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INET 2001 Poster Session |
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June 5th – 8th , 2001 |
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NTT DoCoMo |
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Norihiro Ishikawa |
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(NTT DoCoMo Inc., Multimedia Labs.) |
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Email: ishikawa@mml.yrp.nttdocomo.co.jp |
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Hideharu Suzuki |
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(NTT DoCoMo Inc., Multimedia Labs.) |
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Email: hideharu@mml.yrp.nttdocomo.co.jp |
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Hidetoshi Ueno |
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(NTT DoCoMo Inc., Multimedia Labs.) |
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Email: uenohi@nttdocomo.co.jp |
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Internet access from wireless environment
(mobile phone, PDA) is being increasing. |
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WAP Forum has developed WAP1.x protocol that is
optimized for wireless networks that have the characteristics such as high
latency and/or high error rate. |
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Functions and the performance of the WAP
protocol have not fully evaluated. |
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We have measured the performance of the WAP
protocol and compared it with that of the Internet protocol. |
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WAP is developed by the WAP Forum (established
in 1997). |
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WAP is a protocol that is optimized for wireless
environment (mobile phone, PDA etc.) |
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Consists of WAP client, WAP getaway and Origin
server. |
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Optimized for wireless network characteristics
and provides special functions. |
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Telephony application, push functionality,
suspend & resume |
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WML(Wireless Markup Language) and binary
encoding |
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Many kinds of bearer support (GSM, CDMA, PDC,
SMS…). |
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We evaluated the following items on the WAP
test-bed system. |
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Functionality evaluation |
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WAP Push |
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WAP push is one of the unique functions in WAP.
Investigating feasibility of WAP push is very important. |
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We developed an e-mail application prototype by
using the WAP push function. |
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Performance evaluation |
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Response time |
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Since response time is one of the key factor of
serviceability, we compared the response time of WAP1.1 and HTTP/TCP. |
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WML binary encoding compression rate and
processing time |
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WML binary encoding is one of the unique
functions in WAP. |
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What is WAP push? |
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The WAP Push framework introduces a means to
transmit information to a WAP client. |
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WSP defines push methods (confirmed and
unconfirmed push) in addition to the methods defined by HTTP. |
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We developed an e-mail application prototype by
using the WAP push function. |
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Protocol conversion (SMTP to WSP) is executed at
the WAP gateway, and e-mail messages are pushed to the client immediately. |
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An immediate push of a message (e.g. e-mail,
instant message) is desirable, from the mobile user’s point of view. |
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We concluded that the WAP push functionality
fulfils the above requirement. |
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WAP push is very feasible and usable in the
wireless environment. |
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Evaluated the response time (from request method
to reply method) of WAP1.1 and the Internet protocol (HTTP/TCP) over W-CDMA
environment. |
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W-CDMA emulator emulates W-CDMA environment,
which can set up bearer speed, bearer error rate, latency and so on. |
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Bearer speed |
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Uplink: 64kbps (fixed) |
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Downlink: 384kpbs, 64kbps |
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Bearer error rate:10% |
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Contents size |
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500, 10K, 100Kbytes |
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Protocol parameters |
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WTP maximum group size: 9600bytes |
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TCP receive buffer size: 9600bytes |
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WAP1.x would take an advantage if content size
were small, HTTP/TCP would take an advantage if content size were large. |
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500byte(64kbps): WTP1.x is better than HTTP/TCP. |
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100Kbyte(64kbps): HTTP/TCP is better than
WAP1.x. |
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Reason |
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Because TCP slow start algorithm prevents making
full use of network resources in the slow start phase, WTP is better than
TCP in case of small contents. |
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WTP responder can send the number of packets
based on the window size, but the WTP responder has to wait until the
subsequent acknowledgement is received. That waiting time results in the
increase of total response time. |
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TCP performance is better when transmitting
large contents because dynamic flow control mechanism works well provided
that the large size of buffer is prepared in the client. |
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WAP defines binary encoding of WML. |
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A WML content is encoded into binary format at
the WAP gateway. |
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We evaluated WML binary encoding compression
rate as well as processing time compared with gzip. |
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Content size: 500, 1000, 1400, 20K, 100K, 360K |
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<wml> |
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<card
id="abc" ordered="true"> |
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<p> |
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<do
type="accept"> |
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<go href="http://xyz.org/s"/> |
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</do> |
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X:
$(X)<br/> |
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Y:
$(Y)<br/> |
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Enter
name: <input type="text" name="N"/> |
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</p> |
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</card> |
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</wml> |
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If content size were small, WML binary encoding
would be effective. On the other hand, gzip encoding would be effective if
content size were large. |
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WML encoding processing overhead would increase
considerably if content size were large. (In case of 360K, then 1730ms.) |
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WAP1.x would take an advantage if content size
were small, HTTP/TCP would take an advantage if content size were large. |
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Since 3G network handles larger contents than
1G/2G, HTTP/TCP is more suitable than WAP1.x in the 3G multimedia
environment. |
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We propose the mobile Internet architecture that
is suitable for high-speed wireless networks such as |
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W-CDMA. |
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Seamless Internet access. |
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Provide End-to-End security by using TLS
tunneling. |
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HTTP/TCP would take an advantage if content size
were large. |
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Markup Language |
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Experience with the deployment of i-mode. |
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Since i-mode adopts subset of HTML and contents
developers are familiar with it, there are many i-mode contents in the
Internet. |
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XHTML is expected to be the next generation
markup language. And XHTML Basic is expected to be a core language for
clients such as mobile phones that do not fully support of XHTML features. |
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Push functionality |
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WAP push is very feasible and usable in the
wireless environment. |
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Provide push functionality over TCP by using
HTTP POST (implementing HTTP compact server on the phone, and HTTP client
on the WAP Gateway). |
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We developed WAP1.1 test-bed system. |
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Performance evaluation has shown that WAP1.1 is
suitable for application of small content size. |
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In 3G network, bearer speed is very fast
(384kbps-2Mbps) and contents are becoming large, so that Internet standard
protocols(HTTP/TCP) is applicable to the wireless environment with some TCP
modifications. |
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We proposed Mobile Internet Architecture for
high-speed wireless networks such as 3G. |
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