Content for  TR 22.821  Word version:  16.1.0

Use of 3GPP technology for a 5G PVN allows expansion from only 5G LAN-type services to also encompass services previously considered similar to what a PBX might provide. This is a significant advantage for a multi-site enterprise. For example, in a multi-site enterprise, all sites could be connected to a common 5G PVN for 5G LAN-type services and also use the 5G PVN to communicate among employees across sites using a private addressing scheme that simplifies addressing within the enterprise. The common 5G LAN-type services allow employees to enjoy the same access to all of their files, applications, equipment, and colleagues regardless of which site they might be at physically. The private addressing scheme allows employees on the 5G PVN to contact each other directly using the simplified corporate addresses. Use of a private addressing scheme within a 5G PVN does not preclude a UE from communicating outside of the 5G PVN using its public address.

An large enterprise with many office sites establishes a 5G PVN to provide 5G LAN-type services at all enterprise office locations. To facilitate communication between the office sites, the enterprise provides its own addressing scheme for UEs that are authorized as members of the 5G PVN. An appropriate address is assigned to every UE that is authorized for use on the 5G PVN. Once the address is established, that UE can be reached by other UEs that are members of the 5G PVN, regardless of location, with that address. This allows, for example, an employee who is away from her office to send a file from her smart phone to the office printer using the private address provided for the printer. Employees at different sites can also call, text, or email each other using the private addresses. When an employee needs to communicate with a UE that is not a member of the 5G PVN, the private address is not used.

[PR 5.20.3-1] [PR 5.20.3-2]

Multiple use cases in manufacturing apply sequence-control mechanisms with highly deterministic and periodic (or cyclic) message exchanges that have stringent requirements on latency, reliability and isochronism. The following use cases discussed in Communications for Automation in Vertical Domains (TR 22.803) fall into this category:

• Motion control,
• Control-to-control communications,
• Mobile robots,
• Massive wireless sensor networks.

These use cases rely on industrial Ethernet for communications among the various nodes such as sensors, actuators, controllers, bridges and gateways. The Ethernet network might support different, use-case- or deployment-specific topologies such as ring, star, tree or mesh. From the Ethernet perspective, the various communications nodes group into end stations and bridges. The Time-Sensitive Networking (TSN) framework establishes a set of specifications to meet the strict performance requirements of high performance manufacturing. For the present use cases, the following TSN features are relevant:

• Clock synchronization among all Ethernet nodes (IEEE 802.1AS, which leverages Precision-Time-Protocol PTP defined by IEEE 1588)
• Time-aware scheduling for hard real-time (RT) traffic (IEEE 802.1Qbv, integrated into IEEEE 802.1Q-2014)
• Frame pre-emption to manage coexistence of less performance-constraint traffic with hard-RT traffic (IEEE 802.1Qbu, integrated into IEEE 802.1Q-2014).

IEEE 802.1AS achieves network-wide clock synchronization by propagating a synchronization message with a timestamp generated by a grand master (GM) hop-by-hop across the network (Figure 1). Bridges receive time information on one port and propagate it on all other ports. In addition, the aggregate delay of the Synch message since departure from the GM is updated at each hop and forwarded, too. The update includes link delay, which is due to propagation across the link, as well as residence delay, which is due to processing inside the bridge. IEEE 802.1AS determines link-delay via an RTT-measurement on Ethernet layer, which leverages precise timing information from the underlying physical layer. The IEEE 802.1AS specification assumes that the link delay is symmetric and deterministic. In case it is not symmetric, adjustments have to be taken on lower layers to make it appear symmetric to IEEE 802.1AS. Since the GM can reside on any node in the Ethernet topology, propagation of IEEE 802.1AS messages and delay measurements may have to be supported in both directions of the Ethernet link.

Time-aware scheduling defined by IEEE 802.1Qbv introduces absolute, periodic time bounds to the data delivery for hard-RT applications (Figure 5.21-2). The traffic bounds are referenced to the transmitting node's clock, which is also used by the hard-RT application. In this manner, hard-RT delivery guarantees can be met across the whole protocol stack. The periodic pattern of the time-aware schedule further matches the cyclic nature of the overarching manufacturing application. When network nodes are clock-synchronized via IEEE 802.1AS, time-aware scheduling can be extended over multiple hops. IEEE 802.1AS therefore represents a prerequisite for time-aware scheduling For the use cases defined in TR 22.803, resource reservation for hard-RT traffic typically spans time intervals between 500μs and 10ms. IEEE 802.1Qbv also defines managed objects for Ethernet nodes to enable remote configuration of parameters associated with time-aware scheduling. Frame pre-emption defined by IEEE 802.1Qbu regulates the transport of lower-priority traffic in presence of time-aware schedules configured for hard-RT traffic. It introduces explicit solutions on Ethernet layer such as guard time intervals and frame interruption to circumvent the periodic traffic intervals reserved for hard-RT traffic. Frame pre-emption only considers resource partitioning in the time domain. It further assumes that lower layers lack autonomous frame-segmentation methods or are not aware of the time-interval boundaries configured. For incremental wireline-to-wireless migration in high-performance manufacturing, one can expect that individual wireline links or stars in the Ethernet network are replaced with 5G. From the perspective of the Ethernet network, the end-points of the 5G PDU-session align with the end points of the Ethernet link. Therefore, TSN specifications logically apply to the end-to-end PDU-session. As Ethernet nodes support managed objects for the configuration of time-aware scheduling, the corresponding enhancements for the configuration of time-aware scheduling for 5G are necessary.

An Ethernet network in a high-performance manufacturing location has mesh topology, where one or various links use 5G. The Ethernet network enforces TSN features defined by IEEE 802.1AS, IEEE 802.1Qbv and IEEE 802.1Qbu to support a set of coexisting hard-RT and lower-priority traffic classes. One Ethernet node runs a GM for clock synchronization. Various links are configured to perform time-aware scheduling for a set of the hard-RT traffic classes. The Ethernet nodes interconnected by 5G PDU sessions have means to appropriately conduct clock synchronization across the 5G link.

Periodically, synchronization messages are propagated by the GM throughout the Ethernet network. These messages may traverse the 5G links in either direction. The 5G technology ensures sufficiently accurate determination and propagation of link delay and residence delay. Based on clock synchronization and time-aware schedules, hard-RT traffic propagates across the network without colliding with lower priority traffic. At the same time, lower priority traffic propagates in resource-efficient manner. On the 5G links, forwarding of hard-RT traffic is conducted in compliance with the time bounds configured via time-aware scheduling. Further, lower-priority traffic is forwarded in resource-efficient manner across the 5G links, without impacting the stringent performance targets of hard-RT traffic. Hard-RT and lower-priority traffic may flow in both directions across the 5G links.

The performance targets for hard-RT traffic are met. All hard-RT traffic frames can be delivered with expected reliability within the absolute time bounds configured. Further, remaining resources are efficiently used for transport of lower priority traffic.

IEEE 802.1AS defines an explicit handshake on Ethernet-layer for determination of link delay, which relies on accurate frame departure and -arrival measurements on physical layer. The procedure assumes that link delay is symmetric and deterministic. These assumptions are not met for the 5G access link. The 5G access link, however, supports separate mechanisms to synchronize the frame boundaries between UE and gNB with high level of accuracy. These aspects may be considered in the adaptation of IEEE 802.1AS for 5G. The achievable accuracy of access-link delay measurements depends on channel delay spread and the shortest-path measurement mechanisms applied. IEEE 802.1AS further supports a mechanism to determine relative clock drift between link end-points. Adaptation of this feature should also be considered for the 5G-links. The concept of absolute cyclic time boundaries to scheduling should build on the existing QoS frameworks for delay sensitive traffic (e.g. voice) that is already available in 3GPP. Frame pre-emption aims to accommodate lower-priority traffic together with hard-RT traffic by considering only the time domain. 5G also supports other dimensions such as the frequency or space, which allows simultaneous scheduling of different traffic classes. Frame pre-emption further builds on the assumption that lower-priority transmissions, once they have started, cannot be interrupted when higher priority data arrive. URLLC developed in Rel-15, for instance, is not bound to such a stringent paradigm. Hence, there might be opportunities for further optimization on the 5G access link.

[PR 5.21.6-1] [PR 5.21.6-2] [PR 5.21.6-3] [PR 5.21.6-4] [PR 5.21.6-5] [PR 5.21.6-6]

Grace is responsible for installing networked devices in a new production cell at a factory. She needs to unpack, configure, install, and test devices, and work with her colleagues to get the production process running smoothly.

Grace's devices include sensors, actuators, and controllers that communicate using a 5G LAN service. In this deployment, her factory owns and deploys a private network using 3GPP technology, and serves as the network operator.

Grace uses tools to securely configure devices for service on the factory 5G LAN system.

Devices can communicate on the network, 3GPP 5G LAN service between devices is enabled. The level of security has been decided in this case by the local operator. Operator will include features to support required security level from IEC-62443.

None identified.

[PR 5.22.6-1]

This use case describes a scenario where the 3GPP system sets up a 5GLAN connection between a requesting UE and a reachable requested UE without exposing personal identifying information to either. The requesting device is notified if the requested device is not reachable.

An operator offers a service which makes use of the 5G LAN feature. John owns an expensive harvester which has an onboard UE that is 5GLAN capable. Peter is a technician who works for Harvests Co. who also has a 5GLAN capable UE. Both UEs have an installed app that is capable of communicating with an application server that authorizes them for the 5GLAN service, e.g. by being a part of the same 5GLAN service set. John and Peter have permission to communicate with each other under the 5GLAN service by being part of the same 5GLAN set.

Peter indicates a wish to communicate with John's harvester. If the UE on the harvester is not reachable then a notice is provided to Peter's UE. An authorized application server is able to know of UEs availability in a 5GLAN set it has defined

An optimal communication path is set up between the UEs if both are reachable. A requesting UE or an application server or both are aware of the reachability of the requested UE (and can take corrective action). Neither UE is aware of any identifying information of the other UEs (e.g. MS-ISDN) except as may be provided by the application.

[PR 5.23.6-1] [PR 5.23.6-2] [PR 5.23.6-3] [PR 5.23.6-4]

An advantage a 5G PVN has over existing LANs is the ability to interwork with the larger public network and provide access beyond a limited geographic boundary. This is a significant advantage for an enterprise with a wide spread customer base or with employees who work remotely. It is also well suited to today's sharing economy in which the work is done by contractors working in their own time and space rather than for fixed periods in an office. In all of these cases, the workers need to have access to the enterprise 5G PVN from where ever they are working, be it at home, on the road, or on a customer premises. Since the 5G PVN uses 3GPP technology, it can be used to provide a virtual office environment with 5G LAN-type services for all workers, regardless of location. Using a smartphone or tablet, workers can access the company databases, office equipment, and their colleagues using the 5G LAN-type service from their own home or customer premises at any time of the day or night. An additional benefit of using 3GPP technology is that workers can use their same smart phone to access both other devices on the 5G PVN and other UEs that are not on the 5G PVN such as customers or suppliers. This minimizes the equipment needed by the workers as one smartphone can serve all their communication needs wherever they are. At the same time, some devices such as printers may be restricted to only communicating with other devices that are members of the 5G PVN.

A small sales business employees several individuals who work from their own homes rather than in an office. This allows the employees the flexibility to work when and where there is demand (e.g., early mornings, daytime, evenings) and to freely travel to customer premises for sales and support. In this arrangement, the business needs all employees to have access to product databases, sales reporting databases, shipping information, etc., and to be able to communicate among themselves as they would if they were in the same office space. The business uses a 5G PVN to provide this type of communication service for all employees. The 5G PVN provides a virtual office, enabling each employee to access the company databases, office equipment, and their colleagues using the 5G LAN-type service from their own home or customer premises. For example, a sales rep visiting a customer premises can use a tablet to access the 5G PVN from the remote location to access a product database and share the product information with the client. Using the 5G PVN enables a secure and trusted connection between the sales rep's tablet and the database. When the client selects a product for purchase, the sales rep is again able to use a secure connection over the 5G PVN to immediately place the order and process payment information. The sales rep is able to have the order details printed out on her home printer for her records while still at the customer site. A benefit of using a 5G PVN in this case is that the employee needs only a single smartphone to conduct business at the customer site as they used to make the appointment with the customer in the first place. The same UE can be used to contact devices that are not members of the 5G PVN (e.g., call the customer) and to contact UEs that are also members of the 5G PVN (e.g., the printer). At the same time, the security and integrity of the 5G PVN can be protected by restricting some devices (e.g., printers) to only being able to communicate with other devices that are members of the 5G PVN.

[PR 5.24.3-1] [PR 5.24.3-2] [PR 5.24.3-3] [PR 5.24.3-4]

[PR 5.24.4-1]

An enterprise manager needs a quick and efficient way to provide information regarding devices in his enterprise and the group which these devices should belong to, to the MNO. Traditional approach such as phone call and email, would take more time thus is not efficient, and also is not convenient for manager each time when adding a new device into its enterprise or creating a new private group.

A 5G LAN-style service is already enabled by the MNO for the communication between the UEs inside the enterprise. A new UE is deployed by the manager in his enterprise. The manager wants to add a UE to a newly created group for 5GLAN service.

The manager uses an application which is based on the APIs provided by the MNO to create a new private group. The manager also uses the application based on the APIs provided by the MNO to add this UE to the specific private group.

The 3GPP network has created a new private group, and added the new UE to the new private group.

None identified.

[PR 5.25.6-1] [PR 5.25.6-1]

For traditional Ethernet communication, a device needs to find out the MAC address of its peer device. The device, according to the destination IP address XXX derived from the IP packet that needs to be delivered, would initiate a enquiry "who has the IP address XXX", and this enquiry is broadcasted to all the devices belonging to a same LAN. The device who has this IP address will response and provide its MAC address to the requesting device. For 5GLAN case, it is essential to allow a UE to obtain the identifiers of other UEs in the same private communication of 5G LAN-type service for application communication use. However, the above traditional broadcast-and-response approach does not fit for mobile system, since a massive paging signalling would take place if many UEs belonging to the same 5GLAN are in IDLE mode.

UE X and Y are already members of a private communication of 5G LAN-type service provided by the MNO. A new UE Z is added into the same private communication.

UE Z gets the identifiers of UE X and UE Y by using 3GPP mechanisms.

The UE Z could sends data to UE X and/or UE Y.

None identified.

[PR 5.26.6-1]

In LAN networks, devices make use of discovery mechanism (e.g Bonjour, UPNP) to discover other devices online to be used and their characteristics. This discovery mechanism makes use of the multicast capabilities of the network. Therefore, it is important that 5G LAN support discovery mechanisms.

Bob is using 5GLAN-type services at his home. Bob buys a new 5G LAN-type printer that he installed and added to the 5GLAN group of devices at this house.

Bob is on his couch reading the media at his table when he comes across to a newspaper article that he wants to print on his new fancy 5G LAN-type printer. However, Bob cannot find the printer with his tablet.

Bob goes to the attic and discover that the printer is off. Once the printer is on, the discovery mechanisms allows the tablet to find the printer and Bob can print his article.

[PR 5.27.6-1]

In this use case, the Power Grid Corporation A subscribes to Ethernet-based private data communication service from MNO X. The MNO X uses a 5G PVN to connect the Control Center and all the Smart Terminal Unit (STU) the Power Grid Corporation A has deployed. The STUs can detect the failure events and develop failure reports which can be sent to the neighbour STUs or the Control Center. After failure detection, the STUs can perform fault isolation. The distance between the neighbour STUs can be up to several kilometres, and the whole procedure (from the failure detection to fault isolation) should be completed within for example in 180ms. A Development Company B has new development (e.g., development of new residential area, & demolition of obsolete factory) that requires the Power Grid Corporation A to deploy/ dismantle the power system (including the STUs) in the development zone. While deploying /dismantling the power system, the Power Grid Corporation A requests for addition/removal of these STUs into/from the private data communication service. Hence, the MNO X needs to extend/reduce the 5G PVN's coverage and capacity to serve the new STUs or to exclude the old STUs.

The Power Grid Corporation A subscribes to private data communication service from Operator X. The Operator X establishes (sets up) the 5G PVN to provide the data communication between the Control Center and STUs the Power Grid Corporation A has deployed. The STUs can perform the "fault isolation" procedure in a required time-frame (e.g. 180ms).

Development Company B developing a new residential area, and this area has an obsolete factory that has to be demolished. Development Company B requires Power Grid Corporation A to provide the power in the new residential area, and remove the old STUs from the factory. Power Grid Corporation A installs the power system and new STUs in the new residential area, and dismantles the old power system and STUs from the factory. Power Grid Corporation A requests Operator X to add the new STUs into the private data communication service and remove the old STUs from the private data communication service. The Operator X scales the 5G PVN's coverage to provide data communication service for the new STUs and removes the resources that provided data communication service for the old STUs.

Power Grid Corporation A provides the power to the new developed residential area. The 3GPP private communication service between new STUs and Control Center is enabled. The new STUs can complete the "fault isolation" procedure in the required time (e.g. 180ms). The STUs can use the multicast/broadcast addresses to send the failure reports or fault isolation results to the neighbour STUs and Control Center.

None identified.

[PR 5.28.6-1] [PR 5.28.6-2] [PR 5.28.6-3] [PR 5.28.6-4]

In the enterprise, some equipment may be confidential, e.g., a server stores company's confidential data. This use case describes the restriction of UE to a specific 5G-LAN type service based on the UE's location.

Bob are in the enterprise building and has multiple independent communications between UEs in the enterprise building. One of them is the communication between the confidential server.

The MNO defines the group members for this enterprise 3GPP LAN as A, B and C (for the confidential server). Bob requests to the 3GPP MNO to provide 5G-LAN type services to connect to some of its company's equipments. Bob is added to the LAN A, B and C.

When Bob moves out of the office building, the 3GPP MNO disable Bob from LAN C. Bob is out of LAN C and cannot access to the confidential server any more. Bob is still alive in LAN A and LAN B.

None identified.

[PR 5.29.6-1] [PR 5.29.6-2] [PR 5.29.6-3]

This use case describes the on-demand establishment of a multicast communications within subset of UEs that are members of the 5G PVN, e.g. equipment A create a multicast on demand and B and C joins this multicast to receive A's multicast messages.

Equipment A, B, C, D and E are members of 5G PVN.Equipment A has been allocated a multicast address for multicast message. Equipment B and C are interested in joining equipment A' multicast.

Equipment A create a on demand multicast communication. Equipment B and C joins the multicast communications with A The MNO configures the network such that the multicast communications between A, B & C is enabled.

Equipment B and C can receive A' multicast message.

None identified.

[PR 5.30.6-1] [PR 5.30.6-2]