|Abstract:||In this paper we present ECDP, an efficient incentive
based prioritized content distribution protocol. In ECDP content
which originates from some servers or peers is first distributed to
some users (peers). As soon as the content reaches some of these
peers, other peers can get the content either from the servers or
any of the peers whichever gives the lowest per packet price and
An ECDP content information manager (CIM ) calculates the
weighted (prioritized) fair rate for each stream at each node.
To do this the CIM first obtains the upload and download base
rates from each peer’s rate monitor (PA). A peer selects or looks
up a content in the CIM database using a web interface. The
CIM selects a content source node (CDN server or peer) which
gives the lowest (bandwidth) price, highest rate (throughput) and
lowest delay for each requesting peer.
In ECDP, each content source periodically adjusts its bandwidth
prices and prioritized rates based on the current demand.
Unlike existing incentive-based mechanisms, ECDP enforces the
rate allocations by setting the flows’ sending rates (congestion
window, receive window and maximum window sizes) to ensure
efficient and accurate incentive to the participating nodes.
We have implemented ECDP in the NS2 simulator. Simulation
results show that ECDP can outperform existing schemes in
terms of file download time and throughput. The results also
demonstrate that ECDP obtains fair uplink prices for the uploaders
and fair cost for the downloaders maintaining an overall
system fairness to benefit all peers, content providers and network
operators. The results also demonstrate that ECDP efficiently
enforces the prioritized allocations. ECDP can be deployed in
the current Internet without the need of changes to the TCP/IP
stack or routers. We have also implemented ECDP using an
Apache SQL Server with PHP in Linux virtual machines and
demonstrated that ECDP is a scalable protocol.