Download Sele in In ctive C nforma Cachin ation C ng with Centric h Hop c

Proceedings of the Asia-Pacific Advanced Network 2015 v. 40, p. 102-108.
Network Research Workshop http://dx.doi.org/10.7125/APAN.40.15
ISSN 2227-3026
Selective Cachin
C
ng withh Hop Counnts
in In
nformaation Centric
C
c Netw
workinng
Takumi Saato, and Shigekki Goto
Departmen
nt of Computer Science and Engineering,
E
W
Waseda Universsity, Shinjuku, Tokyo
Em
mails: t-sato@g
goto.info.wased
da.ac.jp and [email protected]
II. BASIC ICN
N
Abstract—Info
ormation Centriic Networking (ICN) is a prom
misingg approach to the future In
nternet. In the original ICN arch
hitecture, each router
r
has a ca
aching function. The same datta is
stoored at all rou
uters along a path. To remo
ove this apparrent
redundancy in th
he ICN architeccture, this papeer proposes a new
n
uplication of data
d
caaching method in ICN, whicch reduces du
am
mong neighborring routers. The proposed method realizes
sellective caching based on hop counts
c
along a path
p
in ICN. It also
a
disstributes cacheed data among
g neighboring routers using an
off
ffset value. The new method tu
unes the param
meters to reflect the
poopularity of con
ntents. In an eva
aluation study, we confirmed that
t
ou
ur approach perrforms an efficiient caching fun
nction in ICN.
Index Terms—
—Information Centric
C
Networking, Selectiv
ve
Caaching, Hop Co
ount, PlanetLab
b.
I. INTROD
DUCTION
Rich contents such as picturres and videoss constitute an increasing proporrtion of the Internet trafffic. Videos are
prrojected to com
mprise 79% of the consumer Internet trafficc in
20018 [1]. To cope with the increasing
g traffic, seveeral
appproaches hav
ve been trialed. Content Delivery
D
Netw
work
(C
CDN) is widely
y deployed. Peeer-to-Peer (P2P
P) network is also
a
poopular. There is another idea of Info
ormation Cen
ntric
Neetworking (IC
CN). In ICN, it
i is emphasized that users are
intterested in co
ontents (what), not in the location
l
of th
hose
coontents (where)). Information Centric Networking (ICN) is
i a
prromising appro
oach to the futu
ure Internet.
In ICN architeecture, one of key functions is caching wh
hich
caan reduce the data traffic tremendously.
t
However, naaive
caaching is not efficient becausse it forces eveery ICN routerr to
caache the conten
nt when the Data packet passees through it.
This study proposes
p
a new method to realize efficiient
caaching in ICN. It is based on
n the hop counts along a path
h in
IC
CN. It also consults an offset value and pop
pularity counter to
deecide whether a router should
d cache the con
ntents or not. The
T
neew method is superior to th
he original cacching mechanism,
annd a simple seleective caching based on hop counts
c
alone.
The remainder of this paper is organized as follows. Secttion
II explains the basic
b
ICN arch
hitecture and its
i functions, and
a
poses our new method. Sectiion IV and V are
Seection III prop
deevoted to the evaluation an
nd characterisstics of our new
n
method, respectiively. The papeer concludes with
w Section VI.
A. Feattures of ICN
ICN is proposed as a new nettwork architeccture which
would rreplace currentt location-baseed network. A typical key
phrase is the following: “Users aare interested in contents
(what) bbut not intereested in the loocation (wheree)” [2]. The
featuress of ICN are suummarized beloow.
ICN
N uses conteents names (IDs) rather thhan location
infformation e.g., URLs.
ICN
N works withh two types off packets: Interest packets
andd Data packetss. An Interest ppacket specifiess the request
forr Data with conntents ID.
Eacch router storees contents (Daata) through a cache functionn.
ICN hhas been impleemented in manny guises: Conntent Centric
Networkking (CCN) [33], Named Datta Networking (NDN) [4],
Networkk of Informatiion (NetInf) [55], and Publish Subscribe
Internett Technology (P
PURSUIT) [6]].
This study focusess on the welll-known impllementations
CCN annd NDN.
B. Archhitecture of ICN
N
CN Router: Thhe componentt of ICN com
mprises users
1) IC
client m
machines, routeers, and contennts servers. Theey are called
ICN noddes. Nodes coommunicate wiith each other via Interest
packets and Data packkets. An ICN roouter has threee tables:
Forrwarding Info
formation Basse (FIB): M
Manages the
rouuting informatiion for Interestt packets
1
Pennding Interest Table (PIT): R
Records face corresponds
to aan unsatisfied Interest
Conteent Store (CS):: Manages cachhed contents (D
Data).
The F
FIB plays a sim
milar role to a rrouting table inn the current
IP netw
work. By conssulting the FIIB, routers deetermine the
directionn to forward an Interest paacket to get thhe requested
content..
The P
PIT retains paairs of an unsaatisfied (pendiing) Interest
and thee face where tthe Interest caame from. Whhen a router
retrievess an Interest paacket for conteent already reccorded in the
PIT, it simply adds tthe new source face of Inteerest. In this
situationn, the router dooes not forwardd the Interest ppacket to the
next rouuter, because iit has earlier ddelivered the saame Interest
packet. Because the roouter retrieves the Data (conttent) without
forwarding, it eliminates dduplicated Inteerest traffic
extra fo
throughh the network.
102
the corrrect face for fforwarding ann Interest packket, an ICN
router ssearches the ccontents ID inn the FIB by the longest
match aalgorithm.
C. Mecchanism of ICN
N
Figg. 1. Flow of Interrest and Data pack
kets
The CS is thee cache storag
ge. Routers caache Data pack
kets
paassing through
h the router. If a router recceives an Interrest
paacket for cacheed contents (D
Data), it immed
diately returns the
Daata packet from
m the CS. Ussers may receiive contents frrom
routers closer thaan the contentss servers.
Figure 1 sho
ows the flow of Interest and
a
Data pack
kets
thrrough the ICN
N router. Wheen an Interest packet reachees a
router, the routeer refers to th
he CS. If the requested
r
conttent
Data) resides in
n the CS, the ro
outer discards the
t Interest paccket
(D
annd returns thee Data packet to the face that sources the
Innterest. If the content is nott cached in th
he CS, the rou
uter
refers to the PIT.
P
If the req
quested content ID (name)) is
ming
recorded in PIT as part of an unsatisfied Interrest, the incom
o the PIT, and the Interest iss discarded. If the
face is added to
nt ID (name) is not recordeed in the PIT, the
requested conten
Innterest is forwaarded to the neext node. Refeerring to FIB, the
router then forw
wards the Interrest to an app
propriate face and
a
D (name) and the face sourccing
addds the tuple off the content ID
the Interest to the PIT.
p
reachess a router, the router
r
refers to the
When a Data packet
PIIT and determines the faces to forward th
he Data packett. If
pluural faces are recorded
r
in thee PIT, the routeer copies the Data
D
paacket and forwards it to each of the recordeed faces. Then the
router updates PIT
P by deletin
ng the PIT reccord, because the
ously, the routeer caches the Data
D
intterest is satisfied. Simultaneo
paacket in the CS
S. If the conten
nt is not record
ded in the PIT, the
Daata packet is diiscarded.
2) Namespace of ICN: ICN nodes interrcommunicate by
sppecifying conttent IDs (Datta names). Co
ontent ID hass a
hierarchical structure delimited
d by “/”, as illu
ustrated in Fig
gure
2.
isition: Figurees 3 and 4 illlustrate the
1) Coontents Acquis
process of data (conteents) acquisitioon. First, a useer sends the
D) of the requuested content iin an Interest ppacket. Each
name (ID
router fo
forwards the Innterest packet ttoward the conntents server
storing tthe requested ccontent. Routeers record the ttuples of the
requesteed contents nam
me and the facces sourcing thhe Interest in
the PIT..
Whenn a contents server storingg the requested contents
receivess an Interest ppacket, it returrns the contennt as a Data
packet. Routers forw
ward this Daata packet too the faces
T while cachinng the Data packet in the
registereed in each PIT
CS. Byy shuttling thee PITs, the D
Data packet reeaches users
requestiing the contentt via the reverrse path of Intterest packet
forwardding (see Fig. 44).
Fig. 3. Foorwarding Interestt packet and PIT R
Registration
Fig. 4. Reeturning Data packket and Caching too CS
Figg. 2. Construction
n of Contents ID
Prefix specifiies a service name or an original conteents
prrovider. The naame part is the filename of th
he contents. Th
here
is a Version info
ormation at the end of contentts ID. To obtain
2) Caaching: Figure 5 shows how ccaches are utiliized in ICN.
Until thhe requested coontent reaches a user as a Daata packet, it
is cacheed by all rouuters through w
which it passees. Caching
markedlly reduces thee traffic. Whenn an Interest frrom another
user hitss a router cachiing the requestted content on the way
103
tow
ward the conteents server, thee router immed
diately returns the
Daata packet from
m the CS. Thuss, users can obttain contents frrom
the closer node than
t
the conten
nts server. Cach
hing improves the
ncy in traffic an
nd the load av
verage of conteents
neetwork efficien
servers. Thus, ro
outer caching is an importan
nt feature of ICN
[7].
Figg. 5. Cache Utilizaation in ICN
Fig. 6. Exxample of Cache D
Distribution in ourr Proposed Methodd
III. PROPOSEED METHOD
A. Selective Cacching
In the originaal CCN and NDN
N
architectu
ures, Data pack
kets
are cached in all routers traaveled by Daata packets. This
T
coonfiguration caches the same contents in neiighboring routers.
Thhus, CS closest to the userrs may be freq
quently accesssed,
whhile Data storeed in routers near
n
to the co
ontents server are
rarrely retrieved.
This study prroposes a new
w method in which a routeer’s
deecision to cachee the contents is based on thee hop counts frrom
the contents seveer.
the fieldds of CtC and Offset to the D
Data packet. Inn this paper,
we add the hop countter to the Dataa packet. Whenn a contents
providerr (or a router) sends a Data packet, the hoop counter is
set to zeero (0). Alternnatively, it is ppossible to addd the TTL to
the Dataa packet. If TT
TL is used, the hop count is ccalculated at
each rouuter. The conteents servers sett the CtC and O
Offset
B. Check to Cacche (CtC) and Offset Fields
The new meth
hod adds two new
n fields to Data
D packets. The
T
firrst field, Check
k to Cache (CtC
C), is an integeer which indicaates
the expected hop
p counts of th
he cached Dataa. For examplee, if
D
packet is 3, the Data packet
p
should be
the CtC of a Data
h, 9th, 12th ... hops. The seco
ond
caached in routers at the 3rd, 6th
fieeld, Offset, is explained
e
below
w.
The above sim
mple method wo
ould accumulatee Data in routerrs at
paarticular hops. For
F example, when
w
CtC is 3,, Data packets are
caached only at router on 3rd
d, 6th, 9th, 12
2th ... hops. Such
cooncentration is prevented by the
t Offset field
d, which stipulaates
thaat Data packets are cached at
Offsset hops.
Figure 6 illusttrates a represeentative cache distribution wh
hen
CttC is 3. The co
ontents server inserts
i
the field
ds CtC and Off
ffset
intto the contentss (Data) packett, and routers cache
c
the conteents
as specified in th
he CtC field.
O
C. Data packet with CtC and Offset
d
between the
Figure 7 illusttrates how the Data packets differ
orriginal ICN and
d our method. In
I particular, our
o method add
ds
Fig. 7. C
Construct of Data packets in the O
Original ICN andd our Proposed
Method
fields w
when returning the contents too users. Each rrouter refers
to the C
CtC and Offset fields when receiving a Dataa packet, and
decides whether it shoould cache the D
Data packet.
Routeers that cache the Data packket also store thhe CtC field
of the ccontents. Whenn a router receeives Interest ppackets that
match tthe contents iin the CS, thee router returnns the Data
packets from the CS. Based on thee CtC field in the CS, the
Offset field inn the Data paacket before
router ssets its new O
releasinng it to users. The offset is set wheneverr a contents
providerr sends a Dataa packet. The ooffset must be lless than the
CtC. Too satisfy this condition, wee can simply sset Offset
, where the sequentiall counter N is iincremented
by the ccontents server when it sends a Data packet..
104
D.. CtC tuning
To determinee an appropriaate CtC value, we consider the
poopularity of thee Data.
When many Interest packeets requesting a certain conttent
(D
Data) arrive att a contents server,
s
the con
ntent is not only
o
poopular but is also
a
insufficien
ntly cached in
n the network
k. If
ennough cached Data
D reside in the network, some
s
routers may
m
respond to the high
h
Interest demand
d
by retu
urning the cach
hed
t users. In this situation
n, there is liittle
Daata packets to
oppportunity for the Interest packets to reeach the conteents
seervers.
A large CtC value
v
implies a long network distance between
the cached Dataa, and a small number of thee cached Data. In
t contents are insufficiently
y cached, cach
hing
othher words, if the
shhould be promo
oted by reducin
ng the CtC.
On the other hand, if the contents
c
are not popular or are
suufficiently cach
hed in the netw
work, few Interrest packets arrrive
at the contents servers. Therefore, if the Interest coun
nter
d be increased.
reggisters low, CttC value should
From the abov
ve consideratio
ons, we conclu
ude that tuning the
CttC value of the Data (contents) wiill improve the
efffectiveness of caching. In particular, as an
n indicator of the
poopularity, we should
s
monitorr the number of
o Interest pack
kets
arrriving at the seerver in a certaiin time period (PoP).
If PoP is larg
ger than a fixeed parameter (Higher
(
PoP), the
seerver sets a low
wer value. If PoP is smaller than
t
another fix
xed
paarameter (Loweer PoP), the serrver sets a larg
ger CtC value.
IV. EVA
ALUATION
A. Experiment Outline
O
The purpose of this study is to demonstrate the superior
caaching efficiency of our method over the origiinal ICN. The ICN
I
meechanism was emulated in Jaava. We measu
ured the cache hit
rattio, the averagee hop counts fro
om the contents provider (or CS)
C
to users, and the unique contentts rate in the neetwork CSs, wh
hich
is defined as the number of unique contents diivided by the total
c
of the routers. The un
nique contents rate
r
coontent storage capacity
inddexes the varietty of the cached
d contents. If vaarious contents are
stoored in the cach
he, these are av
vailable to userrs from the CSss in
rouuters, and need
d not be retriev
ved from the co
ontent server. This
T
coonstruct improv
ves the caching
g efficiency off the network, and
alsso reduces thee Interest trafffic toward the contents serv
vers.
Thherefore, the un
nique contents rate is a usefu
ul indicator of the
eff
fficiency of caching. For instaance, if four rou
uters in a netw
work
caan store five co
ontents, the totaal capacity is 20.
2 If there are ten
unnique contents in
n this network, the unique contents rate is 50 %.
Our evaluatio
on was conduccted in PlanetL
Lab [8], a glo
obal
tesstbed for netw
work research that covers many
m
universitties,
research institutiions, and com
mmercial compaanies. We set the
ussers’ client machines, routerss, and contentss servers on PllanetL
Lab, and evalu
uated two network topologies.
1) Caascade Topologgy: The first eexperiment adoopted a cascade toppology (see Fiigure 8). Cachhing can be coonfigured in
three waays: the originnal ICN architeecture, the CtC
C and Offset
fields w
without tuningg, and the CtC
C and Offset fields with
tuning. Table I lists tthe parameterss in the cascadde topology.
The inittial CtC valuee is 3 when wee do not applyy the tuning
method.. The higher P
PoP is 0.13 (thhe average num
mber of the
Interest packets per second). Thee Lower PoP
P is 0. For
examplee, if there are 3 Interest packeets requesting ffor the same
content in 15 second, then PoP is 00.2. The serverr set smaller
CtC vallue to the Datta packet. Wee used LRU aas the cache
replacem
ment algorithm
m, and assumedd that the popuularity of the
contentss follows Zipff’s law; that iis, the occurreence rate of
incominng content of tthe k-th rank is proportional to 1/k. The
parametter α in Zipf’s law is a constaant of the Zipf--Mandelbrot
law, a generalized version of Z
Zipf’s law. Inn the ZipfMandelbbrot law, the occurrence rate P k, N, α of the k-th
ranking item among N items is givenn by the follow
wing:
, ,
1
In thhe original Zippf’s law, α 1 . The largerr the α , the
larger tthe deviation in the occuurance. We assume the
populariity of contennts follows Z
Zipf’s law, annd generate
Interest packets accordding to Zip’s laaw.
TABLE I
PARA
AMETERS IN EXPERIM
MENT 1
Initial CtC
Higheer PoP [packets/seec]
Loweer PoP [packets/seec]
N
Number of Users
Nuumber of Routers
Nuumber of Servers
Cachee capacity [contennts]
C
Cache algorithm
Conntents Size [Byte]
Totall number of contennts
Totall number of Intereest
Constant α
3
0.13
0
1
5
1
5
LRU
1000
30
100
1.0
Fig. 8. Caascade Topology
2) Pra
ractical Topoloogy: The seconnd experiment aadopts more
practicaal topology shoown in Figure 99. To evaluate the flexibility of thhe proposed m
method, we set the constant α to 0.5, 0.8,
and 1.0.. The parameteers in the seconnd experiment aare listed in
105
Taable II. Each co
ontents server stores 30 conteents, and each
usser sends 200 Interest
I
packetts. We set the Higher PoP 0.26
0
beecause the num
mber of users is 3, which is
i larger than the
prrevious experim
ment 1. Again, we use LR
RU as the caache
repplacement algo
orithm.
TAB
BLE II
PARAMETERS IN EXPERIMENT 2
Initial CtC
Higher PoP
Lower PoP
Number of Userrs
Number of Routeers
Number of Serveers
Caache capacity [con
ntents]
Cache algorithm
m
Contents Size [By
yte]
To
otal number of con
ntents
Total
T
number of Intterest
Constant α
3
0.26
0
3
5
3
5
LRU
1000
90
600
0.5, 0.8,
0 1.0
Fig. 10. C
Cache Hit Ratios inn the Cascade Toppology
Fig. 11. A
Average Hop Counnts in the Cascade Topology
Figg. 9. Practical Top
pology
B. Results
1) Cascade To
opology: Figuree 10 compares the
t cache hit raatios
am
mong the three methods. The CtC field realizzes a much hig
gher
caache hit ratio than
t
the origin
nal ICN. The cache hit ratio
o is
fuurther improved
d by tuning thee CtC.
Figure 11 presents the aveerage hop cou
unts in the th
hree
methods. Tuning
g the CtC neg
gligibly affectss the hop coun
nts.
oposed method
d requires few
wer hop countss to
Cllearly, the pro
deeliver contents than the origin
nal ICN cachin
ng method.
The unique contents rates in
i the CSs aree shown in fig
gure
122. In the original ICN caching
g, Data packetss are cached att all
routers, leading to duplicated Data
D and a low
w unique conteents
ratte (20%).
ots the distribu
ution of the caache hit countss at
Figure 13 plo
eaach router. In the
t original IC
CN caching, alll the routers have
the same conten
nts caches (CS
Ss) with this cascade
c
topolo
ogy.
u
the CS located one hop
h
Thherefore a useer can only utilize
aw
way. The CtC and Offset fiields allow acccess to cachess in
routers (CS) locaated at hops 2,, 3, 4, and 5 ho
ops from the user.
Thhe evaluation is summarized in Table III.
Unique Contents R
Rates in the Cascadde Topology
Fig. 12. U
Fig. 13. H
Hops from User verrsus Number of Cache Hits in the Cascade
Topologyy
106
TAB
BLE III
RESULT IN CASCA
ADE TOPOLOGY
α = 1.0
usual ICN
using CtC
tuning CtC
Cache Hit
Ratio [%]
40.0
69.0
72.0
Average
A
Hop
Count
C
[hop]
4.00
3.08
3.00
Unique
U
Contents
Rate [%]
20.0
68.0
72.0
2) Practical Topology:
T
Thee second expeeriment adopted a
moore practical topology. Figure 14 presen
nts the cache hit
rattios for differeent values of α.. In all three caases, the CtC fiield
im
mproves cache hit ratio. In th
he original ICN
N implementatiion,
the cache hit ratio
r
increasess as α increases, because the
C
Innterest packets deviate more at larger α. Consequently,
the
saame popular Data
D
contents are
a demanded by an increassing
nuumber of Intereest packets.
Figure 15 sho
ows the averag
ge hop counts of a Data paccket
reaching the useer from the con
ntents server (o
or CS). Nevertthem
is smaaller
lesss the decreasee in hop count with the new method
than that of Experiment 1, ourr method can reeduce the num
mber
his configuratio
on.
off hops also in th
The unique contents rates in
i CSs are com
mpared in Fig
gure
166. This index is also impro
oved by the CtC
C field, and
d is
fuurther improveed by tuning the CtC. Thee results for α
1.0, 0.8and 0.5
5 are summariized in Tabless IV, V, and VI,
respectively.
Fig. 16. U
Unique Contents R
Rates in the Practiccal Topology
TABLE IV
RESULT IN PRRACTICAL TOPOLOG
GY (α
α
1.0
ussual ICN
ussing CtC
tun
uning CtC
Cacche Hit
Ratiio [%]
31.5
46.2
49.0
Averagee Hop
Count [[hop]
4.21
3.81
3.72
1.0)
Unique C
Contents
Ratee [%]
40.0
62.2
78.2
V. DISCUSSIO
ON
This section disscusses
conductted in Section IIV.
the
evaluation
experiments
A. Cachhe Hit Ratio
In booth Experimennt, 1 and 2, the cache hiit ratio was
improveed by the CtC field, and furthher improved bby tuning it.
As show
wn in Figure 13, the cachee stores (CSs) in routers
distant from the userr were unusedd in the originnal ICN, but
were renndered accessiible by CtC. Fuurthermore, irrrespective of
the consstant α, using and tuning thee CtC improveed the cache
hit by 440%-70% relattive to the origginal ICN impplementation
in the prractical topologgy (see B2 of S
Section IV).
The ccache hit ratio expresses the effectiveness oof the cache
utilizatioon. The highher the cache hit ratio, thee fewer the
Interest packets reachiing the contentts servers. Suchh effective
Figg. 14. Cache Hit Ratios
R
in the Practiical Topology
TABLE V
RESULT IN PRRACTICAL TOPOLOG
GY (α
α
0.8
ussual ICN
ussing CtC
tun
uning CtC
Cacche Hit
Ratiio [%]
29.3
40.4
42.6
Averagee Hop
Count [[hop]
4.23
4.02
3.96
TABLE VI
RESULT IN PRRACTICAL TOPOLOG
GY (α
α
Figg. 15. Average Ho
op Counts in the Practical Topology
0.5
ussual ICN
ussing CtC
tun
uning CtC
Cacche Hit
Ratiio [%]
18.6
31.2
33.2
Averagee Hop
Count [[hop]
4.54
4.30
4.24
0.8)
Unique C
Contents
Ratee [%]
33.8
57.8
70.2
0.5)
Unique C
Contents
Ratee [%]
35.6
70.5
81.1
107
distribution of the
t caches in the network reduces the lo
oad
avverage on the contents serverss.
B. Average Hop
p Count
In both Expeeriment 1 and
d 2, using and
d tuning the CtC
C
reduced the hop count of data transfer. The average
a
hop co
ount
ween the conteents
deenotes the aveerage number of hops betw
prrovider (s CS)) and the useer. A large av
verage hop co
ount
means that userss retrieve conteents from long--distance conteents
prroviders. Reduccing the averag
ge hop count sh
hortens downlo
oad
tim
me because lon
ng-distance datta transfer is more
m
time consu
umingg than from loccal contents prroviders.
Although ourr method does not significcantly reduce the
avverage hop cou
unt, it download
ds the contentss in less time th
han
the original ICN
N implementatio
on.
C. Unique Conttents Rate
The proposed
d method outpeerforms the orriginal ICN arcchiteccture in terms of the unique contents
c
rate. Tuning
T
CtC exeerts
a greater improv
vement in the unique conten
nt rate than in the
ment indexes, because
b
increaasing the CtC
C of
othher measurem
low
w-popularity contents
c
widen
ns the cache interval, decreassing
the cached conttents and enab
bling caching of more diveerse
coontents.
A high uniqu
ue contents rate provides ussers with various
coontents from th
he router CSs. Routers can send
s
Data pack
kets
in response to Interest
I
packetts requesting different
d
conten
nts.
nterest packetss is
Thhe consequentt reducing thee traffic of In
beeneficial to botth users and contents
c
serverrs. Whereas ussers
ennjoy faster co
ontents retriev
val, the load average on the
coontents servers is reduced.
VI. CONCLUSION
This study haas proposed selective cachin
ng based on hop
h
coounts to remov
ve the redundaancy in the cacche utilization. In
the original ICN
N architecture, Data packets are cached att all
p
meth
hod selects th
hose
routers on the route. The proposed
m effectivelly cache the Daata packets. Th
here
routers that can most
ny research projects
p
on efficient
e
cachiing,
haave been man
including ProbC
Cache [12], WA
AVE [13]. Thiss paper compaared
h the original ICN. It is ou
ur future work
k to
ouur method with
coompare our pro
oposal with oth
her methods.
Evaluations were
w
performed
d on a cascad
de topology an
nd a
prractical topolog
gy. Our propo
osed method prroved superiorr to
the original ICN method in
n terms of thrree measurem
ment
h ratio, averaage hop countt, and the uniq
que
indexes: cache hit
a
all cacched contentss. Moreover, the
coontents rate among
method realizes effective cach
hing for both contents
c
provid
ders
annd users.
The proposed
d method realiizes improvem
ment of cache hit
rattio over the orriginal ICN meethod, potentially shortening the
usser’s download
d time and reducing the serv
ver load. In futture
woork, we will aim
m to further im
mprove the cach
he hit ratio.
The CtC in our
o proposed method
m
can be set to its defaault
vaalue, and the tim
me interval of tuning the CtC
C can be specifi
fied.
Inn this study, wee constructed various evaluatiion scenarios with
w
differennt parameter vaalues. In futuree, we should iinvestigate a
systemaatic means of selecting apppropriate param
meters for a
specific network.
Our m
method adds tw
wo fields to eaach Data packeet. Although
the overrhead of addinng new fields m
may be minor, it is worthy
of prec ise evaluationn. Again, this investigationn is left for
future sttudy.
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Taakumi Sato Takuumi Sato received tthe B.S. degree
inn Computer Sciencce and Engineeringg from Waseda
Unniversity in Marcch, 2015. He is now a master
stuudent at Departm
ment of Computeer Science and
Coommunications E
Engineering, Waseeda University.
Hiis research intereest covers Futuree Internet and
Cyyber Security.
Sh
higeki Goto Shigeeki Goto is a profeessor at Departm
ment of Computter Science andd Engineering,
W
Waseda University,, Japan. He receiveed his B.S. and
M
M.S. in Mathematiccs from the University of Tokyo.
Prrior to becoming a professor at Waseda University,
hee has worked for NTT for many years. He also
eaarned a Ph.D in Innformation Engineeering from the
Unniversity of Tokyoo. He is the presiddent of JPNIC.
Hee is a member off ACM and IEEE,, and he was a
truustee of Internet Society from 1994 to 1997.
© 2015 by the authors; licensee Asia-Pacific Advanced
Network. This article is an open-access article
distributed under the terms and conditions of the
Creative Commons Attribution license (http://
creativecommons.org/licenses/by/3.0/).
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