1 IP multicast and multimedia -...
99
1 Jim Binkley IP multicast and multimedia TCP/IP class
Transcript of 1 IP multicast and multimedia -...
1Ji
m B
inkl
ey
IP m
ultic
ast a
nd m
ultim
edia
TCP/
IP c
lass
2Ji
m B
inkl
ey
outli
ne foun
datio
n co
ncep
ts o
f mul
ticas
t–
HW
leve
lIG
MP
and
mul
ticas
t rou
ting
inte
rlude
–M
BO
NE
and
mul
ticas
t app
sm
ore
mod
ern
mul
ticas
t rou
ting
prot
ocol
sm
ultim
edia
app
licat
ions
/pro
gram
min
gco
nclu
sion
s
3Ji
m B
inkl
ey
fund
amen
tal q
uest
ion/
s:ho
w d
o w
e de
liver
mul
timed
ia
appl
icat
ions
?w
hat a
re th
e pr
oble
ms?
wha
t arc
hite
ctur
al m
odel
s may
exi
st fo
r do
ing
this
(and
als
o ad
dres
sing
mod
els)
–an
d pr
otoc
ol n
eeds
(whi
ch a
re si
mila
r)an
d w
hen
do th
ose
mod
els m
ake
sens
e or
no
t?
4Ji
m B
inkl
ey
mot
ivat
ions
for m
ultic
ast
not a
ll ap
ps a
re p
oint
to p
oint
e.g.
, we
mig
ht h
ave
the
goal
to d
istri
bute
fr
om o
ne so
urce
to m
any
rece
iver
sTV
show
/mov
ie/m
ultip
oint
con
fere
nce
audi
o -r
adio
show
/voi
ce-o
nly
conf
eren
ceno
te h
ow a
bove
are
mor
e or
less
sche
dule
dre
liabl
y di
strib
ute
files
from
one
src
to
man
y an
othe
r pos
sibi
lity
5Ji
m B
inkl
ey
on th
e ot
her h
and
–m
ultic
ast d
oesn
’t fit
all
mul
timed
ia n
eeds
ther
e is
an
MP3
file
or a
“po
dcas
t”an
d on
e m
illio
n pe
ople
wan
t to
dow
nloa
d it
at d
iffer
ent t
imes
and
stre
am it
at t
heir
time
conv
enie
nce
or m
aybe
just
this
lect
ure?
–(d
iffer
ent s
cale
s the
re)
6Ji
m B
inkl
ey
prob
lem
s are
man
ypr
oble
m 1
: ho
w d
o w
e m
ake
appl
icat
ions
and
supp
ort n
et
that
ship
dat
a at
regu
lar r
ate;
i.e.
,iso
chro
nous
(nee
d Q
OS)
? (w
ithou
t los
s)–
note
poi
nt/p
oint
stre
amin
g ha
s sam
e pr
oble
m
p2: h
ow d
o th
ese
appl
icat
ions
add
ress
eac
h ot
her:
1 to
N,
N to
1, N
to N
? (w
hen
not u
nica
st)
p3: h
ow d
o w
e ge
t pkt
s to
each
oth
er a
cros
s rou
ters
p4: w
hat i
s on
chan
nel 1
0 an
yway
; i.e
., th
ere
is a
dire
ctor
y se
rvic
e or
som
e ot
her w
ay to
find
met
a in
form
atio
n?p5
: if f
at c
onte
nt, h
ow d
o w
e de
al w
ith c
onge
sted
link
s;
i.e.,
link
itsel
f is n
ot F
AT
enou
gh
7Ji
m B
inkl
ey
mul
ticas
t sol
ves w
hich
pro
blem
s?m
ultic
ast r
outin
g ta
kes a
stab
at a
ddre
ssin
g an
d m
ulti-
link
reac
habi
lity
(p2/
p3)
–no
t sca
labl
e en
ough
for I
net t
houg
h
RSV
P to
ok a
stab
at p
5–
ther
e is
no
QO
S so
lutio
n cu
rren
tly e
xcep
t get
fatte
r pi
pes,
and
less
hop
s
appl
icat
ion
prog
ram
min
g ca
n de
al w
ith so
me
out
of ti
me
spec
ifica
tion
prob
lem
sSD
R a
pp o
n M
BO
NE
show
s ses
sion
s
8Ji
m B
inkl
ey
circ
uit-s
witc
hed
or p
acke
t sw
itche
d?tra
ditio
nal v
oice
don
e by
rese
rvin
g pi
pe e
nd to
end
-it
is
isoc
hron
ous d
ata
–an
d sp
ace
was
rese
rved
(64K
onl
y ...
)pa
cket
switc
hes d
on’t
rese
rve
anyt
hing
-su
ppor
t bur
sty
(and
loss
y) u
sein
eith
er c
ase,
we
can
mak
e th
e PI
PE F
ATT
ER b
utw
ill it
be
FAT
enou
gh fo
r ful
l-scr
een,
full-
mot
ion
3-d
vide
o?al
so n
ote:
the
telc
osy
stem
has
1 a
pp.
The
Inet
has m
any
apps
.
9Ji
m B
inkl
ey
mul
ticas
ting:
link
laye
r and
L3
prob
lem
s
has h
ardw
are
supp
ort (
ethe
rnet
) on
link
ques
tion:
how
to ro
ute
acro
ss li
nks?
in L
AN
or m
ultic
astin
g ac
ross
WA
NS
(MB
ON
E)w
hat a
pplic
atio
ns e
xist
on
top
of M
BO
NE
whe
re to
go
from
her
e? re
sear
ch?
(yep
...)
“wha
teve
r it
is, i
t’s n
ot d
one
yet..
.”
10Ji
m B
inkl
ey
mul
ticas
t at L
ayer
2M
AC
add
ress
: 01:
xx:x
x:xx
:xx:
xxIP
blo
ck: 0
1:00
:5e.
00.0
0.00
-7f
:ff:ff
1 w
rite,
onl
y in
tere
sted
con
trolle
rs re
adet
hern
et c
ontro
ller o
n re
cvpr
ogra
mm
ed b
y ap
p/IP
to
be
inte
rest
ed in
mul
ticas
t IP
addr
ess
less
inef
ficie
nt th
an b
road
cast
mul
ticas
t add
ress
is D
EST
only
, not
src
mul
ticas
t can
repl
ace
broa
dcas
t in
prot
ocol
stac
k;
e.g.
, RIP
2 ye
s, R
IP1
no
11Ji
m B
inkl
ey
mul
ticas
t writ
e to
link
gro
upw
rite
to 0
1:00
:5E:
01:0
2:03
read
of 0
1:00
:5E:
01:0
2:03
not i
n gr
oup
A
BC
D
note
: A w
rites
, B, C
, rea
d, D
igno
res
12Ji
m B
inkl
ey
cont
rast
mul
tipoi
nt (a
tm) a
nd
mul
ticas
t on
link
mul
ticas
t is m
ore
scal
able
in te
rms o
f N to
N
fano
utbe
twee
n se
nder
s/re
ceiv
erpl
us w
e w
rite
TO a
n ad
dres
s, no
t to
a se
t of
pred
eter
min
ed (p
hone
/NSA
P) n
umbe
rsne
twor
k m
ust m
ake
the
notio
n of
writ
ing
TO a
n ad
dres
s wor
king
this
is a
n in
tere
stin
g pr
opos
ition
for b
oth
loca
l LA
N a
nd W
AN
rout
ers (
net-l
evel
)
13Ji
m B
inkl
ey
mul
tipoi
nt: N
to N
con
nect
ions
# of
par
ticip
ants
# of
con
nect
ions
21
36
412
520
630
N(N
**2)
- N
14Ji
m B
inkl
ey
conc
lusi
on/s
mul
tipoi
nt a
t N**
2 no
t as s
cala
ble
as
mul
ticas
tm
ultip
oint
-ne
ed to
kno
w re
cvad
dres
ses a
pr
iori
–m
ultic
ast -
just
writ
e to
G a
ddre
ssco
unte
r-as
sum
ptio
ns in
clud
e :-.
..:–
1. w
e kn
ow h
ow to
do
mul
ticas
t rou
ting?
!–
2. w
e kn
ow h
ow to
do
IP/is
ochr
onou
s dat
a?!
15Ji
m B
inkl
ey
mul
tipoi
nt -
mul
ticas
tw
ith m
ultic
ast e
very
body
just
writ
es to
the
mul
ticas
t add
ress
-do
n’t n
eed
to k
now
recv
addr
esse
s bef
oreh
and
send
erre
cv
recv
recv
mul
ticas
t add
ress
01:x
x:xx
:...
16Ji
m B
inkl
ey
IP m
ultic
ast a
ddre
ss m
appi
ngIE
TF re
serv
ed o
ne b
lock
of I
EEE
mul
ticas
t ad
dres
ses,
used
hal
f of t
hem
map
ene
tto
IP h
ow?
take
23
botto
m b
its o
f IP
addr
ess,
thus
32
ip
addr
esse
s map
to sa
me
hw a
ddre
ss22
4.0.
0.1
-> 0
1.00
.5E.
00.0
0.01
x.12
8.x.
y an
d x.
0.x.
y w
ill m
ap to
the
sam
e th
ing
(ip to
eth
erne
t)
17Ji
m B
inkl
ey
som
e w
ell-k
now
n m
ultic
ast
addr
esse
s
1 ad
dres
s -1
app
or 1
func
tion
224.
0.0.
1 -a
ll sy
stem
s on
this
subn
et22
4.0.
0.2
-all
rout
ers o
n th
is su
bnet
224.
0.0.
5/6
-OSP
F22
4.0.
0.9
-use
d by
RIP
222
4.0.
0.0
-.25
5 -n
ot fo
rwar
ded
(rou
ting)
224.
0.1.
2 -S
GI’
sdog
fight
app
licat
ion
see
assi
gned
num
bers
for m
ore
18Ji
m B
inkl
ey
mor
e m
ultic
ast
addr
esse
s/M
BO
NE
239.
0.0.
0 -2
39.2
55.2
55.2
55 -
adm
inis
trativ
ely
scop
ed23
9.19
2.0.
0 -2
39.1
95.2
55.2
55 -
orga
niza
tion
loca
l sco
pe23
9.25
5.0.
0-23
9.25
5.25
5.25
5 -l
ocal
scop
elo
cal s
copi
ng in
tend
ed to
repl
ace
TTL-
base
d sc
opin
g as
TTL
cau
ses p
runi
ng p
robl
ems f
or
DV
MR
P
19Ji
m B
inkl
ey
mul
ticas
t ope
ratio
n on
hos
tap
ps (o
r sta
ck) m
ust n
otify
ip th
at th
ey a
re
inte
rest
ed in
recv
a pa
rticu
lar i
p ad
dres
s on
an
inte
rfac
e (p
er in
terf
ace)
ip n
otifi
es d
river
driv
er m
ust b
e M
ULT
ICA
ST c
apab
le–
mos
t mod
ern
ethe
rnet
con
trolle
rs a
re
host
join
s MU
LTIC
AST
GR
OU
P ou
t tha
t in
terf
ace
if m
cast
pkta
rriv
es, m
ust g
o to
all
apps
that
wan
t it
-the
re e
xist
s a m
ultic
ast b
ind(
2) th
ough
20Ji
m B
inkl
ey
assu
me
linux
box
has e
th0
port
acco
rdin
g to
ifco
nfig
-aet
h0 is
pro
gram
med
by
IP to
aut
omag
ical
lyre
ad –22
4.0.
0.1
at b
oot,
why
? (
all h
osts
)–
224.
1.2.
3, b
ecau
se y
ou w
ant t
o w
atch
the
MB
ON
E “i
love
lucy
”re
run
at 4
:00
p.m
21Ji
m B
inkl
ey
IGM
P -m
ultic
ast c
ontro
l on
link
IGM
P -r
fc11
12 (D
eerin
g, 1
989)
enca
psul
ated
like
ICM
P (tr
ansp
ort i
n IP
pro
to
field
, but
con
side
red
at IP
laye
r)fu
nctio
n is
to a
lert
loca
l lin
k m
ultic
ast r
oute
rth
at
host
is in
tere
sted
in IP
mul
ticas
t gro
upqu
ery
(type
=1) s
ent b
y ro
uter
resp
onse
(typ
e=2)
sent
by
host
grou
p ad
dres
s -m
ultic
ast a
ddre
ss in
que
stio
n
22Ji
m B
inkl
ey
RFC
111
2 –
impo
rtant
not
eth
is w
ill re
turn
late
r:on
e as
sum
ptio
n is
that
a m
ultic
ast g
roup
can
hav
e M
OR
E TH
AN
ON
E SR
Cw
e ca
ll th
is (*
, G)
–m
any
sour
ces,
1 gr
oup
also
not
e th
ere
is n
o hi
erar
chy
in a
cla
ss D
add
ress
–as
ther
e ar
e in
cla
ss A
, B, C
nor
mal
uni
cast
–yo
u ca
nnot
find
the
orig
inat
ing
netw
ork
anot
her p
ossi
bilit
y: (
S, G
) –on
ly o
ne so
urce
for a
gr
oup
23Ji
m B
inkl
ey
IGM
P he
ader
0
3
4
7
8
15
16
31
vers
ion:
4 bi
ts(1
)ty
pe: 4
bi
ts (1
,2)
unus
ed
16
-bit
che
cksu
m
32-b
it m
ultic
ast (
grou
p) IP
add
ress
24Ji
m B
inkl
ey
IGM
P pr
otoc
ol -
host
repo
rta
proc
ess j
oins
a m
ultic
ast g
roup
on
a pa
rticu
lar
inte
rfac
eif
1..n
pro
cs, o
ne IG
MP
repo
rt (ty
pe=2
) is s
ent
IGM
P re
port,
IP tt
l= 1
, IG
MP
grou
p ad
dres
s is
grou
p ad
dres
s, IP
dst
is g
roup
add
ress
, IP
src
is
host
uni
cast
ipho
st se
nds t
his r
epor
t to
repo
rt w
hen
it ge
ts ro
uter
qu
ery
too
25Ji
m B
inkl
ey
IGM
P an
d m
ultic
ast r
oute
rro
uter
mus
t pro
mis
cuou
sly
hear
gro
up re
ports
(ip
dest
is A
NY
mul
ticas
t add
ress
)ho
sts d
on’t
repo
rt le
avin
g. r
oute
r mus
t que
ry li
nk
once
it k
now
s tha
t hos
ts a
re in
tere
sted
at p
erio
dic
inte
rval
IGM
P qu
ery,
IP tt
l= 1
, IG
MP
grou
p ad
dr=
0,
dest
IP =
224
.0.0
.1, s
rc IP
= u
nica
st ro
uter
ip
addr
ess
note
: gro
up a
ddr=
0, m
eans
ALL
G a
pps p
leas
e
26Ji
m B
inkl
ey
som
e de
tails
if pr
oces
s wan
ts to
send
/recv
mul
ticas
t, IP
will
m
ap IP
add
ress
to e
ther
neta
ddre
ss a
nd in
form
de
vice
driv
erro
uter
onl
y ne
eds t
o kn
ow th
at o
ne h
ost o
n th
at
link
is in
tere
sted
rout
er m
ust *
som
ehow
* do
mul
ticas
t rou
ting
with
ot
her r
oute
rs to
mak
e id
eal o
f writ
ing
to m
ultic
ast
IP a
ddre
ss w
ork
ICM
P er
rors
are
not
gen
erat
ed fo
r mul
ticas
t add
rs(tr
acer
oute
won
’t w
ork)
27Ji
m B
inkl
ey
IGM
P –
late
r im
prov
emen
tsde
fines
pro
cedu
res t
o el
ect o
ne m
ultic
ast
rout
er to
que
ry e
nd n
odes
(low
er IP
win
s)ne
w q
uery
mes
sage
-ro
uter
can
que
ry o
ne
grou
p as
opp
osed
to a
llle
ave
grou
p m
essa
ge -
host
xm
tsle
ave
G to
22
4.0.
0.2
rout
er c
an tu
rn a
rund
and
send
new
que
ry
and
disc
over
no
mem
bers
pre
sent
28Ji
m B
inkl
ey
mul
ticas
t rou
ting
on L
AN
/WA
Nw
ould
like
mod
el to
be
sim
ple
like
hw m
odel
send
er w
rites
to m
ultic
ast (
IP) a
ddre
ssre
cvsj
ust t
ell n
etw
ork
they
are
inte
rest
edse
nder
doe
sn’t
know
who
the
recv
sare
(unl
ess t
he
recv
smul
ticas
t ses
sion
info
to a
gro
up)
one
“sm
all”
prob
lem
, how
do
the
rout
ers
actu
ally
do
the
mul
ticas
t rou
ting?
29Ji
m B
inkl
ey
mul
ticas
t LA
N/W
AN
rout
ing
send
er
rout
erro
uter
recv
the
Inte
rnet
hmm
m...
.
Inte
rnet
-wid
e flo
odin
g of
you
r atte
mpt
to“t
elev
ise”
the
Jets
onsm
ay n
ot b
e th
e be
st id
ea...
30Ji
m B
inkl
ey
DV
MR
P an
d m
rout
edm
ultic
ast r
outin
g pr
otoc
ols e
xist
(in
thei
r inf
ancy
) D
VM
RP
(rfc
1075
), di
stan
ce v
ecto
r mul
ticas
t ro
utin
g pr
otoc
ol,
MO
SPF,
PIM
prob
lem
has
bee
n th
at c
omm
erci
al ro
uter
s did
n’t
supp
ort I
GM
P, D
VM
RP,
mro
uted
on w
orks
tatio
ns w
as u
sed
to c
onst
ruct
a
mul
ticas
t virt
ual b
ackb
one
-the
MB
ON
E on
top
of th
e In
tern
etse
cret
is IP
IP tu
nnel
(pro
to #
=4)
31Ji
m B
inkl
ey
mul
ticas
t rou
ting
prot
ocol
s/bi
blio
old
3com
whi
te p
aper
goo
d:–
draf
t-iet
f-m
bone
d-in
tro-m
ultic
ast-0
0.tx
t–
cove
red
in H
uite
ma,
IP R
outin
gO
SPF
book
: OSP
F -A
nato
my
of a
n In
tern
et R
outin
g Pr
otoc
ol, J
ohn
Moy
–go
od in
trova
rious
RFC
S/dr
afts
inc
ludi
ng
PIM
/CB
T/D
VM
RP,
etc
.
32Ji
m B
inkl
ey
tree-
base
d, 2
kin
dsso
urce
bas
ed (S
,G) a
nd d
ense
–m
ore
like
span
ning
tree
from
send
/to re
cvs
–D
VM
RP,
PIM
den
se m
ode
»IG
Ps, b
ut D
VM
RP
in u
se a
s “EG
P”an
yway
–M
OSP
F (b
ut re
ally
dom
ain-
wid
e)sh
ared
-tree
of r
oute
rs (s
pars
e)–
PIM
spar
se m
ode,
CB
T (c
ore-
base
d tre
es)
–se
nd/re
cv(r
oute
r sur
roga
tes)
find
tree
s–
inte
nded
as E
GPs
, not
succ
essf
ul
33Ji
m B
inkl
ey
mor
e DV
MR
P -d
ista
nce
vect
or m
ultic
ast r
outin
g pr
otoc
ol–
com
bine
s RIP
like
uni
cast
rout
ing
and
–m
ultic
ast d
ense
floo
ding
(flo
od &
pru
ne)
PIM
-pr
otoc
ol in
depe
nden
t–
inde
pend
ent o
f uni
cast
rout
ing
(not
in th
e pr
otoc
ol li
ke w
ith D
VM
RP)
–ne
eds u
nica
st ro
utin
g ta
ble
in im
plem
enta
tion,
bo
rrow
ed fr
om u
nica
st ro
utin
g pr
otoc
ol
34Ji
m B
inkl
ey
IGP
vsEG
PM
BO
NE
on to
p of
DV
MR
P re
ally
ove
rgro
wn
IGP
–V
.D. p
roto
col n
ot g
ood
basi
s for
scal
abili
ty
MO
SPF
good
but
IGP
by d
efin
ition
shar
ed tr
ees i
nten
ded
to g
o in
that
dire
ctio
n bu
t ha
ve n
othi
erar
chic
al D
VM
RP
prop
osed
by
Dee
ring
rese
arch
are
a at
pre
sent
sugg
estio
ns in
clud
e M
BG
P/M
SDP,
BG
MP,
SI
MPL
E, E
XPR
ESS,
and
mor
e
35Ji
m B
inkl
ey
DV
MR
P/m
rout
edD
VM
RP
orig
inal
RFC
(out
of d
ate)
107
5,
shou
ld b
e la
ter d
raft/
RFC
at t
his p
oint
com
mer
cial
rout
ers o
rigin
ally
did
n’t
supp
ort M
BO
NE
and
DV
MR
Pm
rout
edru
n on
Sun
wor
ksta
tions
-w
as
used
to c
onst
ruct
virt
ual M
BO
NE
on to
p of
un
icas
t Ine
tse
cret
is IP
IP tu
nnel
(IP
prot
o 4)
36Ji
m B
inkl
ey
DV
MR
P an
d IP
IP tu
nnel
cros
s the
Inte
rnet
via
nor
mal
rout
ing
mul
ticas
t IP
pack
et p
ut in
uni
cast
ext
erna
l IP
fram
epa
cket
sent
acr
oss s
tatic
ally
con
figur
ed tu
nnel
, IP
src
is m
1,IP
des
tis m
2w
hen
M2
gets
it, s
trips
the
oute
r IP,
“fo
rwar
ds”
the
norm
al IP
no
rmal
lyth
is a
llow
s us t
o “b
ridge
”ov
er a
rbitr
ary
Inet
topo
logy
mro
uter
2m
rout
er1
tunn
el
37Ji
m B
inkl
ey
IPIP
enc
apsu
latio
n
oute
r ip
head
erip
des
t= m
2,ip
src
= m
1
inne
r ip
head
erip
des
t= g
roup
da
ta
tunn
el, i
s poi
nt to
poi
nt v
irtua
l lin
k to
mro
uted
we
forw
ard
mul
ticas
t dat
a ac
ross
it
38Ji
m B
inkl
ey
DV
MR
P ov
ervi
ewso
urce
bas
ed tr
ee sc
hem
e (S
,G) -
each
so
urce
/gro
up a
diff
eren
t tre
e in
mca
stro
uter
s; e
.g.,
(S1,
G1)
, (S2
, G1)
, (S2
, G2)
diff
eren
tne
ed m
ultic
ast a
nd u
nica
st ro
utin
g ta
ble
infin
ity =
32
cont
ains
RIP
like
uni
cast
rout
ing:
UPD
ATE
m
essa
ge w
ith (n
etm
ask,
subn
et, m
etric
)pl
us “
flood
and
pru
ne”
prot
ocol
for m
ultic
ast D
M
rout
ing
+ vi
rtual
IPIP
inte
rfac
es
39Ji
m B
inkl
ey
over
view
use
IPIP
tunn
els a
s virt
ual i
nter
face
s to
glue
to
geth
er p
ocke
ts o
f den
se m
ode
DV
MR
Pm
rout
erth
us h
as n
ativ
e de
nse
mod
e i/f
s and
tu
nnel
i/fs
mul
ticas
t pac
kets
are
floo
ded
over
bot
h ki
nds o
f i/fs
in o
ne p
ort a
nd o
ut th
e ot
hers
(ro
ughl
y)–
mor
e de
tail
on th
at R
SN
40Ji
m B
inkl
ey
mul
ticas
t rou
ting
idea
s:pr
otoc
ol b
asis
is:
“flo
od a
nd p
rune
”–
src
pack
ets f
lood
ed o
ver e
ntire
tree
of m
ultic
ast
links
to re
cvs
–pr
uned
bac
k fr
om le
afs (
rem
oves
sub-
trees
with
no
recv
s) to
con
stra
in fl
oodi
ng–
perio
dica
lly fl
ood
agai
n in
cas
e of
bug
s or n
ew
recv
sor f
or g
ener
al re
dund
ancy
mca
stal
gorit
hm: R
ever
se P
ath
Forw
ardi
ngin
mro
uter
s
41Ji
m B
inkl
ey
1st:
the
flood
par
t
our i
deal
is a
S-b
ased
span
ning
tree
, but
that
–is
not
floo
ding
...
flood
ing
is m
essi
erw
e m
ust c
onst
rain
floo
ding
els
e us
e up
too
muc
h in
the
way
of r
esou
rces
1st a
ssum
e ba
sic
flood
ing
–flo
odin
g m
ust o
ccur
occ
asio
nally
(con
stra
ined
by
RPF
and
oth
er m
echa
nism
s tho
ugh)
42Ji
m B
inkl
ey
why
floo
d?1.
lin
ks m
ay c
hang
e (u
p/do
wn)
–un
icas
t rou
ting
know
s, bu
t mca
stro
utin
g do
es n
ot
2. e
nd re
cv(a
ctua
lly e
nd m
rout
er) m
ay n
ot k
now
S
--w
hat d
oes i
t do?
–re
mem
ber m
cast
data
pkt
has
(S,G
) in
it, S
is IP
src,
G
ip d
st
3. g
ener
al re
dund
ancy
–gu
ard
agai
nst b
ugs
–lo
st m
ultic
ast p
acke
ts
43Ji
m B
inkl
ey
how
con
stra
in fl
oodi
ng1.
use
Rev
erse
Pat
h Fo
rwar
ding
alg
orith
m
for m
ultic
ast r
outin
g in
MR
OU
TER
S–
do n
ot se
nd p
acke
ts o
ut u
nles
s M p
kt c
omes
in
on
shor
test
uni
cast
pat
h to
S–
do n
ot se
nd p
acke
ts to
pee
r/nei
ghbo
rs w
ho w
e kn
ow (f
rom
uni
cast
hin
ts) h
ave
a sh
orte
r pat
h to
S2.
IGM
P dr
iven
ups
tream
pru
ning
of t
ree
-re
mov
ed b
ranc
hes w
ith n
o R
ecei
vers
44Ji
m B
inkl
ey
mca
stfo
rwar
ding
alg
orith
mde
crem
ent I
P ttl
, if 0
sile
ntly
dis
card
look
pac
ket u
p in
mca
stta
ble
by (S
,G)
–if
not t
here
, dis
card
if pa
cket
acc
. to
unic
ast i
nfo
cam
e in
on
shor
test
pat
h to
SR
C, f
orw
ard
(els
e to
ss)
pack
et is
forw
arde
d ou
t lis
ted
i/fs i
n m
cast
entry
(tun
nels
or e
ther
neti
/fs)
may
hav
e TT
L th
resh
old:
toss
if T
TL le
ss
45Ji
m B
inkl
ey
ttlth
resh
old
idea
can
set t
tlth
resh
old
on m
cast
i/fou
tbou
nd M
pac
kets
are
dis
card
ed if
thei
r TTL
<
thre
shol
dth
is c
an g
ive
RO
UG
H lo
cal a
dmin
scop
ing
–lo
cal m
ultic
ast c
an’t
leav
e ...
som
e M
BO
NE
apps
can
be
roug
hly
cont
rolle
d w
ith th
is (l
et in
X, d
isca
rd Y
)ca
uses
pro
blem
s for
pru
ning
-it’
s a h
ack,
jack
IPv6
mul
ticas
t sco
pe b
it a
bette
r ide
a
46Ji
m B
inkl
ey
S,G
and
rout
er tr
ee d
iagr
am
rece
iver
send
er o
f S, G
MR
MR
MR
(lea
f rou
ter)
disc
arde
dan
y su
btre
ehe
reev
entu
ally
pru
ned
1 ho
p
2 ho
ps
note
: R
PF p
ushe
s tow
ards
span
ning
tree
, S to
tree
of re
ceiv
ers,
floo
d w
ill u
ndo
it
47Ji
m B
inkl
ey
prun
ing
IGM
P us
ed to
lear
n no
gro
up m
embe
rs b
y le
af ro
uter
spr
une
mes
sage
s go
upst
ream
if up
stre
am ro
uter
’s c
hild
inte
rfac
es a
re
prun
ed, i
t sho
uld
send
a p
rune
bac
k SR
C
path
can
GR
AFT
now
too
-dow
nstre
am ro
uter
ca
n se
nd G
RA
FT u
pstre
am–
graf
ts a
re fo
r und
oing
pru
nes
48Ji
m B
inkl
ey
prun
e pr
une
prun
e -
no jo
kes a
bout
fibe
r ple
ase
mca
stflo
odin
g
1. n
o re
cvs,
ther
efor
epr
une
upst
ream
IGM
P,no
body
care
s
1. o
urpr
une
prun
e#2
we
got p
rune
s on
all b
ranc
hes,
ther
efor
e pr
une
upst
ream
upst
ream
prun
e
49Ji
m B
inkl
ey
prun
es m
ake
usst
atef
ul -
we
rem
embe
r thi
s for
aw
hile
in o
rder
to
prev
ent t
he fl
oodi
ng–
mus
t mem
oriz
e “n
ot th
at G
”fo
r a ti
me
perio
d–
mus
t tim
eout
to g
uard
aga
inst
mis
take
s
if R
in p
rune
d tre
e, m
ust G
RA
FT to
rem
ove
the
prun
eG
RA
FTsa
re re
liabl
e (A
CK
) bet
wee
n m
rout
ersi
n or
der t
o ge
t rid
of p
rune
eff
icie
ntly
50Ji
m B
inkl
ey
DV
MR
P pr
otoc
olin
IGM
P pa
cket
s, ty
pe 0
x13,
sub-
code
use
d1
-pro
be, f
or n
eigh
bor d
isco
very
2 -r
epor
t, un
icas
t rou
te e
xcha
nge
–m
ultip
le p
aths
from
src
are
elim
inat
ed7
-pru
ne, p
rune
mul
ticas
t tre
e8
-gra
ft8
-gra
ft ac
k(r
elia
ble)
51Ji
m B
inkl
ey
DV
MR
P un
icas
t rou
ting
not t
here
to d
o un
icas
t rou
ting
BU
T to
adve
rtise
(and
det
erm
ine
path
s) to
mul
ticas
t so
urce
s–
choo
se sh
orte
st e
qual
-cos
t pat
h–
can
get r
id o
f equ
al c
ost m
ultip
ath,
one
mor
e an
ti-flo
odin
g te
chni
que
“sou
rce”
of R
PF u
nica
st in
form
atio
nsp
lit h
oriz
on/p
oiso
n re
vers
e, h
old
dow
n us
ed
52Ji
m B
inkl
ey
PIM
prot
ocol
inde
pend
ent i
n tw
o fo
rms,
spar
se
and
dens
edo
es n
ot re
ly (u
nlik
e D
VM
RP/
MO
SPF)
on
any
parti
cula
r uni
cast
rout
ing
tabl
ebu
t mus
t hav
e a
unic
ast r
outin
g ta
ble
to u
se–
ther
efor
e im
plem
enta
tion
depe
nden
t–
call
it “D
IM”
depe
nden
tly im
plem
ente
d m
ultic
ast..
. sor
ry ..
.bad
joke
!
53Ji
m B
inkl
ey
PIM
den
se m
ode
sim
ilar t
o D
VM
RP
exce
pt n
o un
icas
t ro
utin
g bu
ilt-in
mus
t use
loca
l uni
cast
rout
ing
tabl
ede
nse
mea
ns g
roup
mem
bers
shou
ld b
e m
any
RPF
and
floo
d an
d pr
une
is b
asis
IP p
roto
col 1
03
54Ji
m B
inkl
ey
PIM
den
se m
ode
prot
ocol
Hel
los
Join
, Pru
nes,
Ass
erts
Gra
ft an
d G
raft
Ack
if tw
o ro
uter
s rec
vne
w S
,G p
acke
t, us
e PI
M A
sser
t to
co
mpa
re m
etric
s–
only
smal
ler m
etric
/rout
er w
ill fo
rwar
d–
thus
dat
a-dr
iven
equ
al-c
ost p
ath
rem
oval
leaf
rem
oval
-if
no h
ello
s fro
m li
nk, a
nd n
o IG
MP,
you
ca
n st
art p
runi
ng
55Ji
m B
inkl
ey
CB
T -c
ore
base
d tre
esB
alla
rdie
prop
osed
cor
e ba
sed
tree
S/R
(rou
ter s
urro
gate
s) fo
rwar
d JO
IN
com
man
ds to
war
ds c
ente
r to
setu
pce
nter
-bas
ed p
ath
mul
ticas
t inf
o th
en fl
ows a
long
that
pat
h
56Ji
m B
inkl
ey
CB
T/sp
arse
tree
s pro
s/co
nspr
os:
–m
inim
ize,
if n
ot e
limin
ate,
floo
ding
, if y
ou d
on’t
care
yo
u do
n’t s
ee m
ultic
ast,
ther
efor
e m
ore
scal
able
–m
inim
ize
stat
e in
rout
ers,
only
nee
d G
, not
S,G
cons
:–
mul
ticas
t dat
a pa
th m
ay b
e su
b-op
timal
–m
ay c
once
ntra
te m
ultic
ast r
outin
g on
a fe
w li
nks,
not
spre
ad it
out
as f
lood
ing
does
–ho
w d
o w
e fin
d co
re, e
spec
ially
inte
r-do
mai
n?»
how
do
core
s in
diff
eren
t Rou
ting
Dom
ains
find
eac
h ot
her?
–si
ngle
poi
nt o
f fai
lure
s (e.
g., R
P in
PIM
DM
)
57Ji
m B
inkl
ey
unid
irect
iona
l vs b
idire
ctio
nal
trees
core
/R
P
1. se
nd to
cor
e to
join
S/R
cont
rol+
data
cont
rol
da
ta
core
/R
P
2. b
i-dire
ctio
nal
data
or c
ontro
lop
timiz
edto
use
bette
r pat
h
henc
e w
hine
s abo
ut S
M m
ay b
eal
levi
ated
58Ji
m B
inkl
ey
PIM
spar
seba
sic
idea
: w
e ha
ve R
P, r
ende
zvou
s poi
ntm
essa
ges a
re fo
rwar
ded
to R
P to
join
G,
–w
e kn
ow R
P’s u
nica
st a
ddre
ss, s
end
to it
RP
man
ually
setu
p, m
ay b
e ro
utin
g pr
otoc
ol m
echa
nism
s to
dyna
mic
ally
lear
nhe
nce
unid
irect
iona
l tre
e m
echa
nism
can
switc
h fr
om S
M to
DM
whe
n/if
deci
de
that
gro
up is
den
se e
noug
h
59Ji
m B
inkl
ey
intra
-dom
ain
PIM
may
be li
ke so
?
dens
e m
ode
PIM
intra
net
dens
e m
ode
PIM
intra
net
spar
se m
ode
PIM
in-b
etw
een
RP
wha
t hap
pens
?1.
inte
r-do
mai
n2.
intra
-dom
ain
recv
tries
to fi
ndse
nder
?
man
ual R
PsIn
et-w
ide
not a
goo
d id
ea
60Ji
m B
inkl
ey
MO
SPF
mul
ticas
t osp
fin
trodu
ces g
roup
-mem
bers
hip-
lsa
sim
ply
flood
G in
form
atio
n in
OSP
F m
ultic
ast m
esh
tree
prod
uced
by
Dijk
stra
calc
ulat
ion
whe
n m
ultic
ast p
acke
ts a
rriv
e (d
ata-
driv
en)
inte
ract
ions
bet
wee
n M
OSP
F an
d D
VM
RP
have
bee
n de
fined
(els
e co
uldn
’t fit
in
MB
ON
E)
61Ji
m B
inkl
ey
mtra
ce-m
ultic
ast t
race
rout
eB
ill F
enne
r/Xer
ox P
arc,
mtra
ceut
ility
for
unix
, and
els
ewhe
relik
e tra
cero
ute,
but
not
sam
e m
echa
nism
path
trac
ed b
ackw
ards
from
this
hos
t (a
ssum
e re
cv.)
to sr
c, u
ses R
PF id
eaco
llect
s val
uabl
e pa
cket
stat
istic
s and
in
gene
ral i
s ric
her t
han
trace
rout
ein
info
mus
t hav
e m
rout
ersh
ere
to th
ere
(of
cour
se)
62Ji
m B
inkl
ey
mtra
ce, c
ont.
by d
efau
lt (n
o pa
ram
s) tr
aces
G 2
24.2
.0.1
,–
whi
ch is
MB
ON
E au
dio
chan
nel
–ho
st (r
ecv)
def
aults
to y
ou#
mtra
ce<s
rc (u
nica
st)>
<gr
oup>
uses
IGM
P pa
cket
type
s–
0x1f
-tra
cero
ute
requ
est
–0x
1e -
trace
rout
ere
spon
se
63Ji
m B
inkl
ey
how
it w
orks
(in
over
view
)as
sum
e R
PF li
ke a
lgor
ithm
trace
rout
epa
cket
forw
arde
d ho
p by
hop
to
war
ds so
urce
each
inte
rmed
iate
RO
UTE
R se
nds d
ata
to
send
er o
n th
e w
ayst
ops w
hen
we
get t
he R
OU
TER
nex
t to
src
OR
lose
the
path
OR
rout
er th
at d
oesn
’t un
ders
tand
64Ji
m B
inkl
ey
MB
ON
Eex
perim
enta
l MB
ON
E es
tabl
ishe
d 19
92–
broa
dcas
t IET
F se
ssio
ns (s
till d
oes)
not p
rodu
ctio
n se
rvic
e–
MB
ON
E do
es n
ot (c
anno
t) go
last
mile
–sc
alab
ility
pro
blem
s in
rout
ing
–no
t uni
vers
ally
supp
orte
d by
ISPs
or l
ocal
net
core
use
s DV
MR
P, b
ut M
OSP
F an
d PI
M
used
at e
dges
65Ji
m B
inkl
ey
prob
lem
s with
MB
ON
EM
BO
NE
has 1
000’
s of n
ets,
100
0s o
f rou
tes i
n D
VM
RP
rout
ing
tabl
e -w
asn’
t mea
nt to
scal
e to
that
deg
ree
need
hie
rarc
hy -
Dee
ring,
etc
., ha
ve p
ropo
sed
how
to d
o hi
erar
chic
al m
ultic
ast r
outin
gre
liabl
e da
ta fl
ow is
a g
ood
ques
tion
too
MB
ON
E ap
ps a
re st
eady
-sta
te fl
ow,
and
don’
t bac
k of
f lik
e TC
P (h
ow c
an a
stea
dy-s
tate
bac
koff
?)in
ter-
dom
ain
mul
ticas
t flo
w m
anag
emen
t–
Big
Pip
e 1
does
n’t w
ant t
o so
urce
Big
Pip
e 2’
s rec
eive
rs fo
r tha
t H
DTV
mul
ticas
t ses
sion
66Ji
m B
inkl
ey
MB
ON
E ap
pssd
-ses
sion
dire
ctor
y (n
ow sd
r)au
dio
–va
t (PC
M a
t 78k
bps,
GSM
at 1
7kbp
m)
–ne
vot
–ra
t als
o po
ssib
le
vide
o–
nv(v
ideo
at 1
28kb
ps),
nv
out o
f ser
vice
–vi
c(n
vre
plac
emen
t) -c
omm
only
use
d
imm
-rel
iabl
e im
age
mul
ticas
t (di
sapp
eare
d)
sd-
Sess
ion
Dire
ctor
y
now
rep
lace
d
by s
dr
nv-
netw
ork
vide
o
note
: gre
at G
UI
failu
re
vat -
Vis
ual
Aud
ioTo
ol
70Ji
m B
inkl
ey
old
apps
/new
MB
ON
E ap
pssd
, no
w sd
rnv
, now
vic
vat,
now
vat
/rat
ther
e ar
e ot
her a
pps t
oo o
f int
eres
t,w
b-d
istri
bute
d w
hite
boa
rd
71Ji
m B
inkl
ey
rece
nt d
evel
opm
ents
in
MB
ON
E/m
ultic
ast p
roto
cols
no E
GP,
and
bas
ical
ly–
DV
MR
P/IP
IP–
PIM
den
se/s
pars
e n
ot sc
alea
ble
enou
gh–
also
pro
blem
s of m
appi
ng o
ne ro
utin
g pr
otoc
ol to
an
othe
r (I
hav
e M
OSP
F, y
ou h
ave
DV
MR
P, w
e w
ant
to sh
are)
rece
nt d
evel
opm
ents
incl
ude
MSD
P/M
BG
PB
GM
P a
nd P
erlm
an’s
Sim
ple
Mul
ticas
tSS
M –
sour
ce sp
ecifi
c m
ultic
ast
72Ji
m B
inkl
ey
prob
lem
s aga
in w
ere?
no re
al g
ood
way
to se
nd in
fo a
cros
s ro
utin
g do
mai
ns–
not a
s sca
labl
e as
uni
cast
rout
ing
cons
ider
PIM
spar
e/R
Ps–
if on
ly o
ne R
P -c
an h
ave
sing
le so
urce
of
failu
re
–ho
w d
o w
e fin
d R
Psel
sew
here
? in
ter-
dom
ain
as w
ell a
s int
ra-d
omai
n
73Ji
m B
inkl
ey
MSD
P/M
BG
PB
GP
has b
een
mad
e m
ulti-
prot
ocol
; i.e
.,.
can
do m
ore
than
IPv4
–IP
v6/m
ultic
ast g
roup
info
com
e to
min
d–
ther
efor
e yo
u ca
n ge
t mul
ticas
t inf
o fr
om a
B
GP
peer
(uni
cast
rou
te so
urce
for
PIM
)M
SDP
-Mul
ticas
t Sou
rce
Dis
cove
ry
Prot
ocol
–in
ter-
dom
ain
RP
to R
P flo
odin
g of
sour
ce
“act
ivat
ion”
mes
sage
s usi
ng T
CP
74Ji
m B
inkl
ey
with
MSD
Pso
urce
s mus
t be
next
hop
tow
ards
send
ing
RP
–th
is is
an
RPF
che
ck, m
akes
us l
oop
free
–M
BG
P ta
ble
used
to d
eter
min
e R
PF c
heck
»(S
,G) c
heck
(is s
rcbe
st h
op e
lse
disc
ard
info
)
–M
SDP/
MB
GP
pairi
ng g
ive
us in
ter-
dom
ain
info
but
–re
ally
lim
it tre
es to
intra
-dom
ain,
not
inte
r-do
mai
n»
PIM
can
not f
unct
ion
acro
ss d
omai
ns»
no w
ay to
hav
e bi
-dire
ctio
nal t
ree
thus
, thi
s com
bo v
iew
ed a
s sto
pgap
, not
scal
able
en
ough
–of
cou
rse
...
75Ji
m B
inkl
ey
BG
MP
-nex
tgen
inte
r-do
mai
n?bo
rder
gat
eway
mul
ticas
t pro
toco
lin
dra
ft st
atus
bu
ilds b
i-dire
ctio
nal t
rees
bet
wee
n ro
utin
g do
mai
nsop
erat
es b
etw
een
bord
er ro
uter
scr
oss d
omai
n, in
side
dom
ain
may
use
D
VM
RP,
PIM
, MO
SPF
76Ji
m B
inkl
ey
BG
MP
basi
c id
eabo
rder
rout
ers l
earn
ther
e ar
e in
tern
al h
osts
th
at w
ant t
o se
nd/re
cvse
nd jo
in m
essa
ges t
o “r
oot d
omai
n”of
m
ultic
ast g
roup
give
n a
mul
ticas
t add
ress
, ho
w d
o w
e fin
d “r
oot d
omai
n”, e
h? (
som
e ki
nda
DN
S?!)
mus
t inv
ent m
ultic
ast a
ddre
ss a
lloca
tion
sche
me
to fi
gure
that
out
(MA
SC)
mul
ticas
t add
ress
set c
laim
pro
toco
l
77Ji
m B
inkl
ey
anot
her p
ossi
bilit
y: P
erlm
an-
sim
ple
mul
ticas
tPe
rlman
/Lee
/Bal
lard
ie(C
BT)
/Cro
wcr
oft/W
ang/
Mau
fer
prop
ose
Sim
ple
Mul
ticas
t (IE
TF d
raft)
forg
et a
bout
mul
ti-so
urce
mul
ticas
t (ju
st 1
)pr
opos
e to
NO
T ha
ve a
MA
SC-li
ke p
roto
col
rath
er u
se a
ddre
ss 2
-tupl
e (C
,M),
whe
re C
is u
nica
st
addr
ess,
M m
ultic
ast
rout
ers d
o no
t hav
e to
som
ehow
figu
re o
ut w
here
M is
(use
C
,M) i
nste
ad a
nd C
is n
ot m
ultic
ast
ques
tion
for R
bec
omes
, ho
w d
o I f
ind
C (u
nica
st ro
utin
g)
78Ji
m B
inkl
ey
Che
riton
and
othe
rs, 1
999
Hol
broo
k, C
herit
on. “
Expl
icitl
y R
eque
sted
So
urce
-Spe
cific
Mul
ticas
t: EX
PRES
S su
ppor
t for
Lar
ge-s
cale
Sin
gle-
sour
ce
App
licat
ions
”–
AC
M S
IGC
OM
M, 1
999
lead
s to
sour
ce sp
ecifi
c m
ultic
ast -
SSM
79Ji
m B
inkl
ey
SSM
–th
e w
inne
r and
new
ch
ampi
onm
ultic
ast I
P ad
dres
s is 2
tupl
e(I
P un
icas
t src
, m
ultic
ast d
st)
mus
t kno
w sr
ca
prio
ri (s
ay v
ia w
eb)
RFC
111
2 al
low
ed m
ultip
le sr
cs, 1
gro
upno
mor
e m
ultip
le sr
csth
us n
o ne
ed fo
r M
ASC
, IP
uni
cast
src
addr
esse
s are
uni
que
we
can
build
a si
mpl
e tre
e to
the
sour
cedo
not
nee
d R
Psei
ther
80Ji
m B
inkl
ey
to d
o SS
MIG
MP
v3 a
llow
s a R
to a
nnou
nce
1-N
2-
tupl
es o
f int
eres
t, th
us M
R c
an fi
nd S
RC
PIM
-SSM
send
s im
med
iate
PIM
S,G
join
s 23
2/8
has b
een
prop
osed
to IA
NA
for P
IM-
SSM
–m
ultip
le sr
c, G
not
allo
wed
in th
is ra
nge
81Ji
m B
inkl
ey
mul
timed
ia a
pplic
atio
n pr
ogra
mm
ing
apps
may
be
mul
ticas
tse
nd a
udio
/vid
eo, u
se u
dpm
ay b
e un
icas
t–
broa
dly
cons
ider
voi
ce o
ver I
P he
re–
stre
amin
g m
edia
cont
rol (
stop
/fast
-for
war
d e.
g.,)
may
use
TC
P
82Ji
m B
inkl
ey
com
mon
app
trai
tsus
e U
DP
and
send
con
stan
t stre
amlo
w b
andw
idth
bec
ause
T1
has b
een
a
bottl
enec
k (n
ow D
SL/c
able
-mod
em?)
not r
elia
ble
data
nee
ds to
be
sequ
ence
d an
d th
ere
need
s to
be
timin
g in
form
atio
n -R
TP p
roto
col
prov
ides
sequ
enci
ng/ti
me
info
/form
at
83Ji
m B
inkl
ey
com
mon
enc
apsu
latio
n sc
hem
e
ip
u
dp
rtp
a/v
dat
a
84Ji
m B
inkl
ey
som
e ex
ampl
esau
dio
(usu
ally
not
a fa
t bi
t stre
am)
–pc
m/te
leph
one
“sim
ulat
ion”
–re
al a
udio
vide
o (ty
pica
lly c
ompr
esse
d)–
stre
amin
g m
edia
, 3 c
omm
on fo
rmat
s»
real
/mic
roso
ft/ap
ple
quic
ktim
e»
real
vid
eo a
t 160
kbi
ts-o
ne e
xam
ple
–H
323
ITU
spec
-vo
ice/
vide
o co
nf»
netm
eein
g(u
soft)
/pol
ycom
85Ji
m B
inkl
ey
uppe
r end
has t
ende
ncy
to b
e M
PEG
bas
ed–
e.g.
, “fa
t”H
323
stre
am <
T1
(1.5
44)
–M
peg2
stre
am m
ight
be
2-16
mbi
ts»
note
: com
pres
sed
by d
efin
ition
, N
TSC
unc
ompr
esse
d is
how
bi
g?
–ci
sco
ip/tv
is e
xam
ple
HD
TV is
out
ther
e–
UW
exp
erim
ents
ove
r Ine
t2 >
100
mbi
ts w
ith so
me
stre
ams
obvi
ousa
lly c
ompr
essi
on is
impo
rtant
86Ji
m B
inkl
ey
appl
icat
ion
mod
el/s
on o
rder
of
–1
stre
am fo
r voi
ce/U
DP
–1
stre
am fo
r vid
eo/U
DP
–1
or m
ore
stre
ams f
or c
ontro
l»
use
TCP/
HTT
P ...
som
e m
edia
form
ats M
AY
com
bine
vo
ice/
audi
o (e
.g.,
MPE
G)
note
a/v
dat
a m
ay/m
ay n
ot b
e co
mpr
esse
d
87Ji
m B
inkl
ey
erro
r han
dlin
gby
def
initi
on, w
e fa
ce p
acke
t-los
sby
def
initi
on, w
e m
ay n
ot d
o pa
cket
rese
nds
pack
ets m
ay b
e ou
t of o
rder
rec
vse
es N
+1, N
recv
may
nee
d 2-
way
“re
altim
e”co
nnec
tivity
, hen
ce 2
-w
ay d
elay
may
be
impo
rtant
fcom
pare
d to
1-w
ay o
nly
we
may
als
o ha
ve IP
jitte
r(la
yer 2
jitte
r exi
sts,
but c
an b
e ig
nore
d in
the
face
of l
ayer
3 ji
tter,
unle
ss y
ou a
re p
hone
co
)jit
ter -
-too
muc
h tim
e va
riatio
n be
twee
n tw
o pa
cket
s in
an
a/v
stre
am–
coul
d ca
use
“wow
/flut
ter”
in p
layb
ack
at re
cv
88Ji
m B
inkl
ey
erro
r fix
ups
prot
ocol
/pro
gram
min
g-le
vel o
nly
here
recv
has b
uffe
r of c
erta
in si
ze–
jitte
r buf
fer -
reor
der p
acke
ts to
intro
duce
fixe
d de
lay
betw
een
them
, bef
ore
play
back
/dec
ode
–re
sequ
ence
if po
ssib
le a
cc. t
o tim
ing
rest
rain
ts–
may
hav
e to
dro
p ho
wev
er
one
can
reco
ver b
its o
r eve
n pa
cket
s dep
endi
ng o
n th
e le
vel o
f red
unda
ncy
used
–e.
g., t
here
exi
st F
EC, f
orw
ard
erro
r cor
rect
ion
sche
mes
th
at c
an le
ad to
bit
fixup
s
89Ji
m B
inkl
ey
caus
es o
f jitt
erse
ndin
g ho
st in
trodu
ces t
ime
dela
ys–
OS
sche
dulin
g–
file
i/o if
file
pla
ybac
k–
heav
y ne
twor
k tra
ffic
pro
cess
ing
sam
e fo
r rec
vho
stro
uter
and
switc
hing
Que
ues i
n in
term
edia
te sy
stem
s lay
er2/
laye
r3so
me
rese
arch
ers t
hink
we
need
mul
timed
ia
OS
in a
dditi
on to
“Q
OS”
in n
etw
ork
90Ji
m B
inkl
ey
Rea
l Tim
e Pr
otoc
ol/R
TPR
FC 1
889,
als
o IT
U st
anda
rdba
sica
lly p
rovi
des
–se
quen
ce #
, 16
bit
–tim
esta
mp/
and
som
e ki
nd o
f cod
e to
, 32
bit
–id
AV
form
at–
note
com
pani
on p
roto
col R
TCP;
i.e.
,
91Ji
m B
inkl
ey
RTC
P -R
TP c
ontro
l pro
toco
lde
fined
in sa
me
RFC
as R
TPco
ntro
l -no
t dat
aif
RTP
por
t N u
sed,
RTC
P is
N+1
send
ers m
ay se
nd ti
mes
tam
ps o
r use
r inf
oe.
g.,S
ally
Sm
ith is
send
ing
this
stre
amre
cvm
ight
send
stat
s/er
ror i
nfo/
jitte
r sta
tein
fo c
an b
e ap
p sp
ecifi
c
92Ji
m B
inkl
ey
RTS
P real
tim
e st
ream
ing
prot
ocol
RFC
232
6IE
TF V
CR
like
con
trol p
roto
col
–st
op/s
tart/
ff,
etc.
stre
amin
g m
edia
orie
nted
93Ji
m B
inkl
ey
appl
icat
ion
secu
rity
if pt
. to
pt.,
no d
iffer
ent f
rom
any
oth
er
trans
port
prot
ocol
–en
cryp
t stre
am h
as b
een
done
in p
ast,
but
auth
entic
atio
n he
re is
a g
ood
idea
too
–us
e IP
SEC
/ssh
/ssl
...
if m
ultic
ast
–op
en p
robl
em,
prot
ocol
pro
posa
ls e
xist
–on
e th
ing:
con
side
r gro
up si
ze ..
.–
a gr
oup
of 1
mill
ion
is n
ot se
cure
by
defin
ition
94Ji
m B
inkl
ey
conc
lusi
ons
mul
ticas
t at L
ayer
3 h
as h
ad se
rious
pro
blem
s and
is
not
com
mon
ly a
ccep
ted
–ac
ross
rout
ing
dom
ains
(BG
P w
orld
)to
som
e ex
tent
mul
ticas
t mis
sed
its ti
me
–m
ost A
/V d
eliv
ered
with
a c
ombi
natio
n of
UD
P an
d TC
P–
UD
P fo
r dat
a, T
CP
for c
ontro
l–
and
serv
ers o
f cou
rse
…pl
us m
any
form
ats f
or a
udio
an
d vi
deo
–it’
s uni
cast
, JIM
95Ji
m B
inkl
ey
conc
lusi
ons (
posi
tive
thin
king
)1-
N d
istri
butio
n ca
n st
ill h
ave
its p
lace
–fil
e di
strib
utio
n to
cac
hes
–sc
hedu
led
broa
dcas
t»
unic
ast m
ultip
oint
is a
bsur
d»
but g
ood
for
serv
er se
llers
mul
ticas
t at L
2 an
d w
ithin
a li
mite
d L3
do
mai
n–
has i
ts p
lace
. br
oadc
ast d
omai
n +
inte
rior
rout
ing
dom
ain
96Ji
m B
inkl
ey
rese
arch
lots
of Q
OS
wor
k –
ther
e ar
e tw
o ba
sic
prob
lem
s–
1. N
**2
stat
e in
the
cent
er–
2. N
**2
law
yers
bet
wee
n IS
Ps»
you
wan
t how
muc
h re
serv
ed b
andw
idth
?
QO
S is
doa
ble
with
in o
ne ro
utin
g do
mai
n–
cont
rolle
d by
one
set o
f eng
inee
rs–
this
stat
emen
t app
lies t
o V
oice
ove
r IP
»it’
s jus
t aud
io p
lus a
sign
alin
g pr
otoc
ol
97Ji
m B
inkl
ey
othe
r QO
S sc
hem
esno
t use
end
to e
nd (R
SVP)
but
sim
ply
limit
QO
S ov
er IP
to lo
cal i
nter
net/i
ntra
net
IEEE
-80
2.1P
–IP
v4 p
riorit
y-lik
e bi
ts b
ut in
MA
C h
eade
r po
rtion
IETF
-di
ff-s
erve
and
/or M
PLS
–fu
nctio
nally
end
up
with
ATM
-like
circ
uits
need
que
uing
sche
mes
in ro
uter
s/sw
itche
s
98Ji
m B
inkl
ey
QO
S st
rate
gies
ATM
giv
es h
arde
r (le
ss m
ushy
) for
m o
f QO
S–
but l
imite
d sc
alab
ility
–an
d no
t lik
ely
to g
o to
end
syst
em o
r lan
RSV
P, so
fter f
orm
, end
to e
nd–
but n
ot u
ltim
atel
y sc
alab
le in
cor
e ro
uter
s–
requ
ires h
ost s
w m
ods
IEEE
/diff
-ser
ve si
mpl
est a
nd so
ftest
BIG
PIP
ES
rem
ain
a go
od id
ea–
giga
bit e
ther
net t
o th
e do
orkn
ob?
99Ji
m B
inkl
ey
rese
arch
com
pres
sion
in a
udio
/vid
eo (e
spec
ially
) fo
rmat
s -al
way
s nee
d to
squi
sh v
ideo
–an
d do
it o
n sm
alle
r lin
ks
mul
ticas
t rou
ting
and
secu
rity
of sa
me
–th
ere
is a
que
stio
n of
dim
inis
hing
retu
rns
thou
gh
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