Int
ern
at
i
onal
Journ
al of Ele
ctrical
an
d
Co
mput
er
En
gin
ee
ri
ng
(IJ
E
C
E)
Vo
l.
11
,
No.
1
,
Febr
uar
y
2021
, pp.
567
~
574
IS
S
N: 20
88
-
8708
,
DOI: 10
.11
591/
ijece
.
v11
i
1
.
pp
567
-
574
567
Journ
al h
om
e
page
:
http:
//
ij
ece.i
aesc
or
e.c
om
Multi
-
us
er
m
edia
s
tre
ami
ng
s
ervice for e
-
l
earning
b
ased
w
eb
r
eal
-
t
im
e
c
omm
un
icat
ion
t
echn
ology
Nakt
al
Ed
an
,
Sa
n
ab
il
A
.
M
ahmo
od
Coll
ege of
Com
pute
rs Sci
ences
and
Math
ematic
s,
Univer
sit
y
o
f
Mos
ul
,
Ira
q
Art
ic
le
In
f
o
ABSTR
A
CT
Art
ic
le
history:
Re
cei
ved
Dec
24
, 201
9
Re
vised
Jun
15
,
20
20
Accepte
d
J
u
n
28
, 20
20
W
eb
rea
l
-
ti
m
e
c
om
m
unic
at
ion
(
W
ebRT
C
)
stand
ard
s
do
not
def
i
ne
pre
ci
se
l
y
how
two
brows
ers
esta
b
li
sh
an
d
cont
rol
their
comm
unic
at
ion.
The
r
efo
re
,
a
signalling
m
echani
sm
/prot
ocol
has
not
spec
if
ie
d
in
W
ebRT
C.
Th
e
essentia
l
goal
of
thi
s
r
e
sea
rch
is
to
cr
ea
t
e
and
ap
pl
y
a
W
ebRT
C
bi
-
direct
ion
al
vid
eo
conf
ere
n
cing
base
d
on
m
esh
topol
og
y
(m
a
n
y
-
to
-
m
an
y
)
usi
ng
Google
Chrom
e
,
Firefox
,
Opera
,
and
Expl
ore
r
.
Thi
s
expe
riment
invo
lv
ed
through
Et
her
n
et
and
W
ire
le
ss
of
t
h
e
Inte
rn
et
and
4G
net
works
i
n
e
-
l
ea
rning
.
The
signa
ll
ing
m
ec
hani
sm
of
thi
s
exp
eri
m
ent
has
b
ee
n
cre
a
te
d
an
d
i
m
p
l
e
m
e
n
t
e
d
u
s
i
n
g
J
a
v
a
S
c
r
i
p
t
l
a
n
g
u
a
g
e
a
l
o
n
g
w
i
t
h
M
u
l
t
i
C
o
n
n
e
c
t
i
o
n
l
i
b
r
a
r
i
e
s
.
I
n
a
d
d
i
t
i
o
n
,
a
n
e
v
a
l
u
a
t
i
o
n
o
f
q
u
a
l
i
t
y
o
f
e
x
p
e
r
i
e
n
c
e
(
Q
o
E
)
,
r
e
s
o
u
r
c
e
s
,
s
u
c
h
a
s
b
a
n
d
w
i
d
t
h
c
o
n
s
u
m
p
t
i
o
n
,
a
n
d
C
P
U
p
e
r
f
o
r
m
a
n
c
e
w
a
s
d
o
n
e
.
I
n
t
h
i
s
p
a
p
e
r
,
a
n
o
v
e
l
i
m
p
l
e
m
e
n
t
a
t
i
o
n
w
a
s
a
c
c
o
m
p
l
i
s
h
e
d
o
v
e
r
e
-
l
e
a
r
n
i
n
g
u
s
i
n
g
d
i
f
f
e
r
e
n
t
net
works
,
diffe
ren
t
brows
ers,
m
an
y
pee
rs,
openi
ng
one
or
m
an
y
room
s
conc
urre
nt
l
y
,
d
e
f
i
n
i
n
g
r
o
o
m
i
n
i
t
i
a
t
o
r
,
s
h
a
r
i
n
g
t
h
e
i
n
f
o
r
m
a
t
i
o
n
o
f
t
h
e
n
e
w
u
s
e
r
w
i
t
h
p
a
r
t
i
c
i
p
a
n
t
s
,
u
s
i
n
g
u
s
e
r
i
d
e
n
t
i
f
i
c
a
t
i
o
n
(
u
s
e
r
-
id
)
,
a
n
d
s
o
o
n
.
M
o
r
e
o
v
e
r
,
t
h
e
pap
er al
so
highl
igh
ts
the
adva
nt
age
s
a
nd
disadva
n
ta
g
e
s of
using
W
ebR
TC
vid
eo confe
r
enc
ing
.
Ke
yw
or
d
s
:
4
g
ene
rati
on (4
G)
E
xplore
r
Firef
ox
Goo
gle
c
hr
ome
In
te
r
net
Me
sh
t
op
ology
Op
e
ra
Qu
al
it
y o
f
e
xperience
(QoE
)
Web
r
eal
-
t
im
e
c
omm
un
ic
at
ion
(
W
e
bRTC)
This
is an
open
acc
ess arti
cl
e
un
der
the
CC
B
Y
-
SA
l
ic
ense
.
Corres
pond
in
g
Aut
h
or
:
Nak
ta
l
E
da
n
,
Coll
ege
of
C
om
pu
te
rs
Scie
nc
es an
d
Ma
them
at
ic
s,
Un
i
ver
sit
y
of
Mosu
l
,
Mosu
l,
Iraq
.
Em
a
il
:
edan
na
ktal@gm
ai
l.com
,
nak
ta
l.eda
n@u
om
os
ul.edu
.iq
1.
INTROD
U
CTION
The
inter
net
en
gin
ee
rin
g
ta
sk
force
(
IETF
)
(
wire
pr
oto
c
ol)
and
World
Wi
de
W
e
b
c
on
s
or
ti
u
m
(W
3C
)
(browse
r
API)
hav
e
bee
n
de
velo
ped
a
m
od
ern
c
ollec
ti
on
of
sta
nda
rd
s
,
JavaSc
ript
li
br
a
ries,
an
d
open
so
ur
c
e
cal
le
d
W
e
b
re
al
-
tim
e
co
m
m
un
ic
at
io
n
(
W
e
bRTC)
[
1,
2]
.
Web
RTC
pro
vi
des
interact
i
ve
m
ult
i
m
edia
and
data
com
m
un
ic
at
ion
s
[
3]
.
Also,
it
of
fe
rs
se
ver
al
ben
e
fits
su
c
h
as
no
fee
s,
no
li
cense,
no
re
qu
irem
ent
fo
r
extern
al
so
ft
war
e
,
an
d
si
m
plicity
of
us
e
[4]
.
On
the
oth
er
ha
nd,
no
ag
ree
m
ent
has
bee
n
reac
hed
regardi
ng
the
W3
C
an
d
I
ETF
as
a
fu
ll
protoc
ol
to
e
xa
m
ine
W
e
bRT
C
[5]
.
T
hu
s
,
t
he
sta
ndar
d
of
t
he
si
gn
al
li
ng
c
hannel
was
not
s
pecif
ie
d
in
W
e
bRT
C
[6]
.
In
ot
he
r
words,
W
e
bR
TC
sta
nd
ar
ds
do
not
def
ine
pr
eci
sel
y
how
two
browsers
c
on
t
ro
l
their
com
m
un
ic
at
ion
[7]
.
The
reason
beh
in
d
that
is
sign
al
li
ng
presum
es
to
be
le
ft
t
o
the
dev
el
opers
to
create
an
a
pp
li
cat
io
n
or
t
o
ch
oo
s
e
from
the
existi
ng
prot
oco
ls
(e
.g.
extensi
ble
m
essagin
g
and prese
nce
prot
oco
l
(X
MP
P
))
,
or to
create
their
protoc
ol
[8
-
10]
. S
ig
nalli
ng is cr
ucial
to
d
et
erm
ine u
se
rs
a
nd
set
s
aud
i
o
an
d
vi
deo
c
om
m
un
ic
at
ion
am
on
g
them
;
i
t
al
so
ena
bles
ex
cha
ngin
g
data
am
on
g
use
rs
via
channels
[1]
.
F
ur
t
her
m
or
e, si
gnal
li
ng
sup
ports browse
rs
to
c
onnect eac
h ot
her thr
ough a
s
erv
e
r
[11]
.
In
[
12
]
,
m
entione
d
t
hat
bi
dir
ect
ion
al
vi
de
os
betwe
en
a
s
erv
e
r
a
nd
a
cl
ie
nt
co
uld
be
s
upporte
d
by
S
o
c
k
e
t
.
i
o
(
A
P
I
)
.
B
e
s
i
d
e
s
,
S
o
c
k
e
t
.
i
o
i
s
a
c
o
n
c
e
p
t
f
o
r
W
e
b
S
o
c
k
e
t
s
w
i
t
h
X
M
L
H
t
t
p
R
e
q
u
e
s
t
(
X
H
R
)
,
F
l
a
s
h
a
n
d
J
S
O
N
P
,
a
n
d
i
t
p
e
r
m
i
t
s
d
e
v
e
l
o
p
e
r
s
t
o
u
t
i
l
i
s
e
W
e
b
S
o
c
k
e
t
s
a
n
d
d
e
t
e
r
m
i
n
e
d
i
f
f
e
r
e
n
t
s
y
n
c
h
r
o
n
i
s
e
d
com
m
un
ic
at
ion
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2088
-
8708
In
t J
Elec
&
C
om
p
En
g,
V
ol.
11
, No
.
1,
Febr
uar
y
2021
:
56
7
-
57
4
568
t
e
c
h
n
i
q
u
e
s
m
a
n
a
g
e
d
b
y
t
h
e
c
l
i
e
n
t
’
s
b
r
o
w
s
e
r
[
1
3
,
1
4
]
.
A
c
c
o
r
d
i
n
g
l
y
,
t
h
i
s
s
i
g
n
a
l
l
i
n
g
m
e
c
h
a
n
i
s
m
u
s
i
n
g
J
a
v
a
S
c
r
i
p
t
l
a
n
g
u
a
g
e
a
n
d
M
u
l
t
i
C
o
n
n
e
c
a
t
i
o
n
l
i
b
r
a
r
i
e
s
p
r
o
v
i
d
e
t
h
e
f
o
l
l
o
w
s
:
-
Bi
-
directi
onal
m
ul
tim
edia
com
m
un
ic
at
ion
f
or
m
any
-
to
-
m
any
(m
esh
to
po
l
og
y
),
so
a
ud
i
o
an
d
vid
e
o
com
m
un
ic
at
ion
ca
n
s
har
e
bet
ween a te
ac
her an
d
st
ud
e
nts
, a
nd am
on
g
al
l
stud
e
nts
.
-
Var
i
ou
s
ty
pe o
f
c
omm
un
ic
at
i
on, so all
peer
s
ab
le
to
b
e
a
n
i
niti
at
or
or
pa
rtic
ipant.
-
Keep a ses
sio
n p
rod
uctive e
ve
n othe
r
stu
de
nt
s leave.
-
Connect
c
urrent
sessio
n or
e
sta
blish a
n
e
w o
ne.
-
Stop o
w
n/rem
ote trans
m
issi
on
s.
-
Using
us
er
-
id
to pre
ve
nt the u
nknow
n pee
r j
oin
s
the
room
, etc.
-
I
t
can
be
a
pp
li
ed
to
dif
fe
ren
t
com
m
un
ic
at
io
ns
,
f
or
exam
ple,
e
-
Healt
h
(
be
tween
do
ct
ors
and
patie
nts
)
,
and
e
-
le
ar
ni
ng
(b
et
ween
te
ach
er a
nd stu
den
ts
)
a
nd so on
.
The
or
gan
isa
ti
on
of
t
his
pa
per
is
as
in
di
cat
e
s
:
s
ect
ion
2
disc
u
s
ses
re
la
te
d
work.
I
n
sect
ion
3
,
is
a
pr
ese
ntati
on
of
the
m
et
hodo
l
og
y,
a
pp
l
ic
at
io
n
an
d
analy
sis.
Sect
ion
4
el
a
bor
at
es
the
evaluati
on.
To
c
oncl
ude, t
he
c
on
cl
us
io
n and f
uture e
f
f
ort
h
a
ve
m
entioned in
s
ect
ion
5
.
2.
RELATE
D
W
ORK
It
has
bee
n
s
pecified
in
[4,
6,
13
-
15]
,
that
sign
al
li
ng
has
bee
n
de
picte
d
as
the
cor
e
par
t
of
the
app
li
cat
ion,
wh
ic
h
has
not
been
sta
te
d
in
Web
RTC
bet
w
een
bro
wser
a
nd
ser
ver
.
T
her
e
fore,
the
sig
nalli
ng
protoc
ol
has
to
be
pro
vid
e
d
in
the
a
pp
li
c
at
ion
le
vel
b
y
the
de
velo
per
[7,
16]
;
an
d
it
m
us
t
be
agree
d
on
betwee
n
the
two
e
ntit
ie
s
ei
t
her
with
the
central
node
or
with
the
ot
he
r
us
e
r
[17].
Pr
im
arily,
it
c
an
be
e
m
p
h
a
s
i
s
e
d
t
h
a
t
t
h
e
p
r
o
t
o
c
o
l
b
e
t
w
e
e
n
b
r
o
w
s
e
r
s
a
n
d
s
e
r
v
e
r
h
a
s
n
o
t
y
e
t
s
t
a
n
d
a
r
d
i
s
e
d
i
n
W
e
b
R
T
C
[
3
,
1
8
]
.
N
o
t
o
n
l
y
t
h
a
t
b
u
t
a
l
s
o
,
t
h
e
a
r
c
h
i
t
e
c
t
u
r
e
o
f
c
l
i
e
n
t
-
s
e
r
v
e
r
d
o
e
s
n
o
t
a
p
p
e
a
r
t
o
b
e
a
r
e
a
s
o
n
a
b
l
e
s
o
l
u
t
i
o
n
i
n
W
e
b
R
T
C
[
1
9
]
.
In
[
20,
21]
,
in
dicat
ed
t
hat
vid
eoc
onfe
ren
ci
ng
us
in
g
W
e
bR
TC
te
chn
ol
ogy
is
req
uire
d
as
lon
g
as,
d
i
f
f
e
r
e
n
t
h
o
s
p
i
t
a
l
s
,
e
c
o
n
o
m
i
c
a
n
d
s
o
c
i
a
l
l
e
v
e
l
s
,
l
a
n
g
u
a
g
e
p
r
a
c
t
i
c
e
,
a
n
d
c
o
m
p
a
n
i
e
s
h
a
v
e
n
e
e
d
e
d
v
i
d
e
o
c
o
n
f
e
r
e
n
c
i
n
g
t
o
i
n
t
e
r
a
c
t
w
i
t
h
p
e
o
p
l
e
[
2
2
-
2
4
]
.
H
o
w
e
v
e
r
,
W
e
b
R
T
C
l
a
k
e
s
h
i
g
h
-
e
n
d
o
f
v
i
d
e
o
c
o
n
f
e
r
e
n
c
i
n
g
[
25]
.
T
her
e
fore,
m
any
ty
pes
of
re
sear
ch
ha
ve
desi
gned
We
bRTC
vid
e
o
cal
ls
us
ing
XMLHttpR
equ
e
st
(XHR).
N
eve
rtheless,
us
i
ng
this
prot
oco
l
l
ed
to
c
ons
um
i
ng
ba
ndwi
dth
and
hi
gh
dela
y
[26].
Als
o,
XH
R
does
no
t
support
bid
i
re
ct
ion
al
com
m
un
ic
at
ion
[
12]
.
Like
w
ise
,
va
rio
us
de
velo
per
s
trie
d
to
ap
ply
the
session
init
ia
ti
on
prot
oco
l
(SIP)
t
o
Web
RTC
for
ga
ining
vide
o
ca
ll
s,
bu
t
the
i
ns
t
al
la
ti
on
of
plug
ins
is
sti
ll
req
ui
red
f
or
SIP
[
20]
.
Be
sides,
SIP
has
no p
r
oto
c
ol
tha
t
can work
with W
e
bRTC
[
9,
27]
;
an
d
SIP r
equ
i
res
s
om
e e
nh
a
ncem
ents an
d
le
ads
to d
el
ay
an
d
band
width
c
on
su
m
ption
[
27,
28
]
.
O
n
the
con
t
r
ary,
in
[29],
pro
posed
a
centrali
sed
ar
chite
ct
ur
e
bas
ed
on
the
m
ulti
po
int
con
t
ro
l
unit
(M
CU)
t
o
s
upport
W
e
bRTC
vid
e
o
c
onfer
e
ncin
g.
On
t
he
ot
her
hand,
t
he
a
uthors
ha
ve
not
de
bated
th
e
sign
al
li
ng
instea
d
of
e
xp
la
ining
ho
w
the
propose
d
s
tructu
re
offers
res
olu
ti
ons
li
ke
st
ream
pr
oc
essing.
In
a
ddit
ion
,
in
[
30]
il
lustrate
d
t
ha
t
us
in
g
MC
U
is
ver
y
e
xp
e
ns
i
ve;
an
d
us
es
a
s
a
re
nted
dev
ic
e
du
rin
g
c
onfe
ren
ces
.
Adding
t
o
t
hat,
[
31
]
c
onfirm
ed
th
at
MC
U
does
not
su
pp
or
t a
lar
ge
num
ber
of
part
ic
ipants and
s
upports
heter
og
ene
ous e
ndpo
ints.
In
[
7],
s
uggest
ed
a
vide
oc
on
fer
e
ncin
g
syst
e
m
to
offe
r
a
P2
P
co
nnect
io
n
us
in
g
XMP
P
ser
ve
r
a
nd
Web
RTC
.
Howev
e
r,
t
he
us
e
r
wa
s
no
t
a
ble
to
acce
ss
the
sign
al
li
ng
with
ou
t
i
ns
ta
ll
ing
e
xter
nal
softwa
r
e,
an
d
the
syst
e
m
ena
bles
two
pee
rs
to
com
m
un
i
cate
with
each
ot
her.
Furthe
rm
or
e,
an
oth
e
r
ap
pl
ic
at
ion
of
W
e
bRTC
vid
e
ocon
fer
e
nc
ing
was
desig
ned
t
o
s
upport
a
vid
e
o
cal
l
f
or
m
ulti
peer
s,
bu
t,
it
s
upports
on
ly
tw
o
peers
[32].
Wh
at
is
m
or
e,
[
33
]
deliberat
e
a
syst
em
of
vid
e
o
c
hatti
ng
for
se
niors
util
isi
ng
We
bR
TC,
the
syst
e
m
was
app
li
ed
to
vid
e
o
c
hatti
ng
bet
ween
tw
o
pee
r
s.
Be
sides
,
in
[
34
]
im
ple
m
ent
ed
a
s
uggestio
n
based
on
Ja
va
Script
la
nguag
e
a
nd
m
esh
topolo
gy
;
nev
ertheles
s,
it
of
fe
rs
co
m
m
un
ic
at
ion
betwee
n
tw
o
us
ers
.
Co
ns
e
quently
,
Web
RTC
v
i
de
ocon
fer
e
ncin
g for
m
ulti
-
us
ers
is re
qu
i
red an
d
s
houl
d be
de
sign
e
d
a
nd im
ple
m
ented.
3.
METHO
DOL
OGY, I
MPLE
MENT
ATIO
N,
A
ND AN
A
LYSIS
3.1
.
Metho
do
l
ogy
This
im
ple
m
e
ntati
on
has
be
en
desig
ne
d
an
d
te
st
ed
us
in
g
HTML
5
,
CS
S,
Ja
va
Script
c
ode,
and
Mult
iC
on
necti
on
li
brari
es.
Also,
W
ire
sh
ar
k
analy
ser
(
to
fin
d
out
the
ba
ndwidt
h
consum
ption
)
,
a
ta
sk
m
anag
er
(
to
e
va
luate
a
CPU
perform
ance
),
and
acce
ss
poi
nt
-
NetC
omm
wireless
(
t
o
pr
ov
i
de
4G
)
we
r
e
us
e
d
.
Fu
rt
her
m
or
e,
Goo
gle
Chro
m
e
,
Firefox
,
Op
e
ra,
a
nd
E
xp
l
or
e
r
we
re
util
ise
d
as
a
cl
ie
nt
-
side.
Additi
o
nally
,
m
any
com
pu
te
rs
of
diff
e
re
nt
CPU
c
or
es
a
s
(CP
U
i5,
i
7
&
dif
fer
e
nt
RAMs)
li
nked
via
va
rio
us
l
ocati
ons
thr
ough
(
Ethe
r
net
a
nd
W
i
reless)
of
the
I
nt
ern
et
a
nd
4G
netw
orks
a
s
de
scribe
d
belo
w:
(a
)
one
c
om
pu
te
r
connecte
d
t
hro
ugh
the
4G
ne
twork
,
(
b)
t
w
o
com
pu
te
rs
c
onnected
t
o
I
nter
net
thr
ough
Ethe
rn
et
net
work,
and (c
) five c
om
pu
te
rs
associ
at
ed
to t
he Inte
rn
et
via a
wirel
ess
net
wor
k.
Evaluation Warning : The document was created with Spire.PDF for Python.
In
t J
Elec
&
C
om
p
En
g
IS
S
N: 20
88
-
8708
Multi
-
us
er
m
e
di
a
strea
ming
se
rvi
ce for e
-
le
arnin
g based
web re
al
-
ti
me
c
omm
unic
atio
n
.
..
(
Naktal E
dan)
569
3.2
.
Implem
ent
ati
on
A
n
e
t
w
o
r
k
l
a
b
w
a
s
g
e
n
e
r
a
t
e
d
t
o
t
e
s
t
W
e
b
R
T
C
m
u
l
t
i
m
e
d
i
a
c
o
m
m
u
n
i
c
a
t
i
o
n
b
e
t
w
e
e
n
d
i
f
f
e
r
e
n
t
s
t
u
d
e
n
t
s
a
n
d
t
e
a
c
h
e
r
s
v
i
a
(
E
t
h
e
r
n
e
t
&
W
i
r
e
l
e
s
s
)
o
f
t
h
e
I
n
t
e
r
n
e
t
a
n
d
4
G
s
e
t
u
p
i
n
a
m
e
s
h
t
o
p
o
l
o
g
y
.
I
n
t
h
i
s
ac
hieve
m
ent,
a
signa
ll
ing
m
echan
ism
has
been
create
d
ba
sed
on
Ja
vaSc
ript
la
ng
uag
e
and
Mult
iC
onnecti
on
li
b
ra
ri
es,
al
so
ha
ve
di
vid
e
d
i
nto
t
wo p
a
rts:
-
Buil
d
a
nd adj
ust
the m
ai
n
bro
wser.
-
Util
ise
Mult
iCo
nnect
io
n
li
br
a
ries
in
orde
r
to
set
up
,
est
a
blish
an
d
e
nd
a
c
omm
un
ic
at
ion
a
m
on
g
st
udent
s
and tea
che
rs.
-
Creat
e
"room
-
id",
w
hic
h
ap
pear
s
by
def
a
ult
as
a
m
ixtur
e
of
nu
m
ber
s
,
an
d
le
tt
ers
wh
e
re
it
us
e
s
as
channel
nam
e o
r
label t
hat
shou
l
d be c
on
t
ro
l
le
d
by t
he
i
niti
at
or
.
Accor
ding
to
t
he
m
ai
n
web
bro
wser,
t
he
c
riti
cal
web
br
owser
of
this
te
st
has
m
any
featur
es
s
uc
h
as
create
an
d
sen
d
S
DP
-
offe
r/an
swer,
pe
rm
it
s
a
us
er
t
o
ena
ble
the
cam
era
and
m
ic
ro
phone,
open
or
join
a
r
oo
m
,
m
ute
-
aud
io
or
vid
e
o
an
d
util
ise
fu
ll
-
sc
reen.
It
was
desi
gn
e
d
with
one
bu
t
ton
to
al
lo
w
pe
ers
to
ope
n
or
enter
the
room
.
Also
,
Mult
iC
on
neti
on
li
brary
was
us
e
d
to
init
i
al
i
se
a
con
str
ucto
r
in
order
to:
(
a)
Set
a
session
ty
pe
as
vid
eo
c
onf
eren
ci
ng
,
(b)
Setup
S
DP
vi
deo
directi
ons
as
bi
-
directi
onal
stream
ing
,
(c)
Add
quic
k
eve
nt
handler
(
O
n
-
cl
ic
k)
from
the
m
entioned
bu
t
ton
s
,
a
nd
(
d)
Link
Ja
vaScr
i
pt
c
od
e
to
be
us
e
d
as
a
si
gnal
li
ng
m
echan
ism
that handles
c
omm
un
ic
at
ion
b
et
ween pa
rtic
ipa
nts
.
The
Mult
iC
onnecti
on
li
brar
y
has
been
use
d
to
init
ia
li
se
and
set
up
a
new
sessio
n
f
or
vi
de
o
confere
ncin
g. Also
,
it
has
a
dded
"
onstream
"
,
"functi
on"
a
nd
"e
ve
nt"
obje
ct
to
offer
n
at
ive
an
d
rem
ote
stream
s
us
in
g
a
un
i
qu
e
stre
am
-
id.
More
i
m
po
rtantl
y,
after
app
li
ed
t
his
sign
al
li
ng
m
echan
ism
,
i
t
has
bee
n
fou
nd
that
it
dep
e
nds
on
a
di
ff
ere
nt
num
ber
of
te
chn
i
ques
,
su
c
h
as
sen
d
an
offe
r,
rec
ei
ve
a
res
pons
e
,
exch
a
nge
data,
ope
n
and
cl
ose
cha
nnel
,
us
i
ng
a
soc
ket
in
orde
r
to
determ
ine
wh
ic
h
com
m
un
ic
at
ion
te
ch
nique
is
su
it
able
f
or
eac
h
us
er
.
F
or
insta
nce,
S
oc
ket.io
can
offe
r
sev
er
al
com
m
un
ic
ation
te
ch
niques
instea
d
of
JS
O
N.
I
n
[
14,
28]
,
sta
te
d
that
us
in
g
So
c
ket.io
le
ads
t
o
deal
w
it
h
ser
ve
r
file
and
cl
ie
nt
file
at
the
sa
m
e
tim
e,
inclu
di
ng
it
can
de
ci
de
if
the
co
nnect
ion
est
ablishes
wi
th
AJ
A
X
lo
ng
po
ll
in
g,
Flash
or
We
bSoc
ke
t.
In
li
ke
m
ann
er
,
ser
ve
r
-
si
de
an
d
cl
ie
nt
-
side c
ompone
nts ca
n be
provide
d
us
in
g
S
oc
ket.io
[
29]
.
Roo
m
-
id
is
a
ver
y
si
gn
i
fican
t
aspect
f
or
in
i
ti
at
ing
an
d
j
oi
nin
g
the
r
oom
;
it
is
us
ed
t
o
m
ake
sur
e
releva
nt
-
m
essages
a
re
s
har
e
d
with
releva
nt
par
ti
ci
pa
nts,
and
these
m
essages
a
re
no
t
acce
ssible
by
oth
e
r
stud
e
nts.
T
herefo
re,
al
l
stud
e
nts
m
us
t
po
ssess
the
sam
e
"ro
om
-
id"
to
sen
d
a
par
ti
ci
pati
on
request
an
d
enter
the
sam
e
ro
om
.
Other
wise,
they
will
op
en
a
ne
w
r
oo
m
or
j
oi
n
a
nothe
r
one
.
I
n
this
im
ple
m
e
ntati
on
,
com
m
un
ic
at
ion
has
one
us
e
r
to
sta
rt
the
se
ssion
w
ho
s
pe
ci
fies
"room
-
id"
and
var
i
ous
par
ti
ci
pa
nts
w
ho
m
us
t
us
e
it
.
More
ov
er,
m
any
ro
om
s
can
be
opene
d
but
by
usi
ng
diff
e
re
nt
"roo
m
-
ids".
Wh
e
n
the
init
ia
tor
cr
eat
es
a
new
room
,
it
needs
to
creat
e
a
new
so
c
ke
t.
A
new
s
oc
ke
t
can
be
us
e
d
to
ob
ta
in
var
i
ou
s
t
hings,
s
uc
h
as
SD
P
-
offe
r
a
nd
an
ICE
gathe
red
by
t
he
init
ia
tor
a
nd
ot
he
r
pa
rtic
ipants
.
In
ot
her
w
ord
s,
e
ac
h
peer
s
hould
transm
it
their
detai
ls
ov
e
r
de
fau
lt
-
c
ha
nn
el
,
create
and
e
xch
a
nge
"SD
P
-
offe
r/ans
wer
"
.
At
the
sam
e
tim
e
,
they
are
ex
pec
te
d
to
play
the
ro
le
of
“o
ff
e
r
or
"
f
or
any
ne
w
pa
rtic
ipant
a
fter
ope
ning
a
new
peer
c
onne
ct
ion
.
On the c
ontrar
y, each
pa
rti
ci
pan
t j
oin
i
ng the
room
is exp
ect
ed
to
p
la
y t
he
r
ole of “a
nswer
er".
W
h
e
n
a
n
i
n
i
t
i
a
t
o
r
o
p
e
n
e
d
t
h
e
r
o
o
m
a
f
t
e
r
d
e
t
e
r
m
i
n
i
n
g
r
o
o
m
-
i
d
,
i
t
w
i
l
l
s
h
o
w
m
u
l
t
i
m
e
d
i
a
“
M
e
d
i
a
S
t
r
e
a
m
”
.
A
“
M
e
d
i
a
S
t
r
e
a
m
”
c
a
n
b
e
g
a
i
n
e
d
t
h
r
o
u
g
h
u
t
i
l
i
s
i
n
g
“
n
a
v
i
g
a
t
o
r
.
g
e
t
U
s
e
r
M
e
d
i
a
”
m
e
t
h
o
d
i
n
or
de
r
to
us
e
the
c
a
m
era
and
m
ic
ro
phone
f
or
ca
ptu
ri
ng
scree
n.
U
po
n
granti
ng
the
acce
ssion
;
a
ca
m
era
init
ia
te
s
strea
m
ing
,
an
d
the
n
the
exec
utio
n
can
be
rea
dy
f
or
joinin
g.
All
par
ti
ci
pa
nts
ne
ed
to
i
nvoke
"getUse
rMedia
"
and
sh
a
re
ca
m
eras
and
m
ic
ro
phones.
Fi
g
ure
1
,
sh
ows
the
m
ai
n
bro
wser
usi
ng
Goo
gle
Chrom
e,
F
igu
r
e
2
presents
t
he
m
ai
n
browser
us
i
ng
Firef
ox,
F
ig
ur
e
3
sh
ows
the
m
ai
n
br
owser
us
in
g
O
per
a
,
and
F
i
gure
4
shows
the
m
ai
n
browse
r
us
in
g
E
xplo
rer. A
ls
o,
Fig
ur
e
5,
s
how
s the
P
seu
do
c
ode
of
t
his e
xp
e
rim
ent
.
3.3
.
Analysis
3.3.1.
T
he cre
at
e
d signall
in
g
m
ec
hani
sm
Accor
ding
to
the
netw
ork
a
na
ly
sis
insp
ect
ing
com
ponen
t
s
of
Goo
gle
Chrom
e
,
Firef
ox
,
O
pera,
a
nd
Ex
plo
re
r
at
the
act
ual
co
m
m
un
ic
at
ion
,
this
sign
al
li
ng
m
echan
ism
w
as
ind
ivid
uall
y
analy
sed
am
on
g
te
n
stud
e
nts
an
d
te
achers
dep
e
nd
on
the
delay
fo
r
va
rio
us
th
oughts,
the
fir
st
is
rely
on
the
delay
to
be
prepar
e
d
and
t
he
sec
ond
base
d
on
se
nd
ing
a
request
a
nd
receivi
ng
a
respo
ns
e
f
r
om
us
ers
.
Co
ns
e
qu
ently
,
it
con
s
um
es
betwee
n
a
m
in
i
m
u
m
and
m
a
xim
u
m
con
sum
pt
ion
that
w
a
s
119
m
illi
se
conds
(m
s)
to
185
(m
s)
to
be
read
y
.
It
al
so
co
nsu
m
es
28
0
(m
s)
,
an
d
690
(m
s)
ex
hib
it
s
to
transm
it
and
receive
a
re
qu
e
st
and
a
r
esp
on
se
.
The
si
gn
al
li
ng
m
echan
is
m
can
set
up,
est
a
bl
ish
an
d
e
nd
a
com
m
un
ic
at
ion
sim
ultaneou
s
ly
between
stu
den
ts
and
te
ac
her
.
T
he
va
riat
ion
of
delay
betwee
n
us
in
g
Goo
gle
Chrom
e
,
Firef
ox
,
O
pe
ra,
a
nd
Ex
plo
r
er
was
sli
gh
tl
y
diff
e
re
nt.
How
ever,
CPU
an
d
bandw
i
dth
we
re
i
m
pacti
ng
on
the
qual
it
y
o
f
aud
i
o
an
d
vi
deo.
Be
sides,
a
lon
g
delay
w
as
r
e
ve
al
ed
usi
ng
the
create
d
si
gnal
li
ng
m
echan
ism
.
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2088
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8708
In
t J
Elec
&
C
om
p
En
g,
V
ol.
11
, No
.
1,
Febr
uar
y
2021
:
56
7
-
57
4
570
Figure
1.
S
cree
ns
hot
of the m
ai
n
br
ow
se
r usi
ng
g
oogle
c
hro
m
e
Figure
2
.
S
cree
ns
hot
of the m
ai
n
br
ow
se
r usi
ng
f
ire
f
ox
Figure
3
.
S
cree
ns
hot
of the m
ai
n
br
ow
se
r usi
ng
o
pe
ra
Evaluation Warning : The document was created with Spire.PDF for Python.
In
t J
Elec
&
C
om
p
En
g
IS
S
N: 20
88
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8708
Multi
-
us
er
m
e
di
a
strea
ming
se
rvi
ce for e
-
le
arnin
g based
web re
al
-
ti
me
c
omm
unic
atio
n
.
..
(
Naktal E
dan)
571
Figure
4
.
S
cree
ns
hot
of the m
ai
n
br
ow
se
r usi
ng
e
xplo
rer
Figure
5
.
Im
ple
m
entat
ion
p
se
udoc
od
e
3.3.2.
Qu
ality
of
vide
o
c
onfe
renci
ng
The
qu
al
it
y
of
vid
e
o
a
nd
a
udio
was
done
by
sepa
rate
im
ple
m
entat
ion
am
on
g
te
n
st
ud
e
nts
a
nd
te
achers
o
n
di
ff
e
ren
t
netw
orks,
s
uc
h
as
th
e
In
te
r
net
a
nd
4G.
T
her
e
for
e,
the
qu
al
it
y
of
a
udio
a
nd
vide
o
betwee
n
tw
o
st
ud
e
nts
was
e
xc
el
le
nt.
Wh
en
the
thir
d
pee
r
jo
ined
t
he
r
oom
,
the
qual
it
y
of
vi
deo
a
nd
au
di
o
was
excell
ent
. Nev
ertheless,
once
the fourth
par
ti
ci
pan
t j
oi
ne
d
t
he
r
oo
m
; t
he
qual
it
y of
the
vid
eo was
no
t c
onsta
nt,
so
it
s
qual
it
y
was
inc
reasin
g
and
decre
asi
ng
with
a
delay
as
well
.
A
dd
it
ion
al
ly
,
it
was
no
ti
ced
t
hat
on
e
peer
was
getti
ng
in
and
out
with
cl
ear
a
ud
i
o
bu
t
f
ro
ze
n
im
age
f
or
on
e
m
inu
te
.
The
sam
e
qual
it
y
was
al
so
re
veale
d
wh
e
n
t
he fifth
par
ti
ci
pa
nt join
ed
the
ro
om
.
1
.
SET
U
I
=
New
User
-
Id;
2
.
SET
E
.UI
=
Exis
t
Cu
rr
en
t Use
r
-
Id
;
3
.
SET
NU
=
Ne
w
User
r;
4
.
SET
S
I
=
Sess
i
o
n
Initiato
r;
5
.
SWIT
C
H
St
a
rt
Co
n
n
ectio
n
;
6
.
CASE1
: op
en
a
n
ew
roo
m
;
7
.
STE
P1
: op
en
a
roo
m
;
8
.
IF
SI
=
U
I;
9
.
T
H
EN
o
p
en
a
n
ew
ses
sio
n
;
1
0
.
EL
SE
ask
f
o
r
UI;
1
1
.
STE
P1
: sen
d
o
ff
er;
1
2
.
IF
S
I
=
cr
eated SDP
-
o
f
f
er;
1
3
.
T
H
EN
sen
d
SDP
-
o
f
f
er
to
N
U
;
1
4
.
STE
P2
:
jo
in
the roo
m
;
1
5
.
IF
NU =
E
.UI
&&
acc
ep
ted
SDP
-
o
f
f
er;
1
6
.
T
H
EN
NU
=
crea
t
e SDP
-
an
swer;
1
7
.
EL
SE IF
NU
= un
accepted
SDP
-
o
f
f
er;
1
8
.
T
H
EN
NU
= dis
co
n
n
ect;
1
9
.
EL
SE IF
NU =
UI;
2
0
.
THEN
NU
= op
en
a
n
ew
se
ss
io
n
&
&
c
reate
S
DP
-
o
f
f
er;
2
1
.
STE
P3
:
ICE
cand
id
ate;
2
2
.
IF
S
I
&
&
N
U
=
e
x
ch
an
g
ed
I
CEs;
2
3
.
T
H
EN
start bi
-
d
irect
io
n
al vid
eo
;
2
4
.
EL
SE
re
-
co
n
n
ect;
2
5
.
C
ASE2
: D
isco
n
n
ect;
26.
IF
S
I
=
dis
co
n
n
ect;
2
7
.
T
H
EN
m
o
v
e
con
trol to
the n
ex
t peer;
2
8
.
EL
SE IF
an
y
peer=
dis
co
n
n
ect;
2
9
.
END
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2088
-
8708
In
t J
Elec
&
C
om
p
En
g,
V
ol.
11
, No
.
1,
Febr
uar
y
2021
:
56
7
-
57
4
572
On
t
he
co
ntra
r
y,
wh
e
n
the
si
xth
,
se
ve
nth
a
nd
m
or
e
pe
ers
had
par
ti
ci
pat
ed
in
the
roo
m
,
m
os
t
of
the
co
nn
ect
e
d
peer
s
pr
e
sente
d
a
lo
us
y
qual
it
y
of
au
dio
a
nd
vid
e
o
as
uncl
e
ar
au
dio
a
nd
frozen
vid
e
o
.
N
ot
on
ly
that
bu
t
al
so
,
it
was
no
t
able
to
al
low
m
or
e
t
han
se
ven
peers
to
j
oin
the
r
oom
,
wh
ereas
m
or
e
tha
n
seve
n
peers
dem
olished
th
e
com
m
un
ic
at
i
on.
Co
ncernin
g
to
the
pe
er
who
wa
s
us
i
ng
the
4G
net
w
ork,
al
m
os
t
it
was
not
visible
or
dis
play
ed
in a
fro
ze
n
i
m
age.
As
a
re
su
lt
, usin
g
thi
s
m
echan
is
m
f
or
m
any
-
to
-
m
a
ny co
m
m
un
ic
at
ion
i
s
eff
ic
ie
nt
for
t
hree pee
rs
as
a m
axim
u
m
n
um
ber
.
3.3.3.
CP
U
p
e
rfo
rm
an
ce
an
d mem
ory us
age
In
[
35
]
,
em
ph
a
sised
that
us
i
ng
m
esh
topol
ogy
in
se
ndin
g
and
recei
ving
data
bet
ween
s
tud
e
nts
ca
n
influ
e
nce
t
he
CPU
loa
d.
By
con
tra
st,
m
e
m
or
y
us
a
ge
in
real
-
ti
m
e
was
no
t
a
ff
ec
te
d
by
t
he
qu
al
it
y
of
m
ul
tim
edia
com
m
un
ic
at
ion
[
35
-
37]
.
Fig
ur
e
6
,
show
s
the
per
centa
ges
of
CPU
pe
rform
ance
and
m
e
m
or
y
us
a
ge
in
a m
es
h
to
polo
gy.
Figure
6
.
CPU
perform
ance
and m
e
m
or
y u
sage
betwee
n
st
ud
e
nts
over t
he
i
nter
net
3.3.4.
B
an
dwi
dt
h
c
onsump
ti
on
Ba
ndwidt
h
co
ns
um
ption
wa
s
m
easur
ed
usi
ng
W
i
res
hark
analy
ser,
s
o
the
analy
sis
ha
s
sh
ow
n
that
each
cl
ie
nt
requests a m
ini
m
um
o
f
2
Mb/
s
b
a
ndwidt
h on the
v
ide
o
a
nd
65
kb/s
band
wid
th
on the a
udio
.
3.3.5.
Qu
ality
of e
xper
ie
nce
(Q
oE)
Actual
stu
de
nts
an
d
te
ache
rs
hav
e
i
nvol
ved
in
this
te
st
to
el
aborate
thei
r
vie
ws
on
t
he
recog
nised
us
er
know
le
dg
e
by
t
he
us
e
of
qu
e
sti
on
naire
s,
as
dis
play
ed
in
Table
1
.
This
i
m
ple
m
ent
at
ion
co
nf
irm
ed
an
excell
ent
qual
it
y
of
a
ud
i
o
an
d
vi
de
o,
in
pa
r
ti
cular
am
on
g
three
st
ud
e
nts
via
the
In
te
r
ne
t
and
4G
ne
tw
orks
.
Howe
ver,
the
respo
ns
e
of
s
om
e
peer
s
wa
s
no
t
e
ff
ect
ive
wh
il
e
it
ta
kes
m
or
e
than
th
r
ee
m
inu
te
s
on
s
ome
occasio
ns
.
Ac
cordin
g
to
e
va
luati
on
,
it
can
con
si
der
the
band
width
c
on
su
m
ption
as
a
so
urce
of
re
duci
ng
the
qual
it
y
of
aud
i
o
a
nd
vide
o;
an
d
al
s
o
the
CP
U
pe
rfo
r
m
ance
as
a
s
ource
of
al
lowi
ng
or
co
ntr
olli
ng
t
he
nu
m
ber
of
pee
rs.
Acc
ordin
gl
y,
wh
e
n
a
peer
wait
s
fo
r
ot
he
r
m
e
m
b
ers
un
t
il
the
CPU
set
t
le
s
do
w
n,
the
qu
al
it
y
g
e
t
s
b
e
t
t
e
r
.
A
l
t
e
r
n
a
t
i
v
e
l
y
,
t
h
i
s
s
i
g
n
a
l
l
i
n
g
h
a
s
g
i
v
e
n
e
n
o
r
m
o
u
s
d
e
l
a
y
o
n
c
e
s
e
n
t
a
r
e
q
u
e
s
t
u
n
t
i
l
r
e
c
e
i
v
e
d
a
r
e
s
p
o
n
s
e
.
Table
1
. Q
oE f
ro
m
1
0
stu
den
t
s v
ia
t
he
i
nte
rnet
an
d 4
G netw
orks
Qu
estio
n
s
Ver
y
Bad
Ver
y
an
n
o
y
in
g
Bad
An
n
o
y
in
g
Fair
Slig
h
tly
ann
o
y
in
g
Go
o
d
Perceptib
le
Excellen
t
Rate th
e qu
ality
of
aud
io
du
ring
the
ses
sio
n
in e
-
learni
n
g
3
2
3
2
Rate th
e qu
ality
of
the v
id
eo
du
ring
th
e sess
io
n
in e
-
le
arnin
g
3
3
1
1
2
Rate
th
e ec
h
o
du
ri
n
g
the ses
sio
n
in
e
-
learnin
g
3
2
3
2
Rate th
is ap
p
licati
o
n
us
in
g
Ch
rom
e
10
Rate th
is ap
p
licati
o
n
us
in
g
Fir
ef
o
x
10
Rate th
is ap
p
licati
o
n
us
in
g
Opera
10
Rate th
is ap
p
licati
o
n
us
in
g
E
x
p
l
o
rer
10
Evaluation Warning : The document was created with Spire.PDF for Python.
In
t J
Elec
&
C
om
p
En
g
IS
S
N: 20
88
-
8708
Multi
-
us
er
m
e
di
a
strea
ming
se
rvi
ce for e
-
le
arnin
g based
web re
al
-
ti
me
c
omm
unic
atio
n
.
..
(
Naktal E
dan)
573
4.
EVAL
UA
TI
O
N
It
has
prov
e
d
that
this
m
echan
ism
can
be
consi
der
e
d
to
su
pp
or
t
c
omm
un
ic
at
io
n
am
on
g
di
ff
e
rent
b
r
o
w
s
e
r
s
i
n
a
m
e
s
h
t
o
p
o
l
o
g
y
.
T
h
i
s
i
m
p
l
e
m
e
n
t
a
t
i
o
n
u
s
i
n
g
a
n
o
v
e
l
s
i
g
n
a
l
l
i
n
g
m
e
c
h
a
n
i
s
m
c
a
n
s
e
t
u
p
,
e
s
t
a
b
l
i
s
h
e
d
,
a
n
d
c
l
o
s
e
c
o
n
n
e
c
t
i
o
n
o
v
e
r
t
h
e
I
n
t
e
r
n
e
t
a
n
d
4
G
n
e
t
w
o
r
k
s
.
M
o
r
e
o
v
e
r
,
i
t
o
f
f
e
r
s
bi
-
d
i
r
e
c
t
i
o
n
a
l
vid
eo
s
,
a
nd
it
r
et
ai
ns
the
co
nf
e
re
nce
dynam
ic
even
if
any
cl
ie
nt
de
par
ts,
preve
nt
s
an
u
nk
now
n
us
er
from
par
ti
ci
pating
i
n
the
room
.
Wh
e
reas,
it
has
been
c
re
at
ed
with
ou
t
us
in
g
a
ny
exter
nal
de
vices
an
d
com
m
ercial
cl
ou
d/
serv
e
r.
Th
is
ex
per
im
e
nt
can
be
c
onsidere
d
as
the
fi
r
st
on
e
that
achi
eved
a
Web
RT
C
bid
irect
io
nal
vid
e
o
co
nf
e
re
nci
ng
us
in
g
t
he 4G n
et
w
ork
. Neve
rtheless
, it
do
e
s
no
t
sup
port Op
era
browser.
A
crit
ic
al
pr
ob
lem
du
ring
a
udio
an
d
vide
o
confere
ncin
g
was
a
CPU
pe
rfor
m
ance
and
bandw
i
dth
consum
ption
,
wh
il
e
m
ultim
e
dia
co
nf
e
re
ncing
re
qu
ire
s
hi
gh
CPU
co
re
an
d
ba
ndwi
dth
.
This
can
be
kn
own
a
s
CPU
press
ur
e
,
as
long
as
i
t
r
el
ie
s
on
va
rio
us
com
po
ne
nts
,
e.g
.
t
he
us
e
d
cod
ec
s
.
A
cco
r
ding
to
the
s
pe
ci
fied
sp
eci
ficat
io
ns
,
it
can
co
nf
irm
that
CPU
af
fec
ts
the
num
ber
of
us
e
rs
an
d
ba
ndwidt
h
im
pacts
on
t
he
qual
it
y
of
aud
i
o
a
nd
vi
de
o.
On
the
c
ontr
ary,
this
si
gn
al
li
ng
m
echan
is
m
can
no
t
s
upport
m
or
e
tha
n
t
hr
ee pee
rs
in
orde
r
to
offer
a
n
e
xcell
ent
va
rie
ty
of
a
ud
i
o
a
nd
vid
e
o.
Als
o,
it
co
nsu
m
es
a
m
assive
delay
w
hile
it
t
akes
a
l
ong
ti
m
e
to
est
ablish
com
m
un
ic
at
ion
between
pee
rs.
T
he
Q
oE
c
onfir
m
s
that
this
testb
ed
wor
ks
a
pp
li
cably
s
o
th
at
it
can
enh
a
nce t
hese
exp
e
rim
ents in
the
fu
t
ur
e
.
5.
CONCL
US
I
O
N
AND
F
UT
U
RE EFFO
RT
I
n
t
h
i
s
p
a
p
e
r
,
W
e
b
R
T
C
b
i
-
d
i
r
e
c
t
i
o
n
a
l
m
u
l
t
i
m
e
d
i
a
c
o
n
f
e
r
e
n
c
i
n
g
i
n
m
e
s
h
t
o
p
o
l
o
g
y
t
h
r
o
u
g
h
t
h
e
I
n
t
e
r
n
e
t
a
n
d
4
G
w
a
s
d
e
s
i
g
n
e
d
a
n
d
i
m
p
l
e
m
e
n
t
e
d
i
n
r
e
a
l
-
t
i
m
e
e
x
e
c
u
t
i
o
n
.
M
o
r
e
o
v
e
r
,
a
n
o
v
e
l
s
i
g
n
a
l
l
i
n
g
m
echan
ism
wa
s
create
d
and
te
ste
d
to
s
et
up
,
est
ablis
h
and
en
d
c
omm
un
ic
at
ion
between
par
ti
ci
pa
nts.
Als
o,
a
pr
ofo
und
cl
arific
at
ion
of
CPU p
rese
ntati
on,
m
e
m
or
y
per
f
or
m
ance
,
sig
nalli
ng
us
a
ge
, an
d
Q
oE
in
a
r
eal
te
st
was
co
m
ple
te
d.
This stat
e
is
ben
e
fici
al
as
l
ong
it
offer
s
r
eal
dem
o
ov
er
diff
e
ren
t
br
owsers
a
nd
net
works
with
a
us
er
that
need
s
ph
ysi
cal
c
o
m
m
u
n
i
c
a
t
i
o
n
.
B
e
s
i
d
e
s
,
t
h
i
s
e
x
p
e
r
i
m
e
n
t
h
a
s
b
e
e
n
a
p
p
l
i
e
d
a
m
o
n
g
t
h
r
e
e
t
o
f
i
v
e
p
e
e
r
s
i
n
e
-
l
e
a
r
n
i
n
g
b
e
t
w
e
e
n
t
e
a
c
h
e
r
a
n
d
s
t
u
d
e
n
t
s
.
I
n
t
h
e
f
u
t
u
r
e
,
w
e
h
a
v
e
a
n
i
d
e
a
t
o
d
e
v
e
l
o
p
t
h
i
s
a
c
h
i
e
v
e
m
e
n
t
f
o
r
m
o
r
e
s
c
a
l
a
b
l
e
v
i
d
e
o
i
n
e
-
l
e
a
r
n
i
n
g
.
REFERE
NCE
S
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A.
Loz
ano
,
“
Perform
anc
e
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y
sis
of
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og
i
es
for
W
eb
-
base
d
Rea
l
-
T
ime
Com
m
unic
at
ion
(W
ebRT
C),
”
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to
Univer
sit
y
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[2]
M.
A.
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Sulim
an
and
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cs
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ic
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B.
Y.
Juli
an
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al
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,
“
W
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C
-
base
d
vide
o
co
nfe
ren
c
ing
servi
ce
for
te
l
eheal
t
h,
”
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ad
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Jatur
awa
t,
“
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l
uat
ion
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ec
hn
ic
a
l
Stud
y
and
Perform
anc
e
for
Rea
l
-
Ti
m
e
Fa
c
e
Dete
c
ti
on
Us
ing
W
eb
Rea
l
-
Ti
m
e
Com
m
unic
at
ion,”
in
Inte
rnat
iona
l
Confe
r
enc
e
on
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municat
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,
“
A
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m
anc
e
Eva
lu
at
io
n
of
W
ebRT
C
o
ver
LT
E
,
”
in
12t
h
Annual
Confe
renc
e
on
Wireless
On
-
demand
Networ
k
Syste
ms
an
d
Serv
i
ce
s (
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,
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-
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L.
O.
D.
N.
E
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F
oss
er,
“
Quali
t
y
of
Expe
rie
n
ce
of
W
ebRT
C
base
d
vide
o
comm
unic
ation,
”
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eg
ia
n
Univer
sit
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f
Scie
nc
e and
T
echnolog
y
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2016
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[7]
H.
V.
C.
Cristi
a
n,
“
On
m
ult
i
-
user
web
conf
ere
n
ce
using
W
ebRT
C,
”
in
18th
Int
ernati
onal
Conf
ere
nce
on
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Theory,
Control
and
Computing
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C)
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ton
,
e
t
al.
,
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T
aki
ng
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n
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in
an
enterpri
se
,
”
IEE
E
Comm
un
i
cat
ion
Magazin
e
,
vo
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no
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48
-
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A
.
P
.
G
o
n
z
á
l
e
z
,
“
D
e
f
i
n
i
t
i
o
n
o
f
a
M
e
n
a
O
p
i
n
i
o
n
S
c
o
r
e
f
o
r
V
P
8
O
v
e
r
R
e
a
l
-
T
i
m
e
C
o
n
n
e
c
t
i
o
n
s
,
”
U
n
i
v
e
r
s
i
d
a
d
e
V
i
g
o
,
2
0
1
7
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[10]
J.
H
.
Paik
and
D.
H
.
Lee
,
“
Sca
la
bl
e
signaling
protoc
ol
for
W
e
b
rea
l
-
ti
m
e
com
m
unic
at
ion
b
ase
d
on
a
distri
bu
ted
hash
ta
b
le,”
Co
mput
er
Comm
un
ic
ati
ons
,
vol
.
70
,
pp.
28
-
39,
2015
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[11]
E.
B
ash,
“
Java
sc
ript
Sess
ion Esta
bli
shm
ent
Protoc
ol,
”
in
PhD
Propos
al
,
vo
l. 1, pp.
1
-
85,
2016
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[12]
E.
E. I
.
L
aj
tos
an
d
D.
O’B
y
rne
,
“
W
ebRT
C
to co
m
ple
m
ent
IP Co
m
m
unic
at
ion
Se
rvic
es,
”
GSM
As
sciat
ion
,
2016
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[13]
S
.
R
a
j
a
b
,
“
C
o
m
p
a
r
i
n
g
d
i
f
f
e
r
e
n
t
n
e
t
w
o
r
k
t
o
p
o
l
o
g
i
e
s
f
o
r
W
e
b
R
T
C
c
o
n
f
e
r
e
n
c
i
n
g
,
”
K
t
h
r
o
y
a
l
I
n
s
t
i
t
u
t
e
o
f
T
e
c
h
n
o
l
o
g
y
,
2
0
1
5
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[14]
M.
Grinbe
rg
,
“
Socket
.
IO
Docum
ent
a
ti
on,
”
2017
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[15]
R.
Ra
i,
“
Socket
.
I
O Re
al
-
ti
m
e
W
e
b
Applicati
on
D
eve
lopment
,”
Bi
rm
ingha
m
-
Mu
mba
i
,
PA
CKT,
20
13.
[16]
M
.
Nebra
,
“
Socket
.
io:
le
t
’s
go
to
re
al
ti
m
e,”
OP
E
NCL
ASSR
OO
MS
,
2017.
[On
li
ne]
.
Ava
il
ab
l
e:
htt
ps://
op
enc
l
assroom
s.c
om
/c
ourses/ult
ra
-
f
ast
-
ap
pli
c
at
ions
-
using
-
node
-
js/s
ocket
-
io
-
let
-
s
-
go
-
to
-
r
eal
-
ti
m
e.
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M.
Rob,
“
Gett
in
g
Started
with
W
ebRT
C
,”
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gham
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ck
t
Pu
bli
shing Ltd
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v,
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al
.
,
“
W
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C
te
chnol
og
y
over
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w
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signaling
soluti
on
design
and
implementation,”
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h
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rnational
C
onve
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unic
ati
o
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Curre
nt
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ati
ons
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Evaluation Warning : The document was created with Spire.PDF for Python.
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al.
,
“
Anal
y
sis
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cha
l
le
nges
fa
ced
b
y
W
ebRT
C
vide
oconf
ere
n
cing
and
a
remedi
al
ar
chi
t
ecture
,
”
Int
ernati
onal
J
o
urnal
of
Comput
er
Sci
ence
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I
nf
orm
ati
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[21]
S.
Petra
ngeli
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e
t
al
.
,
“
A
sca
la
ble
W
ebRT
C
-
b
ase
d
fra
m
ework
for
remote
vide
o
col
l
abor
atio
n
appl
icati
ons,
”
Mult
imed
ia
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nc
e
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y
s
te
m
Based
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ebR
TC
W
it
h
Acc
ess
to
the
PS
TN,”
El
e
ct
ron
ic
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s
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e
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l
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er
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[23]
M.
Sağla
m
,
“
Revol
uti
on
iz
i
ng
Tha
iland’s
Rur
al
He
al
th
ca
r
e
a
nd
Mental
He
a
lt
h
Il
lne
ss
Tr
eatm
ent
s
Through
Te
l
emedic
in
e
-
Vi
deo
Confer
encin
g,
”
Si
am Unive
r
sit
y
,
2019
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[24]
A.
Andujar
and
C.
Medina
-
López,
“
Expl
oring
n
e
w
wa
y
s
of
eTan
dem
and
te
l
ec
ol
l
abor
ation
throug
h
the
W
ebRT
C
protoc
ol:
Studen
ts’
enga
gement
and
per
ce
p
ti
ons,
”
Int
ernati
onal
J
ournal
of
Eme
rg
ing
Technol
ogie
s
in
Learn
ing
,
vol.
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,
no
.
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,
pp
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200
-
217
,
2019
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[25]
N.
Eda
n
and
S.
A.
Mahm
ood,
“De
sign
and
imp
le
m
ent
a
new
m
ec
han
ism
fo
r
au
dio,
vide
o
and
s
cre
en
re
cor
ding
base
d
on
W
ebR
TC
technolog
y
,
”
Int
ernati
ona
l
J
ournal
of
E
lectr
ic
al
and
Comput
er
Eng
in
ee
ring
(
IJE
CE)
,
vol.
10
,
no.
3
,
pp
.
2773
-
2778,
2020
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[26]
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M.
Eda
n
,
et
al
.
,
“
Perform
ance
ev
al
u
at
ion
of
QoS
using
SIP
&
amp;
IAX
2
V
VoIP
protoc
ols
with
COD
ECS,”
in
Proc
ee
dings
o
f
2016
S
AI
Com
puti
ng
Conf
ere
n
ce
(
SAI
2016
)
,
2
016.
[27]
W
.
C.
K
.
Ng,
e
t
a
l.
,
“
A
P2P
-
M
CU
Approac
h
t
o
Multi
-
Par
t
y
V
ide
o
Conf
ere
n
ce
with
W
ebRT
C
,
”
Int
ernati
onal
J
ournal
of
Fut
ur
e
Comput
er
and
Comm
un
ic
ati
on
,
vo
l. 3, no. 5, pp. 319
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