A Scalable content-addressable
network
Presenter: Baoning Wu
Motivation
 Many peer-to-peer systems appear, but most
of them are not scalable.
– Napster needs a central server to store index of
all files.
– Gnutella floods request with a certain scope.
 Can we have a scalable p2p file distribution
system?
CAN (content-addressable
network)
 Scalable indexing mechanism is crucial in
scalable p2p systems.
 Hash table is used!
 (key, value) pair
 Each CAN node stores a chunk(zone) of the
entire hash table
Design
 D-dimensional Cartesian co-ordinate space
 Map key to a point P with a determined
hash function
 Routing the request if the point P is not
owned by the requesting node or its
immediate neighbors.
Picture
Routing detail
 Each CAN node maintains coordinate
routing table that holds the IP address and
virtual coordinate zone of its neighbors.
 Routing a message towards its destination
by simple greedy forwarding to the
neighbor with coordinated closest to the
destination coordinates.
Design improvement: Multidimensioned coordinate spaces
Design improvement: Multiple
coordinate spaces
Design improvement: multiple
dimensions vs. multiple realities
Design improvement:
RTT weighted routing
Design improvement:
multiple nodes share a zone
Design improvement:
multiple hash functions
Design improvement:
topologically-sensitive construction
Review
 Dimensionality
 Number of realities
 Number of peer nodes per zone
 Number of hash functions
 Use of RTT weighted routing metric
 Use of topologically-sensitive construction
QUESTIONS?