Title
On the Local Approximations of Node Centrality in Internet Router-Level Topologies
Abstract
In many networks with distributed operation and self-organization features, acquiring their global topological information is impractical, if feasible at all. Internet protocols drawing on node centrality indices may instead approximate them with their egocentric counterparts, computed out over the nodes' ego-networks. Surprisingly, however, in router-level topologies the approximative power of localized ego-centered measurements has not been systematically evaluated. More importantly, it is unclear how to practically interpret any positive correlation found between the two centrality metric variants. The paper addresses both issues using different datasets of ISP network topologies. We first assess how well the egocentric metrics approximate the original sociocentric ones, determined under perfect network-wide information. To this end we use two measures: their rank-correlation and the overlap in the top-k node lists the two centrality metrics induce. Overall, the rank-correlation is high, in the order of 0.8-0.9, and, intuitively, becomes higher as we relax the ego-network definition to include the ego's r-hop neighborhood. On the other hand, the top-k node overlap is low, suggesting that the high rank-correlation is mainly due to nodes of lower rank. We then let the node centrality metrics drive elementary network operations, such as local search strategies. Our results suggest that, even under high rank-correlation, the locally-determined metrics can hardly be effective aliases for the global ones. The implication for protocol designers is that rank-correlation is a poor indicator for the approximability of centrality metrics.
Year
DOI
Venue
2013
10.1007/978-3-642-54140-7_10
IWSOS
Field
DocType
Volume
Internet Protocol,Computer science,Social network analysis,Node (networking),Centrality,Network topology,Betweenness centrality,Network theory,Local search (optimization),Distributed computing
Conference
8221
ISSN
Citations 
PageRank 
0302-9743
5
0.45
References 
Authors
14
3
Name
Order
Citations
PageRank
Panagiotis Pantazopoulos1265.30
Merkourios Karaliopoulos218417.68
Ioannis Stavrakakis31198121.86