Page 112 - Kaleidoscope Academic Conference Proceedings 2021

2021 ITU Kaleidoscope Academic Conference

the first target and the assumption that "large bandwidth is to as "in-time" and "on-time" services, with respect to the
equal to high quality" is no longer universally applicable. latency objectives that are imposed on the packets that
deliver those services. It is necessary not only to engineer
Current internetworking infrastructure provides network and optimize the network for "low" latency: the “actual
services that are fundamentally built on the basis of "best latency” needs to be measured and the latency objectives (the
effort". While differentiated services allow for the “required latency”) provided as a specific parameter for the
prioritization of traffic and the reservation of resources, and service [1].
while the transport-layer protocol can add reliability via As far as the in-time services, they are services that ensure
retransmission schemes, all of these mechanisms are delivery of packets with a required latency that is not to be
associated with significant trade-offs and limitations. In exceeded (delivery at any time before or until the latency
order to support new applications, it is needed to move deadline). On the other hand, the on-time services are
beyond best effort and support a new concept of "high services that ensure the arrival of data within a specific time
precision": high precision in terms of quantifiable latency window. They impose both a maximum latency that is not to
guarantees on a large-scale basis, in terms of synchronization be exceeded and a minimum latency (for on-time services,
of packet flows across multiple communication channels and there are additional challenges with respect to in-time
communicating parties, in terms of behavior in light of services as the network needs to be able to buffer packet or
congestion and resource contention. defer their delivery when needed).
As far as the end-to-end latency, it is the aggregate of
Three of the application scenarios described in Section 2 multiple component latencies, including latency due to
illustrate that precise timing and latency of packet delivery, packet physical propagation and processing for queuing,
coupled with the ability to provide precise control of that packet serialization, and packet processing.
latency, is a critical challenge of future industrial
applications. Technologies for support of time determinism
on a large scale (as described in Section 3) are essential to
enable networking services quantifying precise latency
objectives given various constraints (such as required
throughput and acceptable loss).

The integrated satellite-terrestrial network-enabled
application scenario, exemplifying the diversity of
applications and their deployment environments, highlights
the critical challenge of integrated and flexible addressing
and routing mechanisms. Technologies for flexible
addressing and routing (as described in Section 3) are
essential to leverage in a uniform and seamless way different Figure 4 – In-time vs on-time services
types of network communications, as well as to meet user
and application requirements via appropriate (semantics- Time-deterministic capabilities need to be applied both
based, constraint-based) customization of packet routing. within and beyond single islands of communication, catering
to the increased rigorous QoS of emerging applications.
Two of the application scenarios described in Section 2 Large-scale layer-3 networks should support the coexistence
illustrate that, in case of critical applications such as those of deterministic services and best-effort services.
involving human lives and high-value machinery, high
security, privacy and reliability are critical. Technologies for There is a need to enable time-deterministic capabilities at
intrinsic security and privacy (as described in Section 3) are Layer 3 (Network layer) for large-scale support, extending
essential to address inherent security, privacy and the radio capabilities back through the IP-based backhaul
trustworthiness vulnerabilities of current IP-based networks. network and then across the IP-based core network/Internet.

3. FUNDAMENTAL NETWORKING It is necessary to devise suitable data plane extensions with
TECHNOLOGY ADVANCES accompanying control plane solutions (providing centralized,
distributed and hybrid control signaling). Frequency
This section illustrates three networking technology areas synchronization may be utilized to remove the need for tight
whose advances are fundamental to address the critical time synchronization between routers.
network challenges identified in Section 2.
3.2 Flexible addressing and routing
3.1 Time determinism
The increasingly varied expectations of the services and
Section 2 has described various future industrial network service level objectives that can be required from networks
applications requiring the support of communication places pressure on service providers to be aware of the type
services that adhere to stringent quantifiable latency of services being delivered, and to have access to sufficient
objectives. These communication services are also referred

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