4.2 are expected to be introduced in early 2015. Manufacturers have not yet announced exact dates.
2016: Bluetooth 5
On June 17, 2016, the Bluetooth Special Interest Group (Bluetooth SIG) consortium presented next version Bluetooth standard - 5. Its appearance on the commercial market is planned for late 2016 or early 2017.
Bluetooth 5 will offer four times the range, twice the higher speed data transmission and eight times increased communication capacity of contactless radio transmission.
Bluetooth Contacts Today and Tomorrow, (2016)
This is the first significant update to the standard since 2009, when Bluetooth 4 hit the airwaves.
As the capacity of radio messages increases, it will become possible to transmit more complex, intelligent information. This will change the way Bluetooth devices transmit information. The model of creating a couple will become a thing of the past. In its place will come the so-called contactless connection, say the Bluetooth SIG.
Global shipments of Bluetooth-enabled devices will reach 371 million by 2020, according to ABI Research. Bluetooth 5's eight-fold increase in radio capacity will enable the proliferation of location-based beacons and services in automation, industrial and enterprise sectors.
| There are 8.2 billion Bluetooth devices in use around the world today. Thanks to further development Bluetooth, including Bluetooth 5 release, by 2020 this technology will be present in one third of all running devices Internet of things.
|
2017
Bluetooth virus BlueBorne was able to open a nearby device in 10 seconds
Experts from Armis Labs discovered in September 2017 a virus that can spread and infect smartphones and other devices via Bluetooth without user participation, writes Wired.
This hacking method was given the name BlueBorne, it uses vulnerabilities in the Bluetooth protocol, is transmitted from one device to another, and the virus operates in such a way that users do not suspect that their system is hacked.
According to Armis Labs research director Ben Seri, BlueBorne could lead to the same mass infection, like the WannaCry virus. Infection can occur within ten seconds after scanning nearby devices with the bluetooth program will detect a vulnerability.
Three operating system manufacturers have already announced that they have released updates to eliminate the vulnerabilities. Apple said that BlueBorne is not harmful to systems running iOS 10 or newer, Windows released a corresponding “patch” back in July, and Google released an update in August, but its installation may take some time. Linux is also developing a way to protect against the new virus, but under the control of this operating system There are many devices running (for example, TVs) that either do not receive updates or do so too rarely.
Bluetooth Mesh
In mid-July, the Bluetooth SIG organization, which develops wireless technology, announced the Bluetooth multi-cell format.
The presented Bluetooth standard uses virtual network from many cells. Data in the network is transmitted from one cell to another until it reaches the destination.
Sample bluetooth mesh network diagram
Bluetooth standard Mesh can be used, for example, if you need to send data from a sensor in one room to a computer in another in the same apartment. Information will be transmitted through intermediate nodes: smartphones, tablets, computers and any other devices that support the technology.
Including Bluetooth Mesh can be useful in organizing the interaction of Internet of Things (IoT) devices for a smart home. Sensors and sensors will be able to exchange data with the central node on long distances. A similar signal sent directly to the receiver would require more energy than transmission to the nearest cell. As a result, IoT devices will be able to operate longer on a single battery without needing to be connected via wire.
The peculiarity of Bluetooth Mesh is that it does not require changes to the hardware of the device. The standard can work on all devices with Bluetooth 4.0 and 5.0, but a software update will be required.
Toshiba Bluetooth Low Energy Product Series Supports Bluetooth Mesh Standard
Toshiba's mesh network solutions provide extended range and improved reliability for Bluetooth communications.
According to MYCE, a confidential document predicts that Bluetooth LE, or Bluetooth Low Energy, is likely to be one of the major trends focused on extending battery life for ever-smaller devices.
"Of the major features planned for debut, the most interesting is positioning functionality, which could pair well with Apple's recent acquisition of WiFiSLAM, a small firm that created Wi-Fi-based 'indoor GPS' technology," AppleInsider explained.
“The new iteration of Bluetooth is expected to be ready in 2014 and will be based on an expanded package structure that allows direction finding, motion tracking and “internal GPS” positioning.
Meanwhile, engineers are also working on integrating IPv6 into Bluetooth LE - this would allow each Bluetooth-enabled device to be assigned a unique identifier (IP address), allowing real-world objects to be discovered and accessible over the Internet.
Not surprisingly, future versions of Bluetooth will also offer more high speed transmissions, lower power consumption, extended range and increased privacy.
Competing technologies
- Wi-Fi Direct (Wi-Di) protocol wireless transmission data, which is built on Wi-Fi base, but easier to configure. Its main advantages are the connection speed is 12 times higher than Bluetooth, the communication range is up to 100 meters, and most importantly, good security.
- Visible Light Communication (VLC) - in 2011, using light waves emitted by white LED sources that are modulated at a specific frequency, scientists in Germany were able to transfer a file from one computer to another at a speed of 10 megabits per second. No cables or wireless routers. Only light waves, the vibrations of which are invisible to the human eye. The range of the technology, which is called Visible Light Communication or simply VLC, is about 5 meters. The developers emphasize the incredible security of data transmission from interception.
No matter what brand your smartphone, tablet or laptop belongs to, they always have General characteristics. One of these characteristics is the version Bluetooth module. Last current version"Bluetooth" was introduced back in late 2013 Bluetooth 4.1. Today the characteristics of the next generation of wireless data transfer protocol were announced - Bluetooth 4.2.
The Bluetooth 4.2 standard will allow direct connection to an Internet access point, without requiring a complex connection through intermediate devices. This is especially in demand functional feature will be in the environment of the so-called “ internet of things", which provides the ability for all kinds of items in the house (smart kettles, refrigerators, microwave ovens, etc.) to access the World Wide Web.
Bluetooth 4.2 has become safer– tracking and interception of data without creating a pair is impossible: the protocol’s operating algorithm simply does not allow accidental detection or tracking. The issue of security is relevant for the increasingly popular wearable electronics.
The data transfer speed has also increased significantly. Compared to its predecessor, Bluetooth 4.2 allows you to transfer data to 2.5 times faster, and the size of Bluetooth Smart packages has been increased 10 times. The developers have also reduced the level of energy consumption. The first devices with Bluetooth 4.2 installed will appear at the beginning of 2015. Apple, as a rule, keeps up with the times and the following iPhone generation may well acquire a new protocol. [bluetooth]
Hello.
On December 3, 2014, the Bluetooth SIG officially announced the specification bluetooth versions 4.2.
The press release identifies 3 main innovations:
- increasing the speed of data reception and transmission;
- ability to connect to the Internet;
- improving privacy and security.
In this article I want to tell you how these 3 points are implemented. Anyone interested is welcome.
Everything described below applies only to BLE, let's go...
1. Increasing the speed of receiving and transmitting user data.
The main disadvantage of BLE was the low data transfer speed. Although no matter how you look at it, BLE was originally invented to save the energy of the source powering the device. And in order to save energy, you need to get in touch intermittently and transfer a little data. However, all the same, the entire Internet is filled with indignation about the low speed and questions about the possibility of increasing it, as well as increasing the size of the transmitted data.
And with the advent of version 4.2, Bluetooth SIG announced an increase in transmission speed by 2.5 times and the size of the transmitted packet by 10 times. How did they achieve this?
Let me tell you that these 2 numbers are related to each other, namely: the speed has increased because the size of the transmitted packet has increased.
Let's look at the PDU (protocol data unit) of the data channel: 
Each PDU contains a 16-bit header. So, this header in version 4.2 is different from the header in version 4.1.
Here is the version 4.1 header:
And here is the header of version 4.2:
Note: RFU (Reserved for Future Use) - the field designated by this abbreviation is reserved for future use and is filled with zeros.
As we can see, the last 8 bits of the header are different. The Length field is the sum of the payload lengths and the MIC (Message Integrity Check) field found in the PDU (if the latter is enabled).
If in version 4.1 the “Length” field has a size of 5 bits, then in version 4.2 this field has a size of 8 bits.
From here it is easy to calculate that the “Length” field in version 4.1 can contain values in the range from 0 to 31, and in version 4.2 in the range from 0 to 255. If maximum values subtract the length of the MIC field (4 octets), we get that there can be 27 and 251 octets of useful data for versions 4.1 and 4.2, respectively. In fact, the maximum amount of data is even less, because The payload also contains L2CAP (4 octets) and ATT (3 octets) service data, but we will not consider this.
Thus, the size of transmitted user data has increased approximately 10 times. As for the speed, which, for some reason, increased not 10 times, but only 2.5 times, then we cannot talk about a proportional increase, because everything also depends on the guarantee of data delivery, because guaranteeing the delivery of 200 bytes is a little more difficult than 20.
2. Possibility of connecting to the Internet.
Perhaps the most interesting innovation is why Bluetooth SIG announced that version 4.2 makes the Internet of Things (IoT) better thanks to this feature.Back in version 4.1, L2CAP added the “LE Credit Based Flow Control Mode” mode. This mode allows you to control the data flow using the so-called. credit based scheme. The peculiarity of the scheme is that it does not use signaling packets to indicate the amount of data being transferred, but requests from another device a credit for a certain amount of data to be transferred, thereby speeding up the transfer process. In this case, each time the receiving side receives a frame, it decreases the frame counter, and when the last frame is reached, it can break the connection.
3 new codes have appeared in the list of L2CAP commands:
- LE Credit Based Connection request – request for connection according to the credit scheme;
- LE Credit Based Connection response – response to connection based on the credit scheme;
- LE Flow Control Credit – message about the possibility of receiving additional LE frames.
In the package “LE Credit Based Connection request” 
there is an “Initial Credits” field 2 octets long, indicating the number of LE frames that the device can send at the L2CAP level.
In the response package “LE Credit Based Connection response” 
the same field indicates the number of LE frames that another device can send, and the “Result” field also indicates the result of the connection request. A value of 0x0000 indicates success, other values indicate an error. Specifically, a value of 0x0004 indicates that the connection was refused due to lack of resources.
Thus, already in version 4.1 it became possible to transfer a large amount of data at the L2CAP level.
And now, almost simultaneously with the release of version 4.2, the following is published:
- service: “IP Support Service” (IPSS).
- IPSP (Internet Protocol Support Profile) profile, which defines support for transmitting IPv6 packets between devices that have BLE.
The profile defines the following roles:
- router role – used for devices that can route IPv6 packets;
- node role (Node) – used for devices that can only receive or send IPv6 packets; have service discovery functionality and have an IPSS service that allows routers to discover this device;
Devices with the router role that need to connect to another router can have the host role.
Oddly enough, the transmission of IPv6 packets is not part of the profile specification, and is specified in the IETF RFC “Transmission of IPv6 packets over Bluetooth Low Energy”. This document identifies another interesting point, namely, that when transmitting IPv6 packets, the 6LoWPAN standard is used - this is a standard for interaction using the IPv6 protocol over low-power wireless personal networks of the IEE 802.15.4 standard.
Look at the picture: 
The profile specifies that IPSS, GATT, and ATT are used only for service discovery, and GAP is used only for device discovery and connection establishment.
But the one highlighted in red just means that packet transmission is not included in the profile specification. This allows the programmer to write his own implementation of packet transmission.
3. Improved privacy and security.
One of the responsibilities of the Security manager (SM) is to pair two devices. The pairing process creates keys that are then used to encrypt communications. The pairing process consists of 3 phases:- exchange of information about pairing methods;
- generation of short-term keys (Short Term Key (STK));
- key exchange.
- generation of short-term keys (Short Term Key (STK)) called “LE legacy pairing”
- generation of long-term keys (Long Term Key (LTK)) called “LE Secure Connections”
In this regard, in addition to the 3 existing functions, 5 more functions have appeared in the cryptographic toolbox of the security manager, and these 5 are used only to service the new pairing process “LE Secure Connections”. These functions generate:
- LTK and MacKey;
- confirmatory variables;
- authentication check variables;
- 6-digit numbers used for display on connected devices.
So, if during pairing in the 2nd phase using the “LE legacy pairing” method, 2 keys were generated:
- Temporary Key (TK): 128-bit temporary key used to generate STK;
- Short Term Key (STK): 128-bit temporary key used to encrypt the connection
- Long Term Key (LTK): A 128-bit key used to encrypt subsequent connections.
- preventing tracking, because Now, thanks to “Numeric Comparison”, it is possible to control the ability to connect to your device.
- improving energy efficiency, because no longer requires additional energy to re-generate keys on each connection.
- Industry standard encryption to ensure sensitive data.
4. Is it already possible to touch?
Yes, I have.
NORDIC Semiconductor has released the "nRF51 IoT SDK" which includes a stack, libraries, examples and APIs for the nRF51 series devices. This includes:
- nRF51822 and nRF51422 chips;
- nRF51 DK;
- nRF51 Dongle;
- nRF51822 EK.