BSTJ 50: 9. November 1971: Traffic Analysis of a Ring Switched Data Transmission System. (Hayes, J.F.; Sherman, D.N.)

12.8 MB·English

‘Traffic Analysis of a Ring Switched
Data ‘Transmission System

Dy J. # AYES and D. N, SHERMAN

(otuessgt ese Ai 12,1713

raf at ean ae
isin. nen. Tha ses, ey ingot
‘and date stoeng, share ronson facies envy mang

fers {tio the randon compoven!o] mesg ray te fa buen ha

18 the focal point of ou tay
‘he baaie eanfguration of the syne 16 a vis coun
sere tn eters laces te pen, & svete ole the in
ier nf atti act

‘ey giten poten of rage the rtm
frag pators an which cork ae ie sdenond ud sumac
falters. Sntviute fo the model Gv @recgntion of the Barty nae
of data soces Uther ve nba iote dosnt aor easel
“sive ates ar wi ag eBlog of de ot sce ene prin, Formulae
neh erage aascage ley indeed dag ty the
‘ag can i nt
‘Phe reswts of tie bets me preeatod
ay Bae to tape within specie 9
Iocton the munber of sate aa sone wt. he deny Reve it
worweizl to oeeragewoowze ewgtha, Aw xan arte of he
facts tthe extn source rte to tive wate. Mh ret ek ta,
che newton, dhe sntay fa a then co aero

ssial care wher: norman
"conjure it pe 8

Regs uf 10, 50, an JN) were have heen aia oa paleo
nse Data obtained fot thee hsestigatione ore presutet aul eonpced
fn the thee estate fr tae thy aid le peri and messane
ty. The eels of eimate average meseage dag shoe tiny fr al
satin Uk wisatione of abou pevsent, the tiforence Betwven the

a

thet etn at operat abet
2048 cu a stsomse MULLSHOHT JOPREAL, NOIALOER 151

dn a resens pupae 1K. Pines ne prapaed ¢ data comission
network in hich user ate eeocte in a ing or loop topulogy. 1
this paper we sluly Hie beige of thie network, We examine the
Felasousbop betveen somo at fine atfzaione and. the mnssepr
‘elay wnthis the stem. We propeso eeaceratiee! modes of stains
Uleaior and, by anaking vt” Presoaable ups da trie ces
predil the avorge delay as a fonecion of neieork araracere
Principal ceeult cf war siudy show that, im many cages of tees,
vera ey in nneags le thn ovo maeeoge lena.

"The elon e bere, erates ow ditibued «into pllosop
ud uyer entry is gnined bs axqordomous multiplexing into the fine
bit stream. (cher avstems lve taed the Hg lpwlogy. For exile,
TUM effes e ayzehivros, wmabatfrrd seam I whien a cent
contrlbr nmirrs the log ad alle? aces by che uns Ballered,
crcally urntrlieg aystamy ave een proses! by W. D. Famer
fd FF. Newall” end A. & Prue In he Gast a tamputer controls
Several peripheral devises, while the second, several comptes are
Tnterouanected,

The enaeucertios of dun coureos aul che rmeements of user
vwcke she teebminie uf sewage svitcizaapstialie to data sen
finnicatione Cae enportear tharactarilie flit data. soatees ae
Sten bugs; ie, relatively shore sequences of Tis flowed by Ho
ppinwes A baie need of ny data esters stil teeponse th dnt
Thrace way fo mect ths tas By evotig fine toa sour fe
Song perl a ans, However, bees of the long pss be

fata bursts the ine wil bs waseruied Os the oer hans, droping
the tas betresn daca bursts way Ie iaeliéat oer ut Tons aup
timnos Por ie in svitehing tsiiqees thes axe eurersly werd, the

tu tive will ote be longer Uh the bouding te

‘Message svicehing provides wey nf oft sing the Tine and
ibsaiving, raid rseponrs, Tho is is to arynehronovsly amatiplex
ever yuri enn the rom i, Porexanlo in the present mst,
fea fram eh sores ene formu fate xed sige ecke's al suppl
‘th w lioese ‘Tas howier tsa sores apd deat nn alder
Ive as booksceping informntiou, Packets onl ones ae ane
feud fed oats tvs line actunding te rome seneuling algorths. (One
Sach algorithm willbe srw peeenaly shee the Hild operation of
the vig is doer.) Clr a more packets wc aneess tothe 8s
line, more etorage bt oquinsd. The ctorage requirements nd che al
ise scream mata syste 2040

‘enn Qufosing clay are isporteat. lambert of eystouy opr
tor, This prsisely those ehasurstities Int ave so feel point ef om
study

Asko of the basi ring sytem is show in Hig. 1, Ae indicated,
trefic dows in ome deen azound the rng from station to statin,
‘The stations ary inated ws Pebuxes ia Vig. 1, Hor pra of exe
planation Jet ur beg sith the operation of the L-box bein con
sidering che ether eoraponeet of the Inyp (A-box and C-boa}. Ths
data source is eonnected to che box when ite outpat i fst int
Fx sie Boek or paces an sapptid sith header. A meseage From,
al soutee mu eonslst of several plea. If ube hive is draw a packet
is mlislesed an tl ine ‘mnwalctly, The packer is 40 grasa
from Hebex to Whos ta ite dewinntion, At gael B-boy exile finery
the adress of» pkey wxtrnine to dterinina whetBr he yes
Gestnaton is al at gartesler Lebox. This essanination entails
fixed delay for rach Thor hich ean be eslealsted ven the source
tnd desination. TU i, oseever, the randoms dey exeoterd iy Ure
last it ef a rveeuge before it gots on che loop that eames one

a

Fig 1 Paes
2R0 up aes svonme TeeaNIEAL, JOURNAL, NOVAAER AE

tention, A fundamen phan ofthe spor ia a ene prosntly
In tapanisor has priser rafEe sek'ne vatranpe fo tho sing
1 the ie 2€-¢ Destaton i Trwy with infermation meckets posing
though ity the packers pvduced et hat mation are buttered unt
the na is fee, The reuding se the Ene of meena ensiating of
‘mane dha ome packer el inteneupced when packole from snother
ou poet through Tho rening af the mossug! is nesumed om the
point of interruption when the nei foe

Th onder to explain ive mesheninn of rupli packets on ad
aT tia Line, helpful to dsr aa iggy Hew the rng sud
Conveyor bol (se Fig 2 fora illserion. ‘igs slots inio heh
Dukes roy bo placed npulze gcomrd the lop. ee Aave Ins
hat ayncheniea ie sntained Ger li At the boxing f eae
fie sins isa marker indegcing sieher rhe ens packet elt is
fmt or Tul. Thw Uhr semaes hit marker and ete noningy
Sr ull packet, adress bits lll the aeeupane marker T= Bebo
snes ow addres the puke. i removed from the lin and sent
fits destination. Tis sume B-bux my tle nvnlage of the empty
lotto Teed its ows peeks! om the line, Of curse i yorker eet is fall
Sn tine for yout Invent pier Bee, ten celine i=
‘marcetar.y block for ties B-box

‘Wale there tro murs Dee ing, howe ‘4 onl ane box.
‘the Aebow has to buse fwvatons, ‘he Rist, 14 mwalioned seein,
ese switoweD nara sisorae us

in aynehramivaion of the Hg. Phe vowed Eunetion i thae of pvventing,
the buildup of state in tho ving dine to undeliverable pockets. "Toe
hear of eae pocket passing throug an A-box it mares Ta poset
tiesto gs through an A-box w sand ti it (either deste,
femeting an empty pase slo, of seat hase ro fs detinatin, Sowing
{poke be tis estination idan smply Bp interchanging sours
tal leon reese Te thi wu «busy gna i provide

‘The C box shawn in Fig. 1 provides intereamnection of
ig. 9). Pashels deatined for «stot wale partealar sing have
Ives indivasing thie woe mts eke of by the Choa in race
‘the eante way that insraniza tafe inked ff by Hones, This ti
ie Waforad ard eultiplesed onto sho next sing 3a the fame way Tat
‘tno from lal satin i mulsiplexed ex a ng. Sino tae ale ndy
(on a loop has priority inter-rng tate wll suffer some delay. A key
walaation of the Coe snygastet hy W. J. Kopi i the sanders
nest of bier aad Beboxes shown in Pi.
22 HELL wisiass mowvteM JoERSAL, NUE HTT

Inthe eomuinder of shit paper 8 mathematical model of the sin
sil be develope tiv analy, Lhe ovals of His study el be pre
Need i te formu" sels of gues weigh ilusteale ie Bohavior of
tromeliaed delay: Suactiva of thor the number of sation inthe
Fag or te llantion of the eoure.

Tonle (a oumy thie analisforwnrd 1 wae moessery to make
several esunplive acl approsmations. Thus om order {overly our
feculls and 0 eee orto, simulation program wus devs.
Simulation rls hare been obtained for rings ennging Yom 10 sass
fir 10 stetions, These sua ane oomapam to che recite of lysis

(Line eae in bits pr serond
(Ch ans tee in paves pe ond
{it rate ding. the nevi pea othe ah sonee.
By Number of intron bits por packet
12 Noiber of hl ite pee packet
Li Avorag? uration of ils period uf 1 snares Sn seconds,
Tip -—Avernge Cavatin 0agtive evi uf Gb sure in soeonds,
Gl Averngs sumer of eckote yer caemage a ite sour
Tan af sone pret rat the no pase rate
{OU asin of soiree | Fae quai {3
t—Tatertiy of coutee #2 envaion
Fooeeage nutsbes of park per aecord Eom sour 5
Number of stotions i rng
Portion of tai fom sation £ vo sation j
TRi—Tentbe peesing Urough sesion F in packels pee second,
Fi—Trafe oat of sation & in yokes per soton
{U7} Linw tization oe teen y station F (oe esto a)
(Of Line itemity sr s4on by ettion tows sent 00)
Pe Line allison ate tation feo equation (90)
{Line intensity after satin se eatin (108)
LAE Asumige curation af line il oeied in aeoenda as seen by
toto &
V/s Average dunncon of line buoy pov in sana as seen
tation

Suice Input ale

Th tis scetio w mathemati! rode! for sag 3 petented ee
lene saenenn ies sosnaae 2058

J seco conn.

laying a foundetion for sueonaiay veins wine Us mee gle

We ate primarily incerested iy she tafe ehroetoriatvs wf he
on. the attendant dele, Iver to facut i epeck of ring oper
tion, we akeume thet isre ere nu equuent fires er tease
frome Thal, eran sing. pe) ullangcely severe et

Hlestinacon. "has the get of the Alex ia devresing packets ot
providing & sign el part of sho motel, it present the study
RevcrSnoe toon onalysis of siglo ng. Phualy ta atady wae pode
aed an Tito snes te Inia of che com. An 8 heavily Heded
"stem lon sees twee form an the reverse time of the
Assent any be etrnive far aplontions,

‘Thnsagwnst se nnulssi dhe paruveler ¥ gesienates the number
1 Reboxta or stations that are on the ing. The apres of the lie
fonneting the satis tone annsher sigan a Cy ile

‘Taveaes Blu i women sor, whieh ws ee have me? wae,
ie bursty in ature. The tpt of Mesh dale sourne easel
onsvting of altemser ice aid ative rods, Ting, the liter
trasimission i at aonetant rate af ite/-wrenl, Th suerions
te saree setiity and ll periods ace geamaed to be exponentially
lisbutod end statically independent af one another. Suecexive
ile and baxy periods aves indepen a ow another, The avetage
‘lurutinsin setondvot the setive td ie pesods ofthe pues eonecto
to the sth station inthe Toop ate denoted us Liss ad, eapoctivey
Studies of eomputer user statition” indicate that the forging i 9
reasonable, i samen sno, maxel ot slaty suuree®
954 waa, AYSRY THGHENUEAL DOURKAL, SowESENN TEL

Esch mestoge (bits gerted ins sour wetivty ps) bundled
ino an integral swcter of oe ine packets, The maximum number
tt information hits in euch pact I The rusbce nf eader bits
that accompory ear packet i denoted hy the prumetar AL In
Append it slur tial the rmber of paokete i a message is
sont set! with man
1

Qa alba
Duwing an active period of w musi, the rats at whieh pankets are
produced is (QU ule whoh parkrts mae teananteed on
the ine ie C208, |). Aa izsportont quantity in our consideration
Js the rai ofan pact rte to Tine ptt,

Phage

Page ee

1 oy well We ant in some appliontions a typi mossage conse
fof many paokets, ie, bys 3 BT this ose we have

eb

CGulee -sunee pavametons Ht ane important eur alidy ea be
dvived, The tilnat ua saurer For toe truton oft hat source |

¥. »

‘Toe inanty of sours se ve as

Paha “

‘The avengs mabe of peekets seen teanaited from sourus fis

Le — 6 Qn a

4 Hie UMBaatn

‘ronn He way rio trae is multiplexed onto the line Heese
thar message dala e deporien pow the Bie trafic, As «prelude to
the esleation of dla. the rlevurt earsetessties of Tine trae ape
se syne aaa Sys 068

osidensd in thie action, A. provi matiematied charaetertation
tT trae ig estrone Wife To el, Tor ravens thal lle
plained pessentty, ee enssunter the nae. lifealty ia hin phase

We bein by ealetating the weoraye ws ization et aeeh poi
in he sing The Basie examin This cxouanion Se thet © cam
erection Lae bli so fat, eis 8 sli yang swe ger, The
renee pocket race ino a statin ie eautl to the wverie packet ce
out of a station, Tne teahe vo ard at of station Fastest ta
fal from a eastomer eonmected tn the sain a wel aw lire tei
‘hee fnpicwion thal there fs se voi bul af pokes ts
Hore nt sation, which ite i eboul be foe aorta ing operation.

Tet the mumber of packets/serand emanating from the soueee ean
routed to soto 1 © = 1, 2,007 NY besa ar Tn tm of
peametsrs defined calor r, — QiV/8) + TY] ' Py Be deine a
the portion of trate originating 9 sitio 1 als delim fae sation
swits P= U.'The sverage mimbor af suck sor ove oi eon
Station weation Py A af tho pases ae taebngh eee
Stolen ta the ang Ieleorn saviors Gd je Tee avemge auzaber of
Inkl er coe ram 0 pig aug tin 3 ven By

Wolesehbny

Se, tnpieten
Lo otherwise

‘The tcl volume of tse passing throug: eacion Kis giver by
Eee mi

seanion 6 irelucing teie Fr the

Rt

ie total voluan of eetfie ost
eens sre.

Rea Rtsn, bo x &

Yerhags the disinetion betaora Ry ani Pe howe con be emphasized
12055 gE wm sven eucuNeAs JOFBRAL, NOMINEE 191

by referring to Fig 8. Hesw » tbo is shown a Being elit in ila
tov funtion, vit taking data of the fina ted reading da vinta the
ine, At point 2 te line suerte allot the tiie ont of sation Fat an
‘avenge rate of Ry choles. AL point ¥ the avorage trae cu
een by tse Las source ws ib ntemprs co multiplex da om the Ts
ff 2 pecketssecond, (iemphont he reaasinder of the aon x
fstrsion a Ene trae rsnotersenlie «quantity ae soca by Oke
lovatin stotion afer mosuge deletion Sine she pele

fof toe Ene iC the lire iain a ee: By the source nt sal

eR,

“Th ins intense a tie pone

OF = ARC, aD fs)
‘The ullzabion snd intensity on the lie after station & ane given bye
eRe, @)
1, = BMC, = B can

Thee enge wt ig trae seme,
eo vet ay

lor oy ts
2, owe eepovsion simplify gress, Wie hve

-(E-1) a

442 Buy Peviad
‘We furs sow to the eaoaltion che wvernge duration of ile sad
bog pera the tine, An extet esenhion of either quantity is

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