A Fault Identification Algorithm for Satellite Networks Based on System Level Diagnosis

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1 ISSN , CODEN RUXUEW Journal of Software, Vol17, No3, March 2006, pp DOI: /jos Tel/Fax: by Journal of Software All rights reserved +,,, (, ) A Fault Identification Algorithm for Satellite Networks Based on System Level Diagnosis HOU Xia +, FAN Zhi-Hua, HU Gang, LI Lei (Institute of Software, The Chinese Academy of Sciences, Beijing , China) + Corresponding author: Phn: ext 112, helenhou0927@hotmailcom, Hou X, Fan ZH, Hu G, Li L A fault identification algorithm for satellite networks based on system level diagnosis Journal of Software, 2006,17(3): Abstract: It is a challenge to support the fault tolerance for satellite networks, in which fault identification is primary After modeling satellite networks with two-level-node graph, a fault identification algorithm based on PMC test invalidation model is presented and proved to be correct The effectiveness of the algorithm in different types of satellite networks is compared and studied by simulations The results of experiments illustrate that the algorithm adapts to arbitrary network topology and has robustness Key words: : system level diagnosis satellite network two-level-node graph fault identification,, PMC,,,, : : TP391 : A [1],,,,, (inter-satellite links, ISLs), [2],,,, [3 6], Supported by the National High-Tech Research and Development Plan of China under Grant No2004AA ( (863)) Received Accepted

2 : 389 [5] ad-hoc [6],, [7],,, PMC [2], PMC,, ,,,,,, [5] ad-hoc [6],,, :,,,,,,,,,,,, [7] 2 G=(S,V,L),S={s 1,s 2,,s m },V={v 1,v 2,, v n }, :v i s p s p v i L e L (e S,e V ),,e S e V,,, 1(c), ((s 1,s 3 ),(v 1,v 4 )) L, (v 1,v 4 ) l 1,4 : ISLs G s =(S,L s ) ISLs G v =(S,L v ),L s L v S 2 S 2 S 2 S 1 S 3 S 4 v 2 v 3 S 5 v 1 v 4 v 6 v 8 S 1 v 5 v 7 v 1 v 4 v 2 v 3 S 3 v 5 v 7 v 6 v 8 S 5 S 1 v v v 1 v S 3 4 v 6 v v v 7 S 5 S 4 S 4 (a) Composed of G s (t) (b) Composed of G v (t) (c) Theoretic topology graph G(t) (d) Test graph G T (t) (a) (b) (c) (d) Fig1 An example of the theoretic topology graph, composed of G s (t) and G v (t), and its test graph 1, t, G(t)=(S,V,L(t)) G T (t)=(s T,V T,L T (t)), t (t+1), (1) G(t) t L(t), ISLs 1

3 390 Journal of Software Vol17, No3, March 2006 (c) G(t),(a) (b) G(t) (2) G T (t) t, v i,v j V, v i v j x, (v i,v j ) L(t), l i,j =x 1 (d) (a) 12, : (A1) (A2), (A3) (A4),, [7,8] : (1) : (11) t m tst (12) m tst ( ), m rsp (13),, 0, 1 (14) (t+t out ), ( ) (2), t, G T (t)=(s T,V T,L T (t)), (3) t G(t)=(S,V,L(t)) (4) G(t) G T (t), G T (t), , (fault-free) (faulty), PMC [2] : 0, 1,,,,, x {0,1,2}, 2, PMC, 1 l i,j v i v j G T (t) ( ) 1 Table 1 1 The extended PMC model PMC 22 v i v j l i,j l j,i , , ,1 0,1 0 or 1 or or 1 or : (rule1) l i,j =l j,i =0, v i v j ( 0 1)

4 : 391 (rule2) (rule3) (rule4) (rule5) (rule6) (rule7) l i,j =l j,i =1, v i v j 1 l i,j =1 l j,i =0, v j 1 v j 1 l i,j =0, v i 1 v i 0 l i,j =0, v j 0 v i 0 l i,j =1, v j 1 l i,j =l j,i =2, v i v j 2 (A1),, (rule8): (rule8) v i v j, v i v j, v i v j ( 0 1) 23,,,, V #V=n(# ), V f V V K( ) F1( ) F2( ) U( ), K F1 F2 U=V K,F1 F2, U CoarseSplit,SplitZ Diagnosis (1) CoarseSplit V 1, Z,S,U1,H, Z S U1 H=V Z={(v i,v j ) l i,j =l j,i =0} S={(v i,v j ) l i,j =l j,i =1} U1={(v i,v j ) l i,j l j,i } H={(v i,v j ) l i,j =l j,i =2} (2) SplitZ Z {Z 1,Z 2,,Z h }, Z Z l i,j =l j,i =0,Z Z 1 Z 2 Z h =Z Z i Z j = (i j) δ Z, δ=max (#Z 1,#Z 2,,#Z h ) 1 Z : Z a Z, l (a) l=1, Z a (v i,v j ) rule1,v i v j (b) l>1, (v i,v j ) Z a, Z, (v p,v q ) Z a, (v i,v j ) (v p,v q ), v i v p, rule8,v i v p rule1,v i,v j,v p v q,z a 1 : (rule9) Z Z a, v i Z a x, v j Z a x (3) Diagnosis,,,,v i ownerflag v i (0 1 ) Diagnosis ( ) { 1 K= F1= F2= U U2= 2 for (each (v i,v j ) U1) /* according to rule3 */ if (l i,j =1 and l j,i =0) {F1=F1+v j U2=U2+v i v j ownerflag=1} U h = # Z Z a = δ a a= 1 3 K

5 392 Journal of Software Vol17, No3, March for (each v i K) v i ownerflag=0 5 while (U V K F1 F2) { U=V K F1 F2 /* ports set with unknown states */ for (each Z a Z){ if (any v i (F1 Z a )) { For (each v i Z a ) v i ownerflag=1 F1=F1+Z a Z=Z Z a } if (any v i (K Z a )) { for (each v i Z a ) v i ownerflag=0 K=K+Z a Z=Z Z a } } /* according to rule8 */ for (each v i (Z S U2)) { if (v i ownerflag==0) K=K+v i if (v i ownerflag==1) F1=F1+v i } /* according to rule8 */ for (each (v i,v j ) S) /* according to rule2 */ if (v i K) {F1=F1+v j S=S (v i,v j ) v j ownerflag=1} for (each (v i,v j ) H) /* according to rule7 if (v i (K F1)) {F2=F2+v j H=H (v i,v j )} } /* end while */ } /* diagnosis result is K, F1, F2, and U */ 24,,,, PMC, Diagnosis, 2~ 4 :(1) rule3 U1 F1(2) Z,while 5,, : Z, Diagnosis 3 1 #V f β, Z Z i,δ=#z i δ>β, : Z i 1,Z i δ, #V f δ>β #V f β, δ>β,z i, Diagnosis 3, 2 Z Z i,δ=#z i #V f <β, β=#(s U1 H)/2 #(S U1)+δ #((S U1 H) Z i ) : S U1,H,, S U1 S 1 U1 1, S 0 U1 0 H H 0,H 1,H 2 (A) f A, #(S U1 H) f #(S U1) f +#H 2 =#S 1 +#U1 1 #(S 1 U1 1 )+#H 2 #S 1 +#U1 1 +#H 2 #(S U1) (1) rule2,rule3 rule7 S,U1 H, #S+#U1+#H=(#S 0 +#S 1 )+(#U1 0 +#U1 1 )+(#H 0 +#H 1 +#H 2 ) 2#S 1 +2#U1 1 +2#H 2 (2) (1) (2) #(S U1 H) #S+#U1+#H Z i Z,Z i Z, (S U1 H Z)=V, #(S U1 H) f #(S U1 H)/2 #(S U1) (3) #(S U1 H Z i ) f #V f (4)

6 : 393 Z i, 1,Z i δ (1)~ (3) #(S U1 H Z i ) f #(S U1 H)/2 #(S U1)+δ #((S U1 H) Z i )=β (4) #V f β #V f <β, Z i δ 1 2, Diagnosis 3 4, F1 3 walker [1], walker i:t/p/s, i,t,p,s, T/P, 20/4 64/8, , 2 3, LEO 36/6,MEO 4/2, 172 MEO, MEO MEO ISLs MEO LEO ISLs Fig2 The topology of LEO networks Fig3 An example of MEO/LEO network 2 LEO 3 MEO/LEO, ( ),,, f % p (1) f%: #V f =n f % f% 0%~60%, 10% (2) p PMC, B(1,p): 0 p 1 (1 p), B(1,p 2 ): 0 p 2 1 (1 p 2 ) p ,,, f% p, f% p, C% N, C%=[(n #U)/n] 100%,N m tst m rsp 50, C% N, 2, f% 50%,p f%>50%,p=05 p=025

7 394 Journal of Software Vol17, No3, March 2006 Table 2 Statistical results of experiments 2 Single-layer LEO network(20/4) Single-layer LEO network(64/8) Two-layer MEO/LEO network f% p=05 p=025 p=05 p=025 p=05 p=025 N C% N C% N C% N C% N C% N C% p=05,3 f % C% N 4,N N 5,C%, f %>50%, C% f% 50%, 1 2, K F1 f%>50%, 1 2, F1,,, N /4 64/8 MEO/LEO f % C% /8 20/4 MEO/LEO f % Fig4 Relation of f % and N when p=05 4 p=05 f % N Fig5 Relation of f % and C% when p=05 5 p=05 f % C%, MEO/LEO, f%>50%,,,, (v i,v j ) H, v i v j, (v i,v j ) H,(v i,v k ) U1, v i, rule7,v j,h 4, PMC, PMC,, 30%, 3 80,,,,

8 : 395 References: [1] Quan QY, Hu JD Satellite Communication Beijing: Beijing University of Posts and Telecommunications Press, 2000 (in Chinese) [2] Preparata FP, Metze G, Chien RT On the connection assignment problem of diagnosable systems IEEE Trans on Electronic Computers, 1967,16(6): [3] Somani AK, Agarwal VK, Avis D A generalized theory for system level diagnosis IEEE Trans on Computers, 1987,36: [4] Kranakis E, Pelc A Better adaptive diagnosis of hypercubes IEEE Trans on Computer, 2000,49(10): [5] Su MS, Thulasiraman K, Das A A scalable on-line multilevel distributed network fault detection/monitoring system based on the SNMP protocol In: Proc of the IEEE GlobeCom [6] Chessa S, Santi P Comparison-Based system-level fault diagnosis in ad-hoc networks In: Proc of the 20th IEEE Symp on Reliable Distributed Systems New Orleans: IEEE Computer Society, [7] Hou X, Fan ZH, Li L, Hong ZG Fault diagnosis in satellite network by system-level diagnosis In: Omidyar CG, Bourdoucen H, Naamany A, eds Proc of the 1st IFIP Int l Conf on Wireless and Optical Communications Networks [8] Hou X, Fan ZH, Li L, Xu FJ, She CD, Hu G Algorithm of fault diagnosis for satellite network In: Proc of the Int l Conf on Intelligent Mechatronics and Automation Chengdu: IEEE Computer Society, : [1], :,2000 (1976 ),,,,, (1971 ),,,, (1942 ),,,,, (1971 ),,,,CCF,,,