rfc1144.ps

RFC 的详细文档！

150 2016 p (when)s
7(low-level)m
8(feedback)m
7(\(character)m
7(echo\))m
8(takes)m
7(longer)m
7(than)m
8(100)m
7(to)m
7(200)m
7(ms.)m
16(Protocol)m
8(headers)m
150 2072 p (interact)s
11(with)m
12(this)m
11(threshold)m
12(three)m
11(ways:)m
187 2167 p (\(1\))s
23(If)m
11(the)m
10(line)m
10(is)m
10(too)m
11(slow)m
-2 r 44 c
9(it)m
11(may)m
10(be)m
10(impossible)m
11(to)m
10(\014t)m
10(both)m
11(the)m
10(headers)m
10(and)m
11(data)m
10(into)m
10 r 97 c
10(200)m
264 2224 p (ms)s
12(window:)m
18(One)m
13(typed)m
12(character)m
12(results)m
12(in)m
12 r 97 c
12(41)m
13(byte)m
12(TCP/IP)m
12(packet)m
12(being)m
12(sent)m
12(and)m
264 2280 p 97 c
13(41)m
14(byte)m
14(echo)m
13(being)m
14(received.)m
24(The)m
14(line)m
13(speed)m
14(must)m
14(be)m
13(at)m
14(least)m
14(4000)m
13(bps)m
14(to)m
14(handle)m
264 2336 p (these)s
11(82)m
12(bytes)m
11(in)m
11(200)m
12(ms.)m
150 2373 p 660 2 ru
t-rom.180 @sf 200 2409 p 49 c
t-rom.270 @sf 217 2425 p (The)s
11(tie)m
10(to)m
10(TCP)m
10(is)m
10(deeper)m
10(than)m
10(might)m
10(be)m
10(obvious.)m
17(In)m
10(addition)m
10(to)m
10(the)m
10(compression)m
10(\\knowing")m
10(the)m
10(format)m
10(of)m
150 2471 p (TCP)s
7(and)m
8(IP)m
7(headers,)m
8(certain)m
7(features)m
8(of)m
7(TCP)m
7(have)m
8(been)m
7(used)m
8(to)m
7(simplify)m
7(the)m
8(compression)m
7(protocol.)m
14(In)m
7(particular)m
-1 r 44 c
150 2516 p (TCP')s
-1 r 115 c
9(reliable)m
11(delivery)m
10(and)m
10(the)m
10(byte-stream)m
11(conversation)m
10(model)m
10(have)m
11(been)m
10(used)m
10(to)m
11(eliminate)m
10(the)m
10(need)m
11(for)m
10(any)m
150 2562 p (kind)s
9(of)m
10(error)m
9(correction)m
9(dialog)m
10(in)m
9(the)m
10(protocol)m
9(\(see)m
9(sec.)m
10(4\).)m
t-rom.300 @sf 150 2724 p (Jacobson)s
1357([Page)m
11(1])m
@eop
restore

%%Page: 2 4
save
/Times-SmallCaps /Times-Roman SmallCapsFont
/Times-SmallCaps /t-romsc.300 ReEncodeForTeX /t-romsc.300 /t-romsc.300 41.666629 TeXPSmakefont def
/Times-Roman /t-rom.300 ReEncodeForTeX /t-rom.300 /t-rom.300 41.666629 TeXPSmakefont def
/Times-Roman /t-rom.330 ReEncodeForTeX /t-rom.330 /t-rom.330 45.833249 TeXPSmakefont def
/Times-Italic /t-ita.330 ReEncodeForTeX /t-ita.330 /t-ita.330 45.833249 TeXPSmakefont def
/Times-Roman /t-rom.240 ReEncodeForTeX /t-rom.240 /t-rom.240 33.333265 TeXPSmakefont def
1 /cmmi10.329 @newfont
cmmi10.329 @sf
[<000001C00000078000001E00000078000001E00000078000000E0000003C000000F0000003C000
  000F0000003C000000F0000000F00000003C0000000F00000003C0000000F00000003C0000000E
  0000000780000001E0000000780000001E0000000780000001C0> 32 26 -4 2 35.353] 60 @dc
1 /cmsy10.329 @newfont
cmsy10.329 @sf
[<FFFFFFC0FFFFFFC0> 32 2 -4 -10 35.353] 0 @dc
1 /cmr10.329 @newfont
cmr10.329 @sf
[<7FFFFFE0FFFFFFF000000000000000000000000000000000000000000000000000000000000000
  00FFFFFFF07FFFFFE0> 32 12 -3 -5 35.353] 61 @dc
/Times-Roman /t-rom.180 ReEncodeForTeX /t-rom.180 /t-rom.180 24.999965 TeXPSmakefont def
/Times-Roman /t-rom.270 ReEncodeForTeX /t-rom.270 /t-rom.270 37.499947 TeXPSmakefont def
/Times-Italic /t-ita.270 ReEncodeForTeX /t-ita.270 /t-ita.270 37.499947 TeXPSmakefont def
1 /cmmi9.300 @newfont
cmmi9.300 @sf
[<00000E00003C0000F00003C0000F00003C0000F00003C0000F00003C0000F00000F000003C0000
  0F000003C00000F000003C00000F000003C00000F000003C00000E> 24 22 -3 2 29.864] 60 @dc
[<60F0F060> 8 4 -3 0 10.666] 58 @dc
1 /cmsy9.300 @newfont
cmsy9.300 @sf
[<C00060E000E07001C03803801C07000E0E00071C0003B80001F00001F00003B800071C000E0E00
  1C07003803807001C0E000E0C00060> 24 18 -5 0 29.864] 2 @dc
1 /cmr9.300 @newfont
cmr9.300 @sf
[<FFFFFF80FFFFFF80000000000000000000000000000000000000000000000000FFFFFF80FFFFFF
  80> 32 10 -2 -4 29.864] 61 @dc
2 @bop1
t-romsc.300 @sf 150 50 p (rfc)s
10 r 49 c
(144)s
t-rom.300 @sf 418(Compressing)m
10(TCP/IP)m
10(Headers)m
330(February)m
10(1990)m
t-rom.330 @sf 187 233 p (\(2\))s
23(Even)m
12(with)m
12 r 97 c
12(line)m
12(fast)m
12(enough)m
12(to)m
12(handle)m
12(packetized)m
12(typing)m
12(echo)m
12(\(4800)m
12(bps)m
12(or)m
12(above\),)m
264 289 p (there)s
9(may)m
9(be)m
9(an)m
9(undesirable)m
9(interaction)m
10(between)m
9(bulk)m
9(data)m
9(and)m
9(interactive)m
9(traf)m
(\014c:)s
16(For)m
264 346 p (reasonable)s
14(line)m
15(ef)m
(\014ciency)s
14(the)m
15(bulk)m
14(data)m
15(packet)m
15(size)m
15(needs)m
14(to)m
15(be)m
15(10)m
15(to)m
14(20)m
15(times)m
15(the)m
264 402 p (header)s
10(size.)m
17(I.e.,)m
11(the)m
11(line)m
t-ita.330 @sf 11(maximum)m
10(transmission)m
11(unit)m
t-rom.330 @sf 11(or)m
t-ita.330 @sf 10(MTU)m
t-rom.330 @sf 11(should)m
11(be)m
11(500)m
10(to)m
11(1000)m
264 458 p (bytes)s
9(for)m
9(40)m
10(byte)m
9(TCP/IP)m
9(headers.)m
17(Even)m
9(with)m
10(type-of-service)m
9(queuing)m
9(to)m
10(give)m
9(priority)m
264 515 p (to)s
12(interactive)m
11(traf)m
(\014c,)s
12 r 97 c
11(telnet)m
12(packet)m
12(has)m
12(to)m
12(wait)m
12(for)m
12(any)m
12(in-progress)m
11(bulk)m
12(data)m
12(packet)m
264 571 p (to)s
14(\014nish.)m
24(Assuming)m
14(data)m
14(transfer)m
14(in)m
14(only)m
14(one)m
14(direction,)m
14(that)m
14(wait)m
14(averages)m
14(half)m
14(the)m
264 628 p (MTU)s
11(or)m
12(500)m
11(ms)m
11(for)m
12 r 97 c
11(1024)m
12(byte)m
11(MTU)m
12(at)m
11(9600)m
12(bps.)m
187 741 p (\(3\))s
23(Any)m
18(communication)m
18(medium)m
17(has)m
18 r 97 c
18(maximum)m
18(signalling)m
18(rate,)m
19(the)m
18(Shannon)m
17(limit.)m
264 797 p (Based)s
16(on)m
15(an)m
16 r 65 c
-4(T&T)m
15(study[)m
50 c
(],)s
17(the)m
16(Shannon)m
16(limit)m
16(for)m
16 r 97 c
16(typical)m
16(dialup)m
16(phone)m
15(line)m
16(is)m
264 854 p (around)s
15(22,000)m
15(bps.)m
28(Since)m
15 r 97 c
15(full)m
15(duplex,)m
15(9600)m
15(bps)m
15(modem)m
15(already)m
16(runs)m
15(at)m
15(80%)m
15(of)m
264 910 p (the)s
11(limit,)m
12(modem)m
11(manufacturers)m
12(are)m
11(starting)m
12(to)m
11(of)m
(fer)s
11(asymmetric)m
12(allocation)m
11(schemes)m
264 967 p (to)s
13(increase)m
13(ef)m
(fective)s
12(bandwidth:)m
21(Since)m
13 r 97 c
13(line)m
13(rarely)m
13(has)m
13(equivalent)m
14(amounts)m
13(of)m
13(data)m
264 1023 p (\015owing)s
17(both)m
18(directions)m
18(simultaneously)m
-2 r 44 c
18(it)m
18(is)m
17(possible)m
18(to)m
18(give)m
18(one)m
17(end)m
18(of)m
18(the)m
17(line)m
264 1079 p (more)s
14(than)m
13 r 49 c
(1,000)s
13(bps)m
14(by)m
13(either)m
14(time-division)m
14(multiplexing)m
14 r 97 c
14(half-duplex)m
14(line)m
14(\(e.g.,)m
264 1136 p (the)s
17 r 84 c
-2(elebit)m
16 r 84 c
-1(railblazer\))m
17(or)m
17(of)m
(fering)s
16 r 97 c
18(low-speed)m
17(\\reverse)m
17(channel")m
18(\(e.g.,)m
18(the)m
18(USR)m
264 1192 p (Courier)s
13(HST\).)m
t-rom.240 @sf 533 1176 p 50 c
t-rom.330 @sf 568 1192 p (In)s
14(either)m
13(case,)m
13(the)m
14(modem)m
13(dynamically)m
13(tries)m
13(to)m
14(guess)m
13(which)m
13(end)m
13(of)m
264 1249 p (the)s
13(conversation)m
13(needs)m
13(high)m
13(bandwidth)m
13(by)m
13(assuming)m
13(one)m
13(end)m
13(of)m
13(the)m
13(conversation)m
13(is)m
264 1305 p 97 c
12(human)m
12(\(i.e.,)m
12(demand)m
12(is)m
12(limited)m
12(to)m
cmmi10.329 @sf 15 r 60 c
t-rom.330 @sf 4(300)m
12(bps)m
12(by)m
12(typing)m
12(speed\).)m
19(The)m
12(factor)m
(-of-forty)s
264 1362 p (bandwidth)s
14(multiplication)m
14(due)m
14(to)m
14(protocol)m
14(headers)m
14(will)m
14(fool)m
14(this)m
15(allocation)m
14(heuristic)m
264 1418 p (and)s
11(cause)m
12(these)m
11(modems)m
11(to)m
12(\\thrash".)m
221 1555 p (From)s
9(the)m
10(above,)m
10(it')m
-2 r 115 c
9(clear)m
10(that)m
9(one)m
10(design)m
10(goal)m
9(of)m
10(the)m
10(compression)m
9(should)m
10(be)m
10(to)m
9(limit)m
10(the)m
150 1612 p (bandwidth)s
10(demand)m
10(of)m
10(typing)m
10(and)m
9(ack)m
10(traf)m
(\014c)s
9(to)m
10(at)m
10(most)m
10(300)m
10(bps.)m
16 r 65 c
10(typical)m
10(maximum)m
10(typing)m
150 1668 p (speed)s
11(is)m
11(around)m
11(\014ve)m
11(characters)m
10(per)m
11(second)m
t-rom.240 @sf 921 1651 p 51 c
t-rom.330 @sf 954 1668 p (which)s
11(leaves)m
10 r 97 c
11(budget)m
14(30)m
cmsy10.329 @sf 9 r 0 c
t-rom.330 @sf 9 r 53 c
cmr10.329 @sf 13 r 61 c
t-rom.330 @sf 12(25)m
14(characters)m
150 1724 p (for)s
11(headers)m
11(or)m
11(\014ve)m
11(bytes)m
11(of)m
11(header)m
11(per)m
11(character)m
11(typed.)m
t-rom.240 @sf 1149 1708 p 52 c
t-rom.330 @sf 1188 1724 p (Five)s
11(byte)m
11(headers)m
11(solve)m
11(problems)m
150 1781 p (\(1\))s
10(and)m
10(\(3\))m
10(directly)m
10(and,)m
11(indirectly)m
-2 r 44 c
9(problem)m
10(\(2\):)m
17 r 65 c
10(packet)m
10(size)m
10(of)m
10(100{200)m
10(bytes)m
10(will)m
11(easily)m
150 1837 p (amortize)s
13(the)m
13(cost)m
12(of)m
13 r 97 c
13(\014ve)m
13(byte)m
13(header)m
12(and)m
13(of)m
(fer)s
12 r 97 c
13(user)m
13(95{98%)m
13(of)m
12(the)m
13(line)m
13(bandwidth)m
13(for)m
150 1897 p 660 2 ru
t-rom.180 @sf 200 1934 p 50 c
t-rom.270 @sf 217 1949 p (See)s
15(the)m
15(excellent)m
15(discussion)m
15(of)m
15(two-wire)m
15(dialup)m
15(line)m
15(capacity)m
15(in)m
15 r 91 c
49 c
(],)s
17(chap.)m
15 r 49 c
-1(1.)m
30(In)m
15(particular)m
44 c
15(there)m
15(is)m
150 1995 p (widespread)s
12(misunderstanding)m
13(of)m
12(the)m
12(capabilities)m
13(of)m
12(`echo-cancelling')m
12(modems)m
13(\(such)m
12(as)m
12(those)m
13(conforming)m
12(to)m
150 2041 p (CCITT)s