Comments on “Segment Shared Protection in Mesh Communication Networks With Bandwidth Guaranteed...
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1616 IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 15, NO. 6, DECEMBER 2007 Comments and Corrections Comments on “Segment Shared Protection in Mesh Communication Networks With Bandwidth Guaranteed Tunnels” Hongbin Luo, Hongfang Yu, and Lemin Li Abstract—In this Comment, two typos in Ho et al., 2004, “Segment Shared Protection in Mesh Communication Networks With Bandwidth Guaranteed Tunnels”, are pointed out. These typos may puzzle readers or prevent them from correctly understand this paper. In the second part of this Comment, we present corrections to the typos. Index Terms—Segment shared protection (SSP), survivable routing, working and protection paths. I. TWO TYPOS IN THE PAPER I N [1, p.1114], the authors present an approach (as shown in Fig. 1) to determine the protection switching/merging nodes for a given working path. There is a typo in the initialization process. We present the reason as follows. Let us consider the path shown in Fig. 2(a). As shown, there are six nodes with a nodal degree larger than two and the number in each bracket is the nodal degree of each node. If we as- sume that the dismeter, , of each protection domain is two and that in the initialization process, the resulting protection do- mains will be the case as shown in Fig. 2(a). Clearly, this is not an optimal solution since one domain is within another domain. The second typo is in the if statement “if ” (line 9 in Fig. 1). II. CORRECTIONS TO THE TYPOS Based on the idea of [1], the initial value of in the initial- ization process may be replaced by . The resulting pro- tection domains after the replacement are illustrated in Fig. 2(b). Manuscript received May 8, 2005; accepted September 11, 2007; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor D. Towsley. This work was supported in part by the National Science Foundation of China under Grant 60302010 and Grant 60702008, and in part by the National Basic Research Program of China (“973 Program”) under Grant 2007CB307100 and Grant 2007CB307104. H. Luo is with the School of Communication and Information Engi- neering, University of Electronic Science and Technology of China, Chengdu 610054, China. He is also with the School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China (e-mail: [email protected]) H. Yu and L. Li are with School of Communication and Information Engi- neering, University of Electronic Science and Technology of China, Chengdu 610054, China (e-mail: [email protected]; [email protected]). Digital Object Identifier 10.1109/TNET.2007.909735 Fig. 1. The approach presented in [1]. Fig. 2. An illustration for the reason to set . (a) Before correction. (b) After correction. The second typo should be corrected to be “if ”. ACKNOWLEDGMENT The authors would like to thank Dr. Pin-Han Ho for his openness when these typos were pointed out. REFERENCES [1] P.-H. Ho, J. Tapolcai, and T. Cinkler, “Segment shared protection in mesh communication networks with bandwidth guaranteed tunnels,” IEEE/ACM Trans. Networking, vol. 12, no. 6, pp. 1105–1118, Dec. 2004. 1063-6692/$25.00 © 2007 IEEE
Transcript of Comments on “Segment Shared Protection in Mesh Communication Networks With Bandwidth Guaranteed...
1616 IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 15, NO. 6, DECEMBER 2007
Comments and Corrections
Comments on “Segment Shared Protection inMesh Communication Networks With Bandwidth
Guaranteed Tunnels”
Hongbin Luo, Hongfang Yu, and Lemin Li
Abstract—In this Comment, two typos in Ho et al., 2004, “SegmentShared Protection in Mesh Communication Networks With BandwidthGuaranteed Tunnels”, are pointed out. These typos may puzzle readers orprevent them from correctly understand this paper. In the second part ofthis Comment, we present corrections to the typos.
Index Terms—Segment shared protection (SSP), survivable routing,working and protection paths.
I. TWO TYPOS IN THE PAPER
I N [1, p.1114], the authors present an approach (as shown in Fig. 1)to determine the protection switching/merging nodes for a given
working path. There is a typo in the initialization process. We presentthe reason as follows. Let us consider the path shown in Fig. 2(a). Asshown, there are six nodes with a nodal degree larger than two andthe number in each bracket is the nodal degree of each node. If we as-sume that the dismeter, D, of each protection domain is two and thatPML(0) = 0 in the initialization process, the resulting protection do-mains will be the case as shown in Fig. 2(a). Clearly, this is not anoptimal solution since one domain is within another domain.
The second typo is in the if statement “if (n = N 0)” (line 9 in Fig. 1).
II. CORRECTIONS TO THE TYPOS
Based on the idea of [1], the initial value of PML(0) in the initial-ization process may be replaced by PML(0) = 1. The resulting pro-tection domains after the replacement are illustrated in Fig. 2(b).
Manuscript received May 8, 2005; accepted September 11, 2007; approvedby IEEE/ACM TRANSACTIONS ON NETWORKING Editor D. Towsley. This workwas supported in part by the National Science Foundation of China under Grant60302010 and Grant 60702008, and in part by the National Basic ResearchProgram of China (“973 Program”) under Grant 2007CB307100 and Grant2007CB307104.
H. Luo is with the School of Communication and Information Engi-neering, University of Electronic Science and Technology of China, Chengdu610054, China. He is also with the School of Electronics and InformationEngineering, Beijing Jiaotong University, Beijing 100044, China (e-mail:[email protected])
H. Yu and L. Li are with School of Communication and Information Engi-neering, University of Electronic Science and Technology of China, Chengdu610054, China (e-mail: [email protected]; [email protected]).
Digital Object Identifier 10.1109/TNET.2007.909735
Fig. 1. The approach presented in [1].
Fig. 2. An illustration for the reason to setPML(0) = 1. (a) Before correction.(b) After correction.
The second typo should be corrected to be “if (n == N0)”.
ACKNOWLEDGMENT
The authors would like to thank Dr. Pin-Han Ho for his opennesswhen these typos were pointed out.
REFERENCES
[1] P.-H. Ho, J. Tapolcai, and T. Cinkler, “Segment shared protection inmesh communication networks with bandwidth guaranteed tunnels,”IEEE/ACM Trans. Networking, vol. 12, no. 6, pp. 1105–1118, Dec.2004.
1063-6692/$25.00 © 2007 IEEE
