DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S. TANENBAUM MAARTEN VAN STEEN

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DIGTRIBOTED GYEREOG riewiptes ved Poradiges Geoowd Echos POOREO 9۰ 0000000 DOGGBRTEDO OOO GTEEO Cowwurivatiod ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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Presentation protocol _Session protocol___ Data Physical Network Application Presentation Session Transport Network Data link Physical Piure €-0. bopers, ioterPaves, ued protocols ta the OG ‏.ای‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 1227. 

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Layered Protocols (C) Data link layer header Network layer header Transport layer header Session layer header Presentation layer header ۳ Application layer header Message Data link layer trailer Bits that actually appear on the network igure P-C. © tppicd wessage us if oppeors ‏مه‎ the uetwork. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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Oiddteware (Protocols Application 6 Middleware 5 Transport 4 Network 3 Data link 2 Physical 1 Network igure 6-9. ۲۰ adapted rePereare wodel Por vetworked coweusiciod. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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Dypes of One uizatios Synchronize at Synchronize at Synchronize after request submission request delivery processing by server Client Request Transmission interrupt Storage facility Server Time — CPicgure P-P. Oieuicy woiddiewore os on idterwediate (distributed) service ia uppicotiowtevel pow wunicdtiod. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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ان عمط لممنموروون Stack pointer Main program's Main program's local variables local variables nbytes buf fd return address read's local variables (a) (b) igure -S. (a) Paraveter possiey too lool procedure call: the stack bePore the wall to read. (b) Phe stack while the called procedure is antive. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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Cleat an Gerver Grubs Wait for result Client ‏سم‎ _ ----- / 5 Call remote Return procedure from call Request Reply Server ‏اس‎ nnn Call local procedure Time ——> and return results ‎P-O. Pricciple oP RPO betwers o cles ond server ۳۰‏ سب ‎‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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Rewote Procedure Culls (0) 3 ‏جوم وم‎ cdl pours io the Poftowicry steps! 0. Whe cheat procedure cals the cheat stub to the cord wo. 89 Vke chect stub buds 0 wessage ood calls the loool operation ‏ورد‎ 9. Vke oled’s OG seads the wessuye to the ‏صووص‎ )2۰ ۰ ۰۱۷ rewwote OG ques the wessucp to the server stub. 9. Vke server stub vopacks the poroveters usd cols the server. Oovuticued ... ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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3 ‏جوم وم‎ cal pours ia the Potlowwiery steps (cvcticued): 89 Whe server does the work ocd retures the result ty the stub. °. Dke server stub pucks tio wessage ocd ols its ‏صما‎ OG. 9. Vke server's OG spuds the wessuye to the clicc’s OG. 9. Vke clea's OG qives the wessuye to the clicct stub. QO. Wke stub vopacks the result ced neturas to the cect. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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(Pussicry ‏عون‎ Puraveters (a) Glient machine Server machine Client process Server process 1. Client call to ‏اسك‎ 0 6 Stub makes of add local call to “ada* Server stub eevee 2 1 756 ] 0-0 [ 2. Stub builds ints vat) 5: Stub unpacks int val) ‏ددم‎ iat val) message 2 706 4. Server OS Client OS ints ۲ Server. OS hands message ine 0 to server stub 3, Message is sent across the network P-?. ke steps tovolved io a doc a 4 سب ۰) را موجه مور ranenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13- 

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(a) igure P-O. (a) Phe crigicd wessuge oo the Peoiuc. 3, Inc, All rights reserved. 0-13-239227. idigms, 2e, (c) 2007 Prenti yum & Van Steen, ted Systems: 

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(b) igure P-O. (a) Phe crigicd wessuge oo the Peoiuc. igms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. ‘Tanenbaum & Van Steen, Distributed Systems: 

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(c) igure P-O. (7) he wessage Pier beiogy werted. The litle cucbers ia boxes todicate the address oP rack byte. Hall, Inc. All rights reserved. 0-13-239227. igms, 2e, (c) 2007 Prent ‘Tanenbaum & Van Steen, Distributed Systems: 

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x foobar's local variables ف 5 201 201 ‎z[2]‏ ‏231 ‏241 (b) 1001 1 02 (Puraweter Gpevitivcaioa un Grub Geueration foobar( char x; float y; int z[5] ) (a) 

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0 )انیب Client Wait for result سس 39 Call remote Return procedure from call Request Reply Server Call local procedure Time —> and return results (a) igure -d0. (a) Dhe isteraction betwee cheat ood server too trodiiccal RPO. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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Ospachrouns RPC (C) Client Wait for acceptance 7 3 Call remote Return procedure from call Request Accept request Server Call local procedure Time —> (b) igure ۶-۰ ‏(ط)‎ Che icteractiog usta asyarkrowus RPC. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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@spackrowrs RPC (9) Wait for Interrupt client 5 acceptance Client = = = == = = 3 Call remote ‏ات‎ 57 (۹ rom ea jesus Acknowledge Accept Request request Server -------- _—_—_—_—— = — ———-— 3 -- — Call local procedure \ Time ——> Call client with one-way RPC ‎chest ood server ioteractiog thovughs‏ @ ۰۰ مب ‎tue aspuchrowes (RPOs.‏ ‎‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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لمات هد بت مه )/(( ‎und a Gerver‏ TDL compiler tient code | | ciientstub | {Header | | Serverstub | — | Servercode ‏اه‎ ‎‘Compiler C compiler Cont 29 Sever sub Server object file object le ‘object fe object fe Fantime Fantime Tinker ‏سیم جر‎ Tinker _ ‏شيب‎ ‎Giont Sawer binary binary ‏وسنت‎ 02-00 . Ske steps to voritiog, a cheot cord userver in DOE RPO. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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‎Cleat and a Garver (©)‏ ه بدن( ‎Tree Pes vutput by the IDL coewpiler: ‎° @ keuder Pie (ex, interPuve.k, is C terwe). ‏للك ان‎ ° Whe server stub. ‎ ‎1, Inc. All rights reserved. 0-13-239227- 

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ico a Cleat to a Gerver (() ° Restroicd oP a server wubkes it possible Por ou tliat to loots the server ocd bier tr it. © Gerver lovaiva is door in two steps! C. bow the server's wurhicr. ©. ‏اممو را‎ the server vo thot wackice. aum & Van Steen, Distributed Systems: Princ ‘Hall, Inc. All rights reserved. 0-13-239227. 

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iodo a Cheat to 0 Gerver (©) Directory machine Directory server ۳ 3. Look up server P71 2. Register service Client machine Server machine 3 server [| 1. Register end point Client 51 4. Ask for end point ‏عمو ها‎ 1 daemon]. End point table (Pigqure -19. Olieatrio-server biericry ics OCC. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, In. All rights reserved. 0 

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@erkeley Govhets Primitive Meaning Socket Create a new communication end point Bind Attach a local address to a socket Listen Announce willingness to accept connections Accept Block caller until a connection request arrives Connect Actively attempt to establish a connection Send Send some data over the connection Receive | Receive some data over the connection Close Release the connection Prqure P18, Phe socket privitves Por POPE. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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The Oessuge-Pussing | ‏عمو عصان‎ (0) Server 500161۳] 0100 (۲ 15160 ۳] 01 ۲۵0 ۳-<] ۶ close Synchronization point ‏اس‎ | Communication ۲ 4 1 5006112070861 «118-1520 1] 052 Client موجه مومسم 49۰ صسب۳) موه ری موم ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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Primitive Meaning MPl_bsend | Append outgoing message to a local send buffer MPI_send Send a message and wait until copied to local or remote butter MPl_ssend | Senda message and wait until receipt starts MPI_sendrecv | Send a message and wait for reply MPI_isend Pass reference to outgoing message, and continue MPl_issend | Pass reference to outgoing message, and wait until receipt starts MPI_recv Receive a message; block if there is none MPI_irecv Check if there is an incoming message, but do not block ‎P-10. Goowe oP the sost ichutive‏ سب ‎ WEssuye-pussiny priviives oP OP1.‏ ‎ ‎‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ 

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Oessaye-Queuicg Model (0) Sender Sender ‘Sender Sender running running passive passive ١ Receiver Receiver Receiver Receiver running passive running passive fa) 0 0 0 ‏و۲ موه )۵۰ صب۳)‎ joosely-coupled coe micativas ‏.عصص ری‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, In. All rights reserved. 0 

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Primitive Meaning Put Append a message to a specified queue Get Block until the specified queue is nonempty, and remove the first message Poll Check a specified queue for messages, and remove the first. Never block Notify Install a handler to be called when a message is put into the specified queue مهم و ‎igure -10. Basic icterPace to‏ ارو هو موه ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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Geoerd Orchitecture ve a Opssuye-Queuiegy Look-up | transport-level Receiver address of queue Queuing Queuing Queue-level layer address layer Local OS | Address look-up ‏اوءم ا‎ 05 i | database 5 __3# Transport-tevel address ‘Sender ‎٩-9 ۰ Vke rehtivaship beter queurtevel oddressicgy ort‏ مب .واو وجس كله اوج اجاج ۱ ‎‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ 

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Gevcerd Orchitevture ve a Ovssuye-Queuieg Sender A Application Application Ey queue ae us | 82 ‏الح‎ ۵ Messege [iT Send queue 3 mr Le igure ۵0 ‏جا“‎ ‎ae ‏مرس اي‎ oF a NY 17 1 ‏الجن ج7955‎ 1 von ven ۱ ne Receiver B ‏بت‎ Router ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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Oessuye (rokers Repository with conversion rules Source client Message broker and programs Destination client 1 Broker program [<> Ee Queuing ‏لالحا‎ layer! | Network igure P-Od. Che yecerd ‏اه موه‎ a wessage broker ‏وناك سم موه و نز‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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16005 OebGphere Ovssaye-Queuiegy Gpstew Receiving client Program| P-CC. Gerverd oryacization bP WBO's ‏رنه سم موه‎ syste. Client's receive queue | queue managers Queue: manager Enterprise network ‏بر‎ ‎_~__——“To other remote Send queue Sending client Routing table ‘Queue Program ‏فسعت‎ ‎MQ Interface (aw Server Stub pi RPC Local network (synchronous) ۱ Message passing (asynchronous) icpure 4 ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, In. All rights reserved. 0 

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©) Attribute Description Transport type __| Determines the transport protocol to be used FIFO delivery Indicates that messages are to be delivered in the order they are sent Message length | Maximum length of a single message Setup retry count | Specifies maximum number of retries to start up the remote MCA Delivery retries | Maximum times MCA will try to put received message into queue pure ٩-۰9 ‏اه ومع‎ associated wil: wessaye choot aged. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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Alias table Routing table tai [OMG] ۲7 az lamp] 0۷61 amp | $02 Alias table Routing table TAT [oma] [OMA] sat tA2[aMp] [omc] sot 0119 | ome amc Alias table Lai [OMA sat Laz | OMC| | رو رنه منهج 20) مه اه تمه سم ۲ ‎٩-006‏ مب ‎route fables cod choses.‏ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, In. All rights reserved. 0 

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Primitive Description MQopen | Open a (possibly remote) queue MQclose | Close a queue MQput Put a message into an opened queue MQget Get a message from a (local) queue igure P-CS. Prisviives ‏لاور‎ tc the Wesstye-queuity ioterPace. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

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Duta Gtreucw Stream synchronization Multimedia server Client Stream decoder : ‏وج‎ ‎QoS 005 Compressed control control multimedia data Network ‎dota‏ لول اوه ره ‎P-CO. @ qecerd architecture Por‏ صرت وه ‎Duero‏ ‎‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ 

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Properties Por Quatiy oP Gervice: eB ke required bit rote ot whick data should be trocsported. © De wordt deloy voll 0 sessivd hos bed set up ٠ Dke word eod-to-eod dehy . ۰ ‏هون بل‎ deloy voricace, or jitter. © De word ruedtrip delay. 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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(0) يق ج00 Ele 8 8 Packet departs source fl Packet arrives at buffer 0 Packet removed from buffer | ‏گت‎ 9 Fil] 8 0۵ Gap in playback ja a a ‏لتبلتقبي ةع‎ 6 5 10 15 20 Time (sec) igure 02-27 ‏بجو <(1) . م8‎ a bubPer to reduce jitter. 1227. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2¢, (c) 2007 Prentice-Hall, Inc. Al rights reserved. 0-13 

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CxPororry ۵208 )6( Lost packet sent | [4] [2] [3)[4]|| [5] Ce) (7) [8] || (a) Geo) 311112۱ 13 [14] 1569 Delivered 2] [3] (4) 5) Cel 7) (2) ۲8 ‏لكلا اكلا‎ 152 ]3 14 ]5[ 6 Lost packet Sent |[4][5][9][13]||[2] [6] fro] [14] |) (3) (7) ea) fs) | ‏ل8 | لكا‎ 12| 19 Delivered [7] [2] [B] [4] ]5[ )6[ ]70 ]8[ ]9[ 80 Gaal ]12 5} 14 88 9 Lost frames 0 igure ۰-۵0۰ ۰ ‏لاه مه (م) و وا ملسم ۲و تسه‎ ‏جوم لاه (ط) له مور‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0 

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Receiver's machine Application Procedure that reads two audio data units for each video data unit Incoming stream A A Network igure P-CO. Dke pricvipte oP explicit svackrodizatios vo the bevel date ‏.كلك‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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Application tells Receivers machine —_—s middleware what to do with incoming streams Multimedia control is part of middleware | | APPlication Middleware layer —{ Incoming stream Network igure P-90. (ke pricviple oP spockrocizatioa os ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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End host Router Ali 10 50 ۲ ___ ‏6م احج‎ 5 7 40 ‏دا‎ ۳0 1 [Rb aan 1 Internet D B Overlay network igure ۶4۵4۰ The rebtiog between tobe iad puerto ood ontud oetwork-tevel routes. ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227. 

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۰. ‏موق‎ propucaion wodet - Dede ® picks carter wde GQ ‏و و‎ — Gubsequediy exchanges updates wit © ٠ @pprouchkes to exckooyicy updates = @ oly) pwshes its vw updates to GQ = ody pulse to cew updotes Prow GQ — Puc Q sec updates to euch vier 

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4ePorwuiod Dissewication Oodets (©) k — 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 @rpure 02-26 . Vke relation betwee the Practiog ‏امسو جام لصن تاه ج‎ wwdes ued the pornveter k it pure ‏ری‎ Phe graph displays )( usu Puontivd oF ‏.عا‎ ‘Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- 

DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S. TANENBAUM MAARTEN VAN STEEN Chapter 4 Communication Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Layered Protocols (1) Figure 4-1. Layers, interfaces, and protocols in the OSI model. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Layered Protocols (2) Figure 4-2. A typical message as it appears on the network. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Middleware Protocols Figure 4-3. An adapted reference model for networked communication. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Types of Communication Figure 4-4. Viewing middleware as an intermediate (distributed) service in application-level communication. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Conventional Procedure Call Figure 4-5. (a) Parameter passing in a local procedure call: the stack before the call to read. (b) The stack while the called procedure is active. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Client and Server Stubs Figure 4-6. Principle of RPC between a client and server program. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Remote Procedure Calls (1) A remote procedure call occurs in the following steps: 1. The client procedure calls the client stub in the normal way. 2. The client stub builds a message and calls the local operating system. 3. The client’s OS sends the message to the remote OS. 4. The remote OS gives the message to the server stub. 5. The server stub unpacks the parameters and calls the server. Continued … Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Remote Procedure Calls (2) A remote procedure call occurs in the following steps (continued): 6. 7. 8. 9. 10. The server does the work and returns the result to the stub. The server stub packs it in a message and calls its local OS. The server’s OS sends the message to the client’s OS. The client’s OS gives the message to the client stub. The stub unpacks the result and returns to the client. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Passing Value Parameters (1) Figure 4-7. The steps involved in a doing a remote computation through RPC. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Passing Value Parameters (2) Figure 4-8. (a) The original message on the Pentium. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Passing Value Parameters (3) Figure 4-8. (a) The original message on the Pentium. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Passing Value Parameters (4) Figure 4-8. (c) The message after being inverted. The little numbers in boxes indicate the address of each byte. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Parameter Specification and Stub Generation Figure 4-9. (a) A procedure. (b) The corresponding message. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Asynchronous RPC (1) Figure 4-10. (a) The interaction between client and server in a traditional RPC. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Asynchronous RPC (2) Figure 4-10. (b) The interaction using asynchronous RPC. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Asynchronous RPC (3) Figure 4-11. A client and server interacting through two asynchronous RPCs. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Writing a Client and a Server (1) Figure 4-12. The steps in writing a client and a server in DCE RPC. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Writing a Client and a Server (2) Three files output by the IDL compiler: • • • A header file (e.g., interface.h, in C terms). The client stub. The server stub. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Binding a Client to a Server (1) • Registration of a server makes it possible for a client to locate the server and bind to it. • Server location is done in two steps: 1. Locate the server’s machine. 2. Locate the server on that machine. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Binding a Client to a Server (2) Figure 4-13. Client-to-server binding in DCE. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Berkeley Sockets Figure 4-14. The socket primitives for TCP/IP. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- The Message-Passing Interface (1) Figure 4-15. Connection-oriented communication pattern using sockets. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- The Message-Passing Interface (2) Figure 4-16. Some of the most intuitive message-passing primitives of MPI. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Message-Queuing Model (1) Figure 4-17. Four combinations for loosely-coupled communications using queues. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Message-Queuing Model (2) Figure 4-18. Basic interface to a queue in a message-queuing system. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- General Architecture of a Message-Queuing System (1) Figure 4-19. The relationship between queue-level addressing and network-level addressing. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- General Architecture of a Message-Queuing System (2) Figure 4-20. The general organization of a message-queuing system with routers. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Message Brokers Figure 4-21. The general organization of a message broker in a message-queuing system. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- IBM’s WebSphere Message-Queuing System Figure 4-22. General organization of IBM’s message-queuing system. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Channels Figure 4-23. Some attributes associated with message channel agents. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Message Transfer (1) Figure 4-24. The general organization of an MQ queuing network using routing tables and aliases. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Message Transfer (2) Figure 4-25. Primitives available in the message-queuing interface. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Data Stream Figure 4-26. A general architecture for streaming stored multimedia data over a network. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Streams and Quality of Service Properties for Quality of Service: • The required bit rate at which data should be transported. • The maximum delay until a session has been set up • The maximum end-to-end delay . • The maximum delay variance, or jitter. • The maximum round-trip delay. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Enforcing QoS (1) Figure 4-27. Using a buffer to reduce jitter. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Enforcing QoS (2) Figure 4-28. The effect of packet loss in (a) non interleaved transmission and (b) interleaved transmission. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Synchronization Mechanisms (1) Figure 4-29. The principle of explicit synchronization on the level data units. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Synchronization Mechanisms (2) Figure 4-30. The principle of synchronization as supported by high-level interfaces. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Overlay Construction Figure 4-31. The relation between links in an overlay and actual network-level routes. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Information Dissemination Models (1) • Anti-entropy propagation model – – • Node P picks another node Q at random Subsequently exchanges updates with Q Approaches to exchanging updates – – – P only pushes its own updates to Q P only pulls in new updates from Q P and Q send updates to each other Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227- Information Dissemination Models (2) Figure 4-32. The relation between the fraction s of update-ignorant nodes and the parameter k in pure gossiping. The graph displays ln(s) as a function of k. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved. 0-13-239227-