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光パケット交換機のトラヒック理論(その2)

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(2)    . శࡄࠤ࠶࠻੤឵ᯏߩ࠻࡜ࡅ࠶ࠢℂ⺰㧔ߘߩ 2㧕 ̆ ৻⥸ಽᏓࡄࠤ࠶࠻㐳ߦኻߔࠆㄭૃ⸃ᴺ ̆ A Traffic Theory for Optical Packet Switches (Part 2) – Approximation Formulas for Generally Distributed Packet Length – ᧛਄ ᵏม* Yasuji Murakami Abstract An all-optical network still remains a long way from realistic deployment. However, all-optical packet switches, in which optical packets are buffered and routed in optical form, are still expected to solve the problems of electronic bottlenecks and large power consumption in electronic routers.. An approximation is presented for. blocking probabilities and delays of optical buffers, where optical packets arrive in Poisson distribution at the inputs of the optical buffers and are generally distributed in packet length.. The approximation aims to provide a simple calculation tool for. optical buffer designs without requiring computer simulations or extensive iterative computations.. 㧝㧚ߪߓ߼ߦ  ೨਎♿ᧃࠃࠅࠗࡦ࠲࡯ࡀ࠶࠻࠻࡜ࡅ࠶ࠢ߇Ფᐕ 1.5 ୚ߩિ߮₸ߢჇᄢߒߡ޿ࠆ⁁ᴫߦኻ ᔕߔࠆߚ߼㧘વㅍⵝ⟎㧘੤឵ᯏߥߤᖱႎㅢାࡀ࠶࠻ࡢ࡯ࠢߩ⸳஻ᛩ⾗߇਎⇇ਛߢᵴ⊒ߦⴕ ࠊࠇߡ޿ࠆ㧚శᵄ㐳ᄙ㊀વㅍᛛⴚ߇ㅴᱠߒߚ⚿ᨐ㧘ߎࠇࠄ⸳஻ᛩ⾗ߦࠃࠅࡀ࠶࠻ࡢ࡯ࠢߩ 㜞޿ࠬ࡞࡯ࡊ࠶࠻ߣ㜞ᐲߥᨵエᕈࠍᓧࠆ⚿ᨐߣߥߞߡ޿ࠆ㧚ߒ߆ߒߥ߇ࠄ㧘శવㅍᛛⴚߩ 㛳⇣⊛ߥ⊒ዷߦኻߒߡ㧘੤឵ᯏ㧘࡞࡯࠲ߥߤߩࡀ࠶࠻ࡢ࡯ࠢࡁ࡯࠼ߢߪᧂߛ㔚᳇ಣℂߩ߹ ߹ߢ޽ࠆߚ߼㧘ォㅍ⢻ജߩ㒢⇇߇㗼࿷ൻߔࠆࠃ߁ߦߥߞߚ㧚߹ߚ㧘IP ࡞࡯࠲ߩ㔚ജᶖ⾌㊂ ߽ߎߩ߹߹Ⴧᄢࠍ⛯ߌࠇ߫㧘㔚ജࠦࠬ࠻߇ㆇ↪ࠦࠬ࠻ߩᄢ߈ߥᲧ㊀ࠍභ߼ࠆࠃ߁ߦߥࠆߣ ߣ߽ߦ㧘࿾⃿᷷ᥦൻࠍഥ㐳ߔࠆ⚿ᨐߣߥࠆ[1]㧚ᄢ߈ߊߪߎߩ 2 ߟߩ໧㗴ࠍ⸃᳿ߔࠆᣇᴺߣ ߒߡ㧘శାภߩ߹߹ࡄࠤ࠶࠻ࠍಣℂߔࠆశࡄࠤ࠶࠻੤឵ᯏߩ⊓႐߇ᦼᓙߐࠇߡ޿ࠆ㧚ߔߥ ࠊߜ㧘శࡈࠔࠗࡃㅢାࠪࠬ࠹ࡓߦࠃࠅ 1 ࿁✢ߩવㅍㅦᐲ߇ 100Gbps ߦ㆐ߔࠆ⁁ᴫߦߥࠆ ߣ㧘વㅍ⢻ജߩ㜞޿శᛛⴚࠍ↪޿ߚశ੤឵ᯏ߇㧘ᰴ਎ઍߩ IP ࡞࡯࠲ࠍᜂ߁ߎߣߦߥࠆߪ ߕߢ޽ࠆߣ޿߁ᦼᓙߢ޽ࠆ[2-3]㧚  นᄌ㐳 IP ࡄࠤ࠶࠻ߦኻᔕߔࠆߚ߼㧘㕖หᦼశࡄࠤ࠶࠻੤឵߇ᰴ਎ઍࠗࡦ࠲࡯ࡀ࠶࠻ߩ ォㅍᛛⴚߦᔅ㗇ߢ޽ࠆߣߐࠇߡ޿ࠆ㧚಴ജࡐ࡯࠻ߢߩࡄࠤ࠶࠻ⴣ⓭ࠍ࿁ㆱߔࠆߚ߼ߦߪశ శࡈࠔࠗࡃ ࡃ࠶ࡈࠔ߇ᔅⷐߢ޽ࠅ㧘శࡃ࠶ࡈࠔߦߪᄙߊߩឭ᩺߇޽ࠆ㧚ታ⃻ᕈ߆ࠄߺࠆߣశ ㆃᑧ✢㧔optical fiber delay lines㧦FDL㧕ࠍ೑↪ߔࠆߎߣ߇ㄭ㆏ߢ޽ࠆ㧚శࡃ࠶ࡈࠔߣߒ ߡߺߚ႐ว㧘FDL ߪᰴߩࠃ߁ߥ․ᓽࠍᜬߟ㧚 (1) FDL ߪߘߩ㐳ߐߦᲧ଀ߒߚ৻ቯ㊂ߩ⫾Ⓧᤨ㑆ߒ߆ᓧࠄࠇߥ޿㧚FDL ߢߩ⫾Ⓧᤨ㑆ߪ㧘 ̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̅̆̆̆̆̆̆ *ᄢ㒋㔚᳇ㅢାᄢቇ ᖱႎㅢାᎿቇㇱ ㅢାᎿቇ⑼    . 1- - .

(3) శࡈࠔࠗࡃ㐳ߦᲧ଀ߔࠆߩߢ㧘FDL 㐳ߩන૏ࠍㆃᑧᤨ㑆ߢ⠨߃ࠆ㧚ߎࠇࠍᤨ ᤨ㑆☸ᐲ 㧔time granularity㧕ߣ๭߱㧚 (2) ⴣ⓭࿁ㆱߦ㑆ߦวࠊߥߌࠇ߫㧘ࡄࠤ࠶࠻ߪᑄ᫈ߐࠇࠆ㧚  㕖หᦼశࡄࠤ࠶࠻ߦኻᔕߔࠆశࡃ࠶ࡈࠔߩᕈ⢻ࠍ⹏ଔߔࠆߚ߼㧘ᄙߊߩ⸃ᨆᣇᴺ߇ឭ ᩺ߐࠇߡ޿ࠆ[4-9]㧚޿ߕࠇߩឭ߽᩺ᤨ㑆☸ᐲߩᢛᢙ୚ߩ FDL ࠍᢙᄙߊ↪ᗧߒߡ㧘ᤨ㑆☸ ᐲߩᦨㆡൻࠍ࿑ࠆ߽ߩߣߥߞߡ޿ࠆ㧚ߔߥࠊߜ㧘FDL ߩ㐳ߐಽᏓࠍߤߩࠃ߁ߦߔࠇ߫㧘ࡄ ࠤ࠶࠻ᑄ᫈₸ࠍᛥ߃ࠆߎߣ߇ߢ߈ࠆ߆‫߁޿ߣޔ‬໧㗴ߢ޽ࠆ㧚ߎࠇߦኻߒߡ㧘ㄭૃᢙ୯⸃[4-5]㧘 ᢙ୯ࠪࡒࡘ࡟࡯࡚ࠪࡦ[6-7]㧘ᜰᢙ㑐ᢙಽᏓࡄࠤ࠶࠻㐳ߦኻߔࠆ෩ኒ⸃[9]ߥߤߐ߹ߑ߹ߥข ࠅ⚵ߺ߇ߐࠇߡ޿ࠆ߇㧘⷗ㅢߒߩࠃ޿ℂ⺰ᑼࠍᓧߡ޿ࠆࠊߌߢߪߥ޿㧚 ೨ႎ๔[10]ߢߪ㧘ᜰᢙ㑐ᢙಽᏓࡄࠤ࠶࠻㐳ߦኻߒߡ㧘శࡄࠤ࠶࠻੤឵ᯏࡃ࠶ࡈࠔߩᕈ⢻㧘 ౕ૕⊛ߦߪࡄࠤ࠶࠻ᑄ᫈₸ߣㆃᑧߦ㑐ߔࠆ⷗ㅢߒߩࠃ޿ㄭૃᑼࠍᓧࠆߎߣߦᚑഞߒߚ㧚ᧄ ⺰ᢥߪ㧘೨ႎ๔ߩ⚿ᨐࠍ〯߹߃ߡߐࠄߦ৻⥸ൻߒ㧘৻⥸ಽᏓࡄࠤ࠶࠻㐳ߦኻߔࠆㄭૃᑼࠍ ਈ߃ߡ޿ࠆ㧚ߎߎߢߪ㧘ᣢ⊒⴫[11]ߩౝኈࠍℂ⸃ߒ߿ߔ޿ᒻߦᢛℂߔࠆߣߣ߽ߦ㧘ዉ಴ߒ ߚㄭૃ⸃ߩ♖ᐲࠍ৻ጀ⹦ߒߊ⺑᣿ߔࠆ㧚. 㧞㧚ࡕ࠺࡞ߣቯℂ ᧄ⺰ᢥߢዉ಴ߔࠆࡄࠤ࠶࠻ᑄ᫈₸ߣㆃᑧߩㄭૃᑼߪ㧘ᢥ₂[6]߅ࠃ߮೨ႎ๔[10]ߩ⚿ᨐߦ ၮߠߊ߽ߩߢ޽ࠆ㧚ߒߚ߇ߞߡ㧘ᧄ▵ߢߪߘࠇࠄߩ⺰ᢥߦߡ⸥タߐࠇߚቯ⟵ߣᓧࠄࠇߚቯ ℂࠍ◲ẖߦ⸥ㅀߔࠆ㧚. 2.1 ࡕ࠺࡞ ᓙߜⴕ೉ߣߥࠆ಴ജࡃ࠶ࡈࠔ శࡈࠔࠗࡃㆃᑧ✢. ߦ FDL ࠍ೑↪ߔࠆ᭴ᚑࠍ㧘࿑ 1. 0. ߦ␜ߔ㧚㧝ߟߩ಴ജߦኻߒߡశࡄ ࠤ࠶࠻ߩⴣ⓭ࠍ࿁ㆱߔࠆߚ߼㧘 B. 1D. ᧄߩ FDL ࠍㆬᛯߢ߈ࠆ᭴ᚑߢ㧘i. ࡮࡮࡮. శࠬࠗ䏓࠴. 2D. ⇟⋡ߩ FDL ߪ i  1

(4) D 㧘1 d i d B. 3D. ߩㆃᑧࠍ↢ߓࠆ㧚ߎߎߢ‫ ޔ‬D ߪᤨ 㑆☸ᐲߢ޽ࠅ㧘శࡈࠔࠗࡃߩ㐳ߐ. B  1

(5) D. න૏ࠍ L ߣߔࠆߣ㧘 D. 㨯㨯㨯. nL c 㧘. n 㧦శࡈࠔࠗࡃߩታലዮ᛬₸㧘c 㧦 ⌀ⓨਛߩశㅦߢ޽ࠆ㧚ߒߚ߇ߞߡ㧘. ࿑ 1㧚శࡈࠔࠗࡃㆃᑧ✢ߦࠃࠆశࡃ࠶ࡈࠔ. ߎߩశࡃ࠶ࡈࠔߢߪ㧘 0 㧘 1D 㧘. 2 D 㧘㨯㨯㨯㧘T. B  1

(6) D ߩ㔌ᢔ⊛. ߥㆃᑧᤨ㑆ߣߥࠆ೔⌕㗅ಣℂ㧔first come first service㧦FCFS㧕߇ⴕࠊࠇࠆ㧚T. B  1

(7) D. એ਄ߩㆃᑧᤨ㑆߇ᔅⷐߣߥࠆࡄࠤ࠶࠻ߪ⎕᫈ߐࠇࠆ㧚   ৻⥸⊛ߦߪ㧘೔⌕ߒߚࡄࠤ࠶࠻߇㧘ዋߥߊߣ߽ w ߩᓙߜᤨ㑆߇ᔅⷐߥߣ߈㧘ߎߩࡄࠤ. 2- - .

(8) ࠶࠻ߪᰴߩࠃ߁ߦಣℂߐࠇࠆ㧚 (1) i 1

(9) D d w  iD ߩߣ߈㧘 i  1

(10) ⇟⋡ߩ FDL ߦォㅍߐࠇࠆ㧚ߎߩߣ߈㧘వ㗡ߦߪ.  . W. ªwº iD  w 㧘 « » «D». iD 㧘.  . 㧔1㧕. ߩⓨᦼ㑆 W ߇ઃടߐࠇࠆ㧚ߎߎߢ㧘 ªx º ߪ㧘 x ࠍ⿥߃ࠆᦨዊᢛᢙࠍᗧ๧ߔࠆ㧚 (2) T. B  1

(11) D  w ߩߣ߈㧘ᑄ᫈ߐࠇࠆ㧚.  ࡐࠕ࠰ࡦ౉ജㆊ⒟ߣߒߚ FCFS ࠪࠬ࠹ࡓߢߪ㧘છᗧߩᤨ㑆ߢ޽ࠄߚߦ೔⌕ߒߚ઒ᗐࡄࠤ ࠶࠻߇ฃߌࠆᓙߜᤨ㑆ߪ㧘ታ㓙ߩᓙߜᤨ㑆ߣหߓ⛔⸘ಽᏓߦᓥ߁㧚ߎߎߢ㧘ታ㓙ߩᓙߜᤨ 㑆ߣߪ㧘ࡄࠤ࠶࠻߇೔⌕ߒߡ߆ࠄశࡃ࠶ࡈࠔౝߢṛ࿷ߔࠆᤨ㑆ߢ޽ࠅ㧘ߘߩ⛔⸘ߪࡄࠤ࠶ ࠻ߏߣߦᢙ୯ࠪࡒࡘ࡟࡯࡚ࠪࡦߔࠆߎߣߦࠃߞߡᓧࠆߎߣ߇ߢ߈ࠆ㧚หߓ⛔⸘ߣߥࠆߩߪ㧘 ޽ߊ߹ߢࡐࠕ࠰ࡦ౉ജㆊ⒟ࠍ઒ቯߒߡ޿ࠆߚ߼ߢ޽ࠅ㧘PASTA㧔Poisson arrivals see time averages㧕ߩ㑐ଥߦࠃࠆ㧚  ߘߎߢ㧘ᧄ⺰ᢥߢߪ㧘ታ㓙ߩᓙߜᤨ㑆ಽᏓߢߪߥߊ઒ ઒ᗐᓙߜᤨ㑆㧔virtual waiting time㧕. x ߦኻߔࠆ⏕₸ಽᏓࠍᛒ߁ߎߣߣߔࠆ㧚߹ߚ㧘઒ᗐᓙߜᤨ㑆ࠍ㧘శࡃ࠶ࡈࠔౝߦṛ࿷ߔࠆ ᤨ㑆ߣቯ⟵ߔࠆߣ㧘శࡃ࠶ࡈࠔࠍ 1 ߟߩࠪࠬ࠹ࡓߣ⷗ߚ႐ว㧘ߎࠇߪࠨ࡯ࡆࠬᤨ㑆ࠍ฽߼ ߚṛ ṛ࿷ᤨ㑆㧔sojourn time㧕ߣߥࠆ㧚ࡄࠤ࠶࠻߇೔⌕ߔࠆߣ㧘ࠨ࡯ࡆࠬ⚳ੌ߹ߢߦ x ᤨ㑆 ߆߆ࠆ㧚 ࡄࠤ࠶࠻߇శࡃ࠶ࡈࠔࠍ⚻↱ߔࠆ(1)ߩ႐ว㧘ⓨᦼ㑆߇ઃടߐࠇࠆಽ㧘੤឵ᯏߦ߆߆ࠆࡄ ࠤ࠶࠻⽶⩄ߪታ㓙ߩ⽶⩄ࠃࠅㆊ೾ߣߥࠆ㧚ⓨᦼ㑆ߪ㧘శࡃ࠶ࡈࠔ߇ⓨߩߣ߈೔⌕ߔࠆࡄࠤ ࠶࠻ߦߪઃടߐࠇߥ޿߇㧘శࡃ࠶ࡈࠔߦࡄࠤ࠶࠻߇⫾Ⓧߐࠇߡ޿ࠆߣ߈ߦߪઃടߐࠇࠆ㧚 ߘߎߢ㧘ⓨᦼ㑆ࠍ฽߼ߚࡄࠤ࠶࠻ࠍ޽ࠄߚߦ‫߁޿ߣޠߣߞߌ߬ޟ‬ฬ⒓ߢቯ⟵ߔࠆ㧚ߔߥࠊ ߜ㧘߬ߌߞߣߦߪ㧘 Ԙ శࡃ࠶ࡈࠔ߇ⓨߩߣ߈೔⌕ߔࠆࡄࠤ࠶࠻㧚ߎࠇࠍ㧘ೋᦼ೔⌕ࡄࠤ࠶࠻㧔first arrival packets㧕ߣ๭߮㧘ⓨᦼ㑆ࠍᜬߚߥ޿㧚 㕖ೋᦼ ԙ శࡃ࠶ࡈࠔߦࡄࠤ࠶࠻߇⫾Ⓧߐࠇߡ޿ࠆߣ߈೔⌕ߔࠆࡄࠤ࠶࠻㧚ߎࠇࠍ㧘㕖 ೔⌕ࡄࠤ࠶࠻㧔non-first arrival packets㧕ߣ๭߮㧘ⓨᦼ㑆ࠍ฽ࠎߛ㐳ߐߣߥࠆ㧚 ߩ㧞⒳㘃ߩࡄࠤ࠶࠻߇޽ࠆ㧚. 2.2 ή㒢㐳శࡃ࠶ࡈࠔߩℂ⺰  ᧄ⺰ᢥߦ೑↪ߔࠆ⏕₸ᄌᢙߣቯℂߦߟ޿ߡ㧘೨ႎ[10]ߦᓥ޿㧘◲ẖߦ⸥ㅀߔࠆ㧚ᦨೋߦ ή㒢㐳శࡃ࠶ࡈࠔߩ႐ว㧘ߔߥࠊߜ B o f ߩ႐วߢ޽ࠅ‫࠻࠶ࠤࡄޔ‬ᑄ᫈ߪߥ޿‫ޕ‬. O 㧦 ࡐࠕ࠰ࡦ౉ജߦ߅ߌࠆ೔⌕₸㧚 s0 㧦 ታࡄࠤ࠶࠻㐳㧚  g 0 x

(12) 㧦 s0 ߩ⏕₸ኒᐲ㑐ᢙ㧔pdf㧦probability density function㧕㧚. 3- - .

(13) G0 x

(14) 㧦 s0 ߩ⫾ⓍಽᏓ㑐ᢙ㧔CDF㧦Cumulative Distribution Function㧕㧚 f. s0 㧦 ᐔဋࡄࠤ࠶࠻㐳㧘ߒߚ߇ߞߡ‫ ޔ‬s 0. ³ xg x

(15) dx 㧚. 㧔2㧕. 0. 0. U 㧦 శࡄࠤ࠶࠻ߩ⽶⩄㧘ߒߚ߇ߞߡ‫ ޔ‬U. Os 0 㧚. l x

(16) 㧘 L x

(17) 㧦 W ߩ⏕₸ኒᐲ㑐ᢙ㧔pdf㧕ߣ⫾ⓍಽᏓ㑐ᢙ㧔CDF㧕㧚 sX 㧦 㕖ೋᦼ೔⌕ࡄࠤ࠶࠻ߩታലࡄࠤ࠶࠻㐳㧘ߒߚ߇ߞߡ‫ ޔ‬sX. s0  W 㧚. g x

(18) 㧘 G x

(19) 㧦 sX ߩ⏕₸ኒᐲ㑐ᢙ㧔pdf㧕ߣ⫾ⓍಽᏓ㑐ᢙ㧔CDF㧕㧘ߒߚ߇ߞߡ㧘   g x

(20) g 0 x

(21) l x

(22) {. f. ³ g x  y

(23) l y

(24) dy 㧚 0. (3). f. ߎߎߢ‫ߺ⇥ߪ ޔ‬ㄟߺⓍಽ㧔convolution integral㧕ߢ޽ࠆ㧚. sX 㧦 㕖ೋᦼ೔⌕ࡄࠤ࠶࠻ߩᐔဋࡄࠤ࠶࠻㐳㧘ߒߚ߇ߞߡ㧘 f.   sX. ³ xg x

(25) dx. s0  W. 0. s0 . D 㧚                  (4) 2. v x

(26) 㧦߬ߌߞߣߩ઒ᗐᓙߜᤨ㑆 x ߦ߅ߌࠆ⏕₸ኒᐲ㑐ᢙ㧔pdf㧕㧚 V x

(27) 㧦߬ߌߞߣߩ઒ᗐᓙߜᤨ㑆 x ߦኻߔࠆ⫾ⓍಽᏓ㑐ᢙ㧔CDF㧕㧚  Q 㧦శࡃ࠶ࡈࠔ߇❥ᔔᦼ㑆ߦߥ޿ߣ߈㧘ߔߥࠊߜⓨߩߣ߈ߩ⏕₸㧚  U eq 1  Q 㧦߬ߌߞߣߦኻߔࠆ╬ଔ⽶⩄ߢ㧘ⓨᦼ㑆ࠍ⽶⩄ߦขࠅㄟࠎߛ߽ߩ㧚 ࠪࠬ࠹ࡓ߇ቯᏱ⁁ᘒ㧔steady-state㧕ߦ޽ࠆߣ઒ቯߒߡ㧘ᰴߩቯℂ߇ᓧࠄࠇߡ޿ࠆ[6,10]㧚 ⵬ഥቯℂ 1㧦╬ଔ⽶⩄ߣታ⽶⩄ߪᰴᑼߩ㑐ଥߣߥࠆ㧚  . U eq. U. (5). D 1 U 2s0. ᑼ(5)ߪ㧘 D ! 0 ߢ޽ࠇ߫ U eq ! U ߢ޽ࠆߎߣ㧘U  1 ߩ႐วߢ߽ U eq ! 1 ߣߥࠆߎߣ߇޽ࠅ ߃ࠆߎߣࠍᗧ๧ߔࠆ㧚 ቯℂ 1㧦߬ߌߞߣߩ઒ᗐᓙߜᤨ㑆 x ߦ߅ߌࠆ⏕₸ኒᐲ㑐ᢙ㧔pdf㧕v x

(28) ߪ㧘࡟ࡌ࡞੤Ꮕᴺ[12]. 4- - .

(29) ߦࠃࠆ⸃ᨆ߆ࠄ᳞߼ࠄࠇࠆ㧚ࠪࠬ࠹ࡓ߇቟ቯ⁁ᘒߦ޽ࠆߣ߈㧘ߔߥࠊߜ U eq  1 ߩߣ߈㧘. v x

(30) ߩ࡜ࡊ࡜ࠬᄌ឵Q T

(31) ߪᰴᑼߣߥࠆ㧚  v T

(32) *. OQ[1  g 0 * T

(33) ] T  O[1  g * T

(34) ]. ߎߎߢ㧘 g 0. *.    㧔6㧕. T

(35) 㧘߅ࠃ߮ g * T

(36) ߪ㧘ߘࠇߙࠇ g 0 x

(37) 㧘߅ࠃ߮ g x

(38) ߩ࡜ࡊ࡜ࠬᄌ឵ߢ޽ࠆ㧚. ࡐ࡜࠷ࠚ࠶ࠢ࡮ࡅࡦࠠࡦᄌ឵ᣇ⒟ᑼ㧔the Pollaczek- ᑼ(6)ߪ㧘M/G/1 ࠪࠬ࠹ࡓߦ߅ߌࠆࡐ Khinchin transform equation㧕ߦኻᔕߔࠆ㧚ಽᲣ߇ T ߩߴ߈ਸ਼ߢ޽ࠄࠊߖࠆߩߢ޽ࠇ߫㧘 ㅒᄌ឵ߩߚ߼ߦߪ࿃ᢙಽ⸃ߢ߈ࠆߎߣ߇ᦸ߹ߒ޿㧚. 2.3 ᦭㒢శࡃ࠶ࡈࠔߩℂ⺰ ᦭㒢㐳శࡃ࠶ࡈࠔߢߪ㧘઒ᗐᓙߜᤨ㑆 x ߇ᦨᄢ⸵ኈㆃᑧᤨ㑆ߢ޽ࠆ T. B  1

(39) D ࠍ⿥߃. ࠆߣ㧘߬ߌߞߣߪᑄ᫈ߐࠇࠆ㧚޽ࠄߚ߼ߡ㧘߬ߌߞߣࠍಽ㘃ߔࠆߣ㧘ᰴߩ 3 ⒳㘃ߣߥࠆ㧚 (i) ೋᦼ೔⌕ࡄࠤ࠶࠻㧧ࡃ࠶ࡈࠔߪⓨߢ޽ࠆߩߢ x. 0 ߢ޽ࠅ㧘ㅢㆊࡄࠤ࠶࠻ߢ޽ࠆ㧘 (ii) 㕖ೋᦼ೔⌕ࡄࠤ࠶࠻ߢ߆ߟㅢㆊࡄࠤ࠶࠻㧘ߔߥࠊߜ 0  x d T 㧘 (iii) 㕖ೋᦼ೔⌕ࡄࠤ࠶࠻ߢ߆ߟᑄ᫈ߐࠇࠆࡄࠤ࠶࠻㧘 T  x 㧚 ᦭㒢㐳శࡃ࠶ࡈࠔߦ߅ߌࠆ㑐ᢙࠍ㧘એਅߩࠃ߁ߦ㧘ਅઃ T ࠍᷝ߃ߡή㒢㐳శࡃ࠶ࡈࠔߩ ߘࠇࠄߣ඙೎ߔࠆ㧚ᑄ᫈ߐࠇߚ߬ߌߞߣߪࡃ࠶ࡈࠔౝߦሽ࿷ߒߥ޿ߎߣ߇㧘ή㒢㐳ࡃ࠶ࡈ ࠔࡕ࠺࡞ߣߩ㆑޿ߢ޽ࠆ㧚. wT 㧦 ㅢㆊߒߚታࡄࠤ࠶࠻ߩߺ㧘ߔߥࠊߜ(i)ߣ(ii)㧘ࠍኻ⽎ߣߒ㧘ⓨᦼ㑆ࠍ฽߹ߥ޿ᐔဋ ㆃᑧᤨ㑆㧘. S T 㧦 ㅢㆊ߬ߌߞߣߩߺࠍኻ⽎ߣߒߚᐔဋ߬ߌߞߣ㐳㧘  PB 㧦 ೔⌕ోࡄࠤ࠶࠻ߦኻߔࠆ㐽Ⴇ⏕₸㧘߅ࠃ߮ࡄࠤ࠶࠻ᑄ᫈₸㧘៊ᄬ₸㧘 ቯℂ 3㧦 U eq  1 ߩߣ߈㧘ㅢㆊߔࠆታࡄࠤ࠶࠻ߩߺߩᐔဋㆃᑧᤨ㑆ߪᰴᑼߣߥࠆ㧚. V x

(40) Dª Q º dx  «1  V T

(41) 2 ¬ V T

(42) »¼ 0. T.  wT. T ³. 㧔7㧕. ߎߎߢ㧘ฝㄝߩ╙ਃ㗄ߪㅢㆊ߬ߌߞߣߩⓨᦼ㑆ߦࠃࠅ↢ߓߚㆃᑧߢ޽ࠅ㧘ߎࠇߪ࠲ࠗࡊ(ii). ߬ߌߞߣߩࡄࠤ࠶࠻㐳ᑧ㐳ಽߢ޽ࠆ㧚 ቯℂ 4㧦 U eq  1 ߩߣ߈㧘ࡄࠤ࠶࠻ᑄ᫈₸ߪᰴᑼߢਈ߃ࠄࠇࠆ㧚. 5- - .

(43)   PB. 1. V T

(44) Q  OS T V T

(45). 㧔8㧕. ߎߎߢ   ST. s0 . Dª Q º 1 㧚 « 2 ¬ V T

(46) »¼.            . 㧔9㧕. 㧚㧚㧚 ߢ޽ࠆ㧚ᑼ(8)ߩฝㄝ╙ੑ㗄ߪ㧘᦭㒢㐳శࡃ࠶ࡈࠔߦ߅޿ߡ㧘઒ᗐᓙߜᤨ㑆߇ᦨᄢ⸵ኈㆃᑧ 㧚㧚㧚 ᤨ㑆 T B  1

(47) D ߣߥࠆ⏕₸ߢਈ߃ࠄࠇࠆ㧚ߎߩ㗄ߪ㧘⚿ዪ T B  1

(48) D ߦ߅ߌࠆή㒢㐳 శࡃ࠶ࡈࠔߩ઒ᗐᓙߜᤨ㑆 CDF ߩ୯ V T

(49) ߩ㑐ᢙߣߒߡ޽ࠄࠊߐࠇࠆ㧚. 㧟㧚 ㄭૃ⸃ᴺ 3.1 ⇼ૃ⽶⩄ߦࠃࠆᑄ᫈₸ߩዉ಴  ᑼ(5)ࠃࠅ㧘శࡃ࠶ࡈࠔ߇ⓨߣߥࠆ⏕₸ Q ߪ  Q. 1  U eq. D § · 1  O ¨ s 0  U eq ¸ 2 © ¹. ߢ޽ࠆߩߢ㧘ᑼ(9)ࠍ↪޿ࠆߣ㧘ᑼ(8)ߩฝㄝ╙ੑ㗄ߩಽᲣߪ㧘  Q  OS T V T

(50). § D D D Q · § · ¸V T

(51) 1  O ¨ s 0  U eq ¸  O ¨¨ s0   2 2 2 V T

(52) ¸¹ © ¹ ©. D D· D· § · § § 1  O ¨ s 0  U eq  Q

(53) ¸  O ¨ s 0  ¸V T

(54) 1  O ¨ s 0  ¸>1  V T

(55) @  㧔10㧕 2 2¹ 2¹ © ¹ © © ߣߥࠆ‫⚿ߩߘޕ‬ᨐ㧘ᰴᑼࠍᓧࠆ㧚.   PB. ª D ·º § «1  O ¨ s 0  2 ¸»>1  V T

(56) @ © ¹¼ ¬ D· § 1  O ¨ s 0  ¸>1  V T

(57) @ 2¹ ©. 㧔11㧕. ή㒢㐳శࡃ࠶ࡈࠔߢߩᄌᢙߩߺߢ޽ࠄࠊߐࠇࠆᑼ߇ᓧࠄࠇߚ㧚ߒߚ߇ߞߡ㧘ή㒢㐳శࡃ ࠶ࡈࠔࡕ࠺࡞ߢߩ⸃ࠍ᳞߼ࠇ߫㧘᦭㒢㐳శࡃ࠶ࡈࠔߢߩ⸃ࠍᓧࠆߎߣ߇ߢ߈ࠆ㧚  ᑼ(11)ߪ㧘ㄭૃ⸘▚ࠍታⴕߔࠆߦ޽ߚࠅ㧘ᄙߊߩ␜ໂࠍ฽߻㑐ଥᑼߢ޽ࠆ㧚޽ࠄߚߦᡆ ૃ⽶⩄ U c ࠍᰴᑼߩࠃ߁ߦቯ⟵ߔࠆ㧚  . § ©. U c { O ¨ s0 . D· ¸ 2¹. §. U ¨¨1  ©. D · ¸ 2 s 0 ¸¹. (12). 6- - .

(58) ᡆૃ⽶⩄ࠍ↪޿ࠆߣ㧘ᑼ(11)ߪ   PB. 1  U c

(59) >1  V T

(60) @ 1  U c>1  V T

(61) @. (13). ߣߥࠆ㧚M/G/1/K ࠪࠬ࠹ࡓߩᑄ᫈₸ PK ߇.   PK. 1  U

(62) q K 1  Uq K.                        . (14㧕. ߢ⴫ߐࠇࠆ[13-14]ߎߣࠍ⠨ᘦߔࠆߣ㧘ᑄ᫈₸ࠍ⸘▚ߔࠆ㓙ߦߪ‫ ޔ‬U ߦઍࠊߞߡ U c ࠍ↪޿ ࠆߎߣࠍ␜ໂߒߡ޿ࠆ㧚ߎߎߢ㧘ᑼ(14)ߩ q K ߪ㧘M/G/1 ࠪࠬ࠹ࡓߦ߅޿ߡࠪࠬ࠹ࡓౝቴᢙ ߇ K  1 એ਄ߣߥࠆ⏕₸ࠍ␜ߔ㧚  ᡆૃ⽶⩄ߪ㧘೔⌕ࡄࠤ࠶࠻ߔߴߡߦⓨᦼ㑆߇ઃടߐࠇߚ߽ߩߢ㧘෼᧤᧦ઙ U eq  1 ࠍḩ⿷ ߔࠆ㒢ࠅ╬ଔ⽶⩄ U eq ࠃࠅᄢ߈ߥ୯ߢ޽ࠆ㧚ߔߥࠊߜ㧘. U 1  U eq

(63).   U c  U eq. D                      2s0. (15). ߣߥࠅ㧘෼᧤᧦ઙ U eq  1 ߪ U c  1 ߣ╬ଔߢ޽ࠆ㧚࿑㧞ߦ㧘⽶⩄ߦኻߔࠆ U c  U eq ࠍ␜ߔ㧚. U eq. 1 ߣߥࠆ U ࠍ U max { 1 1  D 2 s 0

(64) ߣ߅ߊߣ㧘U c  U eq ߪ߶߷ U max 2 ߢᦨᄢߣߥࠆ߇㧘. ߘߩ୯ߪ D ߩ 1/10 ⒟ᐲߢ޽ࠆ㧚. 3.2 ᜰᢙ㑐ᢙಽᏓࡄࠤ࠶࠻㐳  ᑼ(13)ࠍ↪޿ߡᑄ᫈₸ࠍ⸘▚ߔࠆߦߪ㧘V T

(65) ߩ୯߇ᔅⷐߢ޽ࠆ㧚ߔߥࠊߜή㒢㐳ࡃ࠶ࡈ ࠔࡕ࠺࡞ߦ߅ߌࠆ઒ᗐᓙߜᤨ㑆ಽᏓࠍ㧘ᓙߜᤨ㑆 x ߩ㑐ᢙᒻߢ᳞߼ࠆᔅⷐ߇޽ࠆ㧚ߎߩ㑐 ᢙߪᑼ(6)ߩ v. *. T

(66) ࠍ࡜ࡊ࡜ࠬㅒᄌ឵ߒߡ᳞߼ࠄࠇࠆ߇㧘ታ㓙ߩߣߎࠈ࡜ࡊ࡜ࠬㅒᄌ឵ߢ᳞. ߼ࠄࠇࠆ㑐ᢙᒻߪ߈ࠊ߼ߡ㒢ࠄࠇߡ޿ࠆ㧚ⶄ㔀ߥ㑐ᢙࠍ࡜ࡊ࡜ࠬㅒᄌ឵ߔࠆߎߣߪ৻⥸ߦ ࿎㔍ߢ޽ࠅ㧘ᑼ(6)ࠍ↪޿ߡ⸘▚ߒߚ଀ࠍ⪺⠪ߩ⍮ࠆ㒢ࠅߥ޿㧚ᢥ₂[6]ߪ㧘ᑄ᫈₸߿ㆃᑧᤨ 㑆ߩ▚಴ߦߎߩᑼࠍ↪޿ߕߦᢙ୯ࠪࡒࡘ࡟࡯࡚ࠪࡦࠍⴕߞߡ޿ࠆ㧚  એਅߢߪ㧘శࡄࠤ࠶࠻㐳߇ᜰᢙ㑐ᢙಽᏓߔࠆ႐วߢߩㄭૃ⸃ࠍ᳞߼ࠆ㧚ߎߩ႐ว㧘ⓨᦼ 㑆߇ሽ࿷ߔࠆߚ߼߬ߌߞߣࠨ࡯ࡆࠬᤨ㑆ߪᜰᢙ㑐ᢙಽᏓߢߪߥ޿߇㧘ዉ಴߇ᦨ߽◲නߥࡕ. 7- - .

(67) ⽶⩄䈱Ꮕ㩷 㱝㵭䋭㱝䌥䌱. 㪇㪅㪉 㪇㪅㪈㪏 㪇㪅㪈㪍 㪇㪅㪈㪋 㪇㪅㪈㪉 㪇㪅㪈 㪇㪅㪇㪏 㪇㪅㪇㪍 㪇㪅㪇㪋. D. 2 .0. D 1 .5 D 1 .0 D. D. 0 .8 D. 0 .6. D. 0 .4. 0 .2. 㪇㪅㪇㪉 㪇 㪇. 㪇㪅㪈. 㪇㪅㪉. 㪇㪅㪊. 㪇㪅㪋. 㪇㪅㪌. 㪇㪅㪍. 㪇㪅㪎. 㪇㪅㪏. 㪇㪅㪐 㪈㪅㪇. ⽶⩄㩷 㱝 ࿑ 2㧚ᡆૃ⽶⩄ߣ╬ଔ⽶⩄ߣߩᏅ   ࠺࡞ߢ޽ࠆߣᕁࠊࠇࠆ㧚  ࿑ 3 ߦ␜ߔࠃ߁ߦ㧘శࡄࠤ࠶࠻㐳ߪᐔဋ୯ s0 ߩᜰᢙ㑐ᢙಽᏓ㧘ⓨᦼ㑆ߪ >0, D @ ߩ㑆ߢߩ ဋ৻ಽᏓߣ઒ቯߔࠆ㧚ฦ⏕₸ኒᐲ㑐ᢙߣߘߩ࡜ࡊ࡜ࠬᄌ឵ߪ㧘ᰴᑼߣߥࠆ㧚. g 0 x

(68) l x

(69). 1. 1  x s0 * 㧘 g 0 T

(70) e s0. s 0T  1. 1 >u x

(71)  u x  D

(72) @㧘 l * T

(73) D. (16). 㧘 . 1 1  e  DT 㧚 DT.

(74). (17㧕. ߎߎߢ㧘u x

(75) ߪන૏ࠬ࠹࠶ࡊ㑐ᢙߢ޽ࠆ㧚ᑼ(3)ߦ߅ߌࠆ⇥ߺㄟߺⓍಽߪ㧘࡜ࡊ࡜ࠬᄌ឵ߢ ߪනߥࠆⓍߣߥࠆߚ߼㧘. g * T

(76). g 0 T

(77) l * T

(78) *. 1. 1 1  e  DT   s 0T  1 DT.

(79). (18). ߢ޽ࠆ㧚ᑼ(16)㧘(18)ࠍᑼ(6)ߦઍ౉ߔࠆߣᰴᑼࠍᓧࠆ㧚. ª. º » ¬ s0T  1¼ ª º 1 1 T  O «1  1  e  DT » ¬ s 0T  1 DT ¼. OQ «1 .   v. *. T

(80). 1.

(81). 8- - . (19).

(82) 1 s0. 1 D. 0. 0. 0 ࡄࠤ࠶࠻㐳 x. D. 0 ⓨᦼ㑆㐳 x. (a)ࡄࠤ࠶࠻㐳ಽᏓ. (b)ⓨᦼ㑆㐳ಽᏓ. ࿑ 3 ࡄࠤ࠶࠻㐳ߣⓨᦼ㑆㐳ߩ⏕₸ኒᐲಽᏓ ᑼ(19)ࠍ࡜ࡊ࡜ࠬㅒᄌ឵ߔࠇ߫ㆃᑧᤨ㑆ߦ㑐ߔࠆ⏕₸ኒᐲ㑐ᢙࠍᓧࠆߎߣ߇ߢ߈ࠆ㧚  ߒ߆ߒߥ߇ࠄ㧘ᑼ(19)ߩ᣿␜⊛ߥㅒᄌ឵ࠍ᳞߼ࠆߎߣߪ࿎㔍ߢ޽ࠆߩߢ‫ ޔ‬DT  1 ߣߒ  . 1 DT 2 1  e  DT | 1   O DT

(83) DT 2. >.

(84). @. (20). ߢㄭૃߒߡ㧘 DT

(85) એ਄ߩߴ߈ਸ਼ࠍήⷞߔࠆ㧚ᑼ(19)ߪ߈ࠊ߼ߡ◲නൻߐࠇߡ 2.   v * T

(86). OQ 1 T s0. OQ. ª D ·º § «1  O ¨ s 0  2 ¸» © ¹¼ ¬. (21). 1 T  1  U c

(87) s0. ߣߥࠅ㧘ߘߩㅒᄌ឵ߪᰴᑼߣߥࠆ㧚   v x

(88). OQe  1 U c

(89) x s. (22). 0. >. @.

(90). ᑼ(21)ߦ߅ߌࠆㄭૃߢߪ O DT

(91) ࠍήⷞߒߚ㧚ߎࠇߪ㧘ᑼ(22)ࠃࠅ O 1  U c

(92) D s 0

(93) ࠍ 2. 2. ήⷞߔࠆߎߣߣห╬ߢ޽ࠆ㧚ߎߩ᧦ઙߪ㧘 D ߇ s0 ߦኻߒߡᭂ߼ߡዊߐ޿߆㧘⽶⩄ U c ߇ 1 ߦㄭߊ㊀޿႐วߦ⋧ᒰߔࠆ㧚ߒߚ߇ߞߡ㧘ᑄ᫈₸߇ᄢ߈޿႐วߩㄭૃߢ޽ࠆ㧚  CDF ߪ㧘ᑼ(22)ࠃࠅ x.   V x

(94). V 0

(95)  ³ OQe  1 U c

(96) [ s0 d[ 1  U eq e  1 U c

(97) x s0. (23). 0. ߣߥࠅ㧘ᑼ(5)ߩ╬ଔ⽶⩄㧘ᑼ(12)ߩᡆૃ⽶⩄ࠍ↪޿ߚ߈ࠊ߼ߡ◲නߥᑼߣߥࠆ㧚 ᑼ(23)ߪ㧘M/M/1 ࠪࠬ࠹ࡓߦ߅ߌࠆቴߩᓙߜᤨ㑆ಽᏓ㑐ᢙߣหᒻߢ޽ࠆ[15]㧚ߚߛߒ㧘 Ყ଀ଥᢙߩ⽶⩄ U ߇╬ଔ⽶⩄ U eq ߣߥࠅ㧘ᜰᢙㇱߢߪ⽶⩄߇ᡆૃ⽶⩄ U c ߣ⟎߈឵ࠊߞߡ޿. 9- - .

(98) ࠆߜ߇޿߇޽ࠆ㧚ᡆૃ⽶⩄ U c ߇㧘઒ᗐᓙߜᤨ㑆 x ߩ⫾ⓍಽᏓ㑐ᢙߦ߅ߌࠆᜰᢙㇱಽ㧔ߎࠇ ᧃ┵ಽᏓ㧔tail distribution㧕ߦ⋧ᒰߔࠆ㧕ߦ߅ߌࠆ⽶⩄ߣߥࠆℂ↱ߪ㧘એਅߩ ߪ޿ࠊࠁࠆᧃ ࠃ߁ߦ⠨߃ࠄࠇࠆ㧚 ⽶⩄߇ᄢ߈޿႐วߦߪ㧘ߔߴߡߩࡄࠤ࠶࠻ߪశࡃ࠶ࡈࠔࠍ⚻↱ߒߡ಴ജߐࠇࠆ㧚․ߦ㧘 ᑄ᫈ߐࠇࠆ⏕₸ࠍ໧㗴ߣߔࠆࠃ߁ߥ႐㕙ߢߪ㧘శࡃ࠶ࡈࠔ߇Ᏹߦḩ᧰ߢ޽ࠆ⁁ᴫߢ޽ࠆߩ ߢ㧘ࡄࠤ࠶࠻ߦߪᔅߕⓨᦼ㑆߇ઃടߐࠇߚ⁁ᘒߣߥࠆ㧚ታ㓙㧘઒ᗐᓙߜᤨ㑆 x ߩ⏕₸ኒᐲ 㑐ᢙߦኻߔࠆၮᧄᑼ(6)ߢߪ㧘ಽᲣߩࠨ࡯ࡆࠬᤨ㑆ߦ㑐ߔࠆಽᏓ㑐ᢙߣߒߡ㧘㕖ೋᦼ೔⌕ࡄ ࠤ࠶࠻ߩࠨ࡯ࡆࠬᤨ㑆㑐ᢙ g x

(99) ߇↪޿ࠄࠇߡ޿ࠆ㧚  ᑼ(23)ࠍᑼ(13)ߦઍ౉ߒߡ㧘ᜰᢙ㑐ᢙಽᏓߦኻߔࠆᦨೋߩᑄ᫈₸ㄭૃᑼ PB , M 1 ࠍᓧࠆ㧚.  . PB , M 1. 1  U c

(100) U eq e  1 U c

(101) T s 1  U cU eq e  1 U c

(102) T. 0. (24). s0. 3.3 ৻⥸ಽᏓࡄࠤ࠶࠻㐳 ᜰᢙ㑐ᢙಽᏓߦ߅޿ߡߪ㧘ᓙߜᤨ㑆ߩ⚥ⓍಽᏓ߇න⚐ߥᜰᢙ㑐ᢙߣߥࠆߎߣࠍ೨▵ߢ᣿ ࠄ߆ߦߒߚ㧚GI/GI/1 ࠪࠬ࠹ࡓߦ߅޿ߡ㧘ᓙߜᤨ㑆ಽᏓࠍන⚐ߥᜰᢙ㑐ᢙߢㄭૃߔࠆߎߣ ߦኻߒߡ⃻࿷߹ߢߦ♖ജ⊛ߥ⎇ⓥ߇ߥߐࠇߡ޿ࠆ[16-20]㧚GI/GI/1 ࠪࠬ࠹ࡓߣߪ㧘ቴߩ೔ ⌕㑆㓒߇⁛┙ߢဋ৻ߦಽᏓߒߡ߅ࠅ㧔iid㧦independent and identically distributed㧕㧘୘‫ޘ‬ ߩቴߩࠨ࡯ࡆࠬᤨ㑆߽⁛┙ߢဋ৻ߦಽᏓߒߡ޿ࠆࡕ࠺࡞ߢ޽ࠆ㧚ߐࠄߦ㧘೔⌕㗅ಣℂࠍ઒ ቯߔࠆ㧚ߎߩࠪࠬ࠹ࡓߦ߅޿ߡ㧘ቴ߇೔⌕ߒߚᤨὐߢߩ઒ᗐᓙߜᤨ㑆 w ߇ x એਅߢ޽ࠆ⏕ ₸ P x ! w

(103) { W x

(104) ࠍᰴᑼߢㄭૃߔࠆ㧚. W A x

(105) 1  Ce Kx                           (25) ߎߎߢ㧘 K ࠍᷫ⴮₸㧔decay rate㧕㧘 C ࠍቯᢙ㧔constant㧕ߣ๭߱㧚ᑼ(25)ߪ㧘 x ߇㕖Ᏹߦ ᄢ߈ߊ㧘⽶⩄ a ߇㊀޿㧔1 ߦㄭ޿㧕႐วߦߪࠃ޿ㄭૃߢ޽ࠆߎߣ߇᣿ࠄ߆ߦߐࠇߡ޿ࠆ㧚 ᑼ(23)ߢߪ㧘ᷫ⴮₸ߪ 1  U c

(106) s0 㧘ቯᢙߪ U eq ߣߥߞߡ޿ࠆ㧚߽ߒ㧘  W x

(107) | W A x

(108). (26). ߢ޽ࠆߥࠄ߫㧘ᐔဋᓙߜᤨ㑆 w ࠍ↪޿ߡ㧘 f.  w. f. dW A ³ xdWA x

(109) ³ x dx dx 0.  W A 0

(110). 0. f. CK ³ xe Kx dx 0. 1 C 1 a. C. K. 㧘         . (27). (28). ࠃࠅ㧘  C. a. (29). - 10 .

(111) a w.  K. (30). ࠍᓧࠆ㧚․ߦ㧘M/G/1 ࠪࠬ࠹ࡓߢߪ㧘ᐔဋᓙߜᤨ㑆 w ߣߒߡᰴᑼߩࡐ ࡐ࡜࠷ࠚ࠶ࠢ࡮ࡅࡦࠠ ࡦߩᐔဋ୯౏ᑼ㧔Pollaczek-Khinchin mean value formula㧕[21]ࠍᓧߡ޿ࠆ㧚. s a 1  Cb.   w. 2.

(112). 㧔31㧕. 2 1  a

(113) 2. ߎߎߢ‫ ޔ‬C b ߪࠨ࡯ࡆࠬᤨ㑆ߩಽᢔ㧔variance㧕ࠍࠨ࡯ࡆࠬᤨ㑆ᐔဋ s ߩੑਸ਼ߢⷙᩰൻ ߒߚ߽ߩߢ޽ࠆ㧚ߒߚ߇ߞߡ㧘M/G/1 ࠪࠬ࠹ࡓߦ߅ߌࠆ઒ᗐᓙߜᤨ㑆⚥ⓍಽᏓߪ. ª 2 1  a

(114) x º 1  a exp « » 2 «¬ 1  C b s »¼.   W x

(115). (32). ߣߥࠆ㧚ᑼ(32)ࠍዉ಴ߔࠆߦᒰࠅ㧘↪޿ߚㄭૃߪᑼ(25)ߩߺߢ޽ࠆ㧚  ᑼ(23)ߢߪ㧘ቯᢙ C ߪ╬ଔ⽶⩄ U eq ߢ޽ࠅ㧘ᷫ⴮₸ߦ߅ߌࠆ⽶⩄ߪᡆૃ⽶⩄ U c ࠍ↪޿ߡ ޿ࠆ㧚ߘߎߢ㧘ᑼ(6)ߩ⸃ߣߒߡᰴᑼߢㄭૃߔࠆ㧚. ª 2 1  U c

(116) x º 1  U eq exp « » 2 «¬ 1  C g sX »¼. (33). s. (34).   V x

(117) ߎߎߢ㧘. Cg. 2. X. 2.  sX. 2.

(118) s. s0  D 2. ᑼ(4)ࠃࠅ sX. 2. X. 㧘. U c O ߢ޽ࠆ㧚ᑼ(13)ߩᑄ᫈₸ߪ 1  V T

(119) ߦ߶߷Ყ଀ߔࠆߩߢ㧘 2. ᷫ⴮₸߇ᄢ߈޿ߣᜰᢙ㑐ᢙ⁁ߦᑄ᫈₸ߪዊߐߊߥࠆ㧚ߔߥࠊߜ㧘ಽᢔ୯ C g ߇ዊߐ޿߶ߤ ᑄ᫈₸ߪዊߐߊߥࠆ㧚  ᑼ(34)ߦ߅ߌࠆಽᢔࠍ㧘ฦࡄࠤ࠶࠻㐳 ಽᏓߦߟ޿ߡ᳞߼ࠆ㧚 (1) ᜰᢙ㑐ᢙಽᏓ. 1 D. ࡄࠤ࠶࠻㐳ಽᏓࠍᰴᑼߣߔࠆߣ. g x

(120). 1  x s0 e s0. g 0 x

(121). ᑼ(3㧕ࠃࠅ㧘 g x

(122) ߪ࿑㧠ߦ␜ߔࠃ߁ߦ. g x

(123). 0 0. 1 1  e  x s0  for 0 d x d D D.

(124). D x. ࿑ 4. ᜰᢙ㑐ᢙಽᏓߦ߅ߌࠆ g x

(125). - 11 .

(126) 1 D s0 e  1 e  x s0  for D  x D. .

(127). 2. ߣߥࠅ㧘ᰴᑼߦࠃ߁ߦᜰᢙ㑐ᢙಽᏓߦኻߔࠆಽᢔ C g ,M ࠍᓧࠆ㧚. ª 2 1 § D ·2 º 2 « s 0  ¨ ¸ » sX    3 © 2 ¹ ¼» ¬«. 2.   C g ,M. (35).  ߎߎߢ㧘. 1  C. 2 g ,M.

(128) s. X. s0. 4§ D 2  ¨¨ 3 © 2s0. · ¸¸ ¹. 2. § D · ¨¨1  ¸¸ ! 2  © 2s0 ¹. ߢ ޽ ࠆ ߩ ߢ 㧘 ⓨ ᦼ 㑆 ߦ 㑐 ߔ ࠆ ಽ ᢔ O D 2s 0

(129). 1  U c

(130) s0 ࠃࠅዊߐ޿㧚߹ߚ‫ ޔ‬O D.

(131) ߇ ข ࠅ ౉ ࠇ ࠄ ࠇ 㧘 ᷫ ⴮ ₸ ߪ ᑼ (23) ߩ. 2.

(132). 2s0

(133) ߇ขࠅ౉ࠇࠄࠇߡ޿ࠆߎߣ߆ࠄ㧘ᑼ(23)ࠃࠅ 2. ♖ᐲ߇㜞޿ߣ޿߃ࠆ㧚 (2). ࿕ቯ㐳ಽᏓ.  g 0 x

(134). 1 D. G x  s0

(135)  g x

(136). ࠃࠅ㧘࿑㧡ߦ␜ߔ   g x

(137). l x  s0

(138). ߣߥࠅ㧘ߘߩಽᢔߪᰴᑼߣߥࠆ㧚   C g ,D. 2. (3). 1§ D· ¨ ¸ 3© 2 ¹. 0. 0. s0  D. s0 x. 2 2. sX    (36). ࿑ 5. ࿕ቯ㐳ߦ߅ߌࠆ g x

(139). ဋ৻ಽᏓ.  ࡄࠤ࠶࠻㐳߇޽ࠆ᏷[0㧘 2s 0 ]ߩ▸࿐ౝߢဋ৻ߦಽᏓߒߡ޿ࠆߣߔࠆߣ㧘. g 0 x

(140). 1 >u x

(141)  u x  2s0

(142) @ 㧘 2s0. ߐࠄߦ g x

(143) ߪ࿑ 6 ߩบᒻߣߥࠅ. g x

(144). g x

(145). x  for 0 d x d D 2s0 D. 1 2s0. 0. 0. 2s0. D. 2s0  D. x 1 2s0. for D  x d 2s 0. ࿑ 6. ဋ৻ಽᏓߦ߅ߌࠆ g x

(146). - 12 .

(147) 1 > 2s0  D

(148)  x@  for 2s0  x d 2s 0  D 2s0 D. 0.        . for 2 s 0  D  x 㧘. ߘߩಽᢔߪᰴᑼߣߥࠆ㧚. C g ,U. 2 1ª 2 §D· º 2 « s 0  ¨ ¸ » sX     3 ¬« © 2 ¹ ¼». 2. (37).  ߎࠇࠄ 3 ߟߩಽᢔߩ߁ߜ㧘ᑼ(36)ߩ࿕ቯ㐳ಽᏓ߇ᦨዊߢ޽ࠆߩߢ㧘ߘߩᑄ᫈₸ߪᦨዊߣ ߥࠆ㧚 (4). ⶄᢙ࿕ቯ㐳ಽᏓ. ࠗࡦ࠲࡯ࡀ࠶࠻ߢォㅍߐࠇࠆ IP ࡄࠤ࠶࠻ߢߪ㧘40‫ޔ‬552‫ޔ‬576‫ޔ‬1500 ࡃࠗ࠻ߥߤ․ቯࡄ ࠤ࠶࠻㐳ߩ߽ߩ߇࿶ୟ⊛ߢ޽ࠆ[22]㧚ታ㓙ߩ IP ࡀ࠶࠻ࡢ࡯ࠢࠍᮨᡆߔࠆߦߪ㧘ⶄᢙ୘ߩ․ ቯࡄࠤ࠶࠻㐳ߩߺߢォㅍࡄࠤ࠶࠻߇᭴ᚑߐࠇߡ޿ࠆߣ⠨߃ࠆᔅⷐ߇޽ࠆ㧚. n ୘ߩ․ቯࡄࠤ࠶࠻㐳ࠍߘࠇߙࠇ s i i 1,2,, n

(149) 㧘ߘࠇߙࠇߩ೔⌕₸ࠍ Oi i 1,2, , n

(150) ߣ߅ߊ㧚ኒᐲಽᏓ㑐ᢙߪ n.   g 0 x

(151). ¦ p G x  s

(152) i. i. i 1. ߣߥࠆ㧚ߎߎߢ   pi. Oi. Oi 㧘 O O. n. ¦O. n. ¦O. i. 㧘ߢ޽ࠅ. i 1. i. i 1. n. s0. n. ¦ps ¦ i i. i 1. i 1. Oi s i O. n U 㧘 U { ¦ Oi s i O i 1. ߢ޽ࠆ㧚ߐࠄߦ   g x

(153). n. ¦ p l x  s

(154) i. i. i 1.   1  C g , MD. 2. 2 2 ªn § D· 1§ D· º 2 «¦ pi ¨ si  ¸  ¨ ¸ » sX    2¹ 3 © 2 ¹ ¼» ¬« i 1 ©. ߣߥࠆ㧚. - 13 . (38).

(155) 㧠㧚 ᢙ୯଀ 4.1 ㄭૃᑼߩ♖ᐲ  ᑼ(33)ߪ㧘ᓙߜᤨ㑆 x ߇චಽᄢ߈ߊߡ㧘㊀޿⽶⩄㧔heavy traffic㧕ߩ႐วߢߩㄭૃߢ޽ ࠆ㧚ߎߩ⸘▚ᑼߩ♖ᐲࠍ᳞߼ࠆߚ߼㧘ᢥ₂[6]ߢߩࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐ߅ࠃ߮ᢥ₂[9]ߢߩ ᜰᢙ㑐ᢙಽᏓߩ෩ኒ⸃ߣᲧセߔࠆ㧚  ᓙߜᤨ㑆 x ߇ᄢ߈ߊ㧘㊀޿⽶⩄ߩ႐วߩ଀ߣߒߡ㧘B=256㧘ǹ㧩0.8 ߦ߅ߌࠆࡄࠤ࠶࠻ ᑄ᫈₸ࠍ FDL ☸ᐲ D ߦኻߒߡ࿑ 7 ߦ␜ߔ㧚ታ✢ߪࡄࠤ࠶࠻㐳ಽᏓ߇ᜰᢙ㑐ᢙಽᏓ㧘⎕✢ ߪဋ৻ಽᏓ㧘߅ࠃ߮ὐ✢ߪ࿕ቯ㐳ߩ႐วߩㄭૃ⸘▚⚿ᨐࠍߘࠇߙࠇ␜ߔ㧚ᑄ᫈₸ߩ⸘▚ߦ ߪ㧘ᑼ(13)ߣ(33)ࠍ↪޿㧘ฦಽᏓߩᷫ⴮₸ߦߪᑼ(35)㧘ᑼ(36)㧘߅ࠃ߮ᑼ(37)ߩಽᢔᑼࠍ↪ ޿ߚ㧚߹ߚ㧘ᐔဋࡄࠤ࠶࠻㐳ߢ޽ࠆ s0 ࠍᤨ㑆න૏㧘ߔߥࠊߜ s 0. 1 ߣߒߚ㧚ਣ㧘ࡃ࠷㧘ਃ. ⷺߩฦශߪ㧘ᢥ₂[6]ߢߩࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐߢ޽ࠆ㧚࿕ቯ㐳ಽᏓߩ႐วߩ⺋Ꮕ߇ᦨ߽ᄢ ߈޿߇㧘ߘࠇߢ߽ 25㧑એౝߦ෼߹ߞߡ߅ࠅ㕖Ᏹߦࠃ޿ㄭૃߢ޽ࠆߎߣ߇ℂ⸃ߐࠇࠆ㧚  ࿑ 8 ߪ㧘⽶⩄ߦኻߔࠆᑄ᫈₸⸘▚⚿ᨐࠍ␜ߔ㧚ᓙߜᤨ㑆 x ߪᲧセ⊛ዊߐ޿႐ว B㧩32 ߣ ߒߡ᳞߼ߚ㧚✢ߣ⸥ภߩᗧ๧ߪ㧘࿑ 7 ߣห᭽ߢ޽ࠆ㧚⽶⩄߇シ޿㧔light traffic㧕ߣ߈㧘ᜰ ᢙ㑐ᢙ㧘ဋ৻ಽᏓ㧘࿕ቯ㐳ߩ㗅ߦ♖ᐲߩᖡ޿⚿ᨐߣߥߞߡ߅ࠅ㧘ߚߣ߃߫⽶⩄߇ 0.3 ߩߣ ߈㧘ဋ৻ಽᏓ㧘࿕ቯ㐳ߩᑄ᫈₸ߪ㧘ࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐࠃࠅ 1 ᩴ⒟ᐲᄢ߈ߥ୯ߢ޽ࠆ㧚 ߚߛߒ㧘⽶⩄߇ 0.7 એ਄ߣߥࠆߣߘߩ⺋Ꮕߪ 10㧑એౝߣߥࠅ㧘ࠃ޿ㄭૃߢ޽ࠆߎߣߪℂ⸃ ߐࠇࠆ㧚ᜰᢙ㑐ᢙಽᏓߩ႐วߦߪ㧘⽶⩄߇ዊߐ޿႐วߢ߽ㄭૃ♖ᐲߪࠃߊ㧘ߔߴߡߩ႐ว  㪈㪅㪇. 㪙㫃㫆㪺㫂㫀㫅㪾㩷㫇㫉㫆㪹㪸㪹㫀㫃㫀㫋㫐 ᑄ᫈₸ PB. 㪈㪇㪄㪈. B. 256. U. 0.8. 㪈㪇㪄㪉 㪈㪇㪄㪊. ᜰᢙ㑐ᢙಽᏓ. 㪈㪇㪄㪋. ဋ৻ಽᏓ. 㪈㪇㪄㪌. ࿕ቯ㐳ಽᏓ. 㪄㪍. 㪈㪇. 㪈㪇㪄㪎. 㪇㪅㪇 㪇㪅㪇㪌 㪇㪅㪈㪇 㪇㪅㪈㪌. 㪇㪅㪉㪇. 㪇㪅㪉㪌. 㪇㪅㪊㪇 㪇㪅㪊㪌 㪇㪅㪋㪇 㪇㪅㪋㪌. FDL ☸ᐲ D 㪝㪛㪣㩷㪾㫉㪸㫅㫌㫃㪸㫉㫀㫋㫐㩷 ࿑ 7.. FDL ☸ᐲ D ߦኻߔࠆᑄ᫈₸.     㧔ታ✢ߪࡄࠤ࠶࠻㐳ಽᏓ߇ᜰᢙ㑐ᢙಽᏓ㧘⎕✢ߪဋ৻ಽᏓ㧘߅ࠃ߮ὐ✢ߪ࿕ቯ 㐳ߩ႐วߩㄭૃ⸘▚⚿ᨐࠍ㧘ਣ㧘ࡃ࠷㧘ਃⷺߩฦශߪᢥ₂[6]ߢߩࠪࡒࡘ࡟࡯ࠪ ࡚ࡦ⚿ᨐߘࠇߙࠇ␜ߔ㧚㧕. - 14 .

(156) 㪈㪅㪇. B. 32. D. 0 .3. 㪄㪈. ᑄ᫈₸ PB. 㪙㫃㫆㪺㫂㫀㫅㪾㩷㫇㫉㫆㪹㪸㪹㫀㫃㫀㫋㫐. 㪈㪇. ᜰᢙ㑐ᢙ. ဋ৻ 㪄㪉. 㪈㪇. 㪈㪇㪄㪊 㪈㪇㪄㪋. ࿕ቯ㐳 㪄㪌. 㪈㪇. 㪈㪇㪄㪍 㪈㪇㪄㪎 㪇㪅㪊. 㪇㪅㪋. 㪇㪅㪌. 㪇㪅㪍. 㪇㪅㪎. 㪇㪅㪏. ⽶⩄ ǹ 㪦㪽㪽㪼㫉㪼㪻㩷㫃㫆㪸㪻 ࿑ 8. ⽶⩄ U ߦኻߔࠆᑄ᫈₸     㧔ታ✢ߣ⸥ภߪ࿑ 7 ߣหߓᗧ๧ߢ޽ࠆ㧚㧕. ߢ 20㧑એౝߩ♖ᐲࠍᓧߡ޿ࠆ㧚ᑄ᫈₸ߩ୯ߣߒߡߪ㧘ࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐࠃࠅᄢ߈ߊ⸘ ▚ߐࠇࠆߎߣ߆ࠄ㧘ᦨᖡߩ⸳⸘୯ߣߒߡߪ೑↪ߢ߈ࠆ㧚 ᜰᢙ㑐ᢙಽᏓߦ߅ߌࠆ♖ᐲࠍ㧘ߐ߹ߑ߹ߥ⽶⩄ U ߣ FDL ᢙ B ߩ୯ߦኻߒߡ⏕⹺ߒߚ㧚 ࿑ 9 ߪ㧘B㧩32 ߦ߅ߌࠆᑄ᫈₸ࠍ㧘ߐ߹ߑ߹ߥ U ߣ FDL ☸ᐲ D ߦኻߒߡ᳞߼ߚ⚿ᨐߢ޽ ࠆ‫ޕ‬ή㒢㐳శࡃ࠶ࡈࠔࡕ࠺࡞ߦ߅ߌࠆ෼᧤᧦ઙ U eq  1 ࠃࠅ‫ ޔ‬D ߦߪᰴᑼߩᦨᄢ୯ Dmax ߇ ሽ࿷ߔࠆ[10].   Dmax. 2s 0 1 U  1

(157). 㧔39㧕. ታ✢ߪㄭૃ⸘▚⚿ᨐߢ޽ࠅ㧘ਣߪᢥ₂[6]ߢߩࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐߢ޽ࠆ㧚⽶⩄߇シ޿ U 0.4 ߩ႐วߢ߽‫ޔ‬චಽߥ♖ᐲࠍ଻ߞߡ޿ࠆ‫ޕ‬ ᑄ᫈₸ࠍᦨዊߣߔࠆ D ߩ୯ Dopt ߪ㧘⽶⩄ߩ୯ߦࠃࠅ⇣ߥࠆߎߣ㧘 Dopt ઃㄭߢߪ D ߩᄌ ൻߦኻߒߡᑄ᫈₸ߪ㊰ᗵߢ޽ࠆߎߣ㧘FDL ᢙ B ߩ୯߅ࠃ߮ࡄࠤ࠶࠻㐳ಽᏓߦߪ޽߹ࠅᓇ㗀 ࠍ߁ߌߥ޿ߎߣ‫ߩߤߥޔ‬ᕈ⾰߇⍮ࠄࠇߡ޿ࠆ[6]㧚࿑ 7㧘࿑ 9 ߣᰴߦ␜ߔ࿑ 10 ߆ࠄ‫ޔ‬Dopt ߩ ୯ߣߘߩᕈ⾰ࠍ⺒ߺขࠆߎߣ߇ߢ߈ࠆ㧚ߚߣ߃߫㧘U. U. 0.8 ߦ߅޿ߡ Dopt | 0.25 ߢ޽ࠆ߇㧘. 0.4 ߢߪ Dopt | 1.4 ߢ޽ࠅ㧘⽶⩄ߦࠃࠅ D ߩᦨㆡ୯ߪ⇣ߥࠆ㧚. - 15 .

(158) 㪈. U. 㪄㪈. 㪙㫃㫆㪺㫂㫀㫅㪾㩷㫇㫉㫆㪹㪸㪹㫀㫃㫀㫋㫐 ᑄ᫈₸ PB. 㪈㪇. B. 0 .8. U. 32. 0 .7. 㪈㪇㪄㪉 U. 㪈㪇㪄㪊. 0 .6. U. 0 .5. 㪄㪋. 㪈㪇. U. 0 .4. 㪈㪇㪄㪌 㪈㪇㪄㪍 㪈㪇㪄㪎 㪇. 㪇㪅㪌. 㪈㪅㪇. 㪈㪅㪌. 㪉㪅㪇. 㪉㪅㪌. 㪊㪅㪇. 㪝㪛㪣㩷㪾㫉㪸㫅㫌㫃㪸㫉㫀㫋㫐㩷㪛 FDL ☸ᐲ D ࿑ 9. B㧩32 ߦ߅ߌࠆᑄ᫈₸    㧔ታ✢ߣㄭૃ⸘▚⚿ᨐ㧘ฦ⸥ภߪࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐ[6]ߢ޽ࠆ㧚㧕. 㪈. ᑄ᫈₸ PB 㪙㫃㫆㪺㫂㫀㫅㪾㩷㫇㫉㫆㪹㪸㪹㫀㫃㫀㫋㫐. 㪈㪇㪄㪇㪌. B. 5. B. 20. 㪈㪇㪄㪈㪇 B. 㪈㪇. 50. 㪄㪈㪌. U. 0.25. 㪈㪇㪄㪉㪇 㪇㩷. 㪈㪅㪇. 㪉㪅㪇 FDL ☸ᐲ D 㪝㪛㪣㩷㪾㫉㪸㫅㫌㫃㪸㫉㫀㫋㫐㩷㪛. ࿑ 10. ǹ㧩0.25 ߦ߅ߌࠆᑄ᫈₸    㧔ታ✢ߪㄭૃ⸘▚㧘⎕✢ߪ෩ኒ⸃[9]ࠍ␜ߔ㧚㧕. - 16 . 㪊㪅㪇. 㪋㪅㪇.

(159) ࿑ 10 ߪ㧘FDL ᢙ B ࠍࡄ࡜ࡔ࡯࠲ߣߒߡシ޿⽶⩄ U. 0.25 ߩ႐วߦ߅ߌࠆᑄ᫈₸⸘▚⚿. ᨐࠍ␜ߔ㧚 B ߩ୯ߪ㧘෩ኒ⸃[9]ߣᲧセߢ߈ࠆࠃ߁ߦㆬᛯߒߚ㧚ታ✢ߪㄭૃ⸘▚㧘⎕✢ߪ෩ ኒ⸃⸘▚ߩ⚿ᨐߢ޽ࠆ㧚 B. 50 ߩ႐ว㧘෩ኒ⸃ߣᲧセߒߡㄭૃ⸘▚⚿ᨐߪᦨᄢ 50 ୚㜞޿. ୯ࠍ␜ߔ߇‫ ޔ‬B ߇ዊߐߊߥࠆߦߟࠇ㧘ᑄ᫈₸߇਄߇ࠆߣ߽ߦ♖ᐲߪჇߔ㧚 ߎࠇࠄߩ⚿ᨐࠃࠅ㧘ㄭૃ⸘▚ߪ෩ኒ⸃ࠃࠅᏱߦ㜞޿୯ࠍ␜ߔߩߢ㧘ᑄ᫈₸ߩᦨᖡ୯ࠍ᳞ ߼ࠆߦߪᧄឭ᩺ㄭૃ⸘▚ߪ᦭ലߢ޽ࠆߎߣ߇ࠊ߆ࠆ㧚߹ߚ㧘ᑄ᫈₸߇ᄢ߈ߊߥࠆߣ♖ᐲ߇ Ⴧߔߎߣ߽᦭೑ߥὐߢ޽ࠆ㧚  ᐔဋㆃᑧᤨ㑆ߪ㧘ᑼ(33)ࠍ↪޿ࠆߣ㧘ᑼ(7)ࠃࠅ   wT. ª 1 º § 1 D ·ª Q º  ¨¨  ¸¸ «1  T «1  » » ¬ V T

(160) ¼ © K 2 ¹ ¬ V T

(161) ¼. (40). ࠃࠅ⸘▚ߢ߈ࠆ㧚ᓙߜᤨ㑆 x ߇ᄢ߈ߊ㧘㊀޿⽶⩄㧔heavy traffic㧕ߩ႐วߩ଀ߣߒߡ㧘B=256㧘 ǹ㧩0.8 ߦ߅ߌࠆᐔဋㆃᑧᤨ㑆ࠍ࿑ 11 ߦ␜ߔ㧚✢ߣ⸥ภߩᗧ๧ߪ㧘࿑ 7 ߣห᭽ߢ޽ࠆ㧚ߔ ߴߡߩಽᏓߦ߅޿ߡ߽♖ᐲߪ߈ࠊ߼ߡ㜞ߊ㧘⺋Ꮕߪᦨᄢߢ߽ 2㧑ߢ⺒ߺขࠅ♖ᐲ⒟ᐲߢ޽ ࠆ㧚  ᓙߜᤨ㑆 x ߇Ყセ⊛ዊߐ޿႐ว B㧩32 ߣߒߡ᳞߼ߚᐔဋㆃᑧᤨ㑆ࠍ㧘࿑ 12 ߦ␜ߔ㧚⽶ ⩄߇シ޿㧔light traffic㧕ߣ߈߶ߤࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐࠃࠅᄢ߈ߊ⸘▚ߐࠇߡ޿ࠆ߇㧘ߘ ߩᏅߪ࿕ቯ㐳㧘⽶⩄ 0.4 ߩߣ߈߇ᦨᄢߢ 20㧑ߢ޽ࠆ㧚ߔߴߡ⽶⩄ߦኻߒߡ㧘ࠪࡒࡘ࡟࡯ࠪ ࡚ࡦ⚿ᨐࠃࠅࠊߕ߆ߦᄢ߈ߊ⸘▚ߐࠇߡ޿ࠆ߇㧘ࠃ޿৻⥌ࠍ⷗ߖߡ޿ࠆ㧚ᄢ߈޿୯ߦࠪࡈ ࠻ߒߡ޿ࠆߎߣ߆ࠄ㧘ᦨᖡ୯ࠍ᳞߼ࠆߎߣߦߪ೑↪ߢ߈ࠆ㧚. 㪍㪇 B. U. 256. 0.8. Ɇ. 㪘㫍㪼㫉㪸㪾㪼㩷㪻㪼㫃㪸㫐㩷 ᐔဋㆃᑧᤨ㑆 WT. 㪌㪇 㪋㪇 ᜰᢙ㑐ᢙಽᏓ 㪊㪇 㪉㪇. ဋ৻ಽᏓ. 㪈㪇 ࿕ቯ㐳ಽᏓ 㪇 㪇. 㪇㪅㪈. 㪇㪅㪉. 㪇㪅㪊. 㪇㪅㪋. 㪝㪛㪣㩷㪾㫉㪸㫅㫌㫃㪸㫉㫀㫋㫐㩷㪛 FDL ☸ᐲ D ࿑ 11. FDL ☸ᐲ D 㧘 B. 256 ߦኻߔࠆᐔဋㆃᑧᤨ㑆.    㧔ታ✢ߣ⸥ภߪ࿑ 7 ߣหߓᗧ๧ߢ޽ࠆ㧚㧕. - 17 . 㪇㪅㪌.

(162) 㪋㪅㪇. B. 32. D. 0.3. Ɇ. 㪘㫍㪼㫉㪸㪾㪼㩷㪻㪼㫃㪸㫐 ᐔဋㆃᑧᤨ㑆 WT. 㪊㪅㪌 㪊㪅㪇. ᜰᢙ㑐ᢙ. 㪉㪅㪌 㪉㪅㪇. ဋ৻. 㪈㪅㪌 㪈㪅㪇. ࿕ቯ㐳. 㪇㪅㪌 㪇 㪇㪅㪊. 㪇㪅㪋. 㪇㪅㪍. 㪇㪅㪌. 㪇㪅㪎. 㪇㪅㪏. ⽶⩄ ǹ. 㪦㪽㪽㪼㫉㪼㪻㩷㫃㫆㪸㪻 ࿑ 12. FDL ☸ᐲ D 㧘 B. 32 ߦኻߔࠆᐔဋㆃᑧᤨ㑆.    㧔ታ✢ߣ⸥ภߪ࿑ 7 ߣหߓᗧ๧ߢ޽ࠆ㧚㧕. 4.2 ታ࠻࡜ࡅ࠶ࠢ߳ߩㆡ↪  ⃻ታߩ IP ࡀ࠶࠻ࡢ࡯ࠢߢߪ㧘․ቯࡄࠤ࠶࠻㐳ߦࡇ࡯ࠢࠍᜬߟಽᏓߣߥߞߡ޿ࠆߎߣߪ ࠃߊ⍮ࠄࠇߡ޿ࠆ㧚ߘߎߢ㧘ⶄᢙ࿕ቯ㐳ಽᏓߢߩᑄ᫈₸ࠍ᳞߼ࠆ㧚 Case.1 2 ࡄࠤ࠶࠻㐳  s1. 64 ࡃࠗ࠻㧘 s 2. 1518 ࡃࠗ࠻㧘ࠃߞߡ s 0. 791 ࡃࠗ࠻㧘 p1. p2. 0.5. Case.2 3 ࡄࠤ࠶࠻㐳  s1. p1. 64 ࡃ ࠗ ࠻ 㧘 s 2 p2. p3. 582 ࡃ ࠗ ࠻ 㧘 s3. 1518 ࡃ ࠗ ࠻ 㧘 ࠃ ߞ ߡ s 0. 721 ࡃ ࠗ ࠻ 㧘. 13. ߎߎߢ㧘ߎࠇࠄߩࡄࠤ࠶࠻ߦߪ࡟ࠗࠕ 2 ߦ߅ߌࠆࠗ࡯ࠨࡀ࠶࠻ࡈ࡟࡯ࡓࠍᗐቯߒߡ޿ࠆ㧚 ߒߚ߇ߞߡ㧘ᦨ⍴ 64 ࡃࠗ࠻㧘ᦨ㐳 1518 ࡃࠗ࠻ߢ޽ࠆ㧚  B=256㧘ǹ㧩0.8 ߦ߅ߌࠆࡄࠤ࠶࠻ᑄ᫈₸ࠍ㧘࿑ 13 ߦ␜ߔ㧚ᄥ✢ߩታ✢ߪ 2 ࡄࠤ࠶࠻㐳 ಽᏓ㧘ᄥ✢ߩὐ✢ߪ 3 ࡄࠤ࠶࠻㐳ಽᏓ㧘߅ࠃ߮⚦✢ߪ࿑ 7 ߣห᭽㧘ታ✢㧘⎕✢㧘ὐ✢ߢᜰ ᢙ㑐ᢙ㧘ဋ৻ಽᏓ㧘࿕ቯ㐳ߩ႐วࠍߘࠇߙࠇ␜ߔ㧚2 ࡄࠤ࠶࠻㐳㧘3 ࡄࠤ࠶࠻㐳ಽᏓߪ㧘 ᜰᢙ㑐ᢙಽᏓߣဋ৻ಽᏓߣߩ㑆ߦ૏⟎ߒ㧘2 ࡄࠤ࠶࠻㐳ಽᏓߩᣇ߇ᑄ᫈₸ߪᄢ߈޿㧚ࡄࠤ ࠶࠻㐳ಽᏓߦ߅ߌࠆಽᢔ߇ᄢ߈޿ߚ߼ߢ޽ࠆ㧚ታ㓙ߩ IP ࡀ࠶࠻ࡢ࡯ࠢߢߪ㧘3 ࡄࠤ࠶࠻ 㐳ಽᏓߣဋ৻ಽᏓࠍว⸘ߒߚಽᏓߣߥߞߡ޿ࠆߚ߼㧘ࡄࠤ࠶࠻㐳ಽᏓࠍታ᷹ߒߚ⚿ᨐࠍᱜ ⏕ߦ෻ᤋߔࠆߣ㧘࿑ 13 ߦ␜ߔࠃ߁ߦ㧘3 ࡄࠤ࠶࠻㐳ಽᏓߣဋ৻ಽᏓߣߩ㑆ߦ૏⟎ߔࠆߣ. - 18 .

(163) 㪈㪅㪇 B. 256. U. 0 .8. 㪄㪈. ᑄ᫈₸ PB. 㪙㫃㫆㪺㫂㫀㫅㪾㩷㫇㫉㫆㪹㪸㪹㫀㫃㫀㫋㫐. 㪈㪇. 㪉㩷 䊌䉬䉾䊃㐳 㪄㪉. 㪈㪇. 㪊㩷 䊌䉬䉾䊃㐳 㪄㪊. 㪈㪇. ᜰᢙ㑐ᢙ. 㪈㪇㪄㪋 㪈㪇㪄㪌. ဋ৻. ࿕ቯ㐳. 㪄㪍. 㪈㪇. 㪇㪅㪇. 㪇㪅㪇㪌. 㪇㪅㪈㪇 㪇㪅㪈㪌 㪇㪅㪉㪇 㪇㪅㪉㪌. 㪇㪅㪊㪇. 㪇㪅㪊㪌. 㪇㪅㪋㪇. 㪇㪅㪋㪌. FDL ☸ᐲ D 㪝㪛㪣㩷㪾㫉㪸㫅㫌㫃㪸㫉㫀㫋㫐㩷㪛 ࿑ 13. B. 256 㧘 U. 0.8 ߦ߅ߌࠆᑄ᫈₸.   㧔ᄥ✢ߪ 2 ࡄࠤ࠶࠻㐳㧘3 ࡄࠤ࠶࠻㐳ಽᏓ㧘⚦✢ߪᜰᢙ㑐ᢙ㧘ဋ৻㧘 ࿕ቯ㐳ಽᏓࠍߘࠇߙࠇ␜ߔ㧚㧕. ⠨߃ࠄࠇࠆ㧚. 㧡㧚 ߅ࠊࠅߦ  ᧄ⺰ᢥߢߪ㧘৻⥸ಽᏓࡄࠤ࠶࠻㐳ߦኻߒߡశࡄࠤ࠶࠻੤឵ᯏࡃ࠶ࡈࠔߦ߅ߌࠆᑄ᫈₸ߣ ㆃᑧᤨ㑆ࠍਈ߃ࠆㄭૃᑼࠍ⏕┙ߒߚ㧚ᓧࠄࠇߚㄭૃᑼߪ㧘ࠗࡦ࠲࡯ࡀ࠶࠻㧘NGN㧔next generation networks㧦ᰴ਎ઍᖱႎㅢାࡀ࠶࠻ࡢ࡯ࠢ㧕ߥߤ㧘ታ㓙ߩࡄࠤ࠶࠻ࡀ࠶࠻ࡢ࡯ ࠢߦ೑↪ߔࠆశࡄࠤ࠶࠻੤឵ᯏࠍ⸳⸘ߔࠆ਄ߢ᦭ജߥᱞེߦߥࠆ߽ߩߣ⏕ାߒߡ޿ࠆ㧚ᓧ ࠄࠇߚ⚿ᨐߪએਅߩߣ߅ࠅߢ޽ࠆ㧚 1). శࡃ࠶ࡈࠔߦ߅ߌࠆᑄ᫈₸ࠍ◲ଢߦ⸘▚ߔࠆ⋡⊛߆ࠄ㧘ᡆૃ⽶⩄ࠍ޽ࠄߚߦቯ⟵ߒߚ㧚 ߎߩᡆૃ⽶⩄ߪ㧘M/G/1/K ࠪࠬ࠹ࡓߦ߅ߌࠆ⽶⩄ߦઍࠊࠆ߽ߩߢ޽ࠆ㧚. 2). ৻⥸ಽᏓࡄࠤ࠶࠻㐳ߦኻߒߡ㧘઒ᗐᓙߜᤨ㑆ߩ⫾ⓍಽᏓ㑐ᢙ CDF ࠍ᳞߼ࠆㄭૃᑼࠍ ዉ಴ߒߚ㧚ߎߩㄭૃᑼߪ㧘ᓙߜᤨ㑆߇චಽᄢ߈ߊߡ㧘⽶⩄߇㊀޿ߣ߈߶ߤ᦭ലߢ޽ࠆ㧚. 3). ⽶⩄߇ 0.7 એ਄ߩߣ߈㧘ㄭૃᑼߦࠃࠆᑄ᫈₸⸘▚⚿ᨐߪ㧘ࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐ߿෩ ኒ⸃⸘▚⚿ᨐߣᲧセߒߡ 10㧑એౝߩ৻⥌ࠍߺߖߚ㧚ߒ߆ߒߥ߇ࠄ㧘⽶⩄߇シ޿႐วߦ ߪ♖ᐲ߇ᖡߊ㧘⽶⩄ 0.3 ߢࠪࡒࡘ࡟࡯࡚ࠪࡦ⚿ᨐߩ 10 ୚ߩ୯ߣߥߞߡ޿ࠆ㧚. 4). ᑄ᫈₸߇㜞޿ߣ♖ᐲߪࠃߊߥࠅ㧘⽶⩄߇シߊߡ♖ᐲ߇ᖡ޿႐วߦ߅޿ߡ߽㧘Ᏹߦ෩ኒ ⸃ࠃࠅ㜞޿ᑄ᫈₸ߢ޽ࠆߚ߼㧘᳞߼ߚㄭૃᑼߪᦨᖡ୯ࠍ᳞߼ࠆߎߣߦ᦭ലߢ޽ࠆ㧚.  ߐࠄߦ㧘੹ᓟߩ⺖㗴ߣᕁࠊࠇࠆ࠹࡯ࡑߪએਅߩߣ߅ࠅߢ޽ࠆ㧚. - 19 .

(164) i) シ޿⽶⩄ߦ߅ߌࠆㄭૃ⸘▚♖ᐲߩะ਄ ii) U ! 1 ߩ㊀޿⽶⩄ߩ႐วߦ߅ߌࠆᑄ᫈₸⸘▚ iii) ఝవᮭઃ߈శࡄࠤ࠶࠻੤឵ᯏߩ᭴ᚑឭ᩺ߣߘߩ࠻࡜ࡅ࠶ࠢℂ⺰ iv) ࡀ࠶࠻ࡢ࡯ࠢో૕ߢࠬ࡞࡯ࡊ࠶࠻ะ਄╷ߩឭ᩺ߣߘߩ࠻࡜ࡅ࠶ࠢℂ⺰ ߥߤߢ޽ࠆ㧚 ෳ⠨ᢥ₂ [1] R. S Tucker, “The Role of Optical and Electronics in High-Capacity Routers,” IEEE J. Lightwave Technol., Vol. 24, No. 12, pp. 4655-4673, 2006. [2] R. S Tucker et al, “Evolution of WDM Optical IP networks: A Cost and Energy Perspective,” IEEE J. Lightwave Technol., Vol. 27, No. 3, pp. 243-252, 2009. [3] G. Grasso et al, “Role of Integrated Photonics Technologies in the Realization of Terabit Nodes,” J. Opt. Commun. Netw., Vol. 1, No. 3, pp. B111-B119, 2009. [4] F. Callegati, “Optical Buffers for Variable Length Packets,” IEEE Commun. Lett., Vol. 4, No. 9, pp. 292-294, 2000. [5] Xiaohua Ma, “Modeling and Design of WDM Optical Buffers in Asynchronous and Variable-Length Optical Packets Switches,” Optical Commun., No. 269, pp. 53-63, 2007. [6] Jianming Liu et al., “Blocking and Delay Analysis of Single Wavelength Optical Buffer with General Packet Size Distribution,” IEEE J. Lightwave Technol., Vol. 27, No. 8, pp. 955-966, 2009. [7] H. E. Kankaya and N. Akar, “Exact Analysis of Single-Wavelength Optical Buffers with Feedback Markov Fluid Queues,” J. Opt. Commun. Netw., Vol. 1, No. 6, pp. 530-542, 2009. [8] W.Rogiest, D. Fiems, K.Laevens, and H. Bruneel, “Modeling the Performance of FDL Buffers with Wavelength Conversion”, IEEE Trans. Commun., Vol. 57, No. 12, pp. 3703-3711, 2009. [9] W. Rogiest, and H. Bruneel, “Exact Optimization Method for an FDL Buffer with Variable Packet Length”, IEEE Photon. Technol. Lett., Vol. 22, No. 4, pp. 242-244, 2010. [10] ᧛਄ᵏม㧘̌ࡄࠤ࠶࠻੤឵ᯏߩ࠻࡜ࡅ࠶ࠢℂ⺰㧔ߘߩ㧝㧕̆ᜰᢙ㑐ᢙಽᏓࡄࠤ࠶࠻㐳 ߦኻߔࠆㄭૃ⸃ᴺ̆̍㧘ᄢ㒋㔚᳇ㅢାᄢቇ⎇ⓥ⺰㓸㧔⥄ὼ⑼ቇ✬㧕㧘╙ 46 ภ㧘p.9-30 (2011) [11] Murakami Y., “An Approximation for Blocking Probabilities and Delays of Optical Buffer With General Packet-Length Distributions,” IEEE J. Lightwave Technol., Vol. 30, No. 1, pp. 54-66, 2012. [12] Percy H. Brill, “A Brief Outline of the Level Crossing Method in Stochastic Models,” CORS Bulletin Vol. 34, No. 4, pp. 1-8, 2000. [13] for example, Villy B. Iversen, “Teletraffic Engineering and Network Planning”, Technical University of Denmark, p. 270, 2010㧚 [14] Ṛᩮື຦‫ޔ‬દ⮮ᄢテ‫⷏ޔ‬የ┨ᴦ㇢⪺‫ޟ‬ጤᵄ⻠ᐳࠗࡦ࠲࡯ࡀ࠶࠻ 5 ࡀ࠶࠻ࡢ࡯ࠢ⸳⸘. - 20 .

(165) ℂ⺰‫ޠ‬ጤᵄᦠᐫ㧔2001 ᐕ㧕‫ޔ‬p.58‫ޔ‬ᑼ(2.42)‫ޕ‬ [15] for example, L. Kleinrock, “Queueing Systems, Vol. 1: Theory”, p.203, John Wiley & Sons, New York, 1975. [16] W. Feller, “An Introduction to the Theory of Probability and its Applications,” NewYork: John Wiley, 1966, 1971. [17] A. A. Fredricks, “A Class of Approximations for the Waiting Time Distribution in a GI/G/1 Queueing System,” Bell Syst. Tech. J. Vol. 61, pp. 295-325, 1982. [18] J. Abate, G. L. Choudhury, and W. Whitt, “Exponential approximations for tail probabilities in queues, I: Waiting Times,” Oper. Res., Vol. 43, No. 3, pp. 885-901, 1995. [19] Y. Jiang, C-K. Tham, C-C. Ko, “An Approximation for Waiting Time Tail Probabilities in Multiclass Systems,” IEEE Commu. Lett., Vol. 5, No. 4, pp. 175-177, 2001. [20] L. Kleinrock, “Queueing Systems, Vol. II: Computer Applications”, John Wiley & Sons, New York, 1976. [21] ߚߣ߃߫㧘᜕⪺‫޿ߒߐ߿ޟ‬ᖱႎ੤឵Ꮏቇ‫ޠ‬᫪ർ಴ 㧔2009 ᐕ㧕㧘p.66㧘ᑼ(2.51)㧚 [22] Fei Xue et al., “Design and Experimental Demonstration of a Variable-Length Optical Packet Routing System With Unified Contention Resolution,” IEEE J. Lightwave Technol., Vol. 22, No. 11, pp. 2570-2581, 2004.. - 21 .

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