ARCNET Host 1Host 2Host n Token-bus net..... Hastighed : max 10 Mbit/s Antal hosts pr. segment: 255 dvs ID: 1-255

Opstart af token Hvis en maskine ikke er med dvs ingen INVITATION TO TRANSMIT i 420  S. Så råber den ''ALLE SKAL DØ'' RECONFIGURATION BURST gange Her efter: Når bus bliver IDLE vent 41  S + 73  S * (255-ID) Hvis stabig IDLE så: Send INVITATION TO TRANSMIT til mig selv samt find næste hoat men mindre ID Ellers: Vent til en sender INVITATION TO TRANSMIT til mig

Find NID NID er ID'en for den host med nærmeste lavere ID. NID = ID NID--; Send ITT to NID hvis ingen aktivitet i 37,4  S så hop: ellers stop ca 3 km frem samt tilbage= 15  S + 15  S plus opstartstid ca 6.4  S.

Pakkeformat Der sendes byte enheder: xxxx-xxxx bit Invitation To Transmit: ITT EOTDID End Of Transmission: 04Hex To gange Distination ID

Pakkeformat Free Buffer Enquiries ENQDID Enquiry: 85Hex To gange Distination ID Acknowledgement ACK 86Hex Negative Acknowledgement NAK 15Hex

Pakkeformat DataPakke SOHDID Start Of Header: 01Hex To gange Distination ID SID Source ID... DATACRCSCCRCCOUNT 256-N for short packet 512-N for long packet 0 for long packet byte X + X + X + X

Data transmision Sender: ID Modtage: DID ITT til ID send FBE send ACK send DataPacket send ACK ITT til NID

TDMA

TTP MEDL-tabel for note Time Buf add. D L I T

Pakkeformat StartOf Frame Header Data CRC Header: 1 Bit I/N-frame og 3bit Mode change CRC Normal Init Global time, current MEDL index, Membership vector

Tradmark (Name)Application areaTechnologyCapacitySupport Controller Area Network (CAN) automotive industry, cars, forklifters, tractors CSMA/CA 40m: 1 mbps 500m: 125kbps Intel embedded controllers (80517). Keil RT-51. DeviceNet from Allen Bradley ProfibusProces control Higher level token rotation. Lower level master slave. 2 mbps on rs-485 Siemens Simatic EN50170 P-net Proces control Virtual higher level token rotation. Lower level master slave kbps on rs-485 P-net from Proces Data EN50170 Attached Ressource Computer Network ARC-net Robot control, Marine automation Token bus.2-5 mbps on rs-485 Mitsubitsi ATOMOS EN50170 Time Triggered ProtocolCar automation, x-by wireTDMA2 mbps Tttech, Tech Univ. of Vienna. Herman Kopetz LONproces controlCSMA/CD mbps EcheLon LonWorks Motorola Highway Adressable Remote Transducer (HART) Transducer communication FSK on 4-20 mA Master Slave 3-4 req. / sec. InterBusProcescontrol Master Slave. Summation Frame Protocol 500 kpbs on rs-485 Bitbus radio broadcast and telecommunication systems building automation Master Slave300 kbps on rs-485 FireWire Connecting video and audio equiptment in PC-env. Combined Daisy Chain and TDMA mbps on tw. pair. (4.5 m.) IEEE 1394 Fiber Distributed Data Interface (FDDI) all purpose LAN space applications Token ring 100 mbps on fiber optics or tw. pair. (100km, max 2 km betw. stations.) IEEE Industrial Ethernet

Transmission Error Control Tilføje ekstra bit til pakker således at der bliver en given mindste afstand (Hamming afstand) mellem lovlige pakker. Fx. Even paritet som giver Hamming afstand på 2.

Transmission Error Control Hamming afstand: d min = 5. Max antal fejl der kan detekteres: d min - 1. Max antal fejl der kan rettes: ( d min - 1) / 2.

CRC - Cyclic Redundancy Check IEEE CRC-32: x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x1+1 Dvs ARCnet: CRC-16 x^16 + x15 + x ^ Dvs CAN bus: CRC-CCITT X^16+X^12+X^5+1 Dvs

CRC - Cyclic Redundancy Check List af de mest brugte CRC polynomier CRC-12: X^12+X^11+X^3+X^2+X+1 CRC-16: X^16+X^15+X^2+1 CRC-CCITT: X^16+X^12+X^5+1 CRC-32: X^32+X^26+X^23+X^22+X^16+X^12+ X^11+X^10+X^8+X^7+X^5+X^4+X^2+X+1 The CRC-12 bruges til 6-bits streams. Både CRC-16 og CCRC-CCITT er for 8 bits streams. CRC-32 giver ekstra sikkerhed da der generes en 32 bit Checksum. CRC-32 bruges i fx. (IEEE-802).

CRC - Cyclic Redundancy Check Polynomie: Data: : Remainder Checksum

CRC - Cyclic Redundancy Check Message M= Pattern P= FCS F=1110 (to be calculated)

QoS – Quality of Service Network layer: ● Reliability ● Delay ● Jitter ● Bandwidth

QoS – Quality of Service Løsning: ● Kapacitet nok. Fx. Telefonsystemet. ● Reciver buffer. Øger delay og mininere jitter. ● Begrænsning af senderes bithastighed. Minder delay, mindre jitter og mindre Bandwidth.

Bucket algoritmen ● En sender buffer. ● En cyklisk task der er aktiv hvis der er data i bufferen og sender disse data med en passende lav bidhastighed.

Token Bucket algoritmen ● En sender buffer der fyldes med token token/sek. ● Senderen sender sine data vha tokens dvs. Nbit pr token fra bufferen.

Netværkslaget Fysisk Data Link Network Transport Session Presentation Application Simpel routing Statisk routes med garanti egenskaber QoS

Transportlaget Fysisk Data Link Network Transport Session Presentation Application Muligøre data overførsel. Tilpasning af QoS faktorerne.

Tilpasning af QoS TCP: Pålidelig, stort jitter og delay. UDP: Upålidelig, mindre jitter og delay. RTP: Upålidelig, ingen jitter og mindre delay.

API Fysisk Data Link Network Transport Session Presentation Application Socket RPC, RMI og CORBA

Socket int sock; sock=socket(,, ); bind(sock,, ); listen(sock, ); newsock=accept(sock,, ) sock=socket(,, ); bind(sock,, ); connect(sock,, )

RPC

program TSTPROG { version TSTVERS { int TSTSTRING(string) = 1; } =1; } = 0x ; int * tststring_1(argp, clnt) char **argp; CLIENT *clnt; { static int clnt_res; memset((char *)&clnt_res, 0, sizeof (clnt_res)); if (clnt_call(clnt, TSTSTRING, (xdrproc_t) xdr_wrapstring, (caddr_t) argp, (xdrproc_t) xdr_int, (caddr_t) &clnt_res, TIMEOUT) != RPC_SUCCESS) { return (NULL); } return (&clnt_res); }

RPC program TSTPROG { version TSTVERS { int TSTSTRING(string) = 1; } =1; } = 0x ; #include #include "rpcprog.h" int * tststring_1(msg) char **msg; { static int result; fprintf(stderr,"strang: %s\n", *msg); result =4; return (&result); }

RPC program TSTPROG { version TSTVERS { int TSTSTRING(string) = 1; } =1; } = 0x ; #include #include "rpcprog.h" main(argc, argv) int argc; char *argv[]; { CLIENT *cl; int *resultat; char *server; char *message; server= argv[1]; message= argv[2]; cl= clnt_create(server,TSTPROG, TSTVERS,"tcp"); resultat= tststring_1(&message,cl); printf("resultat; %d\n",*resultat); }

1.Write and compile Java code for interfaces 2.Write and compile Java code for implementation classes 3.Generate Stub and Skeleton class files from the implementation classes 4.Write Java code for a remote service host program 5.Develop Java code for RMI client program 6.Install and run RMI system

Interface public interface Calculator extends java.rmi.Remote { public long add(long a, long b) throws java.rmi.RemoteException; public long sub(long a, long b) throws java.rmi.RemoteException; public long mul(long a, long b) throws java.rmi.RemoteException; public long div(long a, long b) throws java.rmi.RemoteException; }

Implementation public class CalculatorImpl extends java.rmi.server.UnicastRemoteObject implements Calculator { public CalculatorImpl() throws java.rmi.RemoteException { super(); } public long add(long a, long b) throws java.rmi.RemoteException { return a + b; } public long sub(long a, long b) throws java.rmi.RemoteException { return a - b; } public long mul(long a, long b) throws java.rmi.RemoteException { return a * b; } public long div(long a, long b) throws java.rmi.RemoteException { return a / b; }

Client import java.rmi.Naming; import java.rmi.RemoteException; import java.net.MalformedURLException; import java.rmi.NotBoundException; public class CalculatorClient { public static void main(String[] args) { try { Calculator c = (Calculator) Naming.lookup( "rmi://localhost /CalculatorService"); System.out.println( c.sub(4, 3) ); System.out.println( c.add(4, 5) ); } catch (MalformedURLException murle) { System.out.println(murle); } catch (RemoteException re) { System.out.println(re); } catch (NotBoundException nbe) { System.out.println(nbe); } catch (java.lang.ArithmeticException ae) { System.out.println(ae); }

Server import java.rmi.Naming; public class CalculatorServer { public CalculatorServer() { try { Calculator c = new CalculatorImpl(); Naming.rebind("rmi://localhost:1099/CalculatorService", c); } catch (Exception e) { System.out.println("Trouble: " + e); } public static void main(String args[]) { new CalculatorServer(); }

CORBA