Transcript Ahmed Musa - University of Texas at San Antonio

Circuit Establishment in a Hybrid Optical-CDMA and WDM AllOptical Network Using the Flooding Mechanism
Ahmed Musa, John Medrano, Virgillio Gonzalez,
Cecil Thomas
University of Texas at El Paso
Mehdi Shadaram
University of Texas at San Antonio
Outline
*
Introduction
- A high demand on higher capacities ( Why all-optical network?)
- Approaches to make the transmission medium has a scalable
bandwidth (BW) capacity
*
Backbone network
- Optical-Optical-Optical (OOO)
- Optical-Electrical-Optical (OEO)
*
Routing Benefits and Disadvantages
*
Proposed routing algorithm
*
Routing (Setup Optimal Lightpath) Steps
*
Routing Implementation Using Flooding Mechanism
*
Example
*
Conclusions
Introduction
• A high demand on higher capacities because of
 Multimedia services.
 Video conferences
 Internet.
 Environmental remote sensing.
 Medical imaging
•
Approaches to make the transmission medium has a
scalable bandwidth (BW) capacity
 Install more fiber (costly)
 Exploit the BW of existing fiber using higher data rates and
multiplexing techniques such as
 Wavelength Division Multiplexing (WDM).
- Coarse WDM (# of Lambdas λ’s < 10)
- Dense WDM (# of λ’s > 10)
 Time Division Multiplexing (TDM).
 Code Division Multiplexing (CDM).
Backbone network
Optical – Electrical – Optical (OEO)
Optical – Optical – Optical (OOO or Photonic NW)
Photonic networks
 Advantages
– Solve the electronic equipment bottleneck
– Exploit the existing network
 Disadvantages
- Photonic NW is a complex system ( a large number of
different functions must cooperate for a network such as
–
transmission
–
Routing and Switching
–
Control and management
–
etc.
Routing Benefits
 Support services such as connection on demand
 Enriches the service level agreement (SLA) by supporting (Protection and
Restoration).
 Improves bandwidth (BW) efficiency and source utilization of the network.
Routing disadvantages
 Intractable problem (NP-Complete).
Therefore, assumptions and heuristics are used to reduce the process
complexity.
 Upgrading the Network by :
 Increase bit rate from 2.5 up to 160 Gb/s
 #of wavelength up to 256
 Narrowing the channel spacing
 Is significantly affected by Routing Algorithm due to Physical
impairments
Table 2: Optical Linear and Non-linear Impairments
Class
Linear
Nonlinear
Impairment
Constraint
Attenuation (Loss)
Optical amplification implying OSNR
degradation
Chromatic dispersion (GVD)
Compensation fiber or limit on the
total length of fiber links
Polarization-mode
(PMD)
Total length of fiber links
dispersion
Self-phase modulation (SPM)
NLP constraint
Cross-phase modulation (XPM)
NLP constraint
Four – Wave Mixing (FWM)
Negligible (per system design)
Simulation
(SRS)
Roman
scattering Modification of signal power (and
thus NLP)
Stimulated brillouin scattering
Negligible
(SBS)
Noise
OSNR degradation (resulting in
Amplifier spontaneous emission
constraint on the number of fiber
(ASE)
spans)
Routing algorithm flow diagram
Call Request
Network - Layer Module
Wavelength and
Code Assignment
Look for an
available lightpath
(LP) using a RWA
Calculate lightpath (LP) Metrics
no LP
available
Block call
Candidate LP
Physical - Layer Module
Calculate LPs Metrics
Admit call
Choose the best Path
"Min. Cost Path"
Fiber Metrics
Switch Metrics
Apply Vetirbi
Algorithm on
the closed Loop
Choose the lowest
metric Path
Proposed routing algorithm
– Used Optical CDM and WDM to label the optical signal
– Takes into account the physical impairments existing in NW
– Set up the lightpath based on calculating the cost of all possible paths from
ingress to egress node.
Routing (Setup Optimal Lightpath) Steps
– First Step :- Calculate the fiber metrics.
– Second Step :- Calculate switch metrics.
– Third Step :- Apply Viterbi algorithm on each close loop from the source
to destination to select the minimum metric.
Fiber metrics
L
(
M
i, j
L
 atten.

L
L
GVD
N

L
LPMD
)
x 65,535
Where N is the normalization factor
I/P Metric
1 2
O/P Metric
l
C1 m11 m12 ....... m1l 
C2 m21 m22 ....... m2l 
 
Ck mk1


mk2

Where
 

mkl 
1
Link merits (L) :Attenuation 
Dispersion D
M(o)  M(i)  Δ
 m11
 m'
 21
 
Ck m'k1
C1
C2
'
2
'
m12
m'22

'
mk2
l
....... m'1l 
....... m'2l 

 

 m'kl 
M'  M  Δ , and  is a function of Attenuation  and Dispersion
ij
ij
D
Wavelengths are selected based on ITU-T G.692 WDM grid
10
192.00
1561.42
11
192.10
1560.61
Long band
12
192.20
1559.79
Long band
13
192.30
1558.98
Long band
14
192.40
1558.17
Long band
15
192.50
1557.36
Long band
16
192.60
1556.55
Long band
17
192.70
1555.75
Long band
18
192.80
1554.94
Long band
19
192.90
1554.13
Long band
20
193.00
1553.33
Long band
21
193.10
1552.52
Reference frequency
22
193.20
1551.72
Long band
23
193.30
1550.92
Long band
24
193.40
1550.12
Long band
25
193.50
1549.32
Long band
26
193.60
1548.51
Long band
Routing Implementation Using Flooding Mechanism
(1) The forward signaling procedure
Switch 1
Src.
Hop
Hello
Count Timer
Timer
Output
Port
M11
M12
M13
...
(3) The clearance procedure
Network
Dimension
(number of node)
Input
Port
( C) Input
Source
address
Destinataion
address
M(')nm
Mnm
...
Hop
Count
( C) Input
Src.
Input Output
Port
Port
M(k)11
M(k)12
M(k)13
Switch 1
(2) The backward signaling procedure.
Dest.
...
Mnm
( C) Input
Network
Dimension
...
C) Input
Source
address
Destinataion
address
Input Output Input Output
Port
Port
Port
Port
M11
M(')11
M12
M(')12
M13
M(')13
~ ~
~
~
Dest.
Switch k
Switch 2
M(k)nm
Calculate Switch Metrics
Switch Y
D
A
xx
x
2
1
1
3
1
1
1
1
λ 1C 1
λ 1C 2
λ 2C 1
λ 2C 2
Switch X
λ 1C 1
λ 1C 1
λ 1C 1
λ 1C 1
C1 C2
C1 C2
λ1 4
5
λ1 7
6
λ2 5
7
λ2 9
7
2
4
5
5
7
Min( )
C1 C2
C1 C2
λ1 8
10 λ1 11 9
λ2 7
8
λ2 9
8
λ1
λ2
C1
4
5
C2
5
7
2
λ1C2
λ1C1
3
IP1  
6
C1 C2
C1 C2
λ1 4
5
λ1 7
6
λ2 5
7
λ2 9
7
5
7 
λ2C1
λ1
λ2
λ2C2
1
D
3
A
1
λ1C 1
λ 1 C2
λ2C 1
λ 2 C2
3
1
1
1
1
Switch Y
D
A
2
xx
x
Switch Y
2x2x2x2
D
10
ps
1
λ 1C 1
λ 1C 2
λ 2C 1
λ 2C 2
3
1
1
1
1
λ1
λ2
C1 C2
C1 C2
8
10 λ1 11 9
7
8
λ2 9
8
3
Switch Y
Min( )
A
2
xx
x
1
λ 1C 1
λ 1C 2
λ 2C 1
λ 2C 2
Switch # X
Switch X
1
3
1
1
1
1
λ 1C 1
λ 1C 1
λ 1C 1
λ 1C 1
4
Switch X
1
λ 1C 1
λ 1C 1
λ 1C 1
λ 1C 1
4
4
5
5
7
C1 C2
C1 C2
λ1 4
5
λ1 7
6
λ2 5
7
λ2 9
7
C1 C2
C1 C2
λ1 8
10 λ1 11 9
λ2 7
8
λ2 9
8
Min( )
λ1
λ2
C1
4
5
C1
4
5
C2
5
7
3
4
5
5
7
C2
5
7
Data start brusted through using the selected path (A B
C)
Network Model and Bisectional Bandwidth
Switching Point
(Signal Transfer Point)
2
Bisectional
Bandwidth
1
s witch B
3
4
2
3
2
3
1
4
1
4
s witch D
s witch A
node A
2
node D
1
3
4
Bisectional
Bandwidth
s witch C
External node
photonic switch
Signaling Link
Fiber Link
Network Characteristics and Switch Metrics
Fiber Lengths :
distance (Switch A, Switch B) = 30 km
distance (Switch A, Switch C) = 20 km
distance (Switch B, Switch C) = 25 km
distance (Switch B, Switch D) = 15 km
distance (Switch C, Switch D) = 20 km
Switch Metrics Matrix for 2 wavelengths x 2 codes
λ1 C 1
λ1 C 2
λ2 C 1
λ2 C 2
λ1 C 1
1

λ1 C 2
2
λ2 C 1
2
λ2 C 2
4

2
2
1
4
4
1
2

2

4
2
2
1









λ1
λ2


Blocking probability of NW (2 wavelengths and 2 codes) at different traffic load
Blocking Probability
60%
50%
40%
30%
Blocking due to entry port
20%
Blocking due to NW resources
10%
0%
0
5
10
15
Traffic Load (Erlangs)
20
Blocking probability due to NW resources (2 wavelengths and 2
codes) at different traffic load
Blocking Probability (%)
Blocking Probability due to NW Resources
6.00%
5.00%
Impaired NW
Ideal NW
Ideal Switch/Impaired Fiber
Ideal Fiber/Impaired Switch
4.00%
3.00%
2.00%
1.00%
0.00%
0
2
4
6
8
10
12
Traffic Load (Erlang)
14
16
Conclusions
 This algorithm help improving the NW Performance.
 Flooding mechanism is used to set up the path (used
in the control plane of the network independent of the
information path.
 Flooding mechanism is emulated in in the network
manager.