TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
1
The
Inte
rnet
Pro
toco
l (IP
)
John
Kris
toff
jtk@
depa
ul.e
du+
1 31
2 36
2-58
78D
ePau
l Uni
vers
ityC
hica
go, I
L 60
604
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
2
Will
laye
r 2
net
wo
rkin
g s
uff
ice?
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
3
Lay
er 3
usu
ally
pro
vid
es
�
Inte
rnet
wor
king
for
data
link
tech
nolo
gies
�
Glo
bally
uni
que
addr
esse
s
�
Sca
labl
e ro
utin
g
�
A c
omm
on c
omm
unic
atio
ns fo
rmat
�
Pac
ket f
ragm
enta
tion
capa
bilit
y
�
A h
ardw
are
inde
pend
ent i
nter
face
�
Pac
ket i
ndep
ende
nce
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
4
An
IP R
ou
ter
(or
gat
eway
)
�
Usu
ally
a s
peci
al p
urpo
se, d
edic
ated
dev
ice
�
Con
nect
s he
tero
geno
us n
etw
orks
�
Dire
cts
pack
ets
tow
ard
ultim
ate
dest
inat
ion
�
Dyn
amic
rou
ting
algo
rithm
s of
ten
used
�
The
y m
ake
auto
mat
ic fo
rwar
ding
dec
isio
ns
�
The
y ca
n fo
rwar
d ba
sed
on v
ario
us m
etric
s
�
Offi
cial
pro
noun
ciat
ion
is r
eally
root
er
�
Laye
r 3
switc
h =
rou
ter
= la
yer
3 sw
itch
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
5
IP R
ou
tin
g
�
Sco
pe
�
Aut
onom
ous
syst
em, i
nter
ior,
ext
erio
r
�
Dyn
amic
rou
ting
�
Pro
toco
l for
rou
te e
xcha
nge
and
com
puta
tion
�
Sta
tic r
outin
g
�
Man
ually
con
figur
ed r
oute
s
�
Des
tinat
ion
addr
ess
driv
en
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
6
Inte
rnet
pro
toco
l (IP
)
�
Sta
ndar
dize
d in
RF
C 7
91
�
Con
nect
ionl
ess
�
Unr
elia
ble
�
Fai
rly s
impl
e
�
The
Inte
rnet
Glu
e
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
7
IP a
dd
ress
es
�
Virt
ual –
not
bou
nd to
har
dwar
e
�
32-b
it fix
ed s
ize
�
Uni
que
addr
ess
for
each
IP in
terf
ace
�
Glo
bal a
utho
ries
assi
gn a
pre
fix (
netw
ork)
�
Loca
l adm
inis
trat
ors
assi
gn th
e su
ffix
(hos
t)
�
Usu
ally
writ
ten
as d
otte
d de
cim
al n
otat
ion
�
e.g.
140
.192
.1.6
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
8
IP a
dd
ress
typ
es
�
Uni
cast
(on
e-to
-one
)
�
Sou
rce
addr
ess
shou
ld a
lway
s be
uni
cast
�
Mul
ticas
t (on
e-to
-man
y)
�
Rec
eive
rs jo
in/li
sten
to m
ultic
ast g
roup
add
ress
�
Bro
adca
st (
one-
to-a
ll)
�
Spe
cial
cas
e of
a m
ultic
ast,
usua
lly b
est a
void
ed
�
Any
cast
(on
e-to
-one
-of-
man
y)
�
Pre
fera
bly
one-
to-n
eare
st, d
efin
ed fo
r IP
v6
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
9
IP a
dd
ress
no
tati
on
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
10
Sp
ecia
l IP
ad
dre
sses
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
11
Cla
ssfu
l IP
ad
dre
ssin
g
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
12
Cla
ssfu
l ad
dre
ss s
izes
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
13
Exa
mp
le IP
net
wo
rk
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
14
Exa
mp
le IP
ro
ute
r ad
dre
ssin
g
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
15
Lim
itat
ion
s o
f cl
assf
ul a
dd
ress
ing
�
Inte
rnet
gro
wth
�
Rou
te ta
ble
size
�
Add
ress
dep
letio
n
�
Mis
appr
opria
tion
of a
ddre
sses
�
Lack
of s
uppo
rt fo
r di
ffere
nt s
ized
net
wor
ks
�
Cla
ss B
too
big,
cla
ss C
too
smal
l
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
16
IP a
dd
ress
ing
so
luti
on
s
�
Sub
netti
ng
�
Sup
erne
tting
�
Cla
ssle
ss in
terd
omai
n ro
utin
g (C
IDR
)
�
Var
iabl
e le
ngth
sub
net m
asks
(V
LSM
)
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
17
Su
bn
etti
ng
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
18
Su
bn
et m
ask
�
The
bit
leng
th o
f the
pre
fix (
netw
ork)
�
Pre
fix (
netw
ork)
is n
o lo
nger
cla
ssfu
l
�
Dot
ted
deci
mal
or
'/' n
otat
ion
�
140.
192.
1.6'
s su
bnet
mas
k is
255
.255
.255
.128
�
...or
140
.192
.1.6
/25
�
You
may
wan
t to
conv
ert t
o bi
nary
for
clar
ity
�
A /2
5 or
255
.255
.255
.128
sub
net m
ask
is:
�
1111
1111
.111
1111
1.11
1111
11.1
0000
000
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
19
Exa
mp
le:
Usi
ng
su
bn
et m
asks
�
Giv
en 1
40.1
92.5
0.8/
20, w
hat i
s th
e:
�
subn
et m
ask
in d
otte
d de
cim
al n
otat
ion?
�
dire
cted
bro
adca
st a
ddre
ss in
dot
ted
deci
mal
�
tota
l num
ber
of h
osts
that
can
be
addr
esse
d?
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
20
Su
per
net
tin
g
�
Com
bine
sm
alle
r bl
ocks
into
larg
er a
ggre
gate
�
If cl
ass
B to
o bi
g, c
lass
C to
o sm
all..
.
�
May
be d
o th
is:
�
Com
bine
199
.63.
0.0/
24 to
199
.63.
15.0
/24
�
Equ
als
199.
63.0
.0/2
0
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
21
Exa
mp
le:
Usi
ng
Su
per
net
s
�
Giv
en th
at IS
P h
as 1
28.1
5.0.
0/16
:
�
If a
cust
omer
nee
ds to
add
ress
300
hos
ts, h
ow
mig
ht th
e IS
P a
ssig
n th
em a
ddre
ss s
pace
?
�
Wha
t is
the
addr
ess
spac
e as
sign
ed in
the
exam
ple
abov
e in
'sla
sh' n
otat
ion?
�
How
man
y, if
any
, max
imum
free
IP a
ddre
sses
w
ill th
e cu
stom
er h
ave
at th
eir
disp
osal
?
�
Can
you
thin
k of
any
rea
son
why
the
cust
omer
m
ight
hav
e le
ss th
an th
at m
axim
um?
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
22
CID
R
�
Use
sup
erne
tting
for
rout
ing
tabl
es
�
Rou
tes
adve
rtis
ed a
s sm
alle
r C
IDR
blo
cks
�
So
inst
ead
of a
dver
tisin
g:
�
199.
5.6.
0/24
, 199
.5.6
.1/2
4, 1
99.5
.6.2
/24
and
199.
5.6.
1/24
sep
arat
ely
�
Adv
ertis
e:
�
199.
5.6.
0/22
one
tim
e
�
Inte
rnet
CID
R r
epor
t
�
http
://w
ww
.em
ploy
ees.
org/
~tb
ates
/cid
r-re
port
.htm
l
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
23
Exa
mp
le:
Usi
ng
CID
R
�
Giv
en th
at a
n IS
P a
nnou
nces
net
bloc
ks
64.5
.0.0
/20,
64.
5.16
.0/2
0, 1
92.0
.2.0
/25
and
192.
0.2.
192/
26 a
nd 1
92.0
.2.1
28/2
6:
�
Wha
t is
the
smal
lest
num
ber
of C
IDR
an
noun
cem
ents
that
this
ISP
can
mak
e?
�
If th
ese
rout
es a
re r
ecei
ved
from
ano
ther
pr
ovid
er, c
an y
ou th
ink
of a
ny r
easo
n w
hy th
ey
mig
ht n
ot b
e ab
le to
be
CID
R-iz
ed?
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
24
VL
SM
�
Mul
tiple
sub
net s
izes
in a
sin
gle
AS
�
Allo
ws
effic
ient
use
of a
ddre
ss s
pace
�
Can
be
used
to b
uild
inte
rnal
hie
rarc
hy
�
Ext
erna
l vie
w o
f AS
doe
s no
t cha
nge
�
An
orga
niza
tion
may
hav
e 14
0.19
2.0.
0/16
�
But
inte
rnal
ly m
ay u
se 1
40.1
92.0
.0/1
7,
140.
192.
128.
0/24
, 140
.192
.129
.0/2
4 an
d so
on.
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
25
Exa
mp
le:
Usi
ng
VL
SM
�
Giv
en a
n ad
dres
s sp
ace
of 1
40.1
92.0
.0/1
6 to
w
ork
with
, ass
ign
netb
lock
s an
d ad
dres
ses
base
d on
the
follo
win
g ne
twor
k:
�
6 sa
telli
te s
ites
and
1 m
ain
offic
e ce
nter
�
Abo
ut 7
000
host
s ex
ist o
n en
tire
netw
ork
toda
y
�
Mai
n si
te u
ses
appr
oxim
atel
y 50
% o
f add
ress
es
�
Sat
ellit
es v
ary
from
200
to 7
00 to
tal a
ddre
sses
�
Ove
rall
grow
th fo
r or
gani
zatio
n is
500
hos
ts/y
ear
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
26
Ob
tain
ing
IP a
dd
ress
es
�
IAN
A h
as g
loba
l aut
horit
y fo
r as
sign
men
t
�
Reg
iona
l reg
istr
ies
dele
gate
(A
RIN
/RIP
E/A
PN
IC)
�
ISP
s as
sign
add
ress
es to
end
end
use
rs
�
RF
C 1
918
defin
es p
rivat
e ad
dres
s ne
tblo
cks
�
NO
T g
loba
lly u
niqu
e
�
Mus
t not
app
ear
on th
e pu
blic
Inte
rnet
�
10.0
.0.0
/8, 1
72.1
6.0.
0/12
, 192
.168
.0.0
/16
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
27
IP d
atag
ram
layo
ut
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
28
Insi
de
an IP
v4 d
atag
ram
�
Ver
sion
fiel
d
�
Bin
ary
0100
(eq
uals
wha
t in
deci
mal
?)
�
Hea
der
leng
th
�
Leng
th o
f the
IP h
eade
r in
32
bit w
ords
�
Will
usu
ally
be
equa
l 5 (
in d
ecim
al)
�
Typ
e of
Ser
vice
(no
w D
iffS
erv
field
)
�
An
indi
catio
n of
qua
lity/
clas
s of
ser
vice
�
Rar
ely
used
, but
if s
o us
ually
with
in s
ingl
e A
S
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
29
Insi
de
an IP
v4 d
atag
ram
[co
nt.
]
�
Tot
al le
ngth
�
Tot
al IP
dat
agra
m le
ngth
in o
ctet
s
�
Max
imum
val
ue is
655
35, b
ut r
arel
y >
150
0
�
Iden
tific
atio
n
�
Use
d fo
r to
iden
tify
frag
men
ted
pack
ets
�
Exp
erim
enta
l use
for
trac
ing
(D)D
oS a
ttack
s
�
Fla
gs
�
Bit
0 re
serv
ed, o
ther
s co
ntro
l fra
gmen
tatio
n
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
30
Insi
de
an IP
v4 d
atag
ram
[co
nt.
]
�
Fra
gmen
t offs
et
�
Hel
ps p
iece
toge
ther
frag
men
t dat
agra
ms
�
Tim
e to
live
(T
TL)
�
Bou
nds
time/
hops
of I
P d
atag
ram
in n
etw
ork
�
Cou
nts
dow
n to
zer
o an
d st
ops
bein
g fo
rwar
ded
�
Pro
toco
l typ
e
�
Indi
cate
s ne
xt le
vel p
roto
col i
n da
ta p
ortio
n
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
31
Insi
de
an IP
v4 d
atag
ram
[co
nt.
]
�
Hea
der
chec
ksum
�
Use
d to
ver
ify h
eade
r va
lidity
at e
ach
hop
�
Sou
rce
addr
ess
�
32-b
it IP
add
ress
�
Des
tinat
ion
addr
ess
�
32-b
it IP
add
ress
�
Opt
ions
�
Var
iabl
e, n
ot o
ftenl
y us
ed
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
32
Dem
o:
Un
der
stan
din
g P
ING
�
Set
up p
acke
t cap
ture
ses
sion
usi
ng tc
pdum
p
�
tcpd
ump
-n -
s 15
00 -
w p
ing.
cap
icm
p an
d \(
dst
hos
t <m
y-ip
> o
r sr
c ho
st <
my-
ip>
\)
�
Pin
g re
mot
e ho
st
�
ping
<re
mot
e-ip
>
�
Vie
w c
aptu
re u
sing
Eth
erea
l
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
33
Dem
o:
Un
der
stan
din
g t
race
rou
te
�
Set
up p
acke
t cap
ture
ses
sion
usi
ng tc
pdum
p
�
tcpd
ump
-n -
s 15
00 -
w tr
acer
oute
.cap
\( u
dp o
r ic
mp
\) a
nd \(
dst
<m
y-ip
> o
r sr
c <
my-
ip>
\)
�
Tra
ce r
emot
e ho
st
�
trac
erou
te -
n <
rem
ote-
ip>
�
Vie
w c
aptu
re u
sing
Eth
erea
l
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
34
Oth
er t
oo
ls a
nd
ref
eren
ces
�
Fin
d co
ntac
ts fo
r IP
add
ress
or
netb
lock
s
�
who
is <
ip-a
ddre
ss-o
r-ne
twor
k>
�
Vei
w n
etw
ork
path
from
ext
erna
l site
s
�
http
://w
ww
.trac
erou
te.o
rg
�
Ver
ify D
NS
ent
ry to
IP a
ddre
ss o
r vi
ce v
ersa
�
nslo
okup
<ip
-add
ress
>
�
http
://w
ww
.iana
.org
�
http
://w
ww
.arin
.org
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
35
Su
pp
ort
ing
pro
toco
ls
�
AR
P
�
BO
OT
P/D
HC
P
�
DN
S
�
ICM
P
�
SN
MP
TD
C 3
75 W
inte
r 20
02Jo
hn K
risto
ff -
DeP
aul U
nive
rsity
36
Fin
al t
ho
ug
hts
�
IP is
unr
elia
ble
�
IP a
ddre
ssin
g ca
n be
a p
ain
�
IPv6
doe
sn't
mak
e it
any
easi
er
�
IP a
ddre
ss is
bot
h a
who
and
a w
here
�
IP a
ddre
sses
pro
vide
littl
e se
curit
y
�
Priv
ate
IPs
and
NA
T a
re b
est a
void
ed
�
IP fr
agm
enta
tion
is g
ener
ally
bes
t avo
ided
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