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Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
11
IAST
ED P
DCN
200
4 Tu
tori
al:
IAST
ED P
DCN
200
4 Tu
tori
al:
Shap
ing
the
Futu
re o
fSh
apin
g th
e Fu
ture
of
Inte
rnet
Con
gest
ion
Cont
rol
Inte
rnet
Con
gest
ion
Cont
rol
Mic
hael
Wel
zl
Mic
hael
Wel
zl
http
://w
ww
.wel
zl.a
tht
tp:/
/ww
w.w
elzl
.at
Dis
trib
uted
and
Par
alle
l Sys
tem
s G
roup
Dis
trib
uted
and
Par
alle
l Sys
tem
s G
roup
Inst
itut
e of
Com
pute
r Sc
ienc
eIn
stit
ute
of C
ompu
ter
Scie
nce
Uni
vers
ity
Uni
vers
ity
ofofIn
nsbr
uck
Inns
bruc
k
http://www.welzl.at/
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
22
Out
line
Out
line
1.Co
nges
tion
Con
trol
: a
quic
k in
trod
ucti
on
2.Pr
oble
ms
3.So
me
prop
osed
enh
ance
men
ts
4.H
ow t
o de
sign
you
r ow
n co
nges
tion
con
trol
mec
hani
sm
Rese
arch
pro
cedu
re:
1.ge
t to
kno
w t
he f
ield
2.id
enti
fy p
robl
ems
3.lo
ok a
t w
hat
othe
rs
have
don
e
4.co
me
up w
ith
your
ow
n so
luti
ons
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
33
Cong
esti
on C
ontr
olCo
nges
tion
Con
trol
A qu
ick
intr
oduc
tion
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
44
Prob
lem
sta
tem
ent
Prob
lem
sta
tem
ent
•Ef
fici
ent
tran
smis
sion
of
data
str
eam
s ac
ross
the
Inte
rnet
–va
riou
s so
urce
s, v
ario
us d
esti
nati
ons,
var
ious
typ
es o
f st
ream
s
•W
hat
is „
effi
cien
t“?
–te
rms:
late
ncy,
end
2end
del
ay,
jitt
er,
band
wid
th(n
omin
al/a
vaila
ble/
bott
lene
ck -
), t
hrou
ghpu
t, g
oodp
ut,
loss
rat
io,
..–
goal
s: h
igh
thro
ughp
ut(b
its
/ se
cond
), lo
wde
lay,
jit
ter,
loss
rat
io
•N
ote:
Inte
rnet
= T
CP/I
P ba
sed
wor
ld-w
ide
netw
ork
–no
ass
umpt
ions
abo
ut lo
wer
laye
rs!
–ig
nore
CSM
A/CD
, CS
MA/
CA,
toke
n ri
ng,
base
band
enc
odin
g, f
ram
e ov
erhe
ad,
swit
ches
, et
c. e
tc.
!
typically bit/s
at this level!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
55
A s
impl
eA
sim
ple
rout
er m
odel
rout
er m
odel Q
ueue
1
Que
ue 2
Swit
chin
gFa
bric
In 1
Out
1In
2O
ut 2
In 3 •
Swit
chin
g fa
bric
forw
ards
a pa
cket
(de
st.
addr
.)if
nosp
ecia
l tre
atm
ent
nece
ssar
y: f
ast
path
(har
dwar
e)
•Q
ueue
sgr
ow w
hen
traf
fic
burs
ts a
rriv
e•
low
del
ay=
smal
l que
ues,
low
jit
ter
= m
inor
que
ue f
luct
uati
ons
•Pa
cket
s ar
e dr
oppe
dw
hen
queu
es o
verf
low
(“D
ropT
ailq
ueue
ing“
)•
low
loss
rat
io=
smal
l que
ues
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
66
The
cong
esti
on p
robl
emTh
e co
nges
tion
pro
blem
•Co
nges
tion
cont
rol n
eces
sary
•ad
ding
fast
link
sdo
es n
othe
lp!
S1D
1
D2
S2
100
kb/s
1000
kb/s
100
kb/s
10kb
/s
110
kb/s
Que
ue
S 1
S 2
Swit
chin
gFa
bric
tota
l thr
ough
put
w/o
cc.
: 20
kb/s
tota
l thr
ough
put
w/
cc.:
110
kb/s
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
77
Cong
esti
on c
olla
pse
Cong
esti
on c
olla
pse
“knee“
“cliff“
Goa
l: o
pera
tion
at
the
“kne
e“
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
88
Inte
rnet
con
gest
ion
cont
rol:
His
tory
Inte
rnet
con
gest
ion
cont
rol:
His
tory
•19
68/6
9:da
wn
ofth
eIn
tern
et•
1986
:fi
rst
cong
esti
onco
llaps
e•
1988
:"C
onge
stio
n Av
oida
nce
and
Cont
rol"
(Jac
obso
n)Co
mbi
ned
cong
esti
on/f
low
con
trol
for
TCP
•G
oal:
stab
ility
-in
equi
libru
m,
no p
acke
tis
sen
t in
to t
he n
etw
ork
unti
lan
old
pack
etle
aves
–ac
k cl
ocki
ng,
“con
serv
atio
nof
pack
ets“
prin
cipl
e–
mad
e po
ssib
le t
hrou
gh w
indo
w b
ased
sto
p+go
-be
havi
our
•Su
perp
osit
ion
ofst
able
syst
ems
=st
able
netw
ork
base
don
TCP
wit
h co
nges
tion
con
trol
=st
able
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
99
TCP
Cong
esti
on
TCP
Cong
esti
on C
ontr
olCo
ntro
l/1
:/1
:Ta
hoe
Taho
e , 1
988
, 19
88
•D
isti
ngui
sh:
–fl
owco
ntro
l:pr
otec
t re
ceiv
erag
ains
t ov
erlo
ad(r
ecei
ver
"gra
nts"
ace
rtai
n am
ount
ofda
ta("
rece
iver
win
dow
") )
–co
nges
tion
con
trol
:pr
otec
t ne
twor
kag
ains
t ov
erlo
ad("
cong
esti
on w
indo
w"
(cw
nd)
limit
sth
e ra
te:
min
(cw
nd,r
wnd
) us
ed!
)
•Fl
ow/C
onge
stio
nCo
ntro
l com
bine
din
TCP
.Se
vera
l alg
orit
hms:
•(w
indo
w u
nit:
SM
SS=
Send
er M
axim
um S
egm
ent
Size
, us
ually
adju
sted
to
Path
MTU
; in
it c
wnd
=
ssth
resh
–Co
nges
tion
Avoi
danc
e:ea
chRT
T,in
crea
se c
wnd
by
SMSS
*SM
SS/c
wnd
(lin
ear
grow
th -
"add
itiv
e in
crea
se")
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1010
TCP
Cong
esti
onTC
P Co
nges
tion
Cont
rol
Cont
rol
/2/2
•If
a pa
cket
or a
ck is
lost
(t
imeo
ut,
roug
hly
4*rt
t),
set
cwnd
= 1,
ssth
resh
=cu
rren
t ba
ndw
idth
/ 2
(“m
ulti
plic
ativ
e de
crea
se")
-ex
pone
ntia
lbac
koff
•Se
vera
l tim
ers,
base
don
RT
T; g
ood
esti
mat
ion
is
cruc
ial!
•La
ter
addi
tion
s:(T
CP R
eno,
199
0)Fa
stre
tran
smit
/ fa
stre
cove
ry(n
otif
y se
nder
oflo
ss v
ia d
uplic
ate
acks
)
0123456789
12
34
56
78
910
1112
1314
1516
time
bandwidth
Timeo
ut
ssth
resh Sl
ow Start
Congestion
Avoidance
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1111
Use
r 1 A
lloca
tion
x1
Fairn
ess
Line
Effic
ienc
yLi
ne
User 2 Allocation x2
Sta
rting
Poi
nt
AIM
D
Des
irabl
e
Sta
rting
Poi
nt
AIAD
MIM
D Und
erlo
ad
Ove
rload
Use
r 1 A
lloca
tion
x1
Fairn
ess
Line
Effic
ienc
yLi
ne
User 2 Allocation x2
Sta
rting
Poi
nt
AIM
D
Des
irabl
e
Sta
rting
Poi
nt
AIAD
MIM
D Und
erlo
ad
Ove
rload
Back
grou
nd:
AIM
DBa
ckgr
ound
: A
IMD
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1212
Act
ive
Act
ive
Que
ue M
anag
emen
tQ
ueue
Man
agem
ent
•To
day,
TCP
beha
viou
r do
min
ates
the
Inte
rnet
(W
WW
, ..
)
•(s
omew
hat
old)
exa
mpl
e ba
ckbo
ne m
easu
rem
ent:
98%
TCP
traf
fic
•19
93:
Rand
om E
arly
Det
ecti
on("
Dis
card
", "
Dro
p")
(RED
)(n
ow t
hat
end
node
sba
ck o
ffas
pac
kets
are
dro
pped
,dr
oppa
cket
s ea
rlie
rto
avoi
dqu
eue
over
flow
s)
•An
othe
r go
al:
add
rand
omiz
atio
nto
avoi
d tr
affi
c ph
ase
effe
cts!
•Q
avg
= (1
-W
q) x
Qav
g+
Qin
stx
Wq
(Qav
g=
aver
age
occu
panc
y,Q
inst
=in
stan
tane
ous
occu
panc
y,W
q=
wei
ght
-ha
rdto
tun
e,de
term
ines
how
aggr
essi
ve R
EDbe
have
s)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1313
Act
ive
Act
ive
Que
ue M
anag
emen
t /2
Que
ue M
anag
emen
t /2
•Ba
sed
onex
pone
ntia
lly w
eigh
ted
mov
ing
aver
age
(EW
MA)
of
inst
anta
neou
s qu
eue
occu
panc
y=
low
pass
filt
er–
reca
lcul
ated
eve
ryti
me
a pa
cket
arri
ves
•Q
avg
belo
w t
hres
hold
min
_th:
Not
hing
hap
pens
•Q
avg
abov
e th
resh
old
min
_th:
Dro
ppr
obab
ility
ris
es li
near
ly•
Qav
gab
ove
thre
shol
d m
ax_t
h:D
rop
pack
ets
•RE
Dex
pect
sal
lflo
ws
tobe
have
like
TCP
-bu
t is
itfa
ir?
•Va
rian
ts:
drop
from
fron
t, d
rop
base
don
inst
anta
neou
s qu
eue
occu
panc
y, d
rop
arbi
trar
y pa
cket
s, d
rop
base
don
prio
riti
es..
.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1414
Expl
icit
Expl
icit
Cong
esti
onCo
nges
tion
Not
ific
atio
nN
otif
icat
ion
(ECN
)(E
CN)
•19
99:
Expl
icit
Cong
esti
onN
otif
icat
ion
(ECN
)In
stea
dof
drop
ping
,se
ta
bit
•En
d sy
stem
sar
e ex
pect
edto
act
as if
pack
et w
asdr
oppe
d⇒
actu
al c
omm
unic
atio
n be
twee
nen
dno
des
and
the
netw
ork!
•AT
M a
nd F
ram
eRe
lay:
not
only
ECN
but
also
BEC
N
•In
tern
et B
ECN
:of
ten
prop
osed
and
regu
larl
y di
scus
sed
(ICM
P SQ
),bu
t ve
ry u
nlik
ely
-se
vera
l rea
sons
•Ve
ry p
opul
ar a
mon
g re
sear
cher
s -
lots
of
idea
s to
exp
loit
the
bit
!
•EC
Nca
nnot
tot
ally
rep
lace
loss
mea
sure
men
ts!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1515
Prob
lem
sPr
oble
ms
( =
pote
ntia
l res
earc
h to
pics
)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1616
TCP
TCP
in h
eter
ogen
eous
env
iron
men
tsin
het
erog
eneo
us e
nvir
onm
ents
•TC
P ov
er n
oisy
link
s: p
robl
ems
wit
h „p
acke
t lo
ss =
con
gest
ion“
–w
asba
did
eain
tim
esof
erro
r-pr
one
netw
orks
–se
ems
reas
onab
lein
tim
esof
fibr
e ne
twor
ks–
real
ly b
ad f
orw
irel
ess
links
!
•TC
Pov
er“l
ong
fat
pipe
s“:
larg
e ba
ndw
idth
*del
ay p
rodu
ct–
long
tim
e to
reac
h eq
uilib
rium
, M
D =
prob
lem
atic
!
•TC
P in
hig
hly
asym
met
ric
netw
orks
:(e
.g.
dire
ct s
atel
lite
last
mile
)–
inco
min
g th
roug
hput
(hi
gh c
apac
ity
link)
lim
ited
by
rate
of
outg
oing
ACK
s(„
ACK
com
pres
sion
“)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1717
Fair
ness
Fair
ness
•AT
M A
BR:
Max
-Min
-fai
rnes
s–
“A (
..)
allo
cati
onof
rate
s is
max
-min
fai
rif
fan
incr
ease
ofan
yra
te (
..)
mus
t be
atth
e co
stof
ade
crea
seof
som
e al
read
y sm
alle
rra
te.“
–O
nere
sour
ce:
mat
hem
atic
al d
efin
itio
n sa
tisf
ies
"gen
eral
"un
ders
tand
ing
offa
irne
ss-
reso
urce
is d
ivid
ed e
qual
ly a
mon
g co
mpe
tito
rs–
Usu
ally
requ
ires
kno
wle
dge
offl
ows
inro
uter
s(s
wit
ches
) -
scal
abili
ty p
robl
em!
•In
tern
et:
–TC
P do
min
ant,
but
does
not
sat
isfy
Max
-Min
-fai
rnes
s cr
iter
ion!
–Ac
k-cl
ocke
d-
flow
s w
ith
shor
ter
RTT
reac
t so
oner
(slo
wst
art,
..)
and
achi
eve
bett
er r
esul
ts–
Ther
efor
e, In
tern
etde
fini
tion
offa
irne
ss:
TCP-
frie
ndlin
ess
"Afl
ow is
TCP-
com
pati
ble
(TCP
-fri
endl
y)if
, in
stea
dy s
tate
,it
use
sno
mor
e ba
ndw
idth
tha
na
conf
orm
ant
TCP
runn
ing
unde
r co
mpa
rabl
e co
ndit
ions
."
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1818
Issu
es w
ith
TCP
Issu
es w
ith
TCP
-- fri
endl
ines
sfr
iend
lines
s
•TC
P re
gula
rly
incr
ease
s th
e qu
eue
leng
than
d ca
uses
loss
⇒de
tect
con
gest
ion
whe
n it
is a
lrea
dy (
ECN
: al
mos
t) t
oo la
te!
–po
ssib
le t
o ha
vem
ore
thro
ughp
ut w
ith
smal
ler
queu
es a
nd le
ss lo
ss..
. bu
t: e
xcee
d ra
te o
f TC
P un
der
sim
ilar
cond
itio
ns ⇒
not
TCP-
frie
ndly
!
•W
hat
if I
send
mor
e th
an T
CP i
n th
e ab
senc
eof
com
peti
ng T
CP‘s
?–
can
such
a m
echa
nism
exi
st?
–ye
s! T
CP it
self
, w
ith
max
. w
indo
w s
ize
= ba
ndw
idth
* R
TT–
Doe
s th
is m
ean
that
TC
P is
not
TCP
-fri
endl
y?
•D
etai
ls m
issi
ng f
rom
the
def
init
ion:
–pa
ram
eter
s +
vers
ion
of „
conf
orm
ant
TCP“
–du
rati
on!
shor
t TC
P fl
ows
are
diff
eren
t th
an lo
ng o
nes
•TC
P-fr
iend
lines
s =
com
pati
bilit
y of
new
mec
hani
sms
wit
h ol
d m
echa
nism
–th
ere
was
res
earc
h si
nce
the
80‘s
! e.
g. n
ew k
now
ledg
e ab
out
netw
ork
mea
sure
men
ts
•TC
P ra
te d
epen
ds o
n RT
T -
how
doe
s th
is r
elat
e to
„fa
irne
ss“?
Does TCP-friendliness
hinder research?
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
1919
Prop
orti
onal
Fai
rnes
sPr
opor
tion
al F
airn
ess
Prop
orti
onal
fair
ness
:“A
nal
loca
tion
ofra
tes
xis
pro
port
iona
llyfa
irif
f,fo
r an
y ot
her
(..)
allo
cati
on
y,w
e ha
ve:
“
(rou
ghly
appr
oxim
ated
by
AIM
D!)
01
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2020
Cong
esti
on p
rici
ngCo
nges
tion
pri
cing
•Ba
sic
idea
:hi
gher
sen
ding
rat
e =
mor
e co
nges
tion
= h
ighe
r pr
ice
–Id
ea:
char
ge m
ore
whe
n EC
Nfl
ag is
set
•„S
mar
t“ M
arke
tid
ea:
–ea
ch p
acke
t bi
ds f
or c
apac
ity
–ou
t of
nbi
ds,
mhi
ghes
t bi
ds c
an b
e ac
cept
ed–
pric
e: „
mar
gina
l cos
t“ (
high
est
bid
of u
nacc
epte
d pa
cket
s)⇒
lead
s to
mar
ket
equi
libri
um
•„S
mar
t“ M
arke
t no
t pr
acti
cal (
bidd
ing
per
pack
et),
but
sho
ws:
–ba
lanc
e of
dem
and
and
supp
ly le
ads
to m
arke
t eq
uilib
rium
–st
able
sys
tem
jus
t ba
sed
on e
cono
mic
s su
ffic
es f
or c
onge
stio
n co
ntro
l
•Pr
oble
m:
link
cann
ot k
now
bid
s in
adv
ance
⇒no
QoS
guar
ante
es
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2121
End2
end
real
End2
end
real
-- tim
eti
me
data
tra
nsfe
rda
ta t
rans
fer
•As
sum
ptio
n: n
osp
ecia
l ser
vice
ava
ilabl
eat
appl
icat
ion
leve
l–
(Def
init
ion
of In
tern
et "
real
-tim
e"so
fter
than
usu
al)
•D
iffe
rent
requ
irem
ents
:–
relia
ble
serv
ice
may
not
be
need
ed(n
ore
tran
smis
sion
)–
Tim
ely
tran
smis
sion
impo
rtan
t
–D
iffe
rent
trea
tmen
t:–
nore
tran
smis
sion
/ w
aiti
ng f
or A
CKs
–no
slid
ing
win
dow
(sto
p +
go b
ehav
iour
not
sui
tabl
e)–
but:
–so
me
kind
offl
ow c
ontr
olst
illne
eded
–sy
nchr
oniz
atio
n ne
cess
ary
–of
ten:
Mul
tica
st
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2222
Mul
tim
edia
ada
ptat
ion
Mul
tim
edia
ada
ptat
ion
•M
ista
ke:
–ad
apta
tion
sch
emes
ass
ume
arbi
trar
y da
ta s
trea
m s
cala
bilit
y
•Pr
oble
m:
–D
ata
stre
ams
show
flu
ctua
tion
s (e
xam
ple:
MPE
G I-
, B-
, P-
fram
es)
•So
luti
on:
–Sp
ecia
l CBR
des
ign
for
com
mun
icat
ion
-H
.261
des
igne
d fo
r IS
DN
–no
t al
way
s fe
asib
le
•Pr
oble
m:
–co
mpr
essi
on u
sual
ly n
ot d
eter
min
isti
c -
size
dep
ends
on
cont
ent!
–re
al-l
ife
dist
ance
lear
ning
exa
mpl
e:40
kbps
eno
ugh
for
stre
amin
g vi
deo
(Sm
artb
oard
) +
audi
o (s
peec
h),
but
spee
ch s
uffe
rs d
ram
atic
ally
if t
each
er v
isib
le
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2323
Cong
esti
on C
ontr
ol a
nd Q
ualit
y of
Ser
vice
Cong
esti
on C
ontr
ol a
nd Q
ualit
y of
Ser
vice
•Q
ualit
y of
Ser
vice
(Q
oS):
prov
ide
diff
eren
tiat
ed q
ualit
y ba
sed
on $
$$
•Q
uest
ions
:–
is a
flu
id lo
w-q
ualit
y vi
deo
bett
er t
han
a bu
ckin
g hi
gh-q
ualit
y vi
deo?
–an
d w
hat
abou
t au
dio?
•Sc
alab
le Q
oS =
no
per-
flow
gua
rant
ees
–st
anda
rd a
rchi
tect
ure:
Dif
fere
ntia
ted
Serv
ices
(D
iffS
erv)
plac
es u
sers
in f
low
agg
rega
tes
–co
nges
tion
con
trol
sti
ll ne
cess
ary
wit
hin
an a
ggre
gate
⇒pe
r-fl
ow Q
oS d
epen
ds o
n co
nges
tion
con
trol
mec
hani
sm!
–H
ow d
oes
a co
nges
tion
con
trol
mec
hani
sm in
tera
ct w
ith
QoS
ele
men
ts?
e.g.
TCP
kno
wn
to b
e a
bad
mat
ch f
or t
oken
buc
ket
...modest QoS with adaptive
multimedia? -
still unresolved!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2424
Spec
ial t
ypes
of
traf
fic
Spec
ial t
ypes
of
traf
fic
•G
rid:
pre
dict
able
tra
ffic
pat
tern
–Th
is is
tot
ally
new
to
the
Inte
rnet
!•
Web
: us
ers
crea
te t
raff
ic•
FTP
dow
nloa
d: s
tart
s ..
. en
ds•
Stre
amin
g vi
deo:
eit
her
CBR
or d
epen
ds o
n co
nten
t! (
head
mov
emen
t, .
.)
•Sp
ecia
l req
uire
men
ts a
nd p
rope
rtie
s–
may
req
uire
del
ay b
ound
s or
min
imum
ban
dwid
th–
mix
ture
of
spor
adic
(RP
C ty
pe)
mes
sage
s an
d bu
lk d
ata
tran
sfer
•Re
late
d: s
igna
ling
traf
fic
–us
ually
not
a la
rge
amou
nt o
f da
ta–
to d
ate,
no
seri
ous
effo
rts
for
tailo
red
cong
esti
on c
ontr
ol(S
CTP
= tr
ansp
ort
prot
ocol
des
igne
d fo
r si
gnal
ing;
con
gest
ion
cont
rol=
si
mila
r to
TCP
)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2525
Som
e re
ason
s fo
r TC
P st
abili
tySo
me
reas
ons
for
TCP
stab
ility
“Con
gest
ion
Avoi
danc
e an
d Co
ntro
l“,
Van
Jaco
bson
, SI
GCO
MM
‘88:
•Ex
pone
ntia
l bac
koff
:“F
or a
tra
nspo
rt e
ndpo
int
embe
dded
in a
net
wor
k of
unk
now
n to
polo
gy a
nd w
ith
an u
nkno
wn,
unk
now
able
and
con
stan
tly
chan
ging
popu
lati
on o
f co
mpe
ting
con
vers
atio
ns,
only
one
sch
eme
has
any
hope
of
wor
king
-ex
pone
ntia
l bac
koff
-bu
t a
proo
f of
thi
s is
bey
ond
the
scop
e of
thi
s pa
per.
“
•Co
nser
vati
on o
f pa
cket
s:“T
he p
hysi
cs o
f fl
ow p
redi
cts
that
sys
tem
s w
ith
this
pro
pert
y sh
ould
be
rob
ust
in t
he f
ace
of c
onge
stio
n.“
•Ad
diti
ve In
crea
se,
Mul
tipl
icat
ive
Dec
reas
e:N
ot e
xplic
itel
y ci
ted
as a
sta
bilit
y re
ason
in t
he p
aper
!–
...b
ut in
100
0‘s
of o
ther
pap
ers!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2626
“Pro
ofs“
of
TCP
stab
ility
“Pro
ofs“
of
TCP
stab
ility
•AI
MD
:Ch
iu/J
ain:
dia
gram
+ a
lgeb
raic
pro
of o
f ho
mog
eneo
us R
TT c
ase
•st
eady
-sta
te T
CP m
odel
: w
indo
w s
ize
~ 1/
sqrt
(p)
(p =
pac
ket
loss
)
•Jo
hari
/Tan
, M
asso
ulié
, ..
:–
loca
lsta
bilit
y, n
egle
ct d
etai
ls o
f TC
P be
havi
our
(flu
id f
low
mod
el,
..)
–as
sum
ptio
n:“q
ueue
ing
dela
ys w
ill e
vent
ually
bec
ome
smal
l rel
ativ
e to
pro
paga
tion
del
ays“
•St
even
Low
:–
Dua
lity
mod
el (
base
d on
uti
lity
func
tion
/ F
. Ke
lly,
..):
Stab
ility
dep
ends
on
dela
y, c
apac
ity,
load
and
AQ
M !
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2727
Uni
cast
/ B
road
cast
/ (
over
lay)
Mul
tica
stU
nica
st /
Bro
adca
st /
(ov
erla
y) M
ulti
cast
1 Sender
2 Receivers
SRR
Unicast
SRR
Broadcast
SRR
Overlay Multicast
SRR
IP Multicast
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2828
Mul
tica
st is
sues
Mul
tica
st is
sues
•Re
quir
ed f
or a
pplic
atio
ns w
ith
mul
tipl
e re
ceiv
ers
only
–vi
deo
conf
eren
ces,
rea
l-ti
me
data
str
eam
tra
nsm
issi
on,
..⇒
diff
eren
t da
ta s
trea
ms
than
web
sur
fing
, ft
p do
wnl
oads
etc
!
•Is
sues
:–
grou
p m
anag
emen
t•
prot
ocol
req
uire
d to
joi
n /
leav
e gr
oup
dyna
mic
ally
:In
tern
et G
roup
Man
agem
ent
Prot
ocol
(IG
MP)
•st
ate
in r
oute
rs:
hard
/ s
oft
(los
t un
less
ref
resh
ed)?
•w
ho in
itia
tes
/ co
ntro
ls g
roup
mem
bers
hip?
–co
nges
tion
con
trol
•sc
alab
ility
(ACK
impl
osio
n)•
deal
ing
wit
hhe
tero
gene
ity
of r
ecei
ver
grou
ps•
fair
ness
•M
ulti
cast
con
gest
ion
cont
rol m
echa
nism
cla
ssif
icat
ion:
–se
nder
-vs
. re
ceiv
er-b
ased
, si
ngle
-rat
e vs
. m
ulti
-rat
e (l
ayer
ed),
–re
liabl
e vs
. un
relia
ble,
end
-to-
end
vs.
netw
ork-
supp
orte
d
depends on
content!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
2929
Som
e pr
opos
ed e
nhan
cem
ents
Som
e pr
opos
ed e
nhan
cem
ents
Rese
arch
by
othe
rs
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3030
Inte
rnet
Inte
rnet
traf
fic
char
acte
rist
ics
traf
fic
char
acte
rist
ics
•M
RTG
trac
e(b
ased
on S
NM
P,ac
cess
ing
traf
fic
coun
ters
in M
IB)
http
://w
ww
.switc
h.ch
/lan/
stat
/pee
rings
/link
eune
t.htm
l, 11
. 10.
99,
13:
05
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3131
Inte
rnet
Inte
rnet
traf
fic
char
acte
rist
ics
traf
fic
char
acte
rist
ics
/2/2
•Tr
adit
iona
ltra
ffic
mod
ellin
g:qu
euin
g th
eory
noti
on:
traf
fic
follo
ws
pois
son
dist
ribu
tion
•In
tern
ettr
affi
c is
bur
sty
-in
tuit
ive
reas
ons:
–TC
Pis
bur
sty
byna
ture
:co
nges
tion
avoi
danc
e,pa
yloa
d vs
.ac
ks…
–AC
Kco
mpr
essi
on c
anca
use
payl
oad
burs
ts d
ueto
ACK
-clo
ckin
g (l
ater
!)
–va
riou
spa
cket
size
s
–Bu
rsts
fro
m q
ueue
s ag
greg
ate
as t
raff
ictr
aver
ses
the
net
–Bu
rsti
ness
ofon
e fl
ow a
ffec
ts o
ther
adap
tive
flow
s
Still true
for user
arrival !
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3232
Inte
rnet
Inte
rnet
traf
fic
char
acte
rist
ics
traf
fic
char
acte
rist
ics
/3/3
•O
verl
appi
ngof
inde
pend
ent
on-o
ffso
urce
s le
ads
todi
stri
buti
on w
ith
heav
y-ta
iled
auto
corr
elat
ion
func
tion
•Lo
ng-r
ange
dep
enda
nce:
"pe
aks
sit
onri
pple
sw
hich
sit
onw
aves
"
•N
o "f
latt
enin
g"to
war
dsa
mea
n as
you
zoom
out
-sa
me
stru
ctur
es
may
be
foun
dat
dif
fere
nt t
ime
scal
es,
henc
e se
lf s
imila
r
•ch
arac
teri
stic
sm
odel
edw
ith
tim
ese
ries
(fAR
IMA
mod
els)
or w
avel
ets
–M
easu
rem
ent
ofth
e"d
egre
eof
self
sim
ilari
ty":
Hur
stpa
ram
eter
–⇒
mod
elap
prox
imat
ion
invo
lves
Hur
stpa
ram
eter
est
imat
ion
•TC
P kn
own
to p
ropa
gate
bot
tlen
eck
self
-sim
ilari
tyto
end
sys
tem
–po
ssib
ility
: us
e m
odel
to
pred
ict
traf
fic
inst
ead
of g
uess
ing
–qu
esti
on:
scal
abili
ty(w
hat
if e
very
body
doe
s th
is?)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3333
How
How
totobebe
TCP
TCP
-- fri
endl
yfr
iend
ly
•TC
P-fr
iend
lines
s ca
n be
ach
ieve
d by
em
ulat
ing
the
beha
viou
rof
TCP
(or
the
des
ired
par
tsof
it)
•Si
mpl
ifie
dTC
P: A
IMD
(add
itiv
e in
cr. α
,m
ulti
plic
ativ
e de
cr. β)
–0
< α
, 0
< β
< 1
->st
able
and
fair
cong
esti
on c
ontr
ol–α
= 4
x (1
-β^
2) /
3->
TCP
-fri
endl
y co
nges
tion
con
trol
(G
AIM
D)
–α
= 1,
β
= 1/
2->
TCP
•AI
MD
mec
hani
sms
for
mul
tim
edia
app
licat
ions
: RA
P, L
DA+
•D
iffe
rent
appr
oach
es:
–TC
PEm
ulat
ion
At R
ecei
vers
(TE
AR)
TCP
calc
ulat
ions
(cw
nd c
alcu
lati
on,
fast
reco
very
, ..
.)m
oved
tore
ceiv
er,
dono
t ac
k ev
ery
pack
et,
smoo
th s
endi
ngra
te–
Bino
mia
l con
gest
ion
cont
rol:
gene
raliz
atio
n of
GAI
MD
wit
h no
nlin
ear
cont
rol
–CY
RF f
ram
ewor
k:ge
nera
lizat
ion
of b
inom
ial c
onge
stio
n co
ntro
l
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3434
GA
IMD
GA
IMD
cong
esti
on c
ontr
olco
nges
tion
con
trol
Rela
tion
ship
bet
wee
nα
and β
for
TCP-
frie
ndlin
ess:
00,
20,
40,
60,
811,
21,
4
00,
10,
20,
30,
40,
50,
60,
70,
80,
91
beta
alpha
TCP
smoo
ther
mor
eag
gres
sive
+re
spon
sive
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3535
Equa
tion
bas
ed c
onge
stio
n co
ntro
lEq
uati
on b
ased
con
gest
ion
cont
rol
•Ba
sed
on T
CPst
eady
-sta
te r
espo
nse
func
tion
-gi
ves
uppe
r bo
und
for
tran
smis
sion
rate
T (
byte
s/se
c):
)32
1()
833(
322 p
pp
tp
R
sT
RTO
++
=
)32
1()
833(
322 p
pp
tp
R
sT
RTO
++
=
s: p
acke
tsi
zeR:
rtt
t RTO
: TCP
retr
ansm
it t
imeo
utp:
stea
dy-s
tate
loss
eve
ntra
te (t
he d
iffi
cult
par
t!)
•w
ellk
now
n ex
ampl
e: T
FRC
-TC
P-fr
iend
lyra
teco
ntro
l pro
toco
l–
smoo
th s
endi
ngra
te
•Ex
tens
ion:
TFM
CC -
TCP-
frie
ndly
mul
tica
st c
onge
stio
n co
ntro
l
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3636
Not
Not
-- soso-- T
CPTC
P-- f
rien
dly
solu
tion
sfr
iend
ly s
olut
ions
•O
verc
ome
rate
flu
ctua
tion
s:lim
it e
ncod
ings
(e.
g. 2
or
3 qu
alit
ies)
, le
t us
er d
ecid
e
•Cr
oss-
med
ia-a
dapt
atio
n:ch
oose
fro
m v
ideo
, au
dio,
sin
gle
pict
ures
, te
xt(e
.g.
MPE
G7)
•Li
mit
by
bott
lene
ck b
andw
idth
–of
ten:
"la
st m
ile"
-e.
g. R
ealM
edia
–be
tter
: de
term
ine
actu
al b
ottl
enec
k vi
a pa
cket
pai
r ap
proa
ch
•If
wir
eles
s lin
kin
volv
ed:
smal
l pac
kets
, U
DP
Lite
•An
othe
r po
ssib
ility
:se
nd m
ore
(do
FEC)
in r
espo
nse
to p
acke
t lo
ss–
(ver
y ne
twor
k-un
frie
ndly
beh
avio
ur,
but
may
yie
ld le
ss d
ata
loss
)
Network stability: some
adaptation better than none!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3737
Som
e th
ough
tsSo
me
thou
ghts
•H
ow T
CP-f
rien
dly
are
8 w
eb b
row
sers
?–
Cong
esti
on M
anag
er:
cong
esti
on c
ontr
ol f
or a
ll fl
ows
in O
S co
re–
Mul
TCP:
Em
ulat
e m
ulti
ple
TCP‘
s to
pro
vide
dif
fere
ntia
ted
serv
ices
•H
ow T
CP-f
rien
dly
are
shor
t-liv
ed f
low
s? (
web
-tra
ffic
, ..
)
•H
ow t
o co
nvin
ce In
tern
et m
ulti
med
ia a
pp.
prog
ram
mer
s to
im
plem
ent
TCP-
frie
ndly
con
gest
ion
cont
rol?
•So
luti
on:
Dat
agra
m C
onge
stio
n Co
ntro
l Pro
toco
l (D
CCP)
–W
ell-
defi
ned
fram
ewor
k fo
r (T
CP-f
rien
dly)
con
gest
ion
cont
rol
–Se
nder
app
cho
oses
an
appr
opri
ate
cong
esti
on c
ontr
ol m
echa
nism
–Co
re O
S im
plem
enta
tion
of
mec
hani
sms
–Lo
ts o
f ad
diti
onal
fea
ture
s: n
once
s, p
arti
al /
sep
arat
e ch
ecks
ums
(dis
ting
uish
: co
rrup
tion
⇔co
nges
tion
), .
..
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3838
Het
erog
eneo
us e
nvir
onm
ents
Het
erog
eneo
us e
nvir
onm
ents
TCP
over
hig
h sp
eed
links
:
•la
rger
init
ial w
indo
w /
win
dow
sca
ling
opti
on,
TCP
SACK
•Sc
alab
le T
CP:
incr
ease
/dec
reas
e fu
ncti
ons
chan
ged
(pro
bing
tim
es p
ropo
rtio
nal t
o rt
t bu
t no
t ra
te)
•H
ighS
peed
TCP
(mer
ged
wit
h Sc
alab
le T
CP):
resp
onse
fun
ctio
n le
ss d
rast
ic in
hig
h ba
ndw
idth
env
iron
men
ts o
nly
•Q
uick
-Sta
rt:
quer
y ro
uter
s fo
r in
itia
l sen
ding
rat
e w
ith
IP o
ptio
nsdr
aft
only
-se
ems
to b
e ab
ando
ned?
!
TCP
over
asy
mm
etri
c lin
ks:
•AC
K su
ppre
ssio
n, A
CK c
ompa
ctio
n, T
CP h
eade
r co
mpr
essi
on
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
3939
TCP
over
noi
sy (
wir
eles
s) li
nks
TCP
over
noi
sy (
wir
eles
s) li
nks
•Va
riou
s po
ssib
le e
nhan
cem
ents
:–
split
con
nect
ion
at b
ase
stat
ion
–m
onit
or c
onne
ctio
n at
bas
e st
atio
n, b
uffe
r +
inte
rfer
e (“
Snoo
p TC
P”)
•N
ote:
ECN
is n
ot a
ffec
ted
by li
nk n
oise
!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4040
Beyo
nd E
CNBe
yond
ECN
•AT
M:
Expl
icit
Rat
e Fe
edba
ck(p
art
of A
vaila
ble
Bit
Rate
(AB
R)se
rvic
e)RM
(re
sour
ce m
anag
emen
t) c
ells
:–
sent
by
send
er,
inte
rspe
rsed
wit
h da
ta c
ells
; bi
ts in
RM
cel
l set
by
swit
ches
•
NI b
it:
no in
crea
se in
rat
e (m
ild c
onge
stio
n),
(EF)
CI b
it:
like
Inte
rnet
ECN
•tw
o-by
te E
R (e
xplic
it r
ate)
fie
ld:
may
be
low
ered
by
cong
este
d sw
itch
•se
nder
’ se
nd r
ate
thus
min
imum
sup
port
able
rat
e on
pat
h!
•Pr
oble
m:
ATM
fai
led
(sca
labi
lity?
too
muc
h co
mpl
exit
y in
sw
itch
es?)
•Ex
peri
men
tal I
nter
net
appr
oach
es:
•M
ulti
leve
l ECN
(tw
o bi
ts),
eXp
ress
Con
trol
Pro
toco
l (XC
P),
CAD
PC/P
TP(m
y ow
n)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4141
Oth
er T
CP e
nhan
cem
ents
Oth
er T
CP e
nhan
cem
ents
•FA
ST T
CP–
Vari
ant
base
d on
win
dow
and
del
ay–
Del
ay a
llow
s fo
r ea
rlie
r ad
apta
tion
(aw
aren
ess
of g
row
ing
queu
e)–
Prov
en t
o be
sta
ble
–Co
mm
erci
ally
ann
ounc
ed +
pat
ent
prot
ecte
d, b
y St
even
Low
‘s C
alTe
ch g
roup
–an
othe
r de
lay-
base
d ex
ampl
e: T
CP V
egas
•TC
P W
estw
ood
–di
ffer
ent
resp
onse
fun
ctio
n (p
ropo
rtio
nal t
o ra
te)
–pr
oven
to
be s
tabl
e
•Lo
ts o
f ex
peri
men
tal A
ctiv
e Q
ueue
Man
agem
ent
sche
mes
out
the
re–
Adap
tive
RED
, BL
UE,
REM
, RI
O e
tc.
etc.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4242
How
to
desi
gn y
our
own
mec
hani
smH
ow t
o de
sign
you
r ow
n m
echa
nism
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4343
End
syst
ems:
Mea
sure
...
End
syst
ems:
Mea
sure
...
++w
ell s
tudi
ed
-- lea
ds t
o m
isin
terp
reta
tion
of t
rans
mis
sion
err
ors
thro
ughp
ut("
good
put"
)(
mea
n, f
luct
uati
ons,
pack
et lo
ss r
atio
..)
++ea
sy t
o m
easu
re
++in
depe
nden
t of
tra
nsm
issi
on e
rror
s
-- not
pra
ctic
al w
itho
ut t
hrou
ghpu
t
dela
y(
rtt,
one
way
del
ay,
jitt
er..
)
sim
ilar
dela
y, d
iffe
rent
av
aila
ble
band
wid
th!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4444
...
and
chan
ge!
...
and
chan
ge!
•lo
wer
laye
rs–
thro
ughp
ut(g
ap b
etw
een
pack
ets)
•w
indo
w b
ased
/ r
ate
base
d•
wel
l stu
died
, m
any
opti
ons
-ou
r m
ain
inte
rest
!–
pack
et s
ize
•la
rge:
rec
omm
ende
dle
ss o
verh
ead
•sm
all:
less
impa
ct o
f tr
ansm
issi
on e
rror
s,sm
alle
r la
tenc
y!–
prot
ocol
Not
e:
Not
e: p
acke
t si
ze =
gra
nula
rity
of
thro
ughp
ut m
easu
rem
ents
•co
nten
t–
com
pres
sion
–hi
erar
chic
al e
ncod
ing
–FE
C
Com
mon
dif
ficu
ltie
s:Co
mm
on d
iffi
cult
ies:
band
wid
th k
now
n (d
epen
ding
on
cont
ent)
?gr
anul
arit
y of
rat
e ch
ange
s
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4545
Mea
suri
ng t
he n
etw
ork
Mea
suri
ng t
he n
etw
ork
•W
hen
you
mea
sure
, yo
u m
easu
re t
he p
ast
–pr
edic
tion
s /
esti
mat
ions
wit
h a
?? %
cha
nce
of s
ucce
ss o
r co
ntro
l the
ory
•W
hen
you
mea
sure
, yo
u ch
ange
the
sys
tem
–th
ink
of u
nres
pons
ive
flow
s vs
. TC
P–
non-
intr
usiv
enes
s re
ally
impo
rtan
t (e
.g.,
mon
itor
TCP
beh
avio
r)
•M
easu
rem
ents
yie
ld n
o gu
aran
tees
–In
tern
et t
raff
ic =
res
ult
of u
ser
beha
vior
!
•Re
sear
ch c
arri
ed o
ut in
con
trol
labl
e, is
olat
ed e
nvir
onm
ents
–Fi
eld
tria
ls a
re a
nec
essa
ry e
xtra
whe
n yo
u kn
ow t
hat
som
ethi
ng w
orks
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4646
Poss
ibili
ties
in r
oute
rsPo
ssib
iliti
es in
rou
ters
•Co
mm
unic
ate
wit
h en
d sy
stem
s–
alte
r he
ader
fla
gs (
IP o
nly!
sho
uld
not
look
at
othe
r la
yers
)–
gene
rate
sig
nalin
g pa
cket
s: In
tern
et C
ontr
ol M
essa
ge P
roto
col (
ICM
P)(m
ainl
y er
ror
mes
sage
s)
•Co
ntro
l pac
kets
in q
ueue
s:us
e qu
eue
leng
th o
r po
siti
on in
que
ue t
o–
com
mun
icat
e („
mar
k“)
–dr
op,
mov
e to
oth
er q
ueue
etc
.
•Pr
oble
ms
–CP
U c
ycle
s sc
arce
in (
core
) In
tern
et r
oute
rs–
Scal
abili
ty!
(e.g
., n
o pe
r-fl
ow s
tate
)ex
ampl
e: IC
MP
Sour
ce Q
uenc
h fa
iled
(con
gest
ion
noti
fica
tion
in t
imes
of
cong
esti
on)
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4747
My
Ph.D
. re
cipe
:
My
Ph.D
. re
cipe
: --
))
Und
erly
ing
thou
ght:
“TCP
alw
ays
exce
eds
the
avai
labl
e ba
ndw
idth
in
orde
r to
det
ect
it
(whe
n it
is
alre
ady
too
late
). W
ould
n‘t
it b
e be
tter
to
ask
for
the
avai
labl
e ba
ndw
idth
?“
Proc
ess:
•de
sign
suc
h a
mea
ns:
“Per
form
ance
Tra
nspa
renc
y Pr
otoc
ol (
PTP)
“–
note
:m
ust
lead
to
abso
lute
ly g
reat
res
ults
in o
rder
to
just
ify
rout
er e
ffor
t!
•fi
nd o
ut h
ow t
o us
e th
e (a
vaila
ble
band
wid
th)
info
rmat
ion
...w
itho
ut b
eing
a c
ontr
ol t
heor
y gu
ru!
⇒th
e tr
icky
par
t!
•m
ixtu
re o
f in
tuit
ion,
mat
hs,
sim
ulat
ion,
..
Let‘s look
at this!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4848
Exte
nded
Use
of
Vect
or D
iagr
ams
Exte
nded
Use
of
Vect
or D
iagr
ams
•Pr
oble
m:
–St
abili
ty a
naly
sis
com
plex
–TC
P-lik
e m
echa
nism
des
ign
diff
icul
t
•So
luti
on:
–Ex
tend
ed u
se o
f ve
ctor
dia
gram
s!
•An
alyz
e ac
tual
res
ults
(fr
om s
imul
atio
n or
rea
l lif
e m
easu
rem
ents
)
•In
stea
d of
jus
t ex
plai
ning
a c
once
pt,
desi
gnin
the
2D
dia
gram
spa
ce!
–N
eces
sary
sim
plif
icat
ions
may
eve
n be
les
sdr
amat
ic!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
4949
How
Sta
ble
is A
IMD
/ a
sync
. RT
T?H
ow S
tabl
e is
AIM
D /
asy
nc.
RTT?
U 2
SER
Use
r 1
-0.0
500
0.00
00
0.05
00
0.10
00
0.15
00
0.20
00
0.25
00
0.30
00
0.35
00
0.40
00
0.45
00
0.50
00
0.55
00
0.60
00
0.65
00
0.70
00
0.75
00
0.80
00
0.85
00
0.90
00
0.95
00
1.00
00
0.00
000.
2000
0.40
000.
6000
0.80
001.
0000
Fluid model
(no queues, ..)
RTT: 7 vs. 2
AI=0.1, MD=0.5
Sim. time=175
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5050
Is A
IMD
dis
tort
ed in
TCP
?Is
AIM
D d
isto
rted
in T
CP?
TCP 2
TC
P 1
1.00
00
1.50
00
2.00
00
2.50
00
3.00
00
3.50
00
4.00
00
4.50
00
5.00
00
5.50
00
6.00
00
6.50
00
7.00
00
7.50
00
8.00
00
8.50
00
9.00
00
9.50
00
10.0
000
2.00
004.
0000
6.00
008.
0000
10.0
000
12.0
000
14.0
000
ns-2 simulator
TCP Tahoe
equal RTTs
1 bottleneck link
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5151
Vari
ous
othe
r Po
ssib
iliti
esVa
riou
s ot
her
Poss
ibili
ties
•An
alyz
e re
al li
fe d
ata
•An
alyz
e di
ffer
ent
mec
hani
sms
–m
ore
com
plex
fee
dbac
k: A
TM A
BR–
queu
eing
beh
avio
ur:
AQM
–..
.
•Pe
rfor
m a
naly
sis
in v
ecto
r di
agra
m s
pace
–pl
ot “
dist
ance
fro
m o
ptim
alit
y“ /
tim
e de
velo
pmen
t–
plot
tim
e of
con
verg
ence
/ u
ser
1 al
loca
tion
–..
.
•..
. ve
ctor
dia
gram
aid
ed d
esig
n!
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5252
Inte
ract
ive
Vect
or D
iagr
am A
ided
Des
ign
Inte
ract
ive
Vect
or D
iagr
am A
ided
Des
ign
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5353
A f
oolp
roof
Ph.
D.
thes
is r
ecip
eA
foo
lpro
of P
h.D
. th
esis
rec
ipe
•Ro
ughl
y fo
llow
thi
s ta
ble
from
1 t
o 7
...
if s
omet
hing
fai
ls,
goba
ck!
•In
my
case
:–
Leve
l 2:
intu
itio
n (f
oolin
g ar
ound
wit
h C
AVT)
–Le
vel 4
:th
e “H
eure
ka“
expe
rien
ce -
intu
itio
n w
as r
ight
!–
Leve
l 1:
shee
t of
pap
er–
Leve
l 3:
MS
Exce
l + C
AVT
refi
nem
ent
(foo
ling
arou
nd,
part
2)
–Le
vel 5
:th
e ty
pica
l ns
+ du
mbb
ell e
xper
ienc
e–
Leve
l 6:
addi
tion
al s
imul
atio
ns–
...
that
was
goo
d en
ough
. H
opin
g to
rea
ch le
vel 7
soo
n.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5454
Even
tual
ly:
CAD
PCEv
entu
ally
: CA
DPC
vs.
TCP
vs.
TCP
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5555
CAD
PC v
s. 3
TCP
(+EC
N)
CAD
PC v
s. 3
TCP
(+EC
N)
flav
ors
flav
ors
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5656
Refe
renc
esRe
fere
nces
1. C
onge
stio
n Co
ntro
l: a
qui
ck in
trod
ucti
on
•Ra
j Ja
in a
nd K
. K.
Ram
akri
shna
n, "
Cong
esti
on A
void
ance
in C
ompu
ter
Net
wor
ks w
ith
a Co
nnec
tion
less
Net
wor
k La
yer:
Con
cept
s, G
oals
and
Met
hodo
logy
'',Pr
ocee
ding
s of
Com
pute
r N
etw
orki
ng S
ympo
sium
, W
ashi
ngto
n, D
. C.
, Ap
ril 1
1-13
198
8, p
p. 1
34-1
43.
•Va
n Ja
cobs
on,
"Con
gest
ion
Avoi
danc
e an
d Co
ntro
l'',
Proc
eedi
ngs
of A
CM S
IGCO
MM
198
8, p
p. 3
14-
329.
•D
. Ch
iu a
nd R
. Ja
in,
"Ana
lysi
s of
the
Incr
ease
/Dec
reas
e Al
gori
thm
s fo
r Co
nges
tion
Avo
idan
ce in
Co
mpu
ter
Net
wor
ks'',
Jou
rnal
of
Com
pute
r N
etw
orks
and
ISD
N,
Vol.
17,
No.
1,
June
198
9, p
p. 1
-14.
•Sa
lly F
loyd
and
Van
Jac
obso
n, "
On
Traf
fic
Phas
e Ef
fect
s in
Pac
ket-
Swit
ched
Gat
eway
s'',
Inte
rnet
wor
king
: Re
sear
ch a
nd E
xper
ienc
e, V
.3 N
.3,
Sept
embe
r 19
92,
p.11
5-15
6. E
arlie
r ve
rsio
n:
Com
pute
r Co
mm
unic
atio
n Re
view
, V.
21 N
.2,
Apri
l 199
1.
•Sa
lly F
loyd
and
Van
Jac
obso
n, "
Rand
om E
arly
Det
ecti
on G
atew
ays
for
Cong
esti
on A
void
ance
'',
IEEE
/ACM
Tra
nsac
tion
s on
Net
wor
king
, Au
gust
199
3.
•K.
Ram
akri
shna
n, S
. Fl
oyd,
and
D.
Blac
k, "
The
Addi
tion
of
Expl
icit
Con
gest
ion
Not
ific
atio
n (E
CN)
to
IP'',
RFC
316
8, S
epte
mbe
r 20
01.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5757
Refe
renc
es /
2Re
fere
nces
/2
2. P
robl
ems
•Sc
ott
Shen
ker,
"Fu
ndam
enta
l D
esig
n Is
sues
for
the
Fut
ure
Inte
rnet
'', IE
EE J
ourn
al o
n Se
lect
ed A
reas
in
Com
mun
icat
ions
, 13
, pp
. 11
41-1
149,
199
5.
•Fr
ank
Kelly
, "C
harg
ing
and
rate
con
trol
for
ela
stic
tra
ffic
'', E
urop
ean
Tran
sact
ions
on
Tele
com
mun
icat
ions
, 8.
pp.
33-
37.
An u
pdat
ed v
ersi
on is
ava
ilabl
e at
ht
tp:/
/ww
w.s
tats
lab.
cam
.ac.
uk/f
rank
/ela
stic
.htm
l
•Ra
mes
h Jo
hari
, "M
athe
mat
ical
Mod
elin
g an
d Co
ntro
l of
Inte
rnet
Con
gest
ion"
, SI
AM N
ews,
Vol
. 33
, N
o. 2
.
•L.
Mas
soul
ié a
nd J
. Ro
bert
s, "
Band
wid
th s
hari
ng:
obje
ctiv
es a
nd a
lgor
ithm
s'',
Proc
eedi
ngs
of IE
EE
Info
com
199
9, N
ew Y
ork
City
, N
ew Y
ork,
21.
-25.
3.
1999
.
•Ra
mes
h Jo
hari
and
Dav
id T
an,
"End
-to-
End
Cong
esti
on C
ontr
ol f
or t
he In
tern
et:
Del
ays
and
Stab
ility
'', IE
EE/A
CM T
rans
acti
ons
on N
etw
orki
ng 9
(20
01)
818-
832.
•As
hraf
Mat
raw
y an
d Io
anni
s La
bada
ris,
"A
Surv
ey o
f Co
nges
iton
Con
trol
Sch
emes
for
Mul
tica
st V
ideo
Ap
plic
atio
ns",
IEEE
Com
mun
icat
ions
Sur
vey
& T
utor
ials
, Fo
urth
Qua
rter
200
3, V
ol.
5, N
o. 2
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5858
Refe
renc
es /
3Re
fere
nces
/3
3. S
ome
prop
osed
enh
ance
men
ts
•M
ark
E. C
rove
lla a
nd A
zer
Best
avro
s, ''
Self
-sim
ilari
ty in
Wor
ld W
ide
Web
Tra
ffic
: Ev
iden
ce a
nd
Poss
ible
Cau
ses''
, IE
EE/A
CM T
rans
acti
ons
on N
etw
orki
ng,
Vol.
5,
No.
6,
Dec
embe
r 19
97.
•An
dras
Ver
es,
Zsol
t Ke
nesi
, Sa
ndor
Mol
nar,
Gab
or V
atta
y, ''
On
the
Prop
agat
ion
of L
ong-
rang
e D
epen
denc
y in
the
Inte
rnet
'', P
roce
edin
gs o
f AC
M S
IGCO
MM
200
0, S
tock
holm
, Sw
eden
, Au
gust
28
-Se
ptem
ber
1 20
00.
•G
uang
hui H
e, Y
uan
Gao
, Je
nnif
er C
. H
ou,
Kiho
ng P
ark,
''A
Case
for
Exp
loit
ing
Self
-Sim
ilari
ty o
f N
etw
ork
Traf
fic
in T
CP'',
10t
h IE
EE In
tern
atio
nal C
onfe
renc
e on
Net
wor
k Pr
otoc
ols
(ICN
P'02
), P
aris
, Fr
ance
, N
ov.
12-1
5, 2
002.
•Jö
rg W
idm
er,
Robe
rt D
enda
, an
d M
arti
n M
auve
, "A
Sur
vey
on T
CP-F
rien
dly
Cong
esti
on C
ontr
ol'',
IE
EE N
etw
ork
Mag
azin
e, S
peci
al Is
sue
"Con
trol
of
Best
Eff
ort
Traf
fic'
' Vol
. 15
, N
o. 3
, M
ay 2
001.
•Ph
ilipp
e O
echs
lin a
nd J
on C
row
crof
t, "
Dif
fere
ntia
ted
End-
to-E
nd In
tern
et S
ervi
ces
usin
g a
Wei
ghte
d Pr
opor
tion
al F
air
Shar
ing
TCP"
, AC
M C
ompu
ter
Com
mun
icat
ion
Revi
ew (
CCR)
, 19
98.
•H
ari B
alak
rish
nan,
Har
ihar
an R
ahul
, an
d Sr
iniv
asan
Ses
han,
"An
Inte
grat
ed C
onge
stio
n M
anag
emen
t Ar
chit
ectu
re f
or In
tern
et H
osts
'', P
roce
edin
gs o
f AC
M S
IGCO
MM
199
9, C
ambr
idge
, M
A.,
Sept
embe
r 19
99.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
5959
Refe
renc
es /
4Re
fere
nces
/4
•H
. Ba
lakr
ishn
an a
nd S
. Se
shan
, "T
he C
onge
stio
n M
anag
er'',
RFC
312
4, J
une
2001
.
•Ed
die
Kohl
er,
Mar
k H
andl
ey,
Sally
Flo
yd,
and
Jite
ndra
Pad
hye,
"D
atag
ram
Con
gest
ion
Cont
rol P
roto
col
(DCC
P)",
Inte
rnet
-dra
ft (
wor
k in
pro
gres
s) d
raft
-iet
f-dc
cp-s
pec-
05.t
xt,
Oct
ober
2003
.
•M
etz,
C.,
"TC
P O
ver
Sate
llite
...
The
Fina
l Fro
ntie
r.",
IEEE
Inte
rnet
Com
puti
ng,
1999
.
•Sa
lly F
loyd
, "H
ighS
peed
TCP
for
Lar
ge C
onge
stio
n W
indo
ws"
,RF
C 36
49,
Expe
rim
enta
l, D
ecem
ber
2003
.
•Ba
lakr
ishn
an,
H.,
Pad
man
abha
n, V
. N
., S
esha
n, S
. an
d Ka
tz,
R. H
., "
A Co
mpa
riso
n of
Mec
hani
sms
for
Impr
ovin
g TC
P Pe
rfor
man
ce o
ver
Wir
eles
s Li
nks"
, Pr
ocee
ding
s of
ACM
SIG
COM
M 1
996,
Sta
nfor
d, C
A.
•Ra
mak
rish
nan,
K.,
Flo
yd,
S. a
nd B
lack
, D
., "
The
Addi
tion
of
Expl
icit
Con
gest
ion
Not
ific
atio
n (E
CN)
to
IP",
RFC
316
8.
•D
ina
Kata
bi,
Mar
k H
andl
ey,
and
Char
lie R
ohrs
, ''C
onge
stio
n Co
ntro
l for
Hig
h Ba
ndw
idth
-Del
ay P
rodu
ct
Net
wor
ks'',
Pro
ceed
ings
of
ACM
SIG
COM
M 2
002,
Pit
tsbu
rgh,
PA,
19-
23 A
ugus
t 20
02.
•Ch
eng
Jin,
Dav
id X
. W
ei a
nd S
teve
n H
. Lo
w,
''FAS
T TC
P: m
otiv
atio
n, a
rchi
tect
ure,
alg
orit
hms,
pe
rfor
man
ce'',
IEEE
Info
com
, M
arch
200
4.
Uni
Inn
sbru
ckU
ni I
nnsb
ruck
Info
rmat
ik
Info
rmat
ik --
6060
Refe
renc
es /
5Re
fere
nces
/5
4. H
ow t
o de
sign
you
r ow
n m
echa
nism
•M
icha
el W
elzl
, "V
ecto
r Re
pres
enta
tion
s fo
r th
e An
alys
is a
nd D
esig
n of
Dis
trib
uted
Co
ntro
ls",
Pro
ceed
ings
of
MIC
200
2 (I
ASTE
D M
odel
ling,
Iden
tifi
cati
on a
nd C
ontr
ol
Conf
eren
ce),
Inns
bruc
k, A
ustr
ia,
18-2
2 Fe
brua
ry 2
002.
•M
icha
el W
elzl
, M
ax M
ühlh
äuse
r: "
CAVT
-A
Cong
esti
on A
void
ance
Vis
ualiz
atio
n To
ol",
AC
M C
ompu
ter
Com
mun
icat
ion
Revi
ew,
Volu
me
33,
Issu
e 3,
Jul
y 20
03.
•M
icha
el W
elzl
: "S
cala
ble
Perf
orm
ance
Sig
nalli
ng a
nd C
onge
stio
n Av
oida
nce"
, Kl
uwer
Ac
adem
ic P
ublis
hers
, Au
gust
200
3. IS
BN 1
-402
0-75
70-7
. Fo
rew
ords
by
Jon
Crow
crof
t an
d M
ax M
ühlh
äuse
r.
CAVT
is a
vaila
ble
from
: ht
tp:/
/ww
w.w
elzl
.at/
tool
s/ca
vt/
Thank you!
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