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1 ISS , CODE RUXUEW Journal of Software, Vol7, o4, April 2006, pp DOI: 0360/jos70822 Tel/Fax: by Journal of Software All rights reserved EPFTS +, (, 6003) Timeslot Weighted Fair Scheduling in EPFTS LI Ji +, ZEG Hua-Xin (School of Information Science and Technology, Southwest Jiaotong University, Chengdu 6003, China) + Corresponding author: Phn: ext 60, leejee@63com, Li J, Zeng HX Timeslot weighted fair scheduling in EPFTS Journal of Software, 2006,7(4): Abstract: Based on the technology of EPFTS (ethernet-like physical frame timeslot switching), this paper introduces a new scheduling algorithm call TWFS (timeslot weighted fair scheduling) which could be implemented in EPFTS nodes to fit the requirement of fast data switching and QoS (quality of service) guarantee in SUPAET (single physical layer user-data platform architecture network) By analyzing merits and shortcomings of the typical scheduling techniques such as islip (iteration round-robin match with slip) and Bv-switch (Birkhoff-von neumann switch), TWFS utilizes the same iteration mechanism as islip and takes the total reserved timeslots of an I/O port pair as the weight (priority) for data switching, thus overcomes the shortcoming of the slow response to traffic fluctuation of Bv-switch, while keeping the same calculation complexity in iteration to O(log 2 ) as with islip Simulation results have shown that TWFS can made an optimal balance among effectiveness fairness, and complexity and is most suitable for future high-speed EPFTS nodes in SUPAET Key words: scheduling algorithm; TWFS (timeslot weighted fair scheduling); EPFTS (ethernet-like physical : frame timeslot switching); SUPAET (single physical layer user-data platform architecture network); input queuing EPFTS(ethernet-like physical frame timeslot switching), TWFS(timeslot weighted fair scheduling), EPFTS(ethernet-like physical frame timeslot switching), SUPAET(single physical layer user-data platform architecture network) QoS(quality of service) islip(iteration round-robin match with slip) Bv-switch(Birkhoff-von neumann switch),twfs islip, ( ), Bv-switch, islip O(log 2 ),TWFS Supported by the ational atural Science Foundation of China under Grand o ( ); the Key Laboratory of Broadband Optical Fiber Transmission and Communication etworks, Ministry of Education of China at UESTC ( ( ) ) Received ; Accepted

2 :EPFTS 823, SUPAET EPFTS : ; ; ; : TP393 : A Internet Gbps Tbps, VoIP,IPTV (quality of service, QoS),, / QoS / (switching fabric) QoS,,, ; (crossbar),, VOQ(virtual output queue) HOL(head of line) [], 00%, QoS Crossbar VOQ, (timeslot weighted fair scheduling algorithm, TWFS),,TWFS 00%,, QoS (single physical layer user-data platform architecture network, SUPAET) [2,3] (ethernet-like physical frame timeslot switching, EPFTS) [4,5] EPFTS SUPAET, DWDM, MAC (ethernet-like physical frame, EPF), (PFT) ( ),EPFTS (virtual line, VL) (switched virtual line, SVL) (permanent virtual line, PVL) SUPAET,, (virtual path, VP),EPFTS,,,,,, EPFTS SUPAET EPFTS,, F,, S :S=(s ), s i j,, ( R=(r ) r i j ) S, s =r F( i,j ) S s F, s F, i,j,, i= j=

3 824 Journal of Software Vol7, o4, April Crossbar+VOQ, /, islip(iteration round-robin match with slip) [6],, islip, 3 : ) (request): ; 2) (grant):,,, 3,, ; 3) (accept):,,,, islip log 2, O(log 2 ),, O( 2 ) bit islip,,, Idling-HRR (idling hierarchical round robin) [7],Bv-switch(Birkhoff-von neumann switch) [8,9] [7], CBR(constant bit rate) Best Effort CBR,, f( ), Slepian-Duguid Algorithm f (slot assignment matrix),, f, f=6,=3, R 3 6 ( ), k=4, -2,2-3,3-,Idling-HRR CBR, Best Effort Idling-HRR :, O( 2 f); 2, O() 2 R = Slot k Input Input Input Fig Sample of request matrix and appropriate slot assignment matrix,bv-switch R=(r ) Birkhoff von eumann, K( 2 2+2) φ i K P i,i=,2,,k, R R : K R = ( r ) = φ i Pi, φi = ( 0 r, =, r r r = ) i= i=,,,bv-switch, K 2,Bv-switch WFQ( P-GPS [0] ), φ i P i Bv-switch O( 45 ), 2 O(log 2 ) Idling-HRR,Bv-switch,,, i= j=

4 :EPFTS 825,,,,,, 3 TWFS EPFTS,,, EPFTS,,EPFTS s,twfs,, S=(s ) s i i,s j j, i,j 3 : f=maximum{s i,s j }f ; 0 weight_matrix=(w ), 0 w w = s mark_matrix=(m ), 0 m TWFS, m >0, i j, i( j) f s,w m,j=,,( i=,, ) : islip,, 3 : ) (request):, :, ; 2) (grant):,, ;, ; m 3) (accept):,,, f ;,, i( j), j( i) k k : =m f+,k k f, w k m,m, w w k k 2 k, : =( w +s), w k >f, m, = w k w k mod f( mod ),TWFS, C TWFS, 4,8,6,32,64,28, S, ,, 3, w

5 826 Journal of Software Vol7, o4, April 2006 Table Statistics of iteration count in TWFS TWFS k Ratio of k log 2 (%) Max(m ) , 99%, log 2,,, TWFS log 2 4 m, 2,TWFS :() f O(log 2 );(2) O(log 2 );(3) f s w m, f,s,w l bit, (l+l+2)+l bits, 2 (4l+4)+2 l bits 2 TWFS Idling-HRR,Bv-switch islip Idling-HRR Bv-switch,TWFS f,,, TWFS,, Bv-switch islip Table 2 Comparison of scheduling algorithm complexity 2 4 Algorithms Updating time Scheduling time Space complexity islip one O(log 2 ) O( 2 ) Idling-HRR O( 2 f) O() O(f log 2 ) Bv-switch O( 45 ) O(log 2 ) O( 3 log 2 ) TWFS O(log 2 ) O(log 2 ) O( 2 4l), 8 8, 07, /, Idling-HRR Bv-switch, islip,bv-switch TWFS,, VOQ 000 / 4, ( ) /,, 3, 2 3 ( ) ( ), 2 :,TWFS Bv-switch ;islip,,, 2, 995%, 00%, 995%,

6 :EPFTS 827 Delay (timeslots) Throughput System load System load Fig2 Simulation result under Bernoulli iid and uniform distribution , : ) Bv-switch TWFS,0 ( ) :s 0 ={0%,25%,25%,0%,0%,0%,0%,0%};, 6,7 2, 30% 20%, 0 2) i, (/8=06) i, 90% 3 ), 0,,, 3,TWFS, (05 ) (6 7 ), ;Bv-switch, ;islip, Average delay (timeslots) Throughput vary ratio Inport no Fig3 Average delay and throughput deviation ratio of data arrived at out port 0 under pattern ) Inport no 3 ) 0 4 2), 3,

7 828 Journal of Software Vol7, o4, April 2006 Delay (timeslots) Throughput ratio (%) Fig4 Time (min) Time (min) Comparison of delay and throughput under three algorithms 4 2),iSlip Bv-switch 00%,, TWFS 00%, 000 2) Bv-switch islip, 5 Average delay (timeslots) Throughput ratio (%) Inport no Inport no Fig5 Average delay and throughput of data arrived at out port 0 under pattern 2) 5 2) 0 5 0, TWFS ; Bv-switch, ; islip,, EPFTS, ( ),,, TWFS TWFS islip Bv-switch, Bv-switch, islip,,twfs

8 :EPFTS 829, f,,, TWFS EPFTS, f 2,, References: [] Anderson T, Owicki S, Saxe J, Thacker C High-Speed switch scheduling for local-area networks ACM Trans on Computer Syst, 993,(4): [2] Zeng HX, Dou J, Xu DY Single physical layer u-plane architecture (SUPA) for next generation Internet Comprehensive Report on VoIP and Enhanced IP Communications Services, IEC, [3] Zeng HX, Dou J, Xu DY Replace MPLS with EPFTS to build a SUPAET In: LI VOK, Hamdi M, eds Proc of the HPSR 2005 Hong Kong: IEEE Press, 2005 [4] Zeng HX, Xu DY, Dou J On physical frame time-slot switching over DWDM In: Fan PZ, Shen H, eds Proc of the PACAT 2003 Chengdu: IEEE Press, [5] Zeng HX, Xu DY, Dou J Promotion of physical frame timeslot switching (PFTS) over DWDM Annual Review of Communications, 2004,57, [6] McKeown The islip scheduling algorithm for input-queued switches IEEE/ACM Trans on etworking, 999,7(2):88 20 [7] Hung A, Kesidis G, Mckeown ATM input-buffered switches with guaranteed-rate property In: Kristine L, ed Proc of the IEEE ISCC 98 Athens: IEEE Press, [8] Chang CS, Chen WJ, Huang HY On service guarantees for input buffered crossbar switches: A capacity decomposition approach by Birkhoff and von eumann In: Bhatti S, Crowcroft J, Diot C, eds IEEE IWQoS 99 London: IEEE Press, [9] Chang BCS, Chen WJ, Huang HY Birkhoff-Von neumann input buffered corssbar switches In: Sidi M, ed Proc of the IEEE IFOCOM 2000 Tel Aviv: IEEE Communications Society, [0] Parekh A, Gallager R A generalized processor sharing approach to flow control in Integrated services networks: The single-node case IEEE/ACM Trans on etworking, 993,(3): (978 ),,,, (945 ),,,,,,