format. IP Address IP Addresses - Personal Home...
30
IP Addresses IP Addresses IP Address • To make the IP address easier to use, the address is usually written as four decimal numbers separated by periods. • This way of writing the address is called the dotted decimal format. 2
Transcript of format. IP Address IP Addresses - Personal Home...
IP A
dd
re
sse
sIP
Ad
dre
sse
s
IP A
dd
ress
•To
ma
ke th
e IP
ad
dre
ss ea
sier to
use
, the
ad
dre
ss is usu
ally
w
ritten
as fo
ur d
ecim
al n
um
be
rs sep
ara
ted
by
pe
riod
s.
•T
his w
ay
of w
riting
the
ad
dre
ss is calle
d th
e d
otte
d d
ecim
al
form
at.
2
Do
tted
-de
cima
l no
tatio
n
19
2.2
07
.56
.22
11
00
00
00
11
00
11
11
00
11
10
00
00
01
01
10
•T
he
ne
two
rk p
refix id
en
tifies a
ne
two
rk a
nd
the
ho
st nu
mb
er id
en
tifies a
spe
cific ho
st
(actu
ally, in
terfa
ce o
n th
e n
etw
ork
).
Ne
two
rk p
refix a
nd
Ho
st nu
mb
er
network prefix
host number
CL
AS
SF
UL
AD
DR
ES
SIN
GA
DD
RE
SS
IN
G
In
In cla
ssful
classfu
la
dd
ressing
, a
dd
ressing
,
the a
dd
ress spa
ce is th
e ad
dress sp
ace is
divid
ed in
to five cla
sses: d
ivided
into
five classes:
divid
ed in
to five cla
sses: d
ivided
into
five classes:
AA, , BB, , CC, , DD, , a
nd
a
nd
EE..
The C
lass D
addre
ss c
lass w
as c
reate
d to
enable
multic
astin
g.
IET
F
reserv
es C
lass E
addre
sses fo
r its o
wn re
searc
h.
Fin
din
g th
e cla
ss in b
ina
ry n
ota
tion
Fin
din
g th
e cla
ss in d
ecim
al n
ota
tion
Re
serve
d IP
Ad
dre
sses
•C
erta
in h
ost a
dd
resse
s are
re
serve
d a
nd
can
no
t be
a
ssign
ed
to d
evice
s on
a
ne
two
rk.
•A
n IP
ad
dre
ss tha
t ha
s
10
•A
n IP
ad
dre
ss tha
t ha
s b
ina
ry 0
s in a
ll ho
st bit
po
sition
s is rese
rved
for th
e
ne
two
rk a
dd
ress.
•A
n IP
ad
dre
ss tha
t ha
s b
ina
ry 1
s in a
ll ho
st bit
po
sition
s is rese
rved
for th
e
bro
ad
cast a
dd
ress.
Exa
mp
le: B
lock
s in cla
ss A
Ne
two
rk ID
Ca
n su
pp
ort u
p to
1
28
Ca
n su
pp
ort u
p to
16
,77
7,2
16
ho
sts
12
8
Blo
cks
Pro
ble
ms w
ith C
lassfu
llIP
Ad
dre
sses
•T
he
classfu
la
dd
ress sch
em
e h
ad
a n
um
be
r of p
rob
lem
s
–P
rob
lem
1.
Too
few
ne
two
rk a
dd
resse
s for la
rge
ne
two
rks
–P
rob
lem
2.Tw
o-la
yer h
iera
rchy is n
ot a
pp
rop
riate
for
larg
e n
etw
orks w
ith C
lass A
an
d C
lass B
ad
dre
sses.
larg
e n
etw
orks w
ith C
lass A
an
d C
lass B
ad
dre
sses.
–P
rob
lem
3.
Ad
dre
ss De
ple
tion
»C
lass A
an
d C
lass B
ad
dre
sses a
re g
on
e
Su
bn
ettin
g(3
lev
el h
iera
rchy
)
•S
plit th
e h
ost n
um
be
r po
rtion
of a
n IP
ad
dre
ss into
a
subnet number
an
d a
(sma
ller) h
ost number
.
•R
esu
lt is a 3
-laye
r hie
rarch
y
network prefix
host number
•T
he
exte
nd
ed
ne
two
rk p
refix is a
lso ca
lled
sub
ne
tma
sk
•T
he
n:
•S
ub
ne
ts can
be
free
ly a
ssign
ed
with
in th
e o
rga
niza
tion
•In
tern
ally, su
bn
ets a
re tre
ate
d a
s sep
ara
te n
etw
ork
s
•S
ub
ne
t structu
re is n
ot v
isible
ou
tside
the
org
an
izatio
n
subnet number
network prefix
host number
extended network prefix
•R
ou
ters a
nd
ho
sts use
an
ex
ten
de
d n
etw
ork
pre
fix(su
bn
etm
ask
)to
ide
ntify
the
start o
f the
ho
st n
um
be
rs
Su
bn
etm
ask1
28.143
137.144
netw
ork p
refix
host n
um
ber
128.143
144
netw
ork p
refix
host n
um
ber
subnet
num
ber
137
exte
nded n
etw
ork p
refix
11111111111111111111111100000000
subnetm
ask
Exa
mp
le: S
ub
ne
tma
sk
•1
28
.14
3.0
.0/1
6 is th
e IP
ad
dre
ss of th
e n
etw
ork
•1
28
.14
3.1
37
.0/2
4 is th
e IP
ad
dre
ss of th
e su
bn
et
•W
he
n su
bn
ettin
gis u
sed
, on
e g
en
era
lly sp
ea
ks of a
“sub
ne
tma
sk” (in
stea
d o
f a n
etm
ask
) an
d a
“sub
ne
t” (inste
ad
of a
ne
two
rk)
of a
ne
two
rk)
•U
se o
f sub
ne
tting
or le
ng
th o
f the
sub
ne
tma
skis d
ecid
ed
by
the
ne
two
rk a
dm
inistra
tor
•C
on
sisten
cy o
f sub
ne
tma
sksis re
spo
nsib
ility o
f ad
min
istrato
r
No
Su
bn
ettin
g
•A
ll ho
sts thin
k th
at th
e o
the
r ho
sts are
on
the
sam
e n
etw
ork
With
Su
bn
ettin
g
•H
osts w
ith sa
me
exte
nd
ed
ne
two
rk p
refix b
elo
ng
to th
e sa
me
ne
two
rk
128.143.0.0/16
128.143.137.32/24subnetm
ask: 255.255.255.0
128.143.71.21/24subnetm
ask: 255.255.255.0
128.143.137.144/24subnetm
ask: 255.255.255.0
128.143.71.201/24subnetm
ask: 255.255.255.0
128.143.137.0/24
Subnet
128.143.71.0/24
Subnet
Va
riab
le-Le
ng
th S
ub
ne
t Ma
sk -
VLS
M
•V
LSM
allo
ws yo
u to
use
mo
re th
an
on
e su
bn
et m
ask
with
in th
e
sam
e n
etw
ork
ad
dre
ss spa
ce -
sub
ne
tting
a su
bn
et
SS
ubnet A
dd
18
SS
ubnet A
dd
0207.2
1.2
4.0
/27
1207.2
1.2
4.3
2/2
7
2207.2
1.2
4.6
4/2
7
3207.2
1.2
4.9
6/2
7
4207.2
1.2
4.1
28/2
7
5207.2
1.2
4.1
60/2
7
6207.2
1.2
4.1
92/2
7
7207.2
1.2
4.2
24/2
7
Su
b-s
ub
Su
b-S
ub
net A
dd
Su
b 0
207.2
1.2
4.1
92/ 3
0
Su
b 1
207.2
1.2
4.1
96/3
0
……
..
Su
b 5
207.2
1.2
4.2
12/ 3
0
Su
b 6
207.2
1.2
4.2
16/3
0
Su
b 7
207.2
1.2
4.2
20/3
0
An
Exa
mp
le P
rob
lem
in S
ub
ne
tting
•P
rob
lem
:
Cre
ate
an
IP A
dd
ressin
g P
lan
for a
Co
mp
an
y th
at:
–H
as 5
Ph
ysical se
gm
en
ts tha
t ea
ch h
ave
a
ma
ximu
m o
f 50
00
ho
st on
ea
ch se
gm
en
t
–A
nd
is assig
ne
d a
class B
Ad
dre
ss 15
2.7
7.0
.0–
An
d is a
ssign
ed
a cla
ss B A
dd
ress 1
52
.77
.0.0
ISP
5 p
hysica
l
seg
me
nts w
ith
50
00
ho
sts ea
ch
Su
bn
et ID
s
•P
ortio
ns o
f the
Assig
ne
d N
etw
ork
ID a
re D
efin
ed
by
S
ub
ne
t IDs
–1
52
.77
.0.0
(Ne
two
rk IP
Ad
dre
ss)
–2
55
.25
5.0
.0(D
efa
ult S
ub
ne
t Ma
sk)
•N
etw
ork
. Ne
two
rk. H
ost
. Ho
st(D
efa
ult S
NM
)
•N
etw
ork
. Ne
two
rk.
SN
-ID. H
ost
(Cu
stom
SN
M)
–A
ll De
vice
/Ho
sts Sh
are
the
Assig
ne
d N
etw
ork
ID (A
ll –
All D
evice
/Ho
sts Sh
are
the
Assig
ne
d N
etw
ork
ID (A
ll P
hysica
l Se
gm
en
ts)
–E
ach
Ph
ysical S
eg
me
nt o
f the
Ne
two
rk h
as a
Un
iqu
e
Su
bn
et-ID
an
d th
e S
ub
ne
t ID is C
om
mo
n to
All H
osts o
n a
P
hysica
l Se
gm
en
t
–E
ach
Ho
st on
the
Ne
two
rk h
as a
Ho
st ID U
niq
ue
to its
Su
bn
et ID
Su
bn
et ID
/Ho
st Ch
art fo
r Cla
ss B N
etw
orks
•1
52
.77
.0.0
N
etw
ork
Ad
dre
ss
•2
55
.25
5.0
.0
De
fau
lt SN
M
•1
11
11
11
1.1
11
11
11
1.0
00
0 0
00
0.0
00
0 0
00
0 S
NM
(Bin
ary
)
SN
M (La
st Tw
o O
ctets)
SN
M#
of S
N-ID
s*#
of H
osts P
er S
N-
ID
10
00
00
00
00
00
00
00
1
28
2-2
=0
3
27
68
-2=
32
76
6
11
00
00
00
00
00
00
00
1
92
4
-2=
2
16
38
4-2
=1
63
82
11
10
00
00
00
00
00
00
2
24
8
-2=
6
81
92
-2=
81
90
11
11
00
00
00
00
00
00
2
40
1
6-2
=1
4
40
96
-2=
40
94
11
11
10
00
00
00
00
00
2
48
3
2-2
=3
0
20
48
-2=
20
46
11
11
11
00
00
00
00
00
2
52
6
4-2
=6
2
10
24
-2=
10
22
11
11
11
10
00
00
00
00
2
54
12
8-2
=1
26
5
12
-2=
51
0
11
11
11
11
00
00
00
00
25
52
56
-2=
25
42
56
-2=
25
4
CID
R -
Cla
ssless In
terd
om
ain
Ro
utin
g
•IP
ba
ckb
on
e ro
ute
rs ha
ve o
ne
rou
ting
tab
le
en
try fo
r ea
ch n
etw
ork
ad
dre
ss:–
With
sub
ne
tting
, a b
ack
bo
ne
rou
ter o
nly
ne
ed
s to k
no
w o
ne
en
try fo
r e
ach
Cla
ss A, B
, or C
ne
two
rks
–T
his is a
ccep
tab
le fo
r Cla
ss A a
nd
Cla
ss B n
etw
orks
•2
7=
12
8 C
lass A
ne
two
rks
•2
14
= 1
6,3
84
Cla
ss B n
etw
orks
•2
= 1
6,3
84
Cla
ss B n
etw
orks
–B
ut th
is is no
t acce
pta
ble
for C
lass C
ne
two
rks•
22
1=
2,0
97
,15
2 C
lass C
ne
two
rks
•In
19
93
, the
size o
f the
rou
ting
tab
les sta
rted
to
ou
tgro
w th
e ca
pa
city o
f rou
ters
•C
on
seq
ue
nce
: Th
e C
lass-b
ase
d a
ssign
me
nt o
f IP
ad
dre
sses h
ad
to b
e a
ba
nd
on
ed
CID
R -
Cla
ssless In
terd
om
ain
Ro
utin
g•
Go
als:
–N
ew
inte
rpre
tatio
n o
f the
IP a
dd
ress sp
ace
–R
estru
cture
IP a
dd
ress a
ssign
me
nts to
incre
ase
e
fficien
cy
–H
iera
rchica
l rou
ting
ag
gre
ga
tion
to m
inim
ize ro
ute
ta
ble
en
tries
•C
IDR
(Cla
ssless In
terd
om
ain
rou
ting
) –
ab
an
do
ns th
e n
otio
n o
f classe
s
–K
ey
Co
nce
pt:
Th
e le
ng
th o
f the
ne
two
rk p
refix in
the
IP
ad
dre
sses is ke
pt a
rbitra
ry (V
LSM
)
–C
on
seq
ue
nce
: Size
of th
e n
etw
ork
pre
fix mu
st be
p
rovid
ed
with
an
IP a
dd
ress
CID
R N
ota
tion
•C
IDR
no
tatio
n o
f an
IP a
dd
ress:
19
2.0
.2.0
/18
•"1
8" is th
e p
refix le
ng
th. It sta
tes th
at th
e first 1
8 b
its are
the
ne
two
rk
pre
fix of th
e a
dd
ress (a
nd
14
bits a
re a
vaila
ble
for sp
ecific h
ost a
dd
resse
s)
•C
IDR
no
tatio
n a
llow
s to d
rop
trailin
g ze
ros o
f ne
two
rk a
dd
resse
s:
19
2.0
.2.0
/18
can
be
writte
n a
s1
92
.0.2
/18
19
2.0
.2.0
/18
can
be
writte
n a
s1
92
.0.2
/18
CID
R a
dd
ress b
locks
•C
IDR
no
tatio
n ca
n n
icely
exp
ress b
locks o
f ad
dre
sses
•B
locks a
re u
sed
wh
en
allo
catin
g IP
ad
dre
sses fo
r a co
mp
an
y a
nd
for ro
utin
g ta
ble
s (ro
ute
ag
gre
ga
tion
)
CID
R B
lock
Pre
fix #
of H
ost A
dd
resse
s/2
73
2
/26
64
/25
12
8
/24
25
6
/23
51
2/2
35
12
/22
1,0
24
/21
2,0
48
/20
4,0
96
/19
8,1
92
/18
16
,38
4
/17
32
,76
8
/16
65
,53
6
/15
13
1,0
72
/14
26
2,1
44
/13
52
4,2
88
Su
bn
ettin
ga
nd
Su
pe
rne
tting
•C
IDR
is com
pa
tible
with
sub
ne
tting
:
–S
ub
ne
ts are
crea
ted
by
exte
nd
ing
the
pre
fix
•C
IDR
can
do
mo
re:
–C
IDR
can
refe
r to m
ultip
le n
etw
orks w
ith
a sin
gle
pre
fix:
•1
28
.14
3.0
.0/1
6 a
nd
12
8.1
73
.0.0
/16
can
128.143.0.0/16
128.143.137.32/26subnetm
ask: 255.255.255.192
128.143.71.21/24subnetm
ask: 255.255.255.0
128.143.137.144/26subnetm
ask: 255.255.255.192
128.143.71.201/16subnetm
ask: 255.255.0.0
128.143.71.0/24
Subnet128.143.137.128/26
Subnet
128.143.137.0/26
Subnet
•1
28
.14
3.0
.0/1
6 a
nd
12
8.1
73
.0.0
/16
can
b
e su
mm
arize
d a
s 12
8.1
28
.0.0
/10
–T
his is ca
lled
sup
ern
ettin
g(In
fact, C
IDR
an
d
sup
ern
ettin
ga
re o
ften
use
d a
s the
sam
e
thin
g)
–If n
eig
hb
orin
g n
etw
orks h
ave
simila
r ad
dre
ss b
locks, su
pe
rne
tting
red
uce
s the
size o
f ro
utin
g ta
ble
s
CID
R a
nd
Ad
dre
ss assig
nm
en
ts
•E
xplo
iting
sup
ern
ettin
gto
red
uce
size o
f rou
ting
ta
ble
s:–
Ba
ckb
on
e IS
Ps o
bta
in b
locks o
f IP a
dd
resse
s an
d
allo
cate
po
rtion
s of th
eir a
dd
ress b
locks to
the
ir cu
stom
ers.
–C
usto
me
rs can
allo
cate
a p
ortio
n o
f the
ir ad
dre
ss b
lock
to th
eir cu
stom
ers.
Exa
mp
le:
Exa
mp
le:
•A
ssum
e th
at a
n IS
P o
wn
s the
ad
dre
ss blo
ck 2
06
.0.6
4.0
/18
,w
hich
re
pre
sen
ts 16
,38
4 (2
14) IP
ad
dre
sses
•S
up
po
se a
clien
t req
uire
s 80
0 h
ost a
dd
resse
s
•W
ith cla
ssfula
dd
resse
s: ne
ed
to a
ssign
a cla
ss B a
dd
ress (a
nd
wa
ste
~6
4,7
00
ad
dre
sses) o
r fou
r ind
ivid
ua
l Cla
ss Cs (a
nd
intro
du
cing
4 n
ew
rou
tes
into
the
glo
ba
l Inte
rne
t rou
ting
tab
les)
•W
ith C
IDR
:A
ssign
a /2
2 b
lock
, e.g
., 20
6.0
.68
.0/2
2, a
nd
allo
cate
d a
blo
ck o
f 1
,02
4 (2
10) IP
ad
dre
sses.
Subne
t A:
15 hosts
Sub
net B:
12 hosts
Subnet C
: 45 hosts
R1
128,
to public Internet via IS
P
Usin
g th
e p
ub
lic ad
dre
ss of ro
ute
r R1
12
8.1
19
.40
.0/2
3
CID
R a
nd
Ro
utin
g In
form
atio
n
20
6.0
.64
.0/1
8
20
4.1
88
.0.0
/15
20
9.8
8.2
32
.0/2
1In
tern
et B
ackbone
ISP
X o
wn
s:
Co
mp
an
y X
:
20
6.0
.68
.0/2
2
20
9.8
8.2
32
.0/2
1In
tern
et B
ackbone
ISP
y :
20
9.8
8.2
37
.0/2
4
Org
an
iza
tion
z1
:
20
9.8
8.2
37
.19
2/2
6
Org
an
iza
tion
z2
:
20
9.8
8.2
37
.0/2
6
CID
R a
nd
Ro
utin
g
•A
gg
reg
atio
no
f rou
ting
tab
le e
ntrie
s:
–1
28
.14
3.0
.0/1
6 a
nd
12
8.1
44
.0.0
/16
are
rep
rese
nte
d a
s 12
8.1
42
.0.0
/15
•Lo
ng
est p
refix
ma
tch:
Ro
utin
g ta
ble
loo
kup
find
s the
rou
ting
en
try th
at
ma
tche
s the
lon
ge
st pre
fix
Wh
at is th
e o
utg
oin
g in
terfa
ce fo
r
Pre
fixIn
terfa
ce
12
8.0
.0.0
/4
inte
rface
#5
W
ha
t is the
ou
tgo
ing
inte
rface
for
12
8.1
43
.13
7.0
/24
?
Ro
ute
ag
gre
ga
tion
can
be
exp
loite
d
wh
en
IP a
dd
ress b
locks a
re a
ssign
ed
in a
n h
iera
rchica
l fash
ion
12
8.0
.0.0
/4
inte
rface
#5
12
8.1
28
.0.0
/9in
terfa
ce
#2
12
8.1
43
.12
8.0
/17
inte
rface
#1
Ro
utin
g ta
ble
CID
R a
nd
Ro
utin
g
Lon
ge
st pre
fix m
atch
:R
ou
ting
tab
le lo
oku
p fin
ds th
e ro
utin
g e
ntry
tha
t ma
tche
s
the
lon
ge
st pre
fix
Wh
at is th
e o
utg
oin
g in
terfa
ce fo
r
12
8.1
43
.13
7.0
/24
?
Ap
ply
/17
on
12
8.1
43
.13
7.0
to g
et n
etw
ork
Ad
dre
ss:
Pre
fixIn
terfa
ce
12
8.1
43
.12
8.0
/17
inte
rface
#1
1
00
00
00
0. 1
00
01
11
1. 1
00
01
00
1.0
00
00
00
0
No
w ta
ke 1
7 b
its from
ab
ove
an
d se
t the
rest
To 0
.
10
00
00
00
. 10
00
11
11
.10
00
00
00
.00
00
00
00
=
12
8.1
43
.12
8.0
No
w lo
ok
for th
is in th
e ro
utin
g ta
ble
, we
find
the
first en
try a
s exa
ct ma
tch. S
o
Forw
ard
this p
acke
t thro
ug
h in
terfa
ce #
1
12
8.1
43
.12
8.0
/17
inte
rface
#1
12
8.1
28
.0.0
/9in
terfa
ce
#2
12
8.0
.0.0
/4
inte
rface
#5
Ro
utin
g ta
ble
De
stina
tion
Ad
dre
ssN
ex
t Ho
p
206.0
.64.0
/18
R1
204.1
88.0
.0/1
5R
2
206.0
.68.5
/22
So
lve it:2
04.1
88.0
.0/1
5R
2
209.8
8.2
32.0
/21
R3
De
fau
ltR
4
De
stina
tion
Ad
dre
ssN
ex
t Ho
p
209.8
8.2
32.0
/21
R3
206.0
.64.0
/18
R1
206.0
.68.5
/22
So
lve it:
206.0
.64.0
/18
R1
204.1
88.0
.0/1
5R
2
De
fau
ltR
4
CID
R a
nd
Ro
utin
g In
form
atio
n
20
6.0
.64
.0/1
8
20
4.1
88
.0.0
/15
20
9.8
8.2
32
.0/2
1In
tern
et B
ackbone
ISP
X o
wn
s:
Co
mp
an
y X
:
20
6.0
.68
.0/2
2
Ba
ckb
on
e ro
ute
rs d
o n
ot k
no
w
an
yth
ing
ab
ou
t Co
mp
an
y X
, ISP
Y, o
r Org
an
iza
tion
s z
1, z
2.
ISP
X d
oe
s n
ot k
no
w a
bo
ut
Org
an
iza
tion
s z
1, z
2.
ISP
y s
en
ds e
ve
ryth
ing
wh
ich
ma
tch
es
20
9.8
8.2
32
.0/2
1In
tern
et B
ackbone
ISP
y :
20
9.8
8.2
37
.0/2
4
Org
an
iza
tion
z1
:
20
9.8
8.2
37
.19
2/2
6
Org
an
iza
tion
z2
:
20
9.8
8.2
37
.0/2
6
Ba
ckb
on
e s
en
ds e
ve
ryth
ing
wh
ich
ma
tch
es th
e p
refix
es 2
06
.0.6
4.0
/18
,
20
4.1
88
.0.0
/15
, 20
9.8
8.2
32
.0/2
1to
ISP
X.
ISP
X s
en
ds e
ve
ryth
ing
wh
ich
ma
tch
es th
e p
refix
: 20
6.0
.68
.0/2
2to
Co
mp
an
y X
,
20
9.8
8.2
37
.0/2
4 to
ISP
y
ISP
y s
en
ds e
ve
ryth
ing
wh
ich
ma
tch
es
the
pre
fix:
20
9.8
8.2
37
.19
2/2
6to
Org
an
iza
tion
s z
1
20
9.8
8.2
37
.0/2
6 to
Org
an
iza
tion
s z
2
Ro
utin
g ta
ble
loo
kup
: Lon
ge
st Pre
fix Ma
tch
With
CID
R, th
ere
can
be
mu
ltiple
ma
tche
s for a
de
stina
tion
ad
dre
ss in th
e ro
utin
g ta
ble
Lon
ge
st Pre
fix M
atch
:S
ea
rch fo
r the
rou
ting
tab
le e
ntry
tha
t ha
s
the
lon
ge
st ma
tch w
ith th
e p
refix o
f the
de
stina
tion
IP a
dd
ress
(=M
ost S
pe
cific Ro
ute
r):
1.
Se
arch
for a
ma
tch o
n a
ll 32
bits
1.
Se
arch
for a
ma
tch o
n a
ll 32
bits
2.
Se
arch
for a
ma
tch fo
r 31
bits
…..
32
. S
ea
rch fo
r a m
ach
on
0 b
its
Ne
ed
ed
: Da
ta stru
cture
s tha
t sup
po
rt a fa
st lon
ge
st pre
fix m
atch
loo
ku
p!
Pro
ble
ms w
ith IP
V4
IP A
dd
resse
s
Pro
ble
m 5
.In
CID
R, th
e IP
ad
dre
sses in
a co
rpo
rate
ne
two
rk
are
ob
tain
ed
from
the
serv
ice p
rovid
er. C
ha
ng
ing
the
serv
ice p
rovid
er re
qu
ires ch
an
gin
g a
ll IP a
dd
resse
s in th
e
ne
two
rk
•S
ol
:p
riva
te a
dd
resse
s:
–A
ssign
priva
te a
dd
resse
s to th
e h
osts o
f the
corp
ora
te n
etw
ork
–A
ssign
priva
te a
dd
resse
s to th
e h
osts o
f the
corp
ora
te n
etw
ork
–N
AT
de
vice
ha
s static a
dd
ress tra
nsla
tion
en
tries w
hich
bin
d th
e p
rivate
ad
dre
ss of a
ho
st to th
e p
ub
lic ad
dre
ss.
–M
igra
tion
to a
ne
w n
etw
ork
serv
ice p
rovid
er m
ere
ly re
qu
ires a
n u
pd
ate
of
the
NA
T d
evice
. Th
e m
igra
tion
is no
t no
ticea
ble
to th
e h
osts o
n th
e n
etw
ork
.
Priva
te N
etw
ork
•A
Priv
ate
IP n
etw
ork
is an
IP n
etw
ork
tha
t is no
t d
irectly
con
ne
cted
to th
e In
tern
et
•IP
ad
dre
sses in
a p
rivate
ne
two
rk ca
n b
e a
ssign
ed
a
rbitra
rily.
–N
ot re
giste
red
an
d n
ot g
ua
ran
tee
d to
be
glo
ba
lly
un
iqu
eu
niq
ue
•G
en
era
lly, priva
te n
etw
orks u
se a
dd
resse
s from
th
e fo
llow
ing
exp
erim
en
tal a
dd
ress ra
ng
es (n
on
-ro
uta
ble
ad
dre
sses):
Ra
ng
eTo
tal
10
.0.0
.0 to
10
.25
5.2
55
.25
52
24
17
2.1
6.0
.0 to
17
2.3
1.2
55
.25
52
20
19
2.1
68
.0.0
to 1
92
.16
8.2
55
.25
52
16
Priva
te A
dd
resse
s
Ne
two
rk A
dd
ress Tra
nsla
tion
(NA
T)
•N
AT
is a ro
ute
r fun
ction
wh
ere
IP a
dd
resse
s (an
d
po
ssibly
po
rt nu
mb
ers) o
f IP d
ata
gra
ms a
re
rep
lace
d a
t the
bo
un
da
ry o
f a p
rivate
ne
two
rk
•N
AT
is a m
eth
od
tha
t en
ab
les h
osts o
n p
rivate
n
etw
ork
s to co
mm
un
icate
with
ho
sts on
the
In
tern
et
ne
two
rks to
com
mu
nica
te w
ith h
osts o
n th
e
Inte
rne
t
•N
AT
is run
on
rou
ters th
at co
nn
ect p
rivate
n
etw
ork
s to th
e p
ub
lic Inte
rne
t, to re
pla
ce th
e IP
a
dd
ress-p
ort p
air o
f an
IP p
acke
t with
an
oth
er IP
a
dd
ress-p
ort p
air.
Ba
sic op
era
tion
of N
AT
H1
private address: 10.0.1.2public address: 128.143.71.21
H5
Private
netw
ork
Intern
et
Source
= 10.0.1.2
Destination
= 213.168.112.3
Source
= 128.143.71.21
Destination
= 213.168.112.3
public address: 213.168.112.3N
AT
device
•N
AT
de
vice
ha
s ad
dre
ss tran
slatio
n ta
ble
H1
H5
Source
= 213.168.112.3
Destination
= 128.143.71.21
Source
= 213.168.112.3
Destination
= 10.0.1.2
Private
Address
Public
Address
10.0.1.2128.143.71.21
Co
nce
rns a
bo
ut N
AT
•IP
ad
dre
ssin
ap
plica
tion
da
ta:
–A
pp
licatio
ns
tha
tca
rryIP
ad
dre
sses
inth
ep
aylo
ad
of
the
ap
plica
tion
da
tag
en
era
llyd
on
ot
wo
rk
acro
ssa
priva
te-p
ub
licn
etw
ork
bo
un
da
ry.
–S
om
eN
AT
de
vice
sin
spe
ctth
ep
aylo
ad
of
wid
ely
use
da
pp
licatio
nla
yer
pro
toco
lsa
nd
,if
an
IPu
sed
ap
plica
tion
laye
rp
roto
cols
an
d,
ifa
nIP
ad
dre
ssis
de
tecte
din
the
ap
plica
tion
-laye
rh
ea
de
r
or
the
ap
plica
tion
pa
ylo
ad
,tra
nsla
teth
ea
dd
ress
acco
rdin
gto
the
ad
dre
sstra
nsla
tion
tab
le.
IP d
ata
gra
m fo
rma
t
ver
len
gth
32
bits
16
-bit id
en
tifier
he
ad
er
che
cksum
time
to
live
32
bit so
urce
IP a
dd
ress
IP p
roto
col ve
rsion
nu
mb
er
he
ad
er le
ng
th
(by
tes)
ma
x nu
mb
er
rem
ain
ing
ho
ps
(de
crem
en
ted
at
ea
ch ro
ute
r)
for
frag
me
nta
tion
/
rea
ssem
bly
tota
l da
tag
ram
len
gth
(by
tes)
he
ad
.
len
typ
e o
f
serv
ice“ty
pe
” of d
ata
flg
sfra
gm
en
t
offse
tu
pp
er
laye
r
da
ta
(varia
ble
len
gth
,
typ
ically
a T
CP
or U
DP
seg
me
nt)
ea
ch ro
ute
r)
up
pe
r laye
r pro
toco
l
to d
elive
r pa
ylo
ad
to
32
bit d
estin
atio
n IP
ad
dre
ss
Op
tion
s (if an
y)
E.g
. time
stam
p,
reco
rd ro
ute
take
n, sp
ecify
list of ro
ute
rs
to v
isit.
ho
w m
uch
ove
rhe
ad
with
TC
P?
r2
0 b
yte
s of T
CP
r2
0 b
yte
s of IP
r=
40
by
tes +
ap
p
laye
r ove
rhe
ad
IP F
rag
me
nta
tion
& R
ea
ssem
bly
•n
etw
ork
links h
ave
MT
U
(ma
x.tran
sfer size
) -la
rge
st
po
ssible
link
-leve
l fram
e.
–d
iffere
nt lin
k ty
pe
s, diffe
ren
t
MT
Us
•la
rge
IP d
ata
gra
m d
ivid
ed
(“frag
me
nte
d”) w
ithin
ne
t
frag
me
nta
tion
:
in:
on
e la
rge
da
tag
ram
ou
t:3
sma
ller d
ata
gra
ms
–o
ne
da
tag
ram
be
com
es
seve
ral d
ata
gra
ms
–“re
asse
mb
led
” on
ly a
t fina
l
de
stina
tion
–IP
he
ad
er b
its use
d to
ide
ntify,
ord
er re
late
d fra
gm
en
ts
rea
ssem
bly
IP F
rag
me
nta
tion
an
d R
ea
ssem
bly
ID=x
offse
t
=0
frag
flag
=0
len
gth
=4
00
0
IDo
ffset
frag
flag
len
gth
On
e la
rge
da
tag
ram
be
com
es
seve
ral sm
alle
r da
tag
ram
s
Exa
mp
le
r4
00
0 b
yte
da
tag
ram
rM
TU
= 1
50
0 b
yte
s
ID=x
offse
t
=0
frag
flag
=1
len
gth
=1
50
0
ID=x
offse
t
=1
85
frag
flag
=1
len
gth
=1
50
0
ID=x
offse
t
=3
70
frag
flag
=0
len
gth
=1
04
0
14
80
by
tes in
da
ta fie
ld
offse
t =
14
80
/8
Pro
ble
ms w
ith IP
V4
IP A
dd
resse
s
Pro
ble
m 6
.T
he
Inte
rne
t is go
ing
to o
utg
row
the
32
-bit
ad
dre
sses (2
32
≈ 4
G)
–S
ol :
IP V
ersio
n 6
IPv
6 -
IP V
ersio
n 6
•IP
Ve
rsion
6
–Is th
e su
ccesso
r to th
e cu
rren
tly u
sed
IPv4
–S
pe
cificatio
n co
mp
lete
d in
19
94
–M
ake
s imp
rove
me
nts to
IPv4
(no
revo
lutio
na
ry
cha
ng
es)
•O
ne
(no
t the
on
ly !) fe
atu
re o
f IPv
6 is a
sign
ifican
t incre
ase
in o
f the
IP a
dd
ress to
12
8
bits (1
6 b
yte
s)
•IP
v6
will so
lve –
for th
e fo
rese
ea
ble
futu
re –
the
pro
ble
ms w
ith IP
ad
dre
ssing
IPv
6 H
ea
de
r
vers
ion
(4 b
its)
Tra
ffic C
lass
(8 b
its)
Flo
w L
ab
el
(24 b
its)
Paylo
ad
Len
gth
(16 b
its)
Next H
ead
er
(8 b
its)
Ho
p L
imits
(8 b
its)
So
urc
e IP
ad
dre
ss (1
28 b
its)
32
bits
Ap
plica
tion
da
taT
CP
He
ad
er
Eth
ern
et H
ea
de
rE
the
rne
t Tra
iler
Eth
ern
et fra
me
IPv6 H
ead
er
Destin
atio
n IP
ad
dre
ss (1
28 b
its)
IPv
6 vs. IP
v4
: Ad
dre
ss Co
mp
ariso
n
•IP
v4
ha
s a m
axim
um
of
23
2≈
4 b
illion
ad
dre
sses
•IP
v6
ha
s a m
axim
um
of
21
28
= (2
32)
4 ≈≈≈ ≈
4 b
illion
x4
billio
n x
4 b
illion
x 4
billio
n
21
28
= (2
32)
4 ≈≈≈ ≈
4 b
illion
x4
billio
n x
4 b
illion
x 4
billio
n
ad
dre
sses
No
tatio
n o
f IPv
6 a
dd
resse
s
•C
on
ve
ntio
n: T
he
12
8-b
it IPv
6 a
dd
ress is w
ritten
a
s eig
ht 1
6-b
it inte
ge
rs(u
sing
he
xad
ecim
al d
igits
for e
ach
inte
ge
r)
CE
DF
:BP
76
:32
45
:44
64
:FAC
E:2
E5
0:3
02
5:D
F1
2
•S
ho
rt no
tatio
n:
•A
bb
revia
tion
s of le
ad
ing
zero
es:
CE
DF
:BP
76
:00
00
:00
00
:00
9E
:00
00
:30
25
:DF
12
��� �
CE
DF
:BP
76
:0:0
:9E
:0:3
02
5:D
F1
2
•“:0
00
0:0
00
0:0
00
0” ca
n b
e w
ritten
as “::”
CE
DF
:BP
76
:0:0
:FAC
E:0
:30
25
:DF
12
��� �C
ED
F:B
P7
6::FA
CE
:0:3
02
5:D
F1
2
•IP
v6
ad
dre
sses d
erive
d fro
m IP
v4
ad
dre
sses h
ave
96
lea
din
g ze
ro b
its. C
on
ven
tion
allo
ws to
use
IPv4
no
tatio
n fo
r the
last 3
2 b
its.
::80
:8F
:89
:90
��� �::1
28
.14
3.1
37
.14
4
IPv
6 P
rov
ide
r-Ba
sed
Ad
dre
sses
•T
he
first IPv
6 a
dd
resse
s will b
e a
lloca
ted
to a
pro
vid
er-
ba
sed
pla
n
•Ty
pe
: Se
t to “0
10
” for p
rov
ide
r-ba
sed
ad
dre
sses
Registry
ID
Provider
ID
010
Subscriber
ID
Interface
ID
Subnetwork
ID
•Ty
pe
: Se
t to “0
10
” for p
rov
ide
r-ba
sed
ad
dre
sses
•R
eg
istry: id
en
tifies th
e a
ge
ncy
tha
t reg
istere
d th
e
ad
dre
ss (typ
e+Registry
ID = 8 bits)
Th
e fo
llow
ing
field
s ha
ve
a v
aria
ble
len
gth
(reco
mm
ed
ed
len
gth
in “()”)
•P
rov
ide
r: Id o
f Inte
rne
t acce
ss pro
vid
er (1
6 b
its)
•S
ub
scribe
r:Id
of th
e o
rga
niza
tion
at p
rov
ide
r (24
bits)
•S
ub
ne
two
rk: Id
of su
bn
et w
ithin
org
an
izatio
n (3
2 b
its)
•In
terfa
ce: id
en
tifies a
n in
terfa
ce a
t a n
od
e (4
8 b
its)
Tran
sition
Fro
m IP
v4
To IP
v6
•N
ot a
ll rou
ters ca
n b
e u
pg
rad
ed
simu
ltan
eo
us
–n
o “fla
g d
ays”
–H
ow
will th
e n
etw
ork
op
era
te w
ith m
ixed
IPv4
an
d
IPv6
rou
ters?
•Tw
o p
rop
ose
d a
pp
roa
che
s:•
Two
pro
po
sed
ap
pro
ach
es:
–D
ua
l Sta
ck:
som
e ro
ute
rs with
du
al sta
ck (v
6, v
4)
can
“tran
slate
” be
twe
en
form
ats
–Tu
nn
elin
g:
IPv6
carrie
d a
s pa
ylo
ad
in IP
v4
da
tag
ram
am
on
g IP
v4
rou
ters
Du
al S
tack
Ap
pro
ach
AB
EF
IPv6
IPv6
IPv6
IPv6
CD
IPv4
IPv4
Flo
w: X
Src: A
De
st: F
Flo
w: ?
?
Src: A
De
st: F
Src:A
De
st: FS
rc:A
De
st: F
da
tad
ata
da
ta
A-to
-B:
IPv6
da
ta
B-to
-C:
IPv4
B-to
-C:
IPv4
B-to
-C:
IPv6
Tun
ne
ling
AB
EF
IPv6
IPv6
IPv6
IPv6
tun
ne
lLo
gica
l vie
w:
Ph
ysical v
iew
:A
BE
F
IPv6
IPv6
IPv6
IPv6
CD
IPv4
IPv4
Flo
w: X
Flo
w: X
Src:B
Src:B
Flo
w: X
Src: A
De
st: F
da
ta
Flo
w: X
Src: A
De
st: F
da
ta
Flo
w: X
Src: A
De
st: F
da
ta
Src:B
De
st: E
Flo
w: X
Src: A
De
st: F
da
ta
Src:B
De
st: E
A-to
-B:
IPv6
E-to
-F:
IPv6
B-to
-C:
IPv6
insid
e
IPv4
B-to
-C:
IPv6
insid
e
IPv4
IPv4
da
tag
ram
form
at
ver
len
gth
32
bits
16
-bit id
en
tifier
Inte
rne
t
che
cksum
time
to
live
32
bit so
urce
IP a
dd
ress
IP p
roto
col ve
rsion
nu
mb
er
he
ad
er le
ng
th
(by
tes)
ma
x nu
mb
er
rem
ain
ing
ho
ps
(de
crem
en
ted
at
ea
ch ro
ute
r)
for
frag
me
nta
tion
/
rea
ssem
bly
tota
l da
tag
ram
len
gth
(by
tes)
he
ad
.
len
typ
e o
f
serv
ice“ty
pe
” of d
ata
flg
sfra
gm
en
t
offse
tu
pp
er
laye
r
da
ta
(varia
ble
len
gth
,
typ
ically
a T
CP
or U
DP
seg
me
nt)
ea
ch ro
ute
r)
up
pe
r laye
r pro
toco
l
to d
elive
r pa
ylo
ad
to
32
bit d
estin
atio
n IP
ad
dre
ss
Op
tion
s (if an
y)
E.g
. time
stam
p,
reco
rd ro
ute
take
n, sp
ecify
list of ro
ute
rs
to v
isit.
ho
w m
uch
ove
rhe
ad
with
TC
P?
r2
0 b
yte
s of T
CP
r2
0 b
yte
s of IP
r=
40
by
tes +
ap
p
laye
r ove
rhe
ad
IP F
rag
me
nta
tion
& R
ea
ssem
bly
•n
etw
ork
links h
ave
MT
U
(ma
x.tran
sfer size
) -la
rge
st
po
ssible
link
-leve
l fram
e.
–d
iffere
nt lin
k ty
pe
s, diffe
ren
t
MT
Us
•la
rge
IP d
ata
gra
m d
ivid
ed
(“frag
me
nte
d”) w
ithin
ne
t
frag
me
nta
tion
:
in:
on
e la
rge
da
tag
ram
ou
t:3
sma
ller d
ata
gra
ms
–o
ne
da
tag
ram
be
com
es
seve
ral d
ata
gra
ms
–“re
asse
mb
led
” on
ly a
t fina
l
de
stina
tion
–IP
he
ad
er b
its use
d to
ide
ntify,
ord
er re
late
d fra
gm
en
ts
rea
ssem
bly
IP F
rag
me
nta
tion
an
d R
ea
ssem
bly
ID=x
offse
t
=0
frag
flag
=0
len
gth
=4
00
0
IDo
ffset
frag
flag
len
gth
On
e la
rge
da
tag
ram
be
com
es
seve
ral sm
alle
r da
tag
ram
s
Exa
mp
le
r4
00
0 b
yte
da
tag
ram
rM
TU
= 1
50
0 b
yte
s
ID=x
offse
t
=0
frag
flag
=1
len
gth
=1
50
0
ID=x
offse
t
=1
48
0
frag
flag
=1
len
gth
=1
50
0
ID=x
offse
t
=2
96
0
frag
flag
=0
len
gth
=1
04
0
ICM
P: In
tern
et C
on
trol M
essa
ge
Pro
toco
l
•u
sed
by
ho
sts, rou
ters, g
ate
wa
ys to
com
mu
nica
tion
ne
two
rk-le
vel
info
rma
tion
–e
rror re
po
rting
: un
rea
cha
ble
ho
st,
ne
two
rk, p
ort, p
roto
col
–e
cho
req
ue
st/rep
ly (u
sed
by
pin
g)
•n
etw
ork
-laye
r “ab
ove
” IP:
Type
Code
descrip
tion
0 0
echo re
ply
(pin
g)
3 0
dest. n
etw
ork
unre
achable
3 1
dest h
ost u
nre
achable
3 2
dest p
roto
col u
nre
achable
3 3
dest p
ort u
nre
achable
•n
etw
ork
-laye
r “ab
ove
” IP:
–IC
MP
msg
sca
rried
in IP
da
tag
ram
s
•IC
MP
me
ssag
e:
typ
e, co
de
plu
s first 8
by
tes o
f IP d
ata
gra
m ca
usin
g e
rror
3 3
dest p
ort u
nre
achable
3 6
dest n
etw
ork
unknow
n
3 7
dest h
ost u
nkno
wn
4 0
sourc
e q
uench (c
ongestio
n
contro
l -not u
sed)
8 0
echo re
quest (p
ing)
9 0
route
advertis
em
ent
10 0
route
r dis
covery
11 0
TT
L e
xpire
d
12 0
bad IP
header
DH
CP
: Dy
na
mic H
ost C
on
figu
ratio
n P
roto
col
Go
al:
allo
w h
ost to
dyn
am
ically
ob
tain
its IP a
dd
ress fro
m
ne
two
rk se
rver w
he
n it jo
ins n
etw
ork
Ca
n re
ne
w its le
ase
on
ad
dre
ss in u
se
Allo
ws re
use
of a
dd
resse
s (on
ly h
old
ad
dre
ss wh
ile co
nn
ecte
d a
n “o
n”
Su
pp
ort fo
r mo
bile
use
rs wh
o w
an
t to jo
in n
etw
ork
(mo
re sh
ortly
)
DH
CP
ove
rvie
w:
ho
st bro
ad
casts “D
HC
P d
iscove
r” msg
–h
ost b
roa
dca
sts “DH
CP
disco
ver” m
sg
–D
HC
P se
rver re
spo
nd
s with
“DH
CP
offe
r” msg
–h
ost re
qu
ests IP
ad
dre
ss: “ DH
CP
req
ue
st” msg
–D
HC
P se
rver se
nd
s ad
dre
ss: “DH
CP
ack
” msg
DH
CP
clien
t-serve
r scen
ario
22
3.1
.1.1
22
3.1
.1.2
22
3.1
.1.4
22
3.1
.2.9
22
3.1
.2.1
AD
HC
P
serv
er
22
3.1
.1.3 2
23
.1.1
.42
23
.1.2
.9
22
3.1
.2.2
22
3.1
.3.2
22
3.1
.3.1
22
3.1
.3.2
7
B
Earriv
ing D
HC
P
clie
nt
needs
addre
ss in
this
netw
ork
DH
CP
clien
t-serve
r scen
ario
DH
CP
serve
r: 22
3.1
.2.5
arriv
ing
clien
t
time
