Sir John Tenniel; Alice’s Adventures in Wonderland,Lewis Carroll Chap_16 David L. Mills University...
12
Sir John Tenniel; Alice’s Adventures in Wonderland, Lewis Carroll Chap_16 David L. Mills University of Delaware http://www.eecis.udel.edu/~mills mailto:[email protected] Mar 25, 2022 1
-
date post
21-Dec-2015 -
Category
Documents
-
view
220 -
download
1
Transcript of Sir John Tenniel; Alice’s Adventures in Wonderland,Lewis Carroll Chap_16 David L. Mills University...
Sir John Tenniel; Alice’s Adventures in Wonderland,Lewis Carroll
Chap_16
David L. MillsUniversity of Delawarehttp://www.eecis.udel.edu/~millsmailto:[email protected]
Apr 18, 2023 1
Name State Variable
rec Receive timestamp
dst Destination timestamp
aorg A origin timestamp
borg B origin timestamp
x Transmit interleave switch
h Hold-off counter
Name Packet Variable
torg Orgin timestamp
trec Receive timestamp
txmt Transmit timestamp
Name Peer Variable
Clock offset
Roundtrip delay
Unicast/broadcast offset
fig_16_1
torg = rectrec = dstIf (x == 0) {/* basic mode */ aorg = clock txmt = aorg} else { /* interleaved mode */ if (x > 0) { aorg = clock txmt = borg } else { borg = clock txmt = aorg } x = -x}
Transmit Process. - Basic and Interleaved
Apr 18, 2023 3
if (x == 0) { /* basic mode */ txmt = clock torg = 0} else { /* interleaved mode */ if (x > 0) { aorg = clock txmt = aorg torg = borg } else { borg = clock txmt = borg torg = aorg }}trec = 0
Transmit Process.- Broadcast
fig_16_2
rxproc. Receive proc and receive basic routine
Apr 18, 2023 4
T1 = torg
T2 = trec
T3 = txmt
T4 = dstIf (T1 == 0 || T2 == 0 || T3 == 0) SYNCelse if (T1 != aorg) BOGUS} else { = [(T2 – T1) + (T3 – T4)] / 2 = (T4 – T1) – (T3 – T2)}
Basic Symmetric Mode
if (txmt != 0 && txmt == xmt) { DUPE} else if (x == 0) { rec = txmt
dst = clock If (mode == BROADCAST) Broadcast else Basic Symmetric} else { Interleaved Symmrytric rec = trec
dst = clock}if (h > 0) h- -xmt = txmt
Receive Process
fig_16_3
rxout . Receive interleaved and receive broadcast routines
If (x > 0) T1 = aorgelse T1 = borgT2 = recT3 = txmt
T4 = dstif (torg == 0 || T1 == 0 || T2 == 0 || T3 == 0) { SYNC} else if (torg != 0 && torg != T4) { h = 2 BOGUS} else if (h == 0) { = [(T2 – T1) + (T3 – T4)] / 2 = (T4 – T1) – (T3 – T2)}
Interleaved Symmetric Mode
Apr 18, 2023 5
if (torg == 0) { /* basic mode */ = txmt – dst + d / 2} else { /* interleaved mode */ T1 = torg – borg T2 = torg – aorg aorg = txmt
borg = dst if (T2 > 1) BOGUS else = T1 + d / 2}
Broadcas Modet
fig_16_4
NTP basic on-wire protocol operations (1step)
0
0
T2
T5*
T6
T7*
rec
dst
T3*
T4
T7*
T5*
T6
T5*rec
dst
T1*
T2
T1*
T4
T3*
0
0 T1*
T2
T3*
T3*
T4
T3T2
T1 T5
T6
T8
T7
T6
T1* T5*
T4 T8
T3* T7*
B
A
T3*aorg 0
t1*
aorg
T5*
T5*T1*
torgtrectxmt
Sync
Valid Valid
Valid
Apr 18, 2023 6
fig_16_5
Interleaved on-wire protocol operations (2step)
0
T1 T9
0
borg
dst
0
T2
T2
T4
T5
T6
rec T2 T6
0
T4
T1
T4
T2
0
0
0
T1
T5
T4 T8
0
T10
T6
T8
T10
T10
T8
T7
T5
T9
T8
T6
T12
T5
T4
T3T2
T1 T5
T6
T8
T7
T12
T11T10
T9
torg
T3
Round 1Round 2
Round 3
T9
T12
T10
T10
T12
T9
T13
T14
T13
aorg
trectxmt
T14
borg
dst
T4
0
rec 0 T4
0
T6
T3 T3
T2
0
T3
0 T8
T7
T8
T10
T7
T11
T12
T11aorg 0
T7
T2 T6 T10
Apr 18, 2023 7
Valid
Sync Valid
Sync Valid Valid
Valid
T3
T7
T1
T5
B
A
fig_16_6
Interleaved broadcast on-wire protocol (3step)
T1
aorg
dst
T3*
0
T4
T5*
rec
0
T40
0
T3*
T5*
T4 T8
T5*T1*
T4
T3
T5
T6
T8
T7
torg
T7*
trectxmt
borg T1
T1*
T3 T3T3aorg
T2
Valid
Broadcast Stateless
T2
T1
0
T12
T3
T11*
T12
T11
T3
T11
T11*
T1 T1
Broadcast Broadcast
T1
T3* T3* T11*
T3*
T6
T5*
borg T12
T1*
T2 T4 T4 T4
T7*
Apr 18, 2023 8
B
A
Valid
0
T14
T11
T13*
t14
t13
t11
T13
T13*
Broadcast
T13*
T14
fig_16_7
Automatic protocol detection example (4step)
T1* T9*
0
borg
dst
0
T2
0
T4
0
T6
rec 0 T3
0
T4
0
T5*
T4
0
0
0 0
T3
0
T4
t5*t1*
T8
0
T5*T1*
T3
T8
0
T10
T11*
T8
T11*
0
T9*
T8
T3
T12
T9*
T4
T3T2
T1 T5
T6
T8
T7
T12
T11T10
T9
torg
T3
Bogus
T13*
T12
T11*
T11*
T12
T13*
0
T14
T13
aorg
trectxmt
T14
borg
dst
T4
0
rec 0 T4
0
T6
T3 T3
T2
0
T3
0 T8
T7
T8
T10
T7 T7
T11*
T13*
t11*aorg 0
T7
T2 T6 T10
T13*
T16
T15*
T13*
T14
T15*
0
T14
T7
T15*
T13*
T16
T15
Bogus
Sync Sync Bogus
Valid
Valid
Sync
Apr 18, 2023 9
B
A
Basic
Basic Basic
t5*T5*T1*
Basic Basic Basic
Xleave Xleave
fig_16_8
backroom
Mort .001.100 .046 .015
Macabre .003 .108 .042 .015
GPS .015 .276 .024
GPS .021 .280 .040
Macabre Mort
Macabre .017 .261 .029 .025 .121
Mort .041 .204 .017 .035 .126
Howland
Switch
Switch
GPS
fig_16_9
campus
Bridgeprt .022 .311 .031 .224
Baldwin .040 .359 .096 .176
Rackety .028 .478 .014
Rackety .017 .442 .021
Baldwin Bridgeport
PPS .000 .000.004
Pogo .163 .615 .031 .119
Rackety
PPS .000 .000 .004
Rackety .181 .612 .020 .211
Pogo
Switch
fig_16_10
machines
Name CPU Ethernet NIC Operating System
Baldwin Sun UltraSPARC III 10/100/1000 Mb/s Solaris 5.10
bridgeport Sun UltraSPARC III 10/100/1000 Mb/s Solaris 5.10
Howland Intel P4 1.0 GHz RealTek 8139 10/100 Mb/s FreeBSD 6.1
Macabre InteI P4x2 2.8 GHz Broadcom BCM5751 10/100/1000 Mb/s FreeBSD 6.1
mort InteI P4x2 2.8 GHz Broadcom BCM5751 10/100/1000 Mb/s FreeBSD 6.1
Pogo Sun Ultra-5.10 10/100 Mb/s Solaris 5.10
Rackety Intel Pentium II 300 MHz 3Com 3C905B 10/100 Mb/x FreeBSD 6.1
tbl_16_1
