Information Technology Reference
In-Depth Information
4 Simulation Results
We have detected bottleneck link trac and trac on links between PoPs in
Abilene, and kept a record of the peers' completion time for different swarm
sizes in different topologies. Further, we have obtained the statistics of trac on
links between ASes in interdomain settings.
In this section, we considers a case in which all peers share a 250-MB file, and
discuss the performance of P2P, P4P, and
Improved-P4P
for different swarm
sizes and network topologies within AS .
12000
10000
8000
6000
4000
2000
0
P2P
P4P
Improved−P4P
Fig. 3.
Variance of Trac (Swarm Size = 600)
Figure 3 shows that when the swarm size is 600, compared with the native
Bit-Torrent that is based on P2P, BitTorrent integrated with
Improved-P4P
can reduce the bottleneck trac substantially. Moreover, to some degree, the
Improved-P4P
can reduce the P4P's bottleneck. In particular, in the case of
Abilene, the bottleneck tra
c produced by the native BitTorrent is 1.93 times
that produced by the BitTorrent integrated with
Improved-P4P
, and BitTorrent
integrated with
Improved-P4P
can reduce the bottleneck trac of BitTorrent
integrated with P4P by 4.74%.
We can conclude from the above result that compared with P2P and P4P,
Improved-P4P
can considerably reduce the bottleneck trac and better protect
the bottleneck.
In conclusion,
Improved-P4P
can reduce bottleneck link utilization and the
duration of high-level bottleneck trac. Undoubtedly,
Improved-P4P
can relieve
the pressure on bottleneck links.
We can observe from the result that compared with P2P and P4P,
Improved-
P4P
makes the trac on every link more even, which then reduces the trac
on the bottleneck links.
Figure 4 shows how the normalized completion time varies with the swarm
size. The normalized completion time refers to the normalized value based on the
maximum average downloading time of the peers in the native BitTorrent system.
In particular, in the case of Abilene, the BitTorrent integrated with
Improved-
P4P
and that integrated with P4P has almost the same average completion
