TELK
OMNIKA
,
V
ol.
15,
No
.
3,
September
2017,
pp
.
1061
1071
ISSN:
1693-6930,
accredited
A
b
y
DIKTI,
Decree
No:
58/DIKTI/K
ep/2013
DOI:
10.12928/telk
omnika.v15.i3.5019
1061
P
ac
ket
Loss
Rate
Diff
erentiation
in
slotted
Optical
P
ac
ket
Switc
hing
OCDM/WDM
Omar
Najah
*
,
Kamaruzzaman
Seman
,
and
Khairi
Abdulrahim
F
aculty
of
Science
and
T
echnology
,
Univ
ersiti
Sains
Islam
Mala
ysia,
Bandar
Bar
u
Nilai
7180
0,
Nilai,
Neger
i
Sembilan,
Mala
ysia
*
Corresponding
author
,
e-mail:
omar
.najah@gmail.com
Abstract
W
e
propose
a
m
ulti-class
mechanism
f
or
Opt
ical
Code
Division
Multiple
xing
(OCDM),
W
a
v
elength
Division
Multiple
xing
(WDM)
Optical
P
ac
k
et
Switch
(OPS)
architecture
capab
le
of
suppor
ting
Quality
of
Ser-
vice
(QoS)
tr
ansmission.
O
CDM/WDM
has
been
propose
d
as
a
competitiv
e
h
ybr
id
s
witching
technology
to
suppor
t
the
ne
xt
gener
ation
optical
Inter
net.
This
paper
addresses
perf
or
mance
issues
in
the
slotted
OPS
netw
or
ks
and
proposed
f
our
diff
erentiation
schemes
to
suppor
t
Quality
of
Ser
vice
.
In
addition,
w
e
present
a
compar
ison
betw
een
the
proposed
schemes
as
w
ell
as
,
a
sim
ulation
scheduler
design
which
can
be
suitab
le
f
or
the
core
s
witch
node
in
OP
S
netw
or
ks
.
Using
softw
are
sim
ulations
the
perf
or
mance
of
our
algor
ithm
in
ter
ms
of
losing
probability
,
the
pac
k
et
dela
y
,
and
scalability
is
e
v
aluated.
K
e
yw
or
ds:
Quality
of
Ser
vice
(QoS),
Slotted
Optical
P
ac
k
et
Switching,
P
ac
k
et
Loss
Probability
(PLP),
shared
Fiber
Dela
y
Line
(FDL).
Cop
yright
c
2017
Univer
sitas
Ahmad
Dahlan.
All
rights
reser
ved.
1.
Intr
oduction
Upcoming
optical
netw
or
ks
are
e
xpected
to
suppor
t
man
y
n
umbers
of
users
with
m
ultiple
bit
r
ate
tr
ansmissions
,
finer
g
r
an
ular
ity
capacity
and
quality
of
ser
vice
(QoS)
demands
in
a
fle
x-
ib
le
manner
[1].The
g
ro
wth
of
inter
activ
e
application
and
m
ultimedia,
such
as
video-on-demand,
teleconf
erencing
and
digital
video
broadcasting
depend
on
the
Inter
net
to
e
xchange
data
tr
affic.
Consequently
,
Optical
P
ac
k
et
Switching
(OPS)
is
supposed
to
be
among
one
of
the
g
reatest
can-
didates
to
be
implemented
in
f
uture
optical
bac
kbone
netw
or
k
[2],
[3],
it
is
fundamental
to
de
v
elop
ne
w
QoS
diff
erentiation
mechanisms
that
consider
the
OPS
netw
or
k
char
acter
istics
.
Ov
er
y
ears
,
plenty
of
diff
erent
s
witching
technologies
such
as
optical
code
division
m
ul-
tiple
xing
(OCDM),
and
w
a
v
elength
division
m
ultiple
xing
(WDM)
ha
v
e
been
in
v
estigated
in
optical
fiber
comm
unication
[4],[5].
These
technologies
,
OCDM
constitutes
a
potential
candidate
f
or
the
ne
xt
gener
ation
optical
netw
or
ks
par
ticular
ly
due
to
f
eatures
lik
e
synchronous
and
asynchronous
oper
ation
simplified
netw
or
k
control
the
easy
addition
of
ne
w
users
and
the
possibility
of
diff
eren-
tiated
quality
of
ser
vice
QoS
at
the
ph
ysical.
No
w
ada
ys
,
there
has
been
an
increasing
demand
f
or
ne
w
m
ultimedia
applications
,
f
or
instance
,
e-lear
ning
e-health
high-data-capacity
3-D
full-HD
(high-definition)
the
video
,
m
ultipla
y
er
games
,
video-on-demand,
etc.,
as
a
consequence
,
these
ne
w
applications
will
require
diff
erentiated
QoS
and
m
ultiple
r
ates
tr
ansmission
which
are
becom-
ing
a
challenge
f
or
future
optical
netw
or
ks
.
Ho
w
e
v
er
,
w
a
v
elength
division
m
ultiple
xing,
Optical
code-division
m
ultiple
xing
(OCDM/WDM)
is
a
technic
,
which
can
use
f
or
the
future
gener
ation
of
the
Inter
net
[6].
In
WDM
technology
,
the
optical
media
spectr
um
divided
into
a
n
umber
of
w
a
v
elength
bands
,
which
arent
o
v
er
lapping
and
each
w
a
v
elength
can
pro
vide
a
large
amount
of
r
a
w
bandwidth.
Moreo
v
er
,
WDM
can
suppor
t
a
m
ulti-coded
comm
unication
channels
oper
ating
at
high
data
r
atio
.
Presently
,
WDM
technology
suppor
ts
the
m
ultiple
xing
of
hundreds
of
spectr
um
into
a
single
optical
fiber
,
at
a
tr
ansmission
r
ate
of
10s
Gb/s
per
spectr
um
channel
[7].
In
optical
code-division,
m
ultiple
xing
(OCDM)
can
pro-
vide
fle
xib
le
,
heterogeneous
,
and
synchronous
m
ultiple
bit-r
ate
tr
ansmissions
at
a
sub-w
a
v
elength
le
v
el
to
connections
with
enhanced
secur
ity
and
netw
or
k
scalability
[8].
In
addition,
OCDM
can
Receiv
ed
March
8,
2017;
Re
vised
J
une
26,
2017;
Accepted
J
uly
19,
2017
Evaluation Warning : The document was created with Spire.PDF for Python.
1062
ISSN:
1693-6930
pro
vide
QoS
diff
erentiation
at
the
ph
ysical
la
y
er
le
v
el.
Moreo
v
er
,
optical
code
gener
ation,
process-
ing,
and
decoding
are
perf
or
med
entirely
in
the
optical
domain
[1].
This
ar
ticle
is
orga
niz
ed
as
the
f
ollo
wing
sections
.
In
Section
II,
w
e
descr
ibe
the
related
w
or
k.
The
diff
erentiated
contention
resolution
in
photonic
pac
k
et
s
witching
net
w
or
ks
is
discussed
in
Section
III.
In
Section
IV
,
w
e
discuss
the
sim
ulation
perf
or
mance
.
The
conclusion
has
been
e
xplaining
in
Section
V
.
2.
Related
W
ork
Actually
,
high
bandwidth
does
not
solv
e
the
QoS
issue;
theref
ore
,
ne
w
schemes
f
or
sup-
por
ting
QoS
in
an
optical
bac
kg
round
are
needed.
Currently
,
there
is
diff
erent
ser
vice
diff
eren-
tiation
ha
v
e
been
proposed
to
suppor
t
m
ulti-r
ate
ser
vices
pro
vision
in
OCDM
netw
or
ks
such
as
emplo
ying
codes
with
diff
erent
lengths
[9].
A
diff
erent
approach
is
to
use
the
m
ulti-cored
tech-
nique
,
where
the
n
umber
of
sim
ultaneously
assigned
code
w
ords
to
each
user
is
a
function
of
the
data
r
ate
of
the
ser
vice
class
,
while
QoS
diff
erentiation
is
realiz
ed
b
y
v
ar
iab
le-w
eight
code
w
ords
f
or
each
ser
vice
class
[10].
Adapting
the
n
umber
of
allocated
codes
according
to
the
requested
tr
ansmission
r
ate
,
so
as
to
suppor
t
time-v
ar
iant
data
r
ates
and
m
ultiser
vice
tr
ansmissions
b
y
emplo
ying
a
m
ulti-code
v
ar
iab
le-w
eight
tw
o-dimensional
(2D)
one
coincidence
frequency
hopping
code
,
optical
or
thog-
onal
code
(OCFHC/OOC)
as
the
signature
code
[1].
Ho
w
e
v
er
,
the
author
proposed
dynamic
changes
in
the
req
uested
r
ate
b
y
means
of
allocating/de-allocating
encoders/decoders
to
the
e
xisting
connections
.
T
w
o
m
ulticode
assignment
methods
,
used,
r
andom
m
ulticode
assignment
(RMA)
policy
and
unif
or
m
m
ulticode
assignment
(UMA)
policy
.
Consequently
,
the
result
sho
ws
that
b
loc
king
probability
obser
v
e
w
orse
end-to-end
b
loc
king
probability
.
Fur
ther
more
,
RMA
and
UMA
policies
ha
v
e
the
same
b
loc
king
probability
.
On
the
other
hand,
utilizing
m
ultilength
v
ar
iab
le-w
eight
(ML
VW)
codes
[9,
11],
and
m
ul-
ticode
v
ar
iab
le-w
eight
(MCVW)
codes
[10],
b
oth
m
ulti-r
ate
and
m
ulti-QoS
tr
ansmission
are
sup-
por
ted
sim
ultaneously
,
as
a
compar
ison
is
carr
ied
out
betw
een
using
MCVW
codes
and
ML
VW
codes
in
[10].
In
the
ar
ticle
[9],
the
idea
w
as
based
on
OCDM
scheme
in
gener
aliz
ed
m
ulti-
protocol
label
s
witching
(GMPLS)
netw
or
k
using
m
ultilength
v
ar
iab
le-w
eight
optical,
or
thogonal
codes
(ML
VW
-OOC)
as
signature
se
quences
.
The
w
eight
and
th
e
length
of
codes
w
ere
de-
signed
based
on
the
ser
vice
char
acter
istics
,
with
limitation
the
n
umber
of
connections
based
on
the
activity
n
umber
of
the
connected
users
to
guar
antee
the
desired
ser
vice
.
Moreo
v
er
,
m
ulti-
length
v
ar
iab
le-w
eight,
optical
or
thogonal
codes
(ML
VW
-OOC)
is
used
as
signature
sequences
of
a
h
ybr
id
WDM/OCDM
system,
the
code
length
and
code
w
eight
of
ML
VW
-OOCs
are
designed
based
on
the
char
acter
istics
of
the
demanded
classes
of
ser
vice
[11].
In
[12]
an
o
v
er
all
technique
of
constr
ucting
ML-OOCs
,
with
arbitr
ar
y
correlation
v
alue
f
or
m
ulti-r
ate
OCDM
netw
or
ks
ha
v
e
been
introduced
to
constr
uct
a
v
ar
iab
le-length
mapping
sequence
with
unpar
alleled
positions
,
with
which
map
shor
t-length
OOCs
into
long-length
OOCs
to
realiz
e
the
gener
al
constr
uction
of
ML-OOCs
with
correlation
v
alue
with
high
efficiency
.
Fur
ther
more
,
the
author
in,
[13,
14]
ha
v
e
proposed
f
or
malisms
can
be
successfully
ap-
plied
to
1-D
and
2-D
MWM
L-OOC
OCDM
netw
or
ks
with
an
y
n
umber
of
user
classes
.
In
[13],
the
bit
error
r
ate
(BER)
and
pac
k
et
correct
probability
e
xpressions
w
ere
der
iv
ed,
consider
ing
the
m
ultiple-access
interf
erence
as
binomially
distr
ib
uted.
On
the
other
hand,
P
ac
k
et
through-
put
e
xpressions
w
ere
der
iv
ed
consider
ing
P
oisson,
binomial,
and
Mar
k
o
v
chain
approaches
f
or
the
composite
pac
k
et
arr
iv
als
distr
ib
utions
,
with
the
latter
defined
as
a
benchmar
k.
Numer
ical
results
sho
w
that
the
P
oisson
approach
underestimates
the
throughput
perf
or
mance
in
unaccept-
ab
le
le
v
els
and
incorrectly
predicts
the
n
umber
of
successfully
receiv
ed
pac
k
ets
f
or
most
off
ered
load
v
alues
e
v
en
in
f
a
v
or
ab
le
condit
ions
,
such
as
f
or
the
2-D
MWML
OOC
OCDM
netw
or
k
with
a
consider
ab
ly
large
n
umber
of
sim
ultaneous
users
.
The
authors
in
[15]
ha
v
e
proposed
to
categor
iz
e
the
fiber
w
a
v
elength
spectr
um
into
a
n
umber
of
w
a
v
ebands
and
allocate
the
spectr
um
of
each
w
a
v
eband
f
or
a
par
ticular
class
of
ser-
vice
and
the
corresponding
codes
w
ere
designed
based
on
the
char
acter
istics
of
the
cla
s
s
of
ser
vice
.
The
y
ha
v
e
suggested
tw
o
scenar
ios:
path
estab
lishment
with
tr
affic
management
and
TELK
OMNIKA
V
ol.
15,
No
.
3,
September
2017
:
1061
1071
Evaluation Warning : The document was created with Spire.PDF for Python.
TELK
OMNIKA
ISSN:
1693-6930
1063
path
estab
lishment
without
tr
affic
man
agement.
In
the
first
scenar
io
,
a
controlling
mechanism
manages
the
distr
ib
ution
of
the
connected
paths
so
that
all
w
a
v
elengths
ha
v
e
the
same
n
um-
ber
of
connected
paths;
whereas
,
in
the
second
scenar
io
,
connected
paths
are
divided
among
w
a
v
elengths
r
andomly
.
Moreo
v
er
,
in
[16]
an
or
iented
pa
th
length
based
w
a
v
elength
assignment
str
ategy
f
or
w
a
v
elength-routed
WDM
netw
or
ks
w
as
pur
posed
which
assign
the
w
a
v
elength
to
the
connection
request
according
to
the
path
length.
In
their
scheme
,
the
connection
requests
with
shor
ter
light
path
w
ere
assigned
the
w
a
v
elengths
ha
ving
higher
dispersion
and
the
w
a
v
elengths
ha
ving
lesser
dispersion
w
ere
assigned
to
the
light
paths
with
longer
distance
.
Additionally
,
w
a
v
e-
length
assignment
has
been
used
in
[17,
18]
,
and
w
a
v
elength
reser
v
ation
with
shared
b
uff
ers
in
[19].
In
[19],
the
authors
divided
the
w
a
v
elengt
hs
to
sets
,
theref
ore
regarding
to
the
reser
v
ation
scheme
,
the
high
pr
ior
ity
pac
k
ets
(le
v
el
1)
can
be
shifted
to
an
y
sets
of
a
v
ailab
le
w
a
v
elengths
,
in
decreasing
order
from
L1
to
L4,
where
the
rest
pac
k
ets
of
other
QoS
le
v
els
w
ere
consequently
shifted
to
their
o
wn
sets
.
3.
Diff
erentiated
Contention
Resolution
in
Photonic
P
ac
ket
Switc
hing
Netw
orks
QoS
diff
erentiation
fr
ame
w
or
k
suppor
ts
OPS
netw
or
ks
to
pro
vide
m
ultiple
ser
vice
classes
.
Efficient
and
f
air
resource
categor
ization
betw
een
the
classes
of
ser
vice
increases
the
total
net-
w
or
k
efficiency
and
utilization
[20].
In
this
ar
ticle
,
the
control
and
data
planes
of
the
proposed
WDM/OCDM-based
OPS
scheme
is
designed
consider
ing
QoS
requirements
.
The
measurement
cr
iter
ia
of
QoS
are
PLP
and,
FDL
dela
y
.
Fur
ther
more
,
w
e
pro
vide
a
s
witch
architecture
and
chan-
nel
allocation
scheme
implementation
f
or
suppor
ting
diff
erentiated
b
uff
er
i
ng
and
diff
erentiated
w
a
v
elength
con
v
er
ters
in
photonic
pac
k
et-s
witched
netw
or
ks
.
Gener
ally
,
absolute
le
v
els
can
be
specified
f
or
each
QoS
metr
ic
[20,
21].
Ho
w
e
v
er
,
without
loss
of
pr
inciple
,
tw
o
classes
are
considered
f
or
e
v
e
r
y
metr
ic
,
to
be
specific
,
high
pr
ior
ity
(HP)
and
lo
w
pr
ior
ity
(LP)
classes
.
Consider
ing
HP
and
LP
classes
f
or
the
char
acter
iz
ed
f
our
channel
allo-
cation
schemes
,
there
are
f
easib
le
.
In
an
y
case
,
all
possib
le
combinations
of
allocation
schemes
are
sim
ulated.
W
e
then
discuss
the
v
ar
ious
par
ameters
f
or
pro
viding
diff
erentiated
ser
vice
in
photonic
pac
k
et-s
witched
netw
or
ks
.
3.1.
Node
ar
c
hitecture
In
the
recent
w
or
k
[22]
,
w
e
ha
v
e
proposed
h
ybr
id
OCDM/WDM
combined
with
shared
FDL
as
it
is
demonstr
ated
in
Figurer
1.
The
adv
antages
of
the
h
ybr
id
system
[22]
w
ere
to
impro
v
e
the
perf
or
mance
of
the
node
and,
in
[23]
w
as
to
optimiz
e
the
ultimate
n
umber
of
FDL
to
reduce
the
cost
and
to
k
eep
the
perf
or
mance
high.
The
proposed
algor
ithm,
initially
tr
ies
to
eliminate
the
contention
b
y
means
of
optical
code
b
y
assigning
the
pac
k
et
to
a
v
ailab
le
code
and,
if
the
re
is
no
free
channel
code
in
that
par
ticular
w
a
v
elength,
the
algor
ithm
tr
ies
to
shift
the
pac
k
et
to
another
w
a
v
elength
in
the
same
out
fiber
link
using
the
w
a
v
elength
con
v
er
ter
from
the
shared
w
a
v
elength
con
v
er
ter
pool,
then,
if
there
is
no
free
w
a
v
elength
con
v
er
t
er
,
the
algor
ithm
sends
the
pac
k
et
to
either
FW
b
uff
ers
or
FB
b
uff
ers
regarding
to
their
a
v
ailability
.
The
only
cases
where
the
pac
k
ets
w
ould
be
dropped
are
if
there
is
no
free
FB
b
uff
er
is
a
v
ailab
le
.
In
the
s
witch
assumption,
w
e
assumed
that
all
s
witch
matr
ix
is
function
synchronously
with
constant
length
pac
k
ets
receiv
ed
at
N
ing
ress
optical
link
in
the
fitted
time
slot.
The
matr
ix
of
core
s
witch
has
((
N
M
F
)
+
K
)
((
N
M
F
)
+
R
+
D
+
K
)
s
witching
matr
ix.
It
has
N
Input/output
fiber
por
ts
(IF/OF),
K
FB
,
R
w
a
v
elength
con
v
er
ter
,
D
FW
FDLs
.
Moreo
v
er
,
e
v
er
y
fiber
suppor
ts
M
w
a
v
elengths
,
and
e
v
er
y
w
a
v
elength
can
hold
up
to
F
pac
k
ets
coded
along,
b
y
using
Optical
Code
.
Means
that,
each
input
and
output
channel
is
reco
gniz
ed
b
y
the
three
v
ar
iab
le
(
i;
j
;
O
C
k
)
.
The
proposed
scheduling
algor
ithm
is
e
x
ecuted
at
each
slot
time
of
the
m
ultiser
vice
OCDM/WDM
optical
pac
k
et
s
witch.
The
proposed
scheduling
algor
ithm
has
been
modified
from
[22,
23],
in
order
to
suppor
t
m
ultiser
vice
tr
ansmission
[24].
In
this
paper
,
the
m
ultiser
vice
diff
eren-
tiation
is
assisted
b
y
a
n
umber
of
technologies
such
as
code
con
v
ersion,
w
a
v
elength
con
v
ersion,
and
Fiber
Dela
y
Lines
(FW
and
FB)
b
uff
er
ing
[25].
The
m
ultiser
vice
OCDM/WDM
pac
k
et
s
witch
sho
wn
in
Figure
1
perf
or
ms
the
f
ollo
wing
oper
ations:
(1)
incoming
pa
c
k
et
s
on
each
input
fiber
are
w
a
v
elength
dem
ultiple
x
ed
and
code
decoded
b
y
means
of
M
WDM
dem
ul
tiple
x
er
and
M
:F
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
(Omar
Najah)
Evaluation Warning : The document was created with Spire.PDF for Python.
1064
ISSN:
1693-6930
Figure
1.
Architecture
of
OCDM/WDM
with
shared
FDL.
code
decoders;
(2)
the
control
unit
processes
and
chec
k
f
or
all
High
pr
ior
ity
pac
k
ets
in
entire
input
f
or
a
time
slot
and
giv
e
them
the
pr
ior
ity
to
use
resource
first,
resolv
es
pac
k
et
contentions
,
and
directs
pac
k
ets
either
to
code
w
ord,
w
a
v
elength
con
v
er
ted
or
b
uff
ered
based
on
the
r
ules
of
the
scheduling
algor
ithm,
f
or
HP
pac
k
ets
,
when
a
pac
k
et
arr
iv
es
at
ing
ress
first
tr
y
to
tr
ansmit
it
im-
mediately
to
desired
out
w
a
v
elength
through
free
code
channel,
if
contention
occurs
,
then,
tr
y
to
solv
e
the
prob
lem
using
w
a
v
elength
con
v
er
ter
,
if
there
is
no
free
con
v
er
ter
,
then,
send
the
pac
k
et
to
FW
b
uff
ers
,
if
there
are
no
free
FW
b
uff
ers
and
no
g
uar
antee
of
successful
tr
ansmit
later
on,
at
th
at
time
,
the
HP
pac
k
et
will
be
dropped,
this
scenar
io
r
uns
up
to
finish
all
HP
pac
k
ets
,
same
scenar
io
goes
with
LP
pac
k
ets
accept
that,
if
it
is
not
successfully
sent
to
FW
b
uff
ers
then,
send
it
to
FB
b
uff
ers
unless
all
FB
b
uff
ers
are
occupied
,
at
that
moment,
the
LP
pac
k
et
will
be
dropped;
(3)
all
successful
pac
k
ets
r
outed
either
direct
code
w
ord
pac
k
ets
,
w
a
v
elength
con
v
er
ted
pac
k
ets
and
b
uff
ered
pac
k
ets
are
directed
to
S
F
i
s
witches
based
on
decisions
tak
en
b
y
the
control
unit;
(4)
finally
,
pac
k
ets
are
routed
to
w
ards
to
desired
output
channel
after
been
coded
and
m
ultiple
x
ed
[24].
Once
again,
there
are
only
three
possib
le
places
where
the
pac
k
et
could
be
dropped;
first
place
,
if
HP
or
LP
pac
k
et
d
id
not
get
free
FW
b
uff
er
and
no
guar
antee
of
output
reser
v
ation;
sec-
ond
place
,
if
LP
pac
k
et
did
not
get
free
FB
b
uff
er
;
third
place
,
if
LP
pac
k
et
e
xceed
f
our
round
in
FB
b
uff
er
and
no
chance
to
lea
v
e
the
node
.
Moreo
v
er
,
the
pac
k
et
losses
are
the
main
concer
n
in
the
s
witch
consider
ation,
and
pac
k
et
dela
y
which
is
eff
ected
f
actor
b
y
both
lac
ks
of
w
a
v
elength
con
v
er
ters
and
conte
ntions
at
an
output
por
t
[26].
Hence
,
in
this
ar
ticle
,
w
e
concentr
ate
on
the
P
ac
k
et
Loss
Probability
(PLP)
and
pac
k
et
dela
y
as
the
main
QoS
par
ameters
,
which
means
that
the
v
ar
iety
ser
vice
classes
wil
l
be
diff
eren-
tiated
from
each
other
based
on
diff
erent
PLP
and
pac
k
et
dela
y
.
PLP
is
defined
as
the
a
v
er
age
n
umber
of
dropping
pac
k
ets
per
unit
time
.
Ho
w
e
v
er
,
f
or
the
sak
e
of
perf
or
mance
e
v
aluation
of
the
s
witching
node
under
diff
erent
tr
affic
load,
PLP
is
defined
as
r
atio
of
the
total
n
umber
of
losing
pac
k
ets
to
the
tot
al
n
umber
of
arr
iving
pac
k
ets;
as
w
ell
as
throughput
is
defined
as
r
atio
of
the
total
n
umber
of
successful
depar
ture
pac
k
ets
to
t
he
total
n
umber
of
arr
iving
pac
k
ets
.
The
a
v
er
age
pac
k
et
dela
y
is
defined
as
the
n
umber
of
time
slots
a
pac
k
et
has
w
aited
since
its
arr
iv
al
into
the
input
b
uff
er
till
it
is
tr
ansmitted
to
its
output
por
t.
P
LP
=
P
Lossing
pack
ets
P
ar
r
iv
ing
pack
ets
(1)
T
hr
oug
h
=
P
depar
tur
e
pac
k
ets
P
ar
r
iv
ing
pack
ets
(2)
D
el
ay
=
P
w
aitedsl
ots
P
buf
f
er
dpack
ets
(3)
TELK
OMNIKA
V
ol.
15,
No
.
3,
September
2017
:
1061
1071
Evaluation Warning : The document was created with Spire.PDF for Python.
TELK
OMNIKA
ISSN:
1693-6930
1065
3.2.
Channel
Allocation
Sc
hemes
Basically
,
por
ts
restr
iction
based
QoS
diff
erentiation
scheme
,
the
optical
code
allocation
algor
ithm
(OCAA),
has
been
studied.
In
the
optical
code
allocation,
which
pro
vides
QoS
diff
er-
entiation
in
synchronous
b
uff
ered
OPS
netw
or
ks
wi
th
(full
r
ange
and
limited
n
umber)
of
shared
w
a
v
elength
con
v
er
ters
,
cer
tain
allocation
str
ategies
ha
v
e
been
sim
ulated
in
order
to
obtain
QoS
.
Fur
ther
more
,
the
algor
ithm
has
been
adapted
from
our
pre
vious
w
or
k
[22,
23]
ho
w
e
v
er
,
f
our
mech-
anisms
ha
v
e
been
sim
ulated
f
or
the
single
node
based
QoS
diff
erentiation:
shared
inpu
t,
shared
output
(SSM);
shared
input,
pr
iv
et
output
(SPM);
pr
iv
et
input,
shared
output
(PSM);
and
pr
iv
et
input,
pr
iv
et
output
(PPM)
[25].
In
the
OCAA,
the
total
a
v
ailab
le
codes
(
F
)
at
an
input/output
w
a
v
elengths
are
divided
into
tw
o
pools
according
to
pr
ior
ity
,
i.e
.
a
class
HP
pool
with
FH
codes
and
a
class
LP
pool
with
FL
codes
.
Incoming
pac
k
ets
can
access
these
codes
only
if
the
y
ha
v
e
the
necessar
y
pr
ior
ity
le
v
el.
This
means
that
at
share
mechanism
phase
,
both
classes
are
shar
ing
the
por
ts
with
the
pr
ior
ity
ser
vice
(i.e
.
WC
,
FW)
to
HP
pac
k
ets
.
On
the
other
hand,
at
pr
iv
et
mechanism
phase
,
class
HP
tr
affic
can
access
only
codes
fro
m
the
class
FH
pool,
as
w
ell
as
class
LP
tr
affic
can
access
only
codes
from
the
class
LP
pool,
where
is
the
total
of
F
H
+
F
L
=
F
codes
on
one
w
a
v
elength.
By
adjusting
the
v
ar
iab
le
FH
and
FL,
w
e
achie
v
e
an
y
desired
le
v
el
of
the
PLR
f
or
class
HP
tr
affic
,
which
is
impor
tant
in
order
to
pro
vide
QoS
to
the
core
netw
or
k
nodes
[27].
F
or
incoming
pac
k
ets
which
f
ail
to
acquire
an
y
ser
vices
(FW
b
uff
er
f
or
HP
and
FB
b
uff
er
f
or
LP)
are
immediately
dropped
at
the
node
.
In
order
to
o
btain
sim
ulation
results
f
or
the
PLP
f
or
both
pr
ior
ity
classes
,
w
e
ha
v
e
b
uilt
the
OCAA
algor
ithm.
The
first
algor
ithm
is
PPM,
where
the
coded
channels
are
divided
into
tw
o
sets
FH
and
FL
f
or
in/out
por
ts
.
All
pac
k
ets
arr
iv
ed
at
the
in
puts
are
ser
viced
regarding
their
pr
ior
ity
class
.
Theref
ore
,
the
HP
pac
k
ets
are
ser
viced
at
first,
and
the
y
ha
v
e
the
pr
ior
ity
to
use
nodes
resource
.
Fur
ther
more
,
each
class
pac
k
ets
are
separ
ated
b
y
channels
in
use
(i.
e
.
each
class
has
its
o
wn
channels
in/out).
In
this
phase
,
the
initial
v
a
lue
of
HP
set
is
(FH
=2,
4,
6,
and
8)
channels
,
in
the
same
time
,
the
initial
v
alue
of
FL
is
(FL=
8,
6,
4,
and
2)
channels
.
The
second
algor
ithm
is
PSM,
where
the
input
coded
channels
are
divided
into
tw
o
sets
FH
and
FL,
at
the
same
time
the
output
por
ts
are
shared
among
all
pac
k
ets
,
depend
on
the
channel
a
v
ailability
.
F
or
instance
,
the
HP
pac
k
ets
reach
the
inp
ut
node
in
pr
iv
et
coded
channels
and
lea
ving
the
node
using
shar
ing
channels
with
FL
pac
k
ets
.
The
third
algor
ithm
is
SPM,
where
the
input
coded
channels
are
shared
b
y
all
the
diff
erent
classes
,
b
ut
the
output
is
pr
iv
et
each
class
has
its
o
wn
channel
to
use
.
The
f
our
th
algor
ithm
is
SSM,
where
all
por
ts
are
shared
in
use
f
or
all
diff
erent
classes
.
4.
Sim
ulation
P
erf
ormance
In
this
section,
w
e
e
v
aluate
the
perf
or
mance
of
one
node
based
QoS
mechanisms
f
or
OPS
netw
or
ks
with
off
ered
(0.8)
tr
affic
load,
to
this
end,
w
e
consider
OCAA
QoS
diff
erentiation
mechanisms
as
e
xplained
ear
ly
section.
The
sim
ulation
results
are
obtained
using
Scilab
.
In
the
sim
ulations
,
it
is
assumed
that
time
slots
are
fitted
to
pac
k
et
boundar
y
and
all
are
equal
length
dur
ation.
The
proposed
diff
erentiation
schemes
algor
ithm
has
in
v
olv
ed
fix
ed-lengt
h
pac
k
ets
,
sim-
plifying
the
algor
ithm
and
oper
ation
of
the
s
witching
node
.
In
another
w
ord,
it
is
assumed
that
all
pac
k
ets
entered
the
s
witch
are
synchroniz
ed
with
respect
to
their
boundar
ies
,
consequently
that
all
pac
k
ets
are
fitted
to
their
timeslot.
The
sim
ulation
en
vironment
that
been
used
is
r
un
f
or
a
paired
of
5000-time
slots
.
In
sim
ulation
e
xper
iment,
the
s
witch
node
siz
e
is
N
=
32
,
w
a
v
elength
M
=
16
,
optical
code
F
=
10
,
and
with
share
d
pool
w
a
v
elength
con
v
er
ter
R
=
24
.
A
sim
ulation
r
uns
enough
time
with
the
pur
pose
of
diff
erentiation
mechanism.
The
pac
k
ets
arr
iv
e
according
to
Ber
noulli
distr
ib
ution
ne
w
slot.
T
r
affic
is
equally
distr
ib
uted
to
all
output
of
s
witch
1
=
N
and
it
is
considered
that
pac
k
et
dur
ation
is
fit
to
time
cell.
In
the
e
xper
iments
,
dur
ing
each
time
slot
e
x
ecution,
the
HP
pac
k
ets
ha
v
e
g
iv
en
the
pr
ior
ity
to
be
ser
viced
first,
f
or
instance
,
occupies
free
output
channels
,
use
a
v
ailab
le
w
a
v
elength
con
v
er
ter
s
,
and
FW
b
uff
ers
o
v
er
LP
pac
k
ets
.
On
another
w
ord,
the
HP
pac
k
ets
cant
use
FB
b
uff
ers
to
reduce
the
dela
y
.
In
Figure
2
sho
ws
the
result
of
an
e
xper
imental
sim
ulation
of
PPM.
The
pac
k
et
loss
prob-
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
(Omar
Najah)
Evaluation Warning : The document was created with Spire.PDF for Python.
1066
ISSN:
1693-6930
Figure
2.
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
system
at
diff
erent
n
umbers
of
code
channel,
pr
iv
et
input
pr
iv
et
output
mechanism.
Figure
3.
P
ac
k
et
Dela
y
of
h
ybr
id
OCDM/WDM
system
at
diff
erent
n
umbers
of
code
channel,
pr
iv
et
input
pr
iv
et
output
mechanism.
ability
and
pac
k
et
dela
y
of
h
ybr
id
OCDM/WDM
system
with
diff
erent
n
umbers
of
reser
v
ed
code
channels
f
or
HP
under
(0.8)
total
tr
affic
load.
The
result
of
the
algor
ithm
perf
or
mance
sho
ws
that,
when
FH
increases
,
the
PLP
decre
ases
,
tak
e
note
that
F
H
+
F
L
=
10
is
the
total
n
umb
er
of
coded
channels
in
the
single
w
a
v
elength.
Its
ob
vious
that
when
the
small
n
umber
of
FH
used
the
probability
of
losing
pac
k
ets
is
higher
and
reduced
when
increasing
the
n
umber
of
FH,
because
of
the
contention
is
reduced
b
y
increasing
the
n
umber
of
out
channels
.
On
another
hand,
Figure
3
sho
ws
the
perf
or
mance
of
the
pac
k
et
dela
y
f
or
HP
is
almost
flat
f
or
all
n
umber
of
the
channels
,
as
a
consequence
of
high
tr
affic
directed
from
the
same
n
umber
of
inpu
t
channels
to
the
same
n
umber
of
output
channels
.
Figure
4
and
Figure
5
i
llustr
ated
the
perf
or
mance
of
PSM.
The
n
umber
of
input
coded
channels
which
been
reser
v
ed
to
class
HP
is
FL=2,
4,
6,
8,
at
each
w
a
v
elength,
and
where
the
output
channels
are
shared
among
all
classes
.
The
algor
ithm
policy
receiv
es
the
HP
pac
k
ets
class
from
pr
iv
et
channels
and
sends
them
through
shared
channels
with
t
he
pr
ior
ity
ser
vice
f
or
HP
class
.
The
result
of
the
algor
ithm
perf
or
mance
displa
ys
that,
PLP
f
or
HP
almost
is
z
er
o
f
or
up
to
6
channels
,
and
f
or
8
channels
the
PLP
is
10
4
,
the
e
xplanation
is
that
the
HP
pac
k
ets
are
ser
v
ed
first
as
the
y
ha
v
e
more
out
channels
than
inputs
.
Note
,
e
v
en
that
the
PLP
of
LH
pac
k
ets
has
perf
or
med
better
than
PPM
and
SPM.
The
dela
y
perf
or
mance
of
this
algor
ithm
f
or
HP
class
is
almost
z
er
o
when
reser
v
ed
channels
less
than
6
channels
,
then
star
ts
to
r
ise
up
due
to
the
hea
vy
tr
affic
flo
wing
from
the
increased
n
umber
of
reser
v
ed
channels
.
The
perf
or
mance
of
algor
ithm
SPM
is
presented
in
Figure
6
and
Figure
7.
The
e
xper
i-
ment
tested
all
the
probability
of
input
tr
affic
f
or
a
diff
erent
n
umber
of
reser
v
ed
output
channels
.
TELK
OMNIKA
V
ol.
15,
No
.
3,
September
2017
:
1061
1071
Evaluation Warning : The document was created with Spire.PDF for Python.
TELK
OMNIKA
ISSN:
1693-6930
1067
Figure
4.
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
system
at
diff
erent
n
umbers
of
code
channel,
pr
iv
et
input
shared
output
mechanism.
Figure
5.
P
ac
k
et
Dela
y
of
h
ybr
id
OCDM/WDM
system
at
diff
erent
n
umbers
of
code
channel,
pr
iv
et
input
shared
output
mechanism.
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
(Omar
Najah)
Evaluation Warning : The document was created with Spire.PDF for Python.
1068
ISSN:
1693-6930
Figure
6.
P
ac
k
et
Loss
Probability
of
HP
h
ybr
id
OCDM/WDM
system
v
ersus
a
v
ar
iety
of
HP
tr
affic
from
total
tr
affic
0.
8,
f
or
diff
erent
n
umbers
of
channels
reser
v
ed
to
HP
,
shared
input
pr
iv
et
output
mechanism.
Figure
7.
P
ac
k
et
Dela
y
of
HP
h
ybr
id
OCDM/WDM
system
v
ersus
a
v
ar
iety
of
HP
tr
affic
fr
om
total
tr
affic
0.8,
f
or
diff
erent
n
umbers
of
channels
reser
v
ed
to
HP
,
shared
input
pr
iv
et
output
mechanism.
The
result
is
dro
wned
with
three
v
erbal
,
which
are
PLP
,
tr
affic
load,
and
a
n
umber
of
reser
v
ed
channels
,
the
char
t
sho
ws
the
PLP
only
f
or
HP
class
.
The
SPM
algor
ithm
perf
or
ms
high
pac
k
et
loss
probability
compar
ing
with
the
other
three
proposed
algor
ithms
,
due
to
the
limited
a
v
ailab
le
output
channels
.
Fur
ther
more
,
Figure
7
sho
ws
the
pac
k
et
dela
y
perf
or
mance
,
where
it
perf
or
ms
v
er
y
high
dela
y
,
due
to
v
er
y
high
tr
affic
flo
ws
to
FW
b
uff
ers
.
In
gener
al,
this
algor
ithm
did
not
perf
or
m
w
ell
in
both
PLP
and
dela
y
,
due
to
limited
a
v
ailab
le
output
channels
.
In
Figure
8
and
Figure
9
demonstr
ate
the
results
of
an
e
xper
imental
sim
ulation
of
SSM,
where
the
input
and
output
are
shared
among
the
classes
with
the
respect
of
the
pr
ior
ity
.
The
Figure
8
plotted
the
PLP
v
ersus
the
HP
tr
affic
load
from
total
tr
affic
(0.8).
F
rom
the
plot
dr
a
wn
in
Figure
8,
ob
vious
that
the
SSM
algor
ithm
perf
or
mance
significance
,
with
the
consider
ation,
that
the
node
is
w
or
king
in
h
ybr
id
netw
or
ks
.
The
SSM
algor
ithm
perf
or
ms
v
er
y
lo
w
pac
k
et
loss
probability
compar
ing
with
the
other
three
proposed
algor
ithms
,
due
to
the
v
ar
iety
of
a
v
ailab
le
channels
.
Note
that
the
PLP
of
HP
class
at
hea
vy
tr
affic
is
star
ting
to
r
ise
up
as
a
result
of
HP
pac
k
ets
cant
use
FB
b
uff
ers
where
dropping
pac
k
ets
are
increased.
On
the
other
hand,
the
perf
or
mance
of
pac
k
et
dela
y
is
plotted
in
Figure
9.
The
HP
class
perf
or
med
no
dela
y
at
lo
w
tr
affic
and
toler
ab
le
dela
y
at
hea
vy
tr
affic.
The
reason
behind
this
is
at
high
tr
affic
more
contention
occurs
with
limited
w
a
v
elength
con
v
er
ters
.
TELK
OMNIKA
V
ol.
15,
No
.
3,
September
2017
:
1061
1071
Evaluation Warning : The document was created with Spire.PDF for Python.
TELK
OMNIKA
ISSN:
1693-6930
1069
Figure
8.
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
system
v
ersus
a
v
ar
iety
of
HP
tr
affic
from
total
tr
affic
0.8,
shared
input
shared
output
mechanism.
Figure
9.
P
ac
k
et
Dela
y
of
h
ybr
id
OCDM/WDM
system
v
ersus
a
v
ar
iety
of
HP
tr
affic
from
total
tr
affic
0.8,
shared
input
shared
output
mechanism.
P
ac
k
et
Loss
Probability
of
h
ybr
id
OCDM/WDM
(Omar
Najah)
Evaluation Warning : The document was created with Spire.PDF for Python.
1070
ISSN:
1693-6930
5.
Conc
lusion
This
research
aims
at
reducing
pac
k
et
loss
probability
of
HP
h
ybr
id
OCDM/WDM
system
in
which
a
huge
amount
of
data
is
being
tr
ansmitted
throug
h
high-speed
optical
links
.
In
order
to
do
so
,
our
objectiv
e
is
to
mak
e
QoS
diff
erentiation
and
resource
utilization
propor
tional
to
each
other
.
F
our
diff
erentiation
algor
ithms
called
PPM,
PSM,
SPM,
and
SSM
w
as
proposed
in
order
to
diff
erentiate
bet
w
een
the
classes
.
Sim
ulation
results
indicate
the
f
act
that
the
proposed
algor
ithms
PSM
and
SSM
yield
a
significant
pac
k
et
loss
probability
with
an
acceptab
le
le
v
el
of
pac
k
et
dela
y
compared
with
PPM
and
SPM
algor
ithms
.
Moreo
v
er
,
since
that
the
s
witch
node
is
a
par
t
of
h
ybr
id
netw
or
ks
connected
to
each
other
and
theref
ore
if
w
e
use
PSM
algor
ithm,
the
ne
xt
node
m
ust
use
pr
iv
et
input
mechanism,
where
the
perf
or
mance
of
the
netw
or
k
ma
y
suff
er
from
high
contention.
The
sim
ulations
sho
w
that
SSP
method
has
v
er
y
high
perf
or
mance
efficiency
,
it
can
approach
the
Raddo
bound.
Consequently
,
it
is
clear
that
the
SSP
algor
ithm
is
a
significant
algor
ithm
f
or
such
h
ybr
id
netw
or
ks
.
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an
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m
ulti-quality-of-ser
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passiv
e
optical
net-
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or
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on
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id
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system,
”
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,
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s39–s44,
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and
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of
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ultilength
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with
arbitr
ar
y
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constr
aint
f
or
ocdma
m
ultimedia
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or
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”
Jour
nal
of
Optical
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m
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TELK
OMNIKA
V
ol.
15,
No
.
3,
September
2017
:
1061
1071
Evaluation Warning : The document was created with Spire.PDF for Python.