On the Benefits of Traffic "Reprofiling" -- The Multiple Hops Case -- Part II
Pith reviewed 2026-05-07 17:43 UTC · model grok-4.3
The pith
Reprofiling flows enables simple schedulers to meet hard delay guarantees with less bandwidth in multi-hop networks.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Jointly optimizing flow reprofiling and per-hop bandwidth allocation allows static priority and FIFO schedulers to enforce hard delay guarantees at lower total bandwidth than is possible without reprofiling. This holds across realistic and synthetic multi-hop topologies, and the evaluations reveal a direct relationship between a scheduler's ability to handle complex arrival curves and its capacity to benefit from more intricate reprofiling solutions.
What carries the argument
A joint optimization framework that simultaneously selects reprofiling parameters for each flow and the bandwidth reservations required by the chosen scheduler at every hop.
If this is right
- Reprofiling yields bandwidth savings for simple schedulers comparable to those reported for more advanced schedulers.
- Scheduler capability and reprofiling complexity are coupled: stronger schedulers can leverage more sophisticated shaping profiles.
- Efficient algorithms exist that solve the joint problem at the scale of realistic network topologies.
- The approach extends single-hop reprofiling benefits to the multi-hop case while preserving the same qualitative gains.
Where Pith is reading between the lines
- If the framework scales to online operation, network controllers could periodically recompute reprofiling profiles as traffic patterns change.
- The observed scheduler-reprofiling coupling suggests that future scheduler designs could include explicit support for profiled traffic curves to amplify the savings.
- Deployment in production networks would need to verify that the modeled savings survive variable cross-traffic and imperfect clock synchronization.
Load-bearing premise
The optimization framework and its algorithms correctly capture real multi-hop network dynamics and produce solutions that deliver actual bandwidth savings without hidden interference or timing mismatches.
What would settle it
A side-by-side measurement in a real multi-hop testbed that applies the computed reprofiling versus no reprofiling and checks whether observed delays stay within the guaranteed bounds while bandwidth usage matches the predicted reduction.
Figures
read the original abstract
Delivering hard delay guarantees over packet networks is increasingly important to applications ranging from automotive systems, avionics, industrial control, etc. Traffic control and schedulers play an essential role in enforcing such guarantees. In this paper, we focus on ``simple'' static priority and FIFO schedulers, and explore how reprofiling flows entering the network, i.e., proactively shaping them to a different traffic profile, can deliver delay guarantees with less bandwidth. To that end, we formulate a joint optimization framework and develop efficient algorithms to solve it. Extensive evaluations across both realistic and synthetic topologies demonstrate that, as with more sophisticated schedulers, reprofiling flows is beneficial. They also highlight an intuitive coupling between a scheduler's capability and its ability to leverage more complex reprofiling solutions.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper claims that jointly optimizing reprofiling profiles for flows entering multi-hop networks equipped with static-priority or FIFO schedulers can enforce hard end-to-end delay guarantees while using less total bandwidth than the no-reprofiling baseline. It develops efficient algorithms for the resulting optimization problem and reports extensive numerical evaluations on both realistic and synthetic topologies that demonstrate bandwidth savings, together with an observed coupling between scheduler capability and the complexity of beneficial reprofiling solutions.
Significance. If the multi-hop composition of arrival and service curves is shown to be tight, the work would usefully extend single-hop reprofiling results to the practically relevant multi-hop setting for real-time applications (automotive, avionics, industrial control). The reported evaluations already indicate that even simple schedulers can exploit reprofiling, which could influence scheduler and shaper design choices.
major comments (2)
- [§4.1–4.3] §4.1–4.3 and Eq. (8)–(12): the joint optimization appears to compose per-hop arrival curves by feeding the output curve of hop k directly as the input to hop k+1, but it is unclear whether the formulation fully accounts for scheduler-induced jitter and cross-flow interference that accumulate across hops under static priority or FIFO. If the bounds remain independent per hop or rely on loose network-calculus envelopes, the computed bandwidth savings may be optimistic; a concrete counter-example or tightness proof for a two-hop tandem would strengthen the central claim.
- [§5.2–5.3] §5.2–5.3, Tables 2–4: the reported bandwidth reductions are presented without accompanying optimality gaps for the developed algorithms or explicit rules for excluding infeasible instances. Because the central claim rests on the numerical evidence that reprofiling yields savings, the absence of these diagnostics makes it difficult to judge whether the gains are robust or artifacts of the solver tolerances and topology selection.
minor comments (2)
- [Abstract / §1] The abstract and introduction refer to “Part I” but do not explicitly state which single-hop results are being generalized; a one-sentence recap of the Part I findings would help readers.
- [§3] Notation for the reprofiling parameters (e.g., burst and rate after reprofiling) is introduced in §3 but reused with slight variations in the multi-hop extension; a consolidated table of symbols would improve readability.
Simulated Author's Rebuttal
We thank the referee for the thoughtful and constructive report. The comments help clarify how to better present the multi-hop composition and the numerical evidence. We address each major comment below.
read point-by-point responses
-
Referee: [§4.1–4.3] §4.1–4.3 and Eq. (8)–(12): the joint optimization appears to compose per-hop arrival curves by feeding the output curve of hop k directly as the input to hop k+1, but it is unclear whether the formulation fully accounts for scheduler-induced jitter and cross-flow interference that accumulate across hops under static priority or FIFO. If the bounds remain independent per hop or rely on loose network-calculus envelopes, the computed bandwidth savings may be optimistic; a concrete counter-example or tightness proof for a two-hop tandem would strengthen the central claim.
Authors: The formulation propagates the output arrival curve of hop k as the input arrival curve to hop k+1. By the definition of network calculus, this propagation incorporates the cumulative jitter and cross-flow interference produced by the scheduler at each hop; the per-hop service curves themselves are derived from the static-priority or FIFO discipline and therefore already embed the interference from other flows present at that hop. The resulting end-to-end bounds are therefore not computed independently per hop. To make this explicit and to address the request for tightness evidence, we will add a short subsection containing a two-hop tandem example that demonstrates the bounds are tight for both schedulers under the traffic profiles considered in the paper. revision: partial
-
Referee: [§5.2–5.3] §5.2–5.3, Tables 2–4: the reported bandwidth reductions are presented without accompanying optimality gaps for the developed algorithms or explicit rules for excluding infeasible instances. Because the central claim rests on the numerical evidence that reprofiling yields savings, the absence of these diagnostics makes it difficult to judge whether the gains are robust or artifacts of the solver tolerances and topology selection.
Authors: We agree that reporting optimality gaps (or sub-optimality bounds for any heuristic steps) and the precise rules used to retain or discard instances would improve the transparency of the evaluation. In the revised manuscript we will augment Tables 2–4 with an additional column or footnote that states the optimality gap for each reported solution and we will add a paragraph in §5.2 that details the feasibility filter (instances are retained only when a feasible solution exists under the given delay bounds and topology). revision: yes
Circularity Check
No significant circularity in joint optimization framework
full rationale
The paper formulates a joint optimization framework for reprofiling flows across multiple hops under static-priority and FIFO schedulers, develops algorithms to solve it, and validates benefits via evaluations on realistic and synthetic topologies. No self-definitional steps, fitted inputs renamed as predictions, or load-bearing self-citations that reduce the central claim to its own inputs are present. The derivation relies on standard network calculus composition of arrival and service curves, which is independent of the target results. This is the common honest outcome for papers whose core contribution is an optimization model plus empirical validation.
Axiom & Free-Parameter Ledger
Reference graph
Works this paper leans on
-
[1]
M. Ashjaei, L. L. Bello, M. Daneshtalab, G. Patti, S. Saponara, and S. Mubeen, “Time-sensitive networking in automotive embedded systems: State of the art and research opportunities,”Journal of Systems Architecture, vol. 117, p. 102137, 2021. [Online]. Available: https://www.sciencedirect.com/science/article/pii/S1383762121001028 [2]Avionics Full Duplex S...
work page 2021
-
[2]
Factory communications at the dawn of the fourth industrial revolution,
C. Zunino, A. Valenzano, R. Obermaisser, and S. Petersen, “Factory communications at the dawn of the fourth industrial revolution,” Computer Standards & Interfaces, vol. 71, p. 103433, 2020. [Online]. Available: https://www.sciencedirect.com/science/article/pii/ S0920548919300868
work page 2020
-
[3]
A survey on time-sensitive networking standards and applications for intelligent driving,
Y . Xu and J. Huang, “A survey on time-sensitive networking standards and applications for intelligent driving,”Processes, vol. 11, no. 7, p. 2211, 2023
work page 2023
-
[4]
A comprehensive systematic review of integration of time sensitive networking and 5g communication,
Z. Satka, M. Ashjaei, H. Fotouhi, M. Daneshtalab, M. Sjödin, and S. Mubeen, “A comprehensive systematic review of integration of time sensitive networking and 5g communication,”Journal of systems architecture, vol. 138, p. 102852, 2023
work page 2023
-
[5]
Performance evaluation methodologies for smart grid substation communication networks: A survey,
T. Docquier, Y .-Q. Song, V . Chevrier, L. Pontnau, and A. Ahmed- Nacer, “Performance evaluation methodologies for smart grid substation communication networks: A survey,”Computer Communications, vol. 198, pp. 228–246, 2023. [Online]. Available: https://www.sciencedirect. com/science/article/pii/S0140366422004285
work page 2023
- [6]
- [7]
- [8]
-
[9]
Time-sensitive networking standards,
J. Farkas, L. L. Bello, and C. Gunther, “Time-sensitive networking standards,”IEEE Communications Standards Magazine, vol. 2, no. 2, 2018
work page 2018
-
[10]
The rise of time-sensitive networking (TSN) in automobiles, industrial automation, and aviation,
G. Parsons, “The rise of time-sensitive networking (TSN) in automobiles, industrial automation, and aviation,” In Compliance - Electronic Design, Testing & Standards, January 2022, https://incompliancemag.com/article/the-rise-of-time-sensitive- networking-tsn-in-automobiles-industrial-automation-and-aviation/
work page 2022
-
[11]
Timely survey of time- sensitive networking: Past and future directions,
Y . Seol, D. Hyeon, J. Min, M. Kim, and J. Paek, “Timely survey of time- sensitive networking: Past and future directions,”IEEE Access, vol. 9, pp. 142 506–142 527, 2021
work page 2021
-
[12]
Time- sensitive networking (tsn) for industrial automation: Current advances and future directions,
T. Zhang, G. Wang, C. Xue, J. Wang, M. Nixon, and S. Han, “Time- sensitive networking (tsn) for industrial automation: Current advances and future directions,”ACM Computing Surveys, vol. 57, no. 2, pp. 1–38, 2024
work page 2024
-
[13]
K. Zanbouri, M. Noor-A-Rahim, J. John, C. J. Sreenan, H. V . Poor, and D. Pesch, “A comprehensive survey of wireless time-sensitive networking (tsn): Architecture, technologies, applications, and open issues,”IEEE Communications Surveys & Tutorials, vol. 27, no. 4, pp. 2129–2155, 2024
work page 2024
-
[14]
Deterministic Networking Architecture,
N. Finn, P. Thubert, B. Varga, and J. Farkas, “Deterministic Networking Architecture,” RFC 8655, October 2019. [Online]. Available: https://www.rfc-editor.org/info/rfc8655
work page 2019
-
[15]
Deterministic Networking (DetNet) Data Plane: IP over IEEE 802.1 Time-Sensitive Networking (TSN),
B. Varga, J. Farkas, A. G. Malis, and S. Bryant, “Deterministic Networking (DetNet) Data Plane: IP over IEEE 802.1 Time-Sensitive Networking (TSN),” RFC 9023, Jun. 2021. [Online]. Available: https://www.rfc-editor.org/info/rfc9023
work page 2021
-
[16]
J.-Y . Le Boudec, “A theory of traffic regulators for deterministic networks with application to interleaved regulators,”IEEE/ACM Trans. Netw., vol. 26, no. 6, pp. 2721–2733, 2018. [Online]. Available: https://doi.org/10.1109/TNET.2018.2875191
-
[17]
On the benefits of traffic “reprofiling
J. Song, J. Qiu, R. Guerin, and H. Sariowan, “On the benefits of traffic “reprofiling” the single hop case,”IEEE/ACM Transactions on Networking, vol. 32, no. 3, pp. 2511–2524, 2024
work page 2024
-
[18]
Sced: A generalized scheduling policy for guaranteeing quality-of-service,
H. Sariowan, R. L. Cruz, and G. C. Polyzos, “Sced: A generalized scheduling policy for guaranteeing quality-of-service,”IEEE/ACM trans- actions on networking, vol. 7, no. 5, pp. 669–684, 2002
work page 2002
-
[19]
On the benefits of traffic “reprofiling
J. Qiu, J. Song, R. Guérin, and H. Sariowan, “On the benefits of traffic “reprofiling” the multiple hops case—part i,”IEEE/ACM Transactions on Networking, vol. 32, no. 4, pp. 3421–3436, 2024
work page 2024
-
[20]
J.-Y . Le Boudec and P. Thiran,Network calculus: a theory of deterministic queuing systems for the internet. Springer, 2001. [Online]. Available: https://leboudec.github.io/netcal/
work page 2001
-
[21]
New directions in communications (or which way to the information age?),
J. Turner, “New directions in communications (or which way to the information age?),”IEEE Communications Magazine, vol. 24, no. 10, pp. 8–15, 1986. [Online]. Available: https://doi.org/10.1109/MCOM. 1986.1092946
-
[22]
Efficient net- work QoS provisioning based on per node traffic shaping,
L. Georgiadis, R. Guérin, V . Peris, and K. N. Sivarajan, “Efficient net- work QoS provisioning based on per node traffic shaping,”IEEE/ACM Transactions on Networking, vol. 4, no. 4, 1996
work page 1996
-
[23]
Urgency-based scheduler for time-sensitive switched Ethernet networks,
J. Specht and S. Samii, “Urgency-based scheduler for time-sensitive switched Ethernet networks,” inProc. 28th Euromicro Conf. Real-Time Syst. (ECRTS), July 2016
work page 2016
-
[24]
M. Paulitsch, E. Schmidt, C. Scherrer, and H. Kantz, “Industrial ap- plications,” inTime-Triggered Communication. CRC Press, 2018, pp. 331–388
work page 2018
-
[25]
Analysis of ethernet-switch traffic shapers for in-vehicle networking applications,
S. Thangamuthu, N. Concer, P. J. Cuijpers, and J. J. Lukkien, “Analysis of ethernet-switch traffic shapers for in-vehicle networking applications,” 11 in2015 Design, Automation & Test in Europe Conference & Exhibition (DATE). IEEE, 2015, pp. 55–60
work page 2015
-
[26]
Inside the social network’s (datacenter) network,
A. Roy, H. Zeng, J. Bagga, G. Porter, and A. C. Snoeren, “Inside the social network’s (datacenter) network,” inProc. ACM SIGCOMM Conference, 2015, pp. 123–137. [Online]. Available: https://doi.org/10.1145/2785956.2787472
-
[27]
C. Xue, T. Zhang, Y . Zhou, M. Nixon, A. Loveless, and S. Han, “Real- time scheduling for 802.1 qbv time-sensitive networking (tsn): A system- atic review and experimental study,”arXiv preprint arXiv:2305.16772, 2023
-
[28]
A survey of scheduling in time-sensitive networking (TSN),
T. Stüber, L. Osswald, S. Lindner, and M. Menth, “A survey of scheduling in time-sensitive networking (TSN),” 2022. [Online]. Available: https://arxiv.org/abs/2211.10954
-
[29]
A concise tutorial on traffic shaping and scheduling in time-sensitive networks,
J. Walrand, “A concise tutorial on traffic shaping and scheduling in time-sensitive networks,”IEEE Communications Surveys & Tutorials, pp. 1–1, May 2023
work page 2023
-
[30]
Wireless-aware tsn engineering: Implications for 5g and upcoming 6g networks,
S. Egger, F. Dürr, B. Varga, M. De Andrade, G. P. Sharma, J. Sachs, J. Harmatos, and J. Gross, “Wireless-aware tsn engineering: Implications for 5g and upcoming 6g networks,”IEEE Network, 2025
work page 2025
-
[31]
Software-defined time-sensitive networking for cross-domain deterministic transmission,
M. Guo, G. Shou, Y . Liu, and Y . Hu, “Software-defined time-sensitive networking for cross-domain deterministic transmission,”Electronics, vol. 13, no. 7, p. 1246, 2024
work page 2024
-
[32]
B. Li, Y . Zhu, Q. Liu, and X. Yao, “Development of deterministic communication for in-vehicle networks based on software-defined time- sensitive networking,”Machines, vol. 12, no. 11, p. 816, 2024
work page 2024
-
[33]
P4-TAS: P4-Based Time-Aware Shaper for Time-Sensitive Networking
F. Ihle, M. Flüchter, and M. Menth, “P4-tas: P4-based time-aware shaper for time-sensitive networking,”arXiv preprint arXiv:2511.10249, 2025
work page internal anchor Pith review Pith/arXiv arXiv 2025
-
[34]
M. Eppler, S. Lindner, L. Osswald, T. Stüber, and M. Menth, “Impact of packet loss and timing errors on scheduled periodic traffic with time- aware shaping (tas) in time-sensitive networking (tsn),”arXiv preprint arXiv:2510.05290, 2025
-
[35]
A survey of schedul- ing algorithms for the time-aware shaper in time-sensitive networking (tsn),
T. Stüber, L. Osswald, S. Lindner, and M. Menth, “A survey of schedul- ing algorithms for the time-aware shaper in time-sensitive networking (tsn),”Ieee Access, vol. 11, pp. 61 192–61 233, 2023
work page 2023
-
[36]
Tsn network scheduling—challenges and approaches,
H. Chahed and A. Kassler, “Tsn network scheduling—challenges and approaches,”Network, vol. 3, no. 4, pp. 585–624, 2023
work page 2023
-
[37]
A survey and experimental study of real-time scheduling methods for 802.1 qbv tsn networks,
C. Xue, T. Zhang, Y . Zhou, M. Nixon, A. Loveless, and S. Han, “A survey and experimental study of real-time scheduling methods for 802.1 qbv tsn networks,”ACM Computing Surveys, vol. 58, no. 2, pp. 1–37, 2025
work page 2025
-
[38]
R. Yan, Q. Li, and H. Xiong, “Optimizing traffic management in airborne power line communication networks: A credit-based shaping approach using network calculus,”IEEE Transactions on Network and Service Management, vol. 22, no. 2, pp. 1437–1449, 2025
work page 2025
-
[39]
T. Hirofuchi, A. B. Ahmed, and T. Fukai, “Implementation and evalu- ation of a time-sensitive networking endpoint for asynchronous traffic shaping,”IEEE Access, 2026
work page 2026
-
[40]
Bpnn-based flow classification and admission control for software defined iiot,
C. Wang, H. Xue, and Z. Huan, “Bpnn-based flow classification and admission control for software defined iiot,”IET Communications, vol. 18, no. 15, pp. 882–896, 2024
work page 2024
-
[41]
E. Hernández and J. Vila, “A new approach to optimize bandwidth reser- vation for real-time video transmission with deterministic guarantees,” Real-Time Imaging, vol. 9, no. 1, pp. 11–26, 2003
work page 2003
-
[42]
X. Gong, S. A. V orobyov, and C. Tellambura, “Joint bandwidth and power allocation with admission control in wireless multi-user networks with and without relaying,”IEEE Transactions on Signal Processing, vol. 59, no. 4, pp. 1801–1813, 2011
work page 2011
-
[43]
Bandwidth scheduling and path computation algorithms for connection- oriented networks,
S. Sahni, N. Rao, S. Ranka, Y . Li, E.-S. Jung, and N. Kamath, “Bandwidth scheduling and path computation algorithms for connection- oriented networks,” inSixth international conference on networking (ICN’07). IEEE, 2007, pp. 47–47
work page 2007
-
[44]
Minimizing flow completion times using adaptive routing over inter-datacenter wide area networks,
M. Noormohammadpour and C. S. Raghavendra, “Minimizing flow completion times using adaptive routing over inter-datacenter wide area networks,” inIEEE INFOCOM 2018-IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS). IEEE, 2018, pp. 1–2
work page 2018
-
[45]
D. Bethanabhotla, G. Caire, and M. J. Neely, “Utility optimal scheduling and admission control for adaptive video streaming in small cell net- works,” in2013 IEEE International Symposium on Information Theory. IEEE, 2013, pp. 1944–1948
work page 2013
-
[46]
A review of priority assignment in real-time systems,
R. I. Davis, L. Cucu-Grosjean, M. Bertogna, and A. Burns, “A review of priority assignment in real-time systems,”Journal of systems archi- tecture, vol. 65, pp. 64–82, 2016
work page 2016
-
[47]
Workloadcompactor: Reducing datacenter cost while providing tail latency slo guarantees,
T. Zhu, M. A. Kozuch, and M. Harchol-Balter, “Workloadcompactor: Reducing datacenter cost while providing tail latency slo guarantees,” inProceedings of the 2017 Symposium on Cloud Computing, 2017, pp. 598–610
work page 2017
-
[48]
On priority assignment in fixed priority scheduling,
N. C. Audsley, “On priority assignment in fixed priority scheduling,” Information Processing Letters, vol. 79, no. 1, pp. 39–44, 2001
work page 2001
-
[49]
Optimal priority assign- ment for real-time systems: a coevolution-based approach,
J. Lee, S. Y . Shin, S. Nejati, and L. C. Briand, “Optimal priority assign- ment for real-time systems: a coevolution-based approach,”Empirical Software Engineering, vol. 27, no. 6, p. 142, 2022
work page 2022
-
[50]
Optimal fixed priority scheduling in multi-stage multi-resource distributed real-time systems,
N. Kumar, C. Gao, and A. Easwaran, “Optimal fixed priority scheduling in multi-stage multi-resource distributed real-time systems,” in2024 Design, Automation & Test in Europe Conference & Exhibition (DATE). IEEE, 2024, pp. 1–6
work page 2024
-
[51]
Queues{don’t}matter when you can {JUMP}them!
M. P. Grosvenor, M. Schwarzkopf, I. Gog, R. N. Watson, A. W. Moore, S. Hand, and J. Crowcroft, “Queues{don’t}matter when you can {JUMP}them!” in12th USENIX Symposium on Networked Systems Design and Implementation (NSDI 15), 2015, pp. 1–14
work page 2015
-
[52]
Chameleon: predictable latency and high utilization with queue-aware and adaptive source routing,
A. Van Bemten, N. Ðeri ´c, A. Varasteh, S. Schmid, C. Mas-Machuca, A. Blenk, and W. Kellerer, “Chameleon: predictable latency and high utilization with queue-aware and adaptive source routing,” inProceed- ings of the 16th International Conference on emerging Networking EXperiments and Technologies, 2020, pp. 451–465
work page 2020
-
[53]
J. W. Guck, M. Reisslein, and W. Kellerer, “Function split between delay-constrained routing and resource allocation for centrally managed qos in industrial networks,”IEEE Transactions on Industrial Informatics, vol. 12, no. 6, pp. 2050–2061, 2016
work page 2050
-
[54]
Network calculus approach for packet delay variation analysis of multi-hop wired networks,
R. N. Gore, E. Lisova, J. Åkerberg, and M. Björkman, “Network calculus approach for packet delay variation analysis of multi-hop wired networks,”Applied Sciences, vol. 12, no. 21, p. 11207, 2022
work page 2022
-
[55]
Joint routing, scheduling and power con- trol providing hard deadline in wireless multihop networks,
S. Kumar and V . Sharma, “Joint routing, scheduling and power con- trol providing hard deadline in wireless multihop networks,” in2017 Information Theory and Applications Workshop (ITA). IEEE, 2017, pp. 1–9
work page 2017
-
[56]
N. Petreska, H. Al-Zubaidy, R. Knorr, and J. Gross, “Bound-based power optimization for multi-hop heterogeneous wireless industrial networks under statistical delay constraints,”Computer networks, vol. 148, pp. 262–279, 2019
work page 2019
-
[57]
Statistical delay control and qos-driven power allocation over two-hop wireless relay links,
Q. Du, Y . Huang, P. Ren, and C. Zhang, “Statistical delay control and qos-driven power allocation over two-hop wireless relay links,” in 2011 IEEE Global Telecommunications Conference-GLOBECOM 2011. IEEE, 2011, pp. 1–5. 12 APPENDIXA SUMMARY OFNOTATION ANDACRONYMS Acronyms Definition 2SRC Two-Slope Reprofiling Curve PBOO Pay Burst Only Once FIFO First In ...
work page 2011
-
[58]
This then yieldseT (max) 1 (Γ′ 2)< eT (min) 2 (Γ′ 2)and eT (min) i (Γ′
=G 2(Γ2)∪G ′ 2(Γ2). This then yieldseT (max) 1 (Γ′ 2)< eT (min) 2 (Γ′ 2)and eT (min) i (Γ′
-
[59]
= 14 eT (min) i (Γ2)fori= 1,2, so that the required bandwidth under Γ′ 2 is given by C ∗(Γ′
-
[60]
= max Pn i=1 ri, supt> eT (min) 1 (Γ2) lmax 1 (Γ′ 2)+HG1(Γ′ 2)(t− eT (min) 1 (Γ2)) t , supt> eT (min) 2 (Γ2) HG1(Γ′ 2)(t)+HG2(Γ′ 2)(t− eT (min) 2 (Γ2)) t . We next showC ∗(Γ′ 2)≤C ∗(Γ2). BecauseG 2(Γ2)⊂G 2(Γ′ 2), we havel max 1 (Γ′ 2)≥l max 1 (Γ2). Two cases arise: –Ifl max 1 (Γ′
-
[61]
=l max 1 (Γ2), then sinceG 1(Γ′ 2)⊂G 1(Γ2), we have lmax 1 (Γ2) +H G1(Γ2)(t− eT (min) 1 (Γ2)) ≥lmax 1 (Γ′
-
[62]
–Ifl max 1 (Γ′ 2)> l max 1 (Γ2), there exists ˆi∈G ′ 2(Γ2)such thatl ˆi > l max 1 (Γ2)
+H G1(Γ′ 2)(t− eT (min) 1 (Γ2)). –Ifl max 1 (Γ′ 2)> l max 1 (Γ2), there exists ˆi∈G ′ 2(Γ2)such thatl ˆi > l max 1 (Γ2). Becauseσ ˆi(t)≥l ˆi for allt >0and G1(Γ′ 2)⊆G 1(Γ2)− ˆi, lmax 1 (Γ2) +H G1(Γ2)(t− eT (min) 1 (Γ2)) =lmax 1 (Γ2) +H G1(Γ2)−ˆi(t− eT (min) 1 (Γ2)) +σ ˆi(t− eT (min) 1 (Γ2)) ≥lmax 1 (Γ2) +H G1(Γ′ 2)(t− eT (min) 1 (Γ2)) +lˆi ≥lmax 1 (Γ′
-
[63]
+H G1(Γ′ 2)(t− eT (min) 1 (Γ2)). Finally, sinceH G′ 2(Γ2(t)≥H G′ 2(Γ2)(t− eT (min) 2 (Γ2)), it follows that HG1(Γ2)(t) +H G2(Γ2)(t− eT (min) 2 (Γ2)) =HG1(Γ′ 2)(t) +H G′ 2(Γ2)(t) +H G2(Γ2)(t− eT (min) 2 (Γ2)) ≥HG1(Γ′ 2)(t) +H G′ 2(Γ2)(t− eT (min) 2 (Γ2)) +H G2(Γ2)(t− eT (min) 2 (Γ2)) =HG1(Γ′ 2)(t) +H G2(Γ′ 2)(t− eT (min) 2 (Γ2)). Combining the two ensuresC...
-
[64]
IfΓ k+1 satisfies Condition1, thenΓ k+1 = Γ′ k+1
We first show the existence of an assignmentΓ ′ k+1 satis- fying Condition1. IfΓ k+1 satisfies Condition1, thenΓ k+1 = Γ′ k+1. Otherwise, for all1≤ˆm≤m,G 1(Γk+1)̸={i| eT1 ≤ eTi < eT ˆm}. Define ˆi= min{1≤i≤n|i /∈G 1(Γk+1)} and suppose ˆi∈G ˆh(Γk+1). Further defineG ′ ˆh(Γk+1) ={i∈ G1(Γk+1)| eTi ≥ eT (min) ˆh (Γk+1) = eTˆi}andG ′ 1(Γk+1) = G1(Γk+1)−G ′ ˆh(...
-
[65]
ForΓ k+1, there exists1≤ˆm≤msuch thatG 1(Γk+1) = {i| eT1 ≤ eTi < eT ˆm}
Next we show that for any(k+ 1)-priority assignment Γk+1 satisfying Condition 1, there exists a(k+ 1)-priority assignmentΓ ′ k+1 satisfying Condition 2. ForΓ k+1, there exists1≤ˆm≤msuch thatG 1(Γk+1) = {i| eT1 ≤ eTi < eT ˆm}. IfG 1(Γk+1) =∅, by induction of hypothesisI(k)we haveI(k+ 1). Hence, we focus on the case whereG 1(Γk+1)̸=∅. Consider the subset of...
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.