completed/planned activities of agh in vd-a miroslaw kantor, marcin niemiec department of...
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Completed/planned activities of AGH in VD-A
Miroslaw Kantor, Marcin Niemiec
Department of TelecommunicationsAGH University of Science and Technology
VD-A meeting February 26, 2007Barcelona, Spain
February 26, 2007 Barcelona, Spain
Completed/planned activities
Access network resilience (will be continued) Network protection strategies for access networks
Analytical reliability analysis of access networks
Stochastic simulation for evaluation of access networks
reliability/availability
System reliability design problem
Quantum cryptography (planned) Study of optical network technologies for adaption of quantum
cryptography techniques to optical access networks
February 26, 2007 Barcelona, Spain
Stochastic simulation approach
In most of the practical cases we cannot
specify precisely the model or the value of
its parameters
The assumption of deterministic values for
the uncertainty might lead to faulty models
whose analysis might not be in conformity
with reality
Parameter uncertainty is typically specified
in terms of probability density functions
PDFs
February 26, 2007 Barcelona, Spain
Considered types of system performance: s-expected system lifetime:
mean system lifetime (expected mean value EMV)
-system lifetime: denotes the largest satisfying the inequality:
This means that reaches upwards of with a probability
system reliability:
probability that the system lifetime is larger than or equal to
the given value
Types of system resilience performance
,xTE
TxT ,Pr
0TxT ,Pr
T
T ,xT
February 26, 2007 Barcelona, Spain
Passive Optical Network recovery schemes [G.981.5]
Recovery architecture of type A Recovery architecture of type B
Recovery architecture of type C Recovery architecture of type D
February 26, 2007 Barcelona, Spain
Reliability block diagrams for PON recovery schemes
RBD for recovery architecture of type A RBD for recovery architecture of type B
RBD for recovery architecture of type C RBD for recovery architectureof type D: duplex
RBD for recovery architecture of type D: no duplex
February 26, 2007 Barcelona, Spain
Assumptions for stochastic simulation
No element repair action is taken after the failure
The exponential distribution, as one of the most common
distributions used in the systems reliability analysis, has
been applied
The length of the connection link is 20 km
Survivability parameters of the optical access network
components: Element FIT
MTTF[year]
OLT equipment 20000 5104
Optical fiber500
[FIT/km]2106
[hkm]
Optical splitter 120 8.3106
ONU equipment 8500 1.2105
February 26, 2007 Barcelona, Spain
Stochastic simulation results (basic architecture)
Probability density function of system lifetime
0,00
0,04
0,08
0,12
0,16
0,20
0,0E+00 4,0E+04 8,0E+04 1,2E+05
system lifetime [h]
Stochastic simulation proces
1,5E+04
1,9E+04
2,3E+04
2,7E+04
3,1E+04
0 1000 2000 3000 4000 5000
N
EM
V
PDF of system lifetime
Stochastic simulation process for EMV
February 26, 2007 Barcelona, Spain
Results for considered recovery architectures
Considered architecture
expected system lifetime EMV
system
reliability [T0=EMV]
basic architecture 26029 11911 0.3662
type A architecture 32234 15667 0.3716
type B architecture 45419 29290 0.4018
type C architecture 51278 35632 0.4054
type D arch. duplex 66391 46740 0.4111
type D arch. no duplex 45222 29953 0.4062
T
M. Kantor, K. Wajda, P. Cholda: „Reliability Evaluation of PON Recovery Architectures Using Stochastic Simulation”, BBEurope,11-14 December 2006,Geneva, Switzerland
February 26, 2007 Barcelona, Spain
Planned activity
Study of optical network technology and
architectures (PON, WDM ...) in order to
adapt quantum cryptography techniques
to optical access networks
February 26, 2007 Barcelona, Spain
Quantum Cryptography
Quantum Cryptography (QC) provides unbreakable communications – each eavesdroped intruders are detected.
QC solves key distribution problem over optical fiber networks. QC ensures absolute security by using the laws of quantum physics (a bits are coding by quantum states of photons).
Currently, QC devices are producing and testing (i.e. in Europe by Id Quantique or SmartQuantum) but these devices communicate upon a dedicated fibre.
One of possible applications: FTTH PON technology uses broadcast downlink communication - each entity receives all the network traffic. Therefore, encryption in these networks is crucial in order to avoid frauds.
February 26, 2007 Barcelona, Spain
Possible aspects
Possible aspects to consider: Analysis of necessity Analysis of technical possibility Requirements Security issues Services Business issues Case studies …
Contact person:
Marcin Niemiec
February 26, 2007 Barcelona, Spain
Planned joint activity
Topic:
Experimental evaluation of access network
resilience schemes
Paticipants: FUB, AGH
Planned mobility: October 2007
Thank you!
February 26, 2007 Barcelona, Spain
Conclusions
Different access architectures based on the Passive Optical
Network concept have been compared
The comparison was made taking into account three types of
system performance measures: s-expected system lifetime, -
system lifetime and system reliability
The stochastic simulation was applied for simple PON architecture
to check the applicability of this method for reliability analysis of
more complicated systems
The obtained results allow us to state that stochastic simulation
method can be used for that purpose