Peer-to-Peer Computing

90 Peer-to-Peer Computing

N

1

N

2

N

S

Submitting bids

1

b

2

b

1

t()

x

2

x

S

W

1

x

2

x

Bandwidth Allocation

Result

t()

t()

t()

t()

t()

FIGURE 5.5: Two file requesting peers (N

1

and N

2

) compete for uploading

bandwidth of a source peer (N

S

) [Ma et al., 2004a].

where:

N

X

i=1

x

i

≤ W

S

(5.9)

Here, the loga rithmic function represents the utility as perce ived by each

peer i.

The above optimization problem can be solved by a progr e ssive filling

algorithm that prioritizes competing peers in descending order of the marginal

utility C

i

/(b

i

+ x

i

).

Given values of b

i

and C

i

, the source peer can compute the allocations in

a deterministic manner. However, from the perspective of a requesting peer,

a pro ...