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11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 1
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Gig
abit
Buf
fere
d D
istr
ibut
or P
ropo
sal
(a.k
.a. F
ull D
uple
x R
epea
ter)
(a.k
.a. B
uffe
red
Rep
eate
r)
Ber
nard
Dai
nes
Pac
ket E
ngin
es(5
09)
922-
9190
FA
X (
509)
922
-918
5be
rnar
dd@
pack
eten
gine
s.co
m
Mai
ling
Add
ress
Shi
ppin
g A
ddre
ssB
ox 1
4497
1170
7 E
Spr
ague
Spo
kane
WA
992
14S
poka
ne W
A 9
9206
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 2
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
The
Issu
e
Des
ire b
ette
r pe
rfor
man
cefo
r fib
er li
nks
than
pro
pose
dha
lf du
plex
rep
eate
r sc
hem
es
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 3
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
With
Gig
abit
Eth
erne
t
We
have
Ful
l Dup
lex
Med
iaF
ull D
uple
x P
HY
’sF
ull D
uple
x M
AC
’s
Let’s
hav
e a
repe
ater
/sw
itch
sort
of d
evic
eth
at is
not
hal
f dup
lex.
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 4
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
The
Bre
akth
roug
h!
If al
l we
have
to d
ois
sup
port
full-
dupl
ex li
nks,
the
prob
lem
bec
omes
ver
y ea
sy.
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 5
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
MO
TIV
AT
ION
FO
R T
HE
GIG
AB
IT B
UF
FE
RE
D D
IST
RIB
UT
OR
IS C
OS
T V
S. G
IGA
BIT
SW
ITC
H
An
Impo
rtan
t Poi
nt!
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 6
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Buf
fere
dD
istr
ibut
or
N p
ort h
ubw
ithfu
ll du
plex
links
Ful
l Dup
lex
Link
s
N P
orts
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 7
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Add
sm
all o
utpu
t FIF
O fo
r co
nven
ienc
e.
Ste
p 1:
Pro
vide
a F
IFO
for
each
inco
min
g lin
eto
avo
id c
ollis
ion
dom
ain
timin
g a
nd d
ista
nce
rest
rictio
ns.
Tx
Rx
PH
Y
Ful
l Dup
lex
Link
Tx
Rx
PH
Y
FIF
O
FIF
O
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 8
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Sol
utio
n!
Use
fram
e ba
sed
flow
con
trol
to
keep
eac
h in
put F
IFO
from
ove
rflo
win
g.
•It’
s al
read
y st
anda
rd.
•W
e do
n’t h
ave
to in
vent
any
thin
g ne
w.
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 9
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Det
aile
d vi
ew o
f por
t int
erfa
ce s
how
ing
how
flow
con
trol
circ
uitr
y co
nnec
ts.
Ste
p 2:
Add
802
.3x
flow
con
trol
to e
ach
port
.
Tx
Rx
PH
Y
FIF
O
FIF
O
Flo
w C
ontr
olF
low
Con
trol
Tx
Rx
PH
Y
Ful
l Dup
lex
Link
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 10
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Ste
p 3:
Hoo
k po
rts
to th
e ar
bitr
atio
n m
etho
d o
f you
r ch
oice
insi
de th
e bo
x.
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 11
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
PH
Y
Tx
Rx
Flo
w C
ontr
ol
PH
Y
Tx
Rx
Flo
w C
ontr
ol
PH
Y
Tx
Rx
Flo
w C
ontr
ol
A R B I T R A T I O N A N D
R E P E A T E R C O R E
PH
Y
Rx
FIF
O
Tx
FIF
O
Flo
w C
ontr
ol
PH
Y
Rx
FIF
O
Tx
FIF
O
Flo
w C
ontr
ol
PH
Y
Rx
FIF
O
Tx
FIF
O
Flo
w C
ontr
ol
Ful
l Dup
lex
Link
Ful
l Dup
lex
Link
Ful
l Dup
lex
Link
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 12
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
The
box
arb
itrat
es a
mon
g its
loca
l FIF
O’s
and
forw
ards
pac
kets
, one
at a
tim
e, b
ack
to a
ll th
e de
vice
s -
exc
ept t
he s
ourc
e po
rt.
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 13
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Link
Len
gth
(up
to 2
km)
Rec
eive
r F
IFO
Siz
e (1
0KB
ytes
)
Rep
eate
r C
ore
Alg
orith
m (
your
cho
ice)
Out
boun
d F
IFO
(yo
ur c
hoic
e)
Spe
cific
atio
ns
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 14
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
1000
BA
SE
-T/F
Buf
fere
dD
istr
ibut
or
Just
One
Dis
trib
utor
!
DT
ED
TE
DT
ED
TE
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 15
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Con
clus
ion
•F
orm
aliz
e a
one
dist
ribut
or to
polo
gy•
Sta
ndar
dize
asy
mm
etric
flow
con
trol
•S
tand
ardi
ze o
nly
min
imal
beh
avio
r of
buffe
red
dist
ribut
or le
avin
g fe
atur
es a
ndlin
k le
ngth
s to
impl
emen
ters
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 16
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
1518
Byt
e P
acke
ts -
Rou
nd R
obin
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3
Off
ere
d L
oa
d (
Gb
/S)
Core Bandwidth (Gb/S)
010203040506070
XOFF Fames
Cor
e B
andw
idth
XOF
F F
ram
es
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 17
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Ran
dom
Siz
e P
acke
ts -
Rou
nd R
obin
00.
10.
20.
30.
40.
5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3O
ffe
red
Lo
ad
(G
b/S
)
Core Bandwidth (Gb/S)
0102030405060708090
XOFF Frames
Cor
e B
andw
idth
XOF
F F
ram
es
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 18
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
64 B
yte
Pac
kets
- R
ound
Ro
bin
00.
10.
20.
30.
40.
5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3O
ffe
red
Lo
ad
(G
b/S
)
Core Bandwidth (Gb/S)
020406080100
120
XOFF Frames
Cor
e B
andw
idth
XOF
F F
ram
es
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 19
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
1518
Byt
e P
acke
ts -
CS
MA
/CD
00.
10.
20.
30.
40.
5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3O
ffe
red
Lo
ad
(G
b/S
)
Core Bandwidth (Gb/S)
010203040506070
XOFF Frames &Contentions
Cor
e B
andw
idth
XOF
F F
ram
es
Con
tent
ions
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 20
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
Ran
dom
Siz
e P
acke
ts -
CS
MA
/CD
00.
10.
20.
30.
40.
5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3O
ffe
red
Lo
ad
(G
b/S
)
Core Bandwidth (Gb/S)
0102030405060708090
XOFF Frames &Contentions
Cor
e B
andw
idth
XOF
F F
ram
es
Con
tent
ions
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
11/2
1/96
Buf
fere
d D
istr
ibut
or -
- 21
IEE
EN
ov96
.ppt
AT
MM
PE
GM
PE
GF
DD
I802
802
802
802
PA
CK
ET
EN
GI
NE
SI
NC
OR
PO
RA
TE
D
SC
SI
TM
64 B
yte
Pac
kets
- C
SM
A/C
D
00.
10.
20.
30.
40.
5
0.6
0.7
0.8
0.91
0.12
0.36
0.6
0.84
1.08
1.32
1.56
1.8
2.04
2.28
2.52
2.76
3O
ffe
red
Lo
ad
(G
b/S
)
Core Bandwidth (Gb/S)
020406080100
120
XOFF Frames &Contentions
Cor
e B
andw
idth
XOF
F F
ram
es
Con
tent
ions
Rep
eate
d P
orts
= 1
2S
imul
atio
n Ti
me
= 2
MS
