Exploiting Similarity for Multi- Source Downloads Using File Handprints
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Transcript Exploiting Similarity for Multi- Source Downloads Using File Handprints
Exploiting Similarity for MultiSource Downloads Using File
Handprints
Internet
Many files available on Internet
Many people download files from Internet
Resource is limited, long time to download
files
Client bandwidth
Server capacity
Router congestion
Solutions
Many files on Internet are duplicate
By use of all the available sources, client
use shorter time to download files
per-file (Bit Torrent)
per-chunk (CFS and Shark)
O(N) lookup where N is no of chunks
O(1) lookup
O(1) insert mappings per file
How to do?
Similarity
Lookup the similar file in O(1)
Low overhead of locating source
Similarity
MP3 with different header
Movies with different language
Damage files (only few bytes of error)
Compressed file with different additional
files
Parallelism
Optimistic metric
Download different chunks at the same time
Client select different source for different chunks
Each source send one chunk at a time
C
max C s
Parallelism
Conservative parallelism metric
Download one chunk at a time
Download chunk at different source
C
1
i 1 S
i
C
Parallelism
Parallelism
Parallelism
Handprinting
Two files A and B
Na no of chunks of A
Nb no of chunks of B
m chunks in common
k selected hashes
Handprinting
How many chunks (k) we selected
p (1 (1 s) )
k 2
log( 1 p )
k
log( 1 s)
Two files A and B
Na no of chunks of A
Nb no of chunks of B
m chunks in common
k selected hashes
Implemention
Evaluation
Evaluation
Evaluation
Evaluation
Evaluation
Evaluation
Q&A
Thank You