Internet DRAFT - draft-lai-bmwg-istn-methodology
draft-lai-bmwg-istn-methodology
Benchmarking Methodology Working Group Z. Lai
Internet-Draft H. Li
Intended status: Informational Y. Deng
Expires: 26 October 2023 Q. Wu
J. Liu
Tsinghua University
24 April 2023
Problems and Requirements of Evaluation Methodology for Integrated Space
and Terrestrial Networks
draft-lai-bmwg-istn-methodology-03
Abstract
With the rapid evolution of the aerospace industry, many "NewSpace"
upstarts are actively deploying their mega-constellations in low
earth orbits (LEO) and building integrated space and terrestrial
networks (ISTN), promising to provide pervasive, low-latency, and
high-throughput Internet service globally. Due to the high
manufacturing, launching, and updating cost of LEO mega-
constellations, it is expected that ISTNs can be well designed and
evaluated before the launch of satellites. However, the progress of
designing, assessing, and understanding new network functionalities
and protocols for futuristic ISTNs faces a substantial obstacle: lack
of standardized evaluation methodology with acceptable realism (e.g.
can involve the unique dynamic behaviors of ISTNs), flexibility, and
cost. This memo first reviews the unique characteristics of LEO
mega-constellations. Further, it analyzes the limitation of existing
evaluation and analysis methodologies under ISTN environments.
Finally, it outlines the key requirements of future evaluation
methodology tailored for ISTNs.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notation and Terminology . . . . . . . . . . . . . . . . . . 4
3. Quick Primer for Integrated Space and Terrestrial Networks . 5
3.1. Mega-constellation . . . . . . . . . . . . . . . . . . . 5
3.2. Topological Dynamics . . . . . . . . . . . . . . . . . . 6
3.3. Limited Resources . . . . . . . . . . . . . . . . . . . . 7
3.4. Long Manufacturing and Deployment Duration . . . . . . . 8
4. Problem Statement: We Need the Right Evaluation
Methodology . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Live networks and platforms . . . . . . . . . . . . . . . 9
4.2. Network Simulators . . . . . . . . . . . . . . . . . . . 10
4.3. Network Emulators . . . . . . . . . . . . . . . . . . . . 11
4.4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Requirements: New Evaluation Methodology Tailored for
ISTNs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1. Realism . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2. Flexibility . . . . . . . . . . . . . . . . . . . . . . . 13
5.3. Low-cost and Easy-to-use . . . . . . . . . . . . . . . . 13
5.4. Cross-domain Dataset Support . . . . . . . . . . . . . . 13
6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
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1. Introduction
Integrated Space and Terrestrial Networks (ISTN), combining diverse
spacecrafts and ground infrastructures, are extending the frontier of
today’s terrestrial network, promising to provide low-latency, high-
bandwidth Internet access with broader coverage globally.
Low earth orbit (LEO) satellites are the key building block for
constructing ISTNs. Recently, we have witnessed a renaissance in the
space industry, stimulating an exponential increase in constructing
mega-constellations. As compared with their predecessor, cutting-
edge satellites can be equipped with high-resolution sensors, space-
grade multi-core processors, high-data-rate communication links, and
multifunctional space software.
While ISTNs hold great promise, to completely unleash the network
potential of emerging ISTN, it still needs to address a series of new
technical issues. The unique characteristics of LEO satellites
(e.g., high-dynamics), not only impose new challenges at various
layers of the ISTN networking stack but also open the door to many
new technical problems. With many unexplored problems facing the
"NewSpace" industry, it is thus foreseen that in the near future,
there will be a surge of new efforts (e.g. topology, addressing,
routing, transport, etc.) to rethink and reshape the networking stack
in ISTNs. In addition, the cost/timeline of manufacturing,
launching, operating, and updating satellite constellations is
typically much higher/longer than that in traditional terrestrial
networks. Therefore, it is expected that new network functionalities
and protocols can be well evaluated before they are launched and
deployed in realistic satellite constellations.
However, the network community lacks the proper analysis tools and
evaluation methodologies that can mimic the unique dynamic behavior
to analyze many of the ISTN challenges that have been highlighted by
prior works. At high level, existing evaluation methodologies in the
network community can typically be grouped into three major
categories: live networks or platforms, simulation, and emulation.
However, the feasibility and flexibility of live satellite networks
are technically and economically limited. The abstraction level of
network simulation could be too high to capture low-level system
effects. Existing network emulators fail to characterize the high
dynamicity of LEO satellites and thus cannot accomplish an
environment with acceptable fidelity. The community hence needs a
reasonable and standardized evaluation methodology to build proper
experimental environments which can mimic the behavior of ISTNs,
supporting the community to deeply understand the problems, and to
evaluate new functionalities and protocols (e.g. for topology,
addressing, routing, transport, etc.) for ISTNs, before the mega-
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constellation is completely deployed. In this memo, we first review
the unique characteristics of emerging LEO mega-constellations and
the key challenges of integrating satellites and terrestrial
Internet. Further, we analyze the limitation of existing network
analysis tools and evaluation methodologies in ISTNs. Finally, we
outline key requirements of evaluation methodologies tailored for
ISTNs.
2. Notation and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
This document uses the following acronyms and terminologies:
Mega-constellation: A group of satellites working as a system.
LEO: Low Earth Orbit with an altitude no more than 2000 km.
MEO: Medium Earth Orbit with an altitude from 2000 km to 35786 km.
GEO: Geostationary Earth Orbit with an altitude of 35786 km.
NGSO: Non-Geostationary Orbit
LSN: LEO Satellite Networks
ISTN: Integrated Satellite and Terrestrial Network
ISL: Inter-satellite Links
EO: Earth Observation
GS: Ground Station
AS: Autonomous System
EOS: Earth Observation Satellite
BGP: Border Gateway Protocol [RFC4271]
OSPF: Open Shortest Path First [RFC2328]
VM: Virtual Machine
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3. Quick Primer for Integrated Space and Terrestrial Networks
Emerging mega-constellations with inter-satellite links (ISLs) can
build a satellite network in outer space, and further be integrated
with terrestrial ground infrastructures to construct an integrated
space and terrestrial network (ISTN).
3.1. Mega-constellation
A constellation is a group of satellites working as a system to give
a coverage of the earth surface, among which satellites are
positioned in fixed orbital planes with regular trajectories. LEO
and MEO satellites often belong to a constellation, because a single
satellite only covers a small area with high angular velocity. Thus,
continuous coverage over an area could be maintained by the relay
within a constellation, as compared with GEO satellites that only
provides a permanent coverage over a target area. Walker Delta
constellation is the most common formation for constellations. It is
defined as a bunch of circular orbits with a fixed inclination,
satellite number, number of equally spaced planes and the relative
spacing between satellites in adjacent planes. The famous Ballard
rosette constellation is another name of Walker Delta constellation,
where it uses a different notation. Near-polar Walker Star is one of
this kind, initially used by Iridium [Iridium]. Constellations with
a higher inclination give the polar regions more chances to get
accessed. The well-known emerging commercial constellations are
Starlink [Starlink-Fcc], Kuiper [Kuiper-Fcc] and Telesat
[Telesat-Fcc], as shown in Table 1 below. And all of them contain
more than one shell.
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+==========+==========+=============+========+=================+
| Name and | Altitude | Inclination | # of | # of satellites |
| Shell | (km) | (degree) | orbits | per orbit |
+==========+==========+=============+========+=================+
| Starlink | 550 | 53 | 72 | 22 |
| S1 | | | | |
+----------+----------+-------------+--------+-----------------+
| Starlink | 540 | 53.2 | 72 | 22 |
| S2 | | | | |
+----------+----------+-------------+--------+-----------------+
| Starlink | 570 | 70 | 36 | 20 |
| S3 | | | | |
+----------+----------+-------------+--------+-----------------+
| Starlink | 560 | 97.6 | 6 | 58 |
| S4 | | | | |
+----------+----------+-------------+--------+-----------------+
| Starlink | 560 | 97.6 | 4 | 43 |
| S5 | | | | |
+----------+----------+-------------+--------+-----------------+
| Kuiper | 630 | 51.9 | 34 | 34 |
| K1 | | | | |
+----------+----------+-------------+--------+-----------------+
| Kuiper | 610 | 42 | 36 | 36 |
| K2 | | | | |
+----------+----------+-------------+--------+-----------------+
| Kuiper | 590 | 33 | 28 | 28 |
| K3 | | | | |
+----------+----------+-------------+--------+-----------------+
| Telesat | 1015 | 98.98 | 27 | 13 |
| T1 | | | | |
+----------+----------+-------------+--------+-----------------+
| Telesat | 1325 | 50.88 | 40 | 33 |
| T2 | | | | |
+----------+----------+-------------+--------+-----------------+
Table 1: Mega-constellation information.
3.2. Topological Dynamics
Unlike geostationary satellite networks or terrestrial core
infrastructure that keep a stable topology, LEO satellite networks
suffer from high topological dynamics, since LEO satellites move
fast, causing short-lived coverage for fixed terrestrial users. For
example, considering the first shell of Starlink Phase-I, a fixed
user sees each satellite for only up to 3 minutes in one pass, after
which the satellite moves away from the user’s perspective. Table 2
shows the medium space-ground link churn intervals
[link-churn-interval] between existing GS and constellations. If
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each GS only uses one antenna to connect the satellite with the
shortest distance, the medium interval is no more than one minute.
This kind of high dynamic motion incurs frequent link changes between
LEO satellites and GS or users, thus causing frequent topology
changes. Moreover, inter-satellites visibility may also change if
LEO satellites move in different directions or in different shells,
resulting in connectivity change of ISLs.
Such high LEO dynamics can impose significant challenges in the
networking stack of ISTNs. The high dynamics make the logical
network and mega-constellations and physical ISTN inconsistent. One
big challenge is how to overcome the routing oscillation properly in
the high dynamic ISTN environment. Frequent satellite-GS link
changes make the inter-connectivity of space and ground segments in
ISTNs unstable. Thus, the routing have to be re-calculated every
time the link changes. In addition, the topological dynamics also
result in RTT fluctuations in end-to-end paths, involving new
challenges for congestion control in ISTNs, as a RTT variation
observed by end-host might not indicate congestions.
+==========+==============+
| Name | Interval (s) |
+==========+==============+
| Starlink | 3.0901 |
+----------+--------------+
| Kuiper | 5.0562 |
+----------+--------------+
| OneWeb | 10.6824 |
+----------+--------------+
| Telesat | 45.5696 |
+----------+--------------+
Table 2: Space-ground
link churn interval.
3.3. Limited Resources
Space resources (e.g. CPU, energy) on satellites are limited, as
compared with terrestrial network. Since resource-constrained
satellites such as nanosatellites are only able to carry certain
sennsing or transferring missions, energy-consuming or complex tasks
may not be achievable in these satellites. Such complicated tasks
include on-board target identification and instant and continuous
disaster monitoring.
For example, the CPU frequency of current spaceborne processors (e.g.
RAD5545 [RAD5545], RAD750 [RAD750]) is only up to 466MHz per core.
More recently, some low energy-consuming commodity processors are
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used in space to complete certain remote sensing missions under a
limited CPU capacity. [raspberry-pi] With a constrained computation
ability and limited storage and energy, satellite functions and
lifetime are greatly repressed.
3.4. Long Manufacturing and Deployment Duration
Different from terrestrial network infrastructures, the timeline of
manufacturing and deploying satellite networks could be much longer
due to the high cost and complex process during the development and
launch period. Satellites, as well as the orbit and spectrum they
used, have to be regulated, and launches have to be carefully
scheduled (e.g. to avoid the impact of poor weather conditions). In
addition, the maintenance and update cost of a satellite network is
also typically much higher than that in a terrestrial network.
For example, a review of 24 Air Force and Navy space vehicle (SV)
development programs found that on average it took about 7.5 years
from contract start to launch a government satellite.
[Development-Timeline] Commercial satellite programs typically take 2
to 3 years from contract start to launch. [Production-Cycles]
SpaceX’s Starlink constellation plan to launch about 42,000
satellites to construct a mega-constellation in outer space. On 15
October 2019, the United States Federal Communications Commission
(FCC) submitted filings to the International Telecommunication Union
(ITU) on SpaceX's behalf to arrange spectrum for 30,000 additional
Starlink satellites to supplement the 12,000 Starlink satellites
already approved by the FCC. As of the end of 2022, SpaceX has
launched about 3,000 Starlink satellites, which is about 7% of the
ultimate constellation plan consisting of 42,000 satellites. In the
meanwhile, Starlink has attracted more than one million subscribers.
Foreseeably, it may take many years to complete the entire
constellation deployment. Even the first phase of Starlink which
consists of about 4400 satellites is not expected to be completed
until 2024.
4. Problem Statement: We Need the Right Evaluation Methodology
The unique characteristics of LEO mega-constellations involve new
challenges on various layers of the networking stack of ISTNs. On
one hand, it is foreseen that in the near future, there will be a
surge of new network functionalities and protocols designed or
optimized for ISTNs. On the other hand, because the cost/timeline of
manufacturing, launching, operating, and updating satellite
constellations is typically much higher/longer than that in
traditional terrestrial networks, it is expected that those new
network functionalities and protocols tailored for ISTNs should be
well evaluated before they are launched and deployed in realistic
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satellite constellations.
Existing methodologies for testing, assessing, and understanding a
network functionality or protocol can typically be classified into
three categories: (1) live networks; (2) network simulators; and (3)
network emulators. The subsections discuss these three categories of
network evaluation methodologies, along with their using deficiencies
and possible remedies respectively.
4.1. Live networks and platforms
Representative platforms such as Emulab [Emulab] and Sparta [Sparta]
are successful pioneers that build a large-scale experimental network
environment. These test environments are originally designed to
provide special and exclusive test services for affiliated
universities, scientific research institutions or Internet business
companies. And for the resource competition, each independent
experiment needs to completely monopolize a part of the test bed, so
the researcher cannot deploy the experiment until being allocated
with enough nodes. PlanetLab [PlanetLab] is truly global ground
testbed prototype. Started from 2003, it consists of 1353 nodes at
717 sites spanning 48 countries. Together the nodes form a global
network system to support new design of network services.
The live platforms described above were initially proposed for
terrestrial networks and they are developed and repaired at the same
time. The key limitation of them in an ISTN environment is that they
are designed for terrestrial network experiments, and do not
incorporate the realistic characteristic of LEO mega-constellations
to support experiments and evaluations in ISTNs.
We may search for help from live satellites, but still there is only
limited help. It seems that with the help of live ISTN, researchers
are capable to assess, verify and evaluate their ideas and thoughts.
Live ISTN can give a real constellation-consistency and stack-
consistency testing environment. However, current satellites only
provide users a bent-pipe service, which is purely relaying the
transmission messages, such as the current deployment of Starlink
[Starlink]. The construction is far from a comprehensive ISTN, so
the research scope is limited. Even if there is a live ISTN, it
lacks flexibility, owning to the inconvenient control over
satellites. Besides, the access to satellites is also limited.
Therefore, live networks or platforms for terrestrial networks can
give us a large-scale experimental environment but they lack the
support for ISTN characteristics. On the other hand, live ISTN is
able to guarantee a real space environment, but it is not that
affordable and flexible.
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4.2. Network Simulators
Simulators are tools that enable researchers to reproduce their
testing experiments by simulating a real-world process or system over
time. Simulators work by using discrete event simulation to
calculate the interactive states among all the network entities,
ranging from switches, routers, nodes, access points, links and so
on. While working fast and efficiently, the fidelity is only brought
by the state variable changes at discrete points.
Such tools like Systems Tool Kit (STK) [Systems-Tool-Kit] and General
Mission Analysis Tool (GMAT) [General-Mission-Analysis-Tool] are good
for orbit analysis. STK is a powerful tool to help researchers to
model the behavior of mission entities in aerospace,
telecommunications and so forth. It also provides visualization and
analysis functions. GMAT is a similar tool for space trajectory
optimization and mission modeling. Nevertheless, these tools do not
support networking simulations such as topology and protocol
simulations. ns-3 [ns-3] goes a step further with support for
Internet simulation, but on the contrary, it was not designed for
ISTN and lacks the support for high-dynamics of ISTN. StarPerf
[StarPerf] is a simulator that helps researchers to study network
performance under a range of constellation conditions. But still, it
lacks the ability to support interactive network traffic simulation
and system codes in the systems.
Overall, while flexible and low-cost, the realism of simulators is
not content enough, because they are difficult to describe the low-
level characteristics. In other words, simulators are being too
object-oriented to involve additional overhead in the actual
execution of programs. Besides, when accessing the network
performance, a number of recent emerging algorithms for congestion
control, reliable transmission or even protocols are not supported,
for example ns-3 [ns-3] only supports basic congestion control like
Reno [RFC6582] and so forth, so the need to work with some new
algorithms cannot be satisfied and the research to discover new
mechanisms, such as new routing algorithms and re-transmission
schemes, is extensively prohibited. Another problem of simulators,
such as ns-3 [ns-3], is that it difficult to trace or understand the
previous codes, without appropriate documentations. Simulators
usually face the additional compatibility problem, which means they
are not portable with other systems, or they do not support kernel
codes. Since there are multiple simulators developed by different
group of users, sometimes users are required to be familiar with the
writing language, scripting style and modelling technique.
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4.3. Network Emulators
Emulators are another kind of paradigm for network evaluation over a
virtual network. The difference between a simulator and an emulator
is that emulators leverage VM or containers to keep the realism which
is close to actual performances. Therefore, in emulators, virtual
nodes. virtual network links, virtual models of traffic, and
protocols are all applied. Emulators are capable to run real kernel
and application code. Thus, emulators not only support diverse
topology design, but also protocol emulation in a synthetic network
environment. They emulate the network behavior in a more real way.
Mininet [Mininet] is commonly regarded as the most illustrious
emulator for networking with its strong ability to support
experiments with Software-Defined Networking (SDN)
[Software-defined-networking] systems. EstiNet [EstiNet] is another
emulator that supports evaluating and testing the performances of
software-defined networks. Based on containers, they can emulate
real TCP/IP protocol stack in the Linux kernel. However, existing
emulation tools lack the ability to construct the dynamic links and
orbits in ISTN like simulators. Thus, more problems could happen in
higher-level protocols such as routing protocols (e.g. OSPF and
BGP). Besides, since emulators run containers or virtual machines
which occupy more software overhead, as compared with simulators, it
will be hard to emulate the large-scale mega-constellations.
To conclude, emulators are relatively good methodologies for network
experiments, but emulators still have limitations when using them for
ISTN research. While keeping a moderate realism by using VM or
containers for entity emulation and flexibility, emulators still lack
the supports for ISTN characteristics, such as frequent link changes,
satellite network topology uncertainty, and so on. More
specifically, current emulators only support fixed network topology
emulation. It is not flexible to emulate the time-varying link
packet loss, bandwidth, and other traits. A possible way is to
frequently replace the link with a new one from time to time
sequentially for the entire ISTN. However, it is far from the real
situation. Besides, VM or containers are able to deploy a range of
network nodes in a physical server, but the actual CPU, memory and
other resources should not be shared in reality for each satellite.
In addition, it is still difficult to emulate thousands or ten
thousand of satellites for ISTN even with VM or containers, subject
to hardware limitations. For flexibility, some emulators do not
support a good network animator tool. Especially in ISTN emulation,
GUI is important for users to observe and analyze orbit trajectories
and real time satellite positions.
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4.4. Summary
In this section, we explain the necessity of an evaluation
methodology specifically for ISTNs. Then we demonstrate the problems
with existing methodologies related to ISTNs. The performance
comparison result is shown in Table 3. Above all, ISTNs should be
designed first and then launched. Live satellites enable good
realism but they lack flexibility and require very high cost as well
as a very long deployment period. Other testing tools such as
simulators and emulators are either functional for merely aerospace
analysis or simply terrestrial networks. None of the existing
methodologies guarantees a practical and user-friendly methodology
while keeping the evaluation environment realism with low costs.
+================+=========+=============+======+=================+
| Platform/Tool | Realism | Flexibility | Cost | Cross-domain |
| | | | | Dataset Support |
+================+=========+=============+======+=================+
| Live satellite | Y | N | High | Y |
| network | | | | |
+----------------+---------+-------------+------+-----------------+
| ns-3 [ns-3] | N | Y | Low | N |
+----------------+---------+-------------+------+-----------------+
| Hypatia | N | Y | Low | N |
| [Hypatia] | | | | |
+----------------+---------+-------------+------+-----------------+
| StarPerf | N | Y | Low | N |
| [StarPerf] | | | | |
+----------------+---------+-------------+------+-----------------+
| Mininet | N | Y | Low | N |
| [Mininet] | | | | |
+----------------+---------+-------------+------+-----------------+
Table 3: Existing platforms/tools for network analysis and
evaluation. (Y for yes/N for no)
5. Requirements: New Evaluation Methodology Tailored for ISTNs
A proper evaluation methodology tailored for ISTNs is expected to
help developers, researchers, engineers to explore various design-
space of the networking stack of ISTNs in a technically and
economically feasible manner. Based on the comparative analysis
results in the prior section, we sum up the following requirements
for the new evaluation methodology in ISTNs.
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5.1. Realism
The first requirement is realism. Realism represents the testing
authenticity and fidelity. The evaluation methodology is expected to
keep the actual characteristics of mega-constellations. In other
words, the orbit-level information including the latitude, longitude,
and height of each satellite in any given time and the same
information for GS and elevation angles of antennas of each GS. Note
that the constellation information also determines the visibility,
links and even topology of ISTN.s Since the mega-constellations are
unstable, how the temporal satellite locations, visibility, link
propagation delays and so on should also be considered carefully. In
addition, it requires the network nodes to communicate and negotiate
their messages following the actual protocol process. For example,
when doing a test for OSPF in an ISTN, we would like the nodes to
send Hello packets, Link-State-Request (LSR) packets, Link-State-
Update (LSU) packets and so on. A real network stack is preferred to
provide researchers an opportunity to see the performance of
different protocols in ISTNs.
5.2. Flexibility
Another requirement is flexibility and feasibility. The testing
methodology should be technically easy to use and easy to learn.
Without extra modifications or process, the methodology should help
researchers learn and use it without much effort and can evaluate
their ideas as they wish, which means it should support flexible,
controllable environments for researchers.
5.3. Low-cost and Easy-to-use
Meanwhile, the evaluation methodology is expected to be low-cost. A
well-acceptable methodology should be economically feasible for users
to create an evaluation environment. Researchers do not want to
conduct their tests all in live ISTN, which is over-cumbersome and
unaffordable, let alone launching their own spacecraft. Even if
there are a number of orbiting satellites, whether users can easily
gain access to satellites is also a problem.
5.4. Cross-domain Dataset Support
The evaluation methodology is expected to be driven by realistic
datasets from multi-dimensions to support its realism. Multi-
dimension refers to multi-disciplinary research on ISTNs. Since a
standard ISTN evaluation methodology not only contains high-level
benchmarks from topology, routing to transmission, but also considers
the low-level traits such as wireless link conditions, weather
conditions and Earth rotations. To be more concrete, the former one
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requires knowledge in networks while the latter one relies more on
aerospace. Hence, to build a high-fidelity methodology, we need
community efforts both from networks and aerospace. On the other
hand, an authentic dataset is an indispensable element for data
driven testing methodology. Actual data is the first step to obtain
a realistic emulation. with characteristics of a real ISTN. Thus,
the dataset is a collection of messages for testing, in which
geographical mega-constellation information (orbit number, satellite
number, height), orbital information (orbit inclination angle and
link strategies), weather information as well as ground station
information (positions, antenna angle and so forth) are involved.
6. Conclusion
To conclude, the emergence of mega-constellations brings us new
opportunities for the development of ISTN that extends the Internet
to the space era. Combined with terrestrial networks, ISTN is
expected to supply pervasive, low-latency and high-speed services to
users globally, which greatly enhances the current Internet. At the
same time, the unique characteristics (e.g. high-dynamics) of ISTN
impose challenges in topology, routing, transportation, application,
and security. However, we simply believe addressing the challenges
also gives us open opportunities for future research by our
community-driven effort. To accelerate the research speed and to
help make testing more feasible, new methodologies that satisfy user
requirements should be proposed. To this extent, this draft reviews
the limitation of existing network analysis tools in ISTNs,
considering the unique characteristics of emerging LSNs and the key
challenges. This draft further analyzes the limitation of existing
evaluation methodologies in ISTN environments. Finally, this draft
outlines key requirements of evaluation methodologies tailored for
future ISTNs.
7. Acknowledgements
8. IANA Considerations
This memo includes no request to IANA.
9. Security Considerations
This entire draft discusses security considerations from different
perspectives of ISTN in Section 3.
10. References
10.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271,
January 2006, <https://www.rfc-editor.org/info/rfc4271>.
[RFC6582] Henderson, T., Floyd, S., Gurtov, A., and Y. Nishida, "The
NewReno Modification to TCP's Fast Recovery Algorithm",
RFC 6582, DOI 10.17487/RFC6582, April 2012,
<https://www.rfc-editor.org/info/rfc6582>.
10.2. Informative References
[Development-Timeline]
"Development-Timeline", <http://www.iceaaonline.com/ready/
wp-content/uploads/2014/03/Davis-Satellite-ICEAASoCal-
090915.pdf>.
[Emulab] "Emulab", <https://www.emulab.net/portal/frontpage.php>.
[EstiNet] "EstiNet", <http://www.estinet.com/
fckimages/14117014621397232509.pdf>.
[General-Mission-Analysis-Tool]
"General-Mission-Analysis-Tool",
<https://en.wikipedia.org/wiki/
General_Mission_Analysis_Tool>.
[Hypatia] "Hypatia", <http://people.inf.ethz.ch/asingla/papers/
imc2020-hypatia.pdf>.
[Iridium] "Iridium", <https://en.wikipedia.org/wiki/Iridium>.
[Kuiper-Fcc]
"Kuiper-Fcc", <https://www.itu.int/ITU-
R/space/asreceived/Publication/DisplayPublication/8716>.
[link-churn-interval]
"link-churn-interval",
<https://conferences.sigcomm.org/hotnets/2021/
accepted.html>.
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[Mininet] "Mininet", <http://mininet.org/>.
[ns-3] "ns-3", <https://www.nsnam.org/>.
[PlanetLab]
"PlanetLab", <https://citeseerx.ist.psu.edu/viewdoc/
download?doi=10.1.1.99.7006&rep=rep1&type=pdf>.
[Production-Cycles]
"Production-Cycles",
<http://www.futron.com/upload/wysiwyg/Resources/
Whitepapers/Satellite_Manufacturing_Productio
n_Cycles_0504.pdf>.
[RAD5545] "RAD5545", <https://www.baesystems.com/en-media/
uploadFile/20210407074148/1434594567983.pdf>.
[RAD750] "RAD750", <https://www.baesystems.com/en-media/
uploadFile/20210407041505/1434555689265.pdf>.
[raspberry-pi]
"raspberry-pi", <https:// www.raspberrypi.com/news/
raspberry-pi-in-space/>.
[Software-defined-networking]
"Software-defined-networking",
<https://en.wikipedia.org/wiki/Software-
defined_networking>.
[Sparta] "Sparta", <https://s3-us-west-
2.amazonaws.com/ieeeshutpages/xplore/xplore-shut-
page.html>.
[Starlink] "Starlink", <https://en.wikipedia.org/wiki/Starlink>.
[Starlink-Fcc]
"Starlink-Fcc",
<https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158350>.
[StarPerf] "StarPerf", <https://www.semanticscholar.org/paper/
StarPerf%3A-Characterizing-Network-Performance-for-Lai-
Li/18aa32309eb857afdace1ad02d1091ae64dcd330>.
[Systems-Tool-Kit]
"Systems-Tool-Kit", <https://www.agi.com/products/gmat>.
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[Telesat-Fcc]
"Telesat-Fcc", <https://fcc.report/IBFS/SAT-MPL-
20200526-00053/2378318.pdf>.
Authors' Addresses
Zeqi Lai
Tsinghua University
30 ShuangQing Ave
Beijing
100089
China
Email: zeqilai@tsinghua.edu.cn
Hewu Li
Tsinghua University
30 ShuangQing Ave
Beijing
100084
China
Email: lihewu@cernet.edu.cn
Yangtao Deng
Tsinghua University
30 ShuangQing Ave
Beijing
100084
China
Email: dengyt21@mails.tsinghua.edu.cn
Qian Wu
Tsinghua University
30 ShuangQing Ave
Beijing
100084
China
Email: wuqian@cernet.edu.cn
Jun Liu
Tsinghua University
30 ShuangQing Ave
Beijing
100084
China
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Email: juneliu@mail.tsinghua.edu.cn
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