ACME: a New Mobile Content Delivery Architecture Michal - - PowerPoint PPT Presentation

2005-02-23 ACME: a New Mobile Content Delivery Architecture 1

ACME: a New Mobile Content Delivery Architecture

Michal Zajaczkowski Grzegorz Iwacz

T-110.456: Next Generation Cellular Networks

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Agenda:

Introduction Revision of wireline content delivery techniques Bottlenecks in wireline and wireless networks ACME cache Multicast ACME director ACME Performance Analysis ACME in CDMA Networks Conclusions

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Introduction [ 1]

Goals for 2.5G and 3G mobile network applications:

As close to the wireline apps as possible Satisfactory user experience

Interactivity Good visualization

New types of apps are available Power efficiency

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Introduction [ 2]

To achieve our goals we have to face a problem of latancy. It is mainly caused by: air interface high frame corruption rate limited bandwidth symmetric bandwidth

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Introduction [ 3]

Architecture for Content delivery in M obile Environment

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Revision of wireline content delivery techniques

Network Scaling End-System Acceleration Content and Protocol Optimization

Web caching

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Bottlenecks in wireline and wireless networks

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ACME cache

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multicast

Caching previous browsed content is not enough! Terminals cache should have the demanded content in advance! It is possible by m ulticasting every single response from the server, and caching it in terminal cache even if the terminal didn’t send the request. The problems are lim ited „disk” space and the battery usage in mobile devices.

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ACME Director [ 1]

• The solution for those problems is ACME Director

0.7-6% of size of bc groups to achieve 50% caching effectiveness from 17 to 144 times less power consumption better scalability!

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ACME Director [ 2]

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ACME Director [ 3]

when network utilization increases, multicast requested content more aggressively multicast content to active terminals only integrate terminal battery information into multicast decision For further improvement of the bandwidth-delay- battery balance:

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ACME Performance Analysis [ 1]

Assumptions:

• we analyze ACME’s performance in a slotted ALOHA

system (benefits in other systems are similar)

• each requested Web object is broadcast to every terminal

in the cell

• caches are of infinite capacity
• content request and reply messages are of the same fixed

size

• the aggregate new request rate of N terminals is λ
• collisions only in the uplink (if collision, retransmit with

probability qr)

• the total offered load is G

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ACME Performance Analysis [ 2]

• First we consider a base system with no ACME cache in
• use. The expected user-perceived network latency is:

r G

q e E 1 2 − + =

• Two key improvements ACME makes over Baseline:

Some requests can be served immediately from the ACME cache Faster medium access due to reduced medium contention

) 1 ( 1 2 h q e E

r G

− ⋅ ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − + =

h – hit ratio of the ACME cache

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ACME Performance Analysis [ 3]

lightly loaded system improvement of ACME mostly due to caching content locally as load (probability of collision) increases caching reduces contentions, improving latency even in the case of cache misses

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ACME Performance Analysis [ 4]

The slope of the curves becomes steeper as the new arrival rate increases the medium contention reduction effect is more pronounced under heavy load

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ACME in CDMA Networks

ACME’s major benefit is reduced interference

„near-far” problem the solution is the terminal power control ACME can be thought of as a way of „ultimate” power control (transmission power reduced to zero if the content has been previously requested)

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Conclusions

air interface the bottleneck of mobile Web user experience ACME extends the network edge to the terminal ACME reduces the effect of air interface on user experience the effectiveness of Web caching lies in user interest correlation ACME can offer optimal balance between radio bandwidth, terminal storage and power usage

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References

Books:

• Sudhir Dixit and Tao Wu „Content Networking In The Mobile Internet”
• K. Sripanidkulchai, B. Maggs, H. Zhang „Efficient content location using

interest-based locality in peer-to-peer systems”, Proc. INFOCOM 2003

• Z. Jiang and L. Kleinrock „Web prefetching in mobile environment”, IEEE
• Pers. Commun. (Oct. 1998)
• Y. Guo and H. Chaskar „Class-based quality of service over air interfaces in

4G mobile networks”, IEEE Commun. Mag. 40(3) (2002)

Links:

• http: / / www.3gpp.org/ ftp/ specs/ archive/ 23_series/ 23.846
• http: / / www.3gpp.org/ ftp/ specs/ archive/ 25_series/ 25.855
• http: / / ietf.org/ html.charters/ opes-charter.html
• http: / / www.bamboomc.com