作业_5

作业_5 - 200628017029197

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Unformatted text preview: 200628017029197 ARQ(Automatic Retransmission Request) R R ARQ(Stop-and-Wait ARQ) s7 - 6» @ @E 0 A0 B H x X . ª · tA h ‚ . ª · tBh ‚ B0 A ¨ .ª · t ‚ h (NAK); tA‚ h ª· B0 ACK ª · t‚h ) x¨ ª · t (h ‚ . ª · t )h ‚ ª ·t‚ h 0 A E 0 - EP-BE¹Š .`¹ -± ð ¹ N ÿ ƒ » lp (SN)h ª· t‚ (RN)0 SN RN ARQ 0 0 0 PSN ð lŽ G |.¸ ª · P‚l Ž € RN˜ tGñ CRC ¨ .ª · t ‚ h 10 a .¸ ª · P‚l Ž • G S ˜ t ñ →m SN 20 ¶ b] |.0 · tP Ž ` G R ˜ ¸ª ‚l ñ 30 c 0 R0 CRC ð PŽ G l SN0 =RN timeout .C· CS h ª t‚ ·, p (ACK); tB‚ h .ª · ª · tAh ‚ ACK · H x X B0 A0 . ª · t (h ‚ NAK0 0 CRC SN 0 SN 0 m0 S?m0 update(SN)0 RN 0 R!m0 update(RN) 40 d 0 .ª · t‚ ˆ R 50 t.ª S‚ ˆ t · 60 m, m S 0 R 0 70 k , k R 0 S 0 80 n, n R 0 S 0 ¨ m mR 0 ack 0 nak 0 S0 S0 m m a! m m b? m ack 0 nak 0 ª · t S¸ ‚ b!ack0 a?ack b!nak0 a?nak R0 . C· CS ¸ ª t‚ . ARQ ¸ ª·t‚ S = a .m.S1 S1 = k .S + t.m.S1 + n .m.S1 R = m .( c.n.R + d .k .R + b.k .R ) .ª ·t η ‚ . ARQ h ª·t‚ .Sª 0t R h ·‚ P=S|R ð Pl Ž G 200628017029197 Hwh . ª · Pl ð ARQ ˜¸ J 2Ž G ñ P=S|R = a .m.S1 | m .( c.n.R + d .k .R + b.k .R ) = a .( m.S1 | m .( c.n.R + d .k .R + b.k .R ) ) = a .I .( S1 | ( c.n.R + d .k .R + b.k .R ) ) = a .Q Q = S1 | ( c.n.R + d .k .R + b.k .R ) = k .S + t.m.S1 + n .m.S1 | ( c.n.R + d .k .R + b.k .R ) = t.( m.S1 | ( c.n.R + d .k .R + b.k .R ) ) + c. n.R | k .S + t.m.S1 + n .m.S1 + d . k .R | k .S + t.m.S1 + n .m.S1 + b. k .R | k .S + t.m.S1 + n .m.S1 = t.( c.( n.R | m.S1 ) + d .( k .R | m.S1 ) + b.( k .R | m.S1 ) ) + c.( t.( m.S1 | n.R ) + I .( R | m.S1 ) ) + d .( I .( S | R ) + t.( m.S1 | k .R ) ) + b.( I .( S | R ) + t.( m.S1 | k .R ) ) = c.W + ( b + d ).( S | R ) W = R | m.S1 = m .( c.n.R + d .k .R + b.k .R ) | m.S1 = I .( S1 | ( c.n.R + d .k .R + b.k .R ) ) = I .Q =Q .BJ ª0 · ARQJ 0 .ª · B ( ) ( ( )) ( ( )) ( ( )) = c.I .( R | m.S1 ) + d .I .( S | R ) + b.I .( S | R ) P = a .Q Q = c.Q + ( b + d ).P ...
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This note was uploaded on 10/20/2009 for the course CS G22 taught by Professor Sam during the Fall '06 term at Academy of Art University.

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