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Technion

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Title: Technion


1
Technion Israel Institute of Technology
Computer Networks Laboratory Digital laboratory
Real Time Ethernet
Semester Winter 2001
       Students Shay Auster Hagit Chen
      Supervisor Vitali Sokhin
2
RTE - Preview
  • An Ethernet protocol for Real-Time.
  • Analytic analisys of estimated performance.
  • Design an adiqute simulation.
  • Run various scenarios in simulation.
  • Conclusions.

3
Abstract
  • Real Time Streaming requires a bound on the time
    of which a packet is created until it reaches its
    destination.
  • IEEE 802.3u protocol does not support this
    requirment.
  • Hence, a Real Time Ethernet protocol needs to be
    defined.

4
RTE Protocol - Overview
  • Combine Ethernet and RTE transmisions on the same
    network.
  • On the same Lan All RTE stations support the
    same application.
  • In order to coordinate transmisions between RTE
    stations A mechanism to serializes
    transmisions.

5
  • Serializations of RTE transmitsions
  • Head and Tail are required for the Handshaking -
    a mechanism which serealizes RTE transmisions.

6
RTE frame
Ethernet frame bounded between a head and a tail
  • Head
  • Clean channel for RT transmisions.
  • Notify all other RT stations on RTE transmision
    status.
  • Tail
  • Notify all other RT stations on RTE transmisions
    status.

7
Overview cont.
  • Two possible situations in channel
  • RTE transmision in channel A new RTE station
    join the end of the chain.
  • No RTE transmision The RTE station generates a
    new chain.
  • A RTE chain transmision in channel
  • RTE station interupt at the end of the chain no
    handshaking at 1st time.
  • Part of chain - handshaking from next time.

8
Final ResultsAnalysis
9
Ethernet always transmits
  • Basic Ethernet simulation.
  • Stations always have packets to transmit.

10
Ethernet always transmits
  • Ethernet simulation results are used as a
    reference in analysing RTE simulation results.

11
RTE Always transmits
  • Ethernet always transmit.
  • RTE According to protocol.

12
RTE always transmits
  • A Single RTE Station
  • Various number of Ethernet stations

13
RTE always transmits
  • Three RTE Station
  • Various number of Ethernet stations

14
RTE always transmits
  • Five RTE Station
  • Various number of Ethernet stations

15
Ethernet The poissonic case
  • Poissonic arrival of packets to stations.
  • The interval between arrival of packets is
    exponential distributed ? poissonic arrival of
    packets.
  • For exponential probability function we used an
    inverse distribution function.

16
Ethernet poissonic case
  • Ethernet packets arrival rate is poissonic.
  • t 1000uSec mue 1

17
Ethernet poissonic case
  • Ethernet packets arrival rate is poissonic.
  • t 500uSec differnet mue (0.5/1/2)

18
Ethernet poissonic case
  • Ethernet packets arrival rate is poissonic.
  • Different t (500/1000/2000uSec) mue 1

19
RTE The poissonic case
  • Ethernet Poissonic arrival of packets to
    stations.
  • RTE According to protocol.

20
RTE poissonic case
  • Ethernet packets arrival rate is poissonic.
  • A single RTE station.
  • t 1000uSec mue 1

21
RTE poissonic case
  • Ethernet packets arrival rate is poissonic.
  • Three RTE stations.
  • t 1000uSec mue 1

22
RTE poissonic case
  • Ethernet packets arrival rate is poissonic.
  • Five RTE stations.
  • t 1000uSec mue 1

23
RTE poissonic case
  • Ethernet packets arrival rate is poissonic.
  • Different RTE stations.
  • t 1000uSec mue 1

24
Ethernet The On/Off case
  • On Always transmits.
  • Off Never transmits.
  • The on/off intervals are exponentily distributed.

25
Ethernet On/Off case
  • 64 Bytes packet.
  • Different On/Off data.

26
Ethernet On/Off case
  • 256 Bytes packet.
  • Different On/Off data.

27
Ethernet On/Off case
  • 1024 Bytes packet.
  • Different On/Off data.

28
RTE The On/Off case
  • Ethernet -
  • On Always transmits.
  • Off Never transmits.
  • RTE According to protocol.

29
RTE On/Off case
  • 1024 bytes Ethernet packets.
  • A Single RTE station.
  • Different On/Off data.

30
RTE On/Off case
  • 1024 bytes Ethernet packets.
  • Three RTE stations.
  • Different On/Off data.

31
RTE On/Off case
  • 1024 bytes Ethernet packets.
  • Five RTE stations.
  • Different On/Off data.

32
Ethernet Stations Wait Time
  • Ethernet Allways transmit.
  • No RTE.
  • Wait time increases with packet size.

33
RTE Stations Wait Time
  • Ethernet Allways transmit.
  • One RTE station.
  • Wait time increases with packet size.
  • Wait time increases with number of RTE stations.

34
RTE Stations Wait Time
  • Ethernet Allways transmit.
  • Three RTE stations.
  • Wait time increases with packet size.
  • Wait time increases with number of RTE stations.

35
RTE Stations Wait Time
  • Ethernet Allways transmit.
  • Five RTE stations.
  • Wait time increases with packet size.
  • Wait time increases with number of RTE stations.

36
RTE - Jitter
  • Ethernet Allways transmit.
  • Various number of RTE stations.
  • Jitter increases with packet size number of RTE
    stations.

37
Time to genrate RTE chain
  • Ethernet Allways transmit.
  • Various number of RTE stations.
  • Chain time increases with number of RTE stations.

38
Application example
  • Ethernet Allways transmit.
  • Various number of RTE stations.
  • Application sampeling rate 1.5Mbps.

39
Conclusions
  • RTE stations uses a part of the Ethernet channel
    ? Ethernet stations Efficiency decreases.
  • The total chanel efficiency increases.
  • For Ethernet allways transmit on/off arrival
    times we get an immediate reduce of efficiency.
  • For poisonic arrival of packets we dont get an
    immediate reduce of efficiency.

40
Conclusions
  • For each arrival pattern channel efficiency
    converges to the allways transmits results (for
    sufficient number of stations).
  • More stations (regular/RTE) ? Larger wait time.
  • Bigger packets ? Larger wait time.? Larger
    Jitter.
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