A method for designing proximity-aware routing algorithms for structured overlays

In many structured overlays, nodes strictly maintain their routing tables using node identifiers. However, building routing tables while taking account of the physical network is difficult. We propose proximity-aware flexible routing tables (PFRT) in this paper as a method to systematically design proximity-aware routing algorithms for structured overlays. PFRT was developed by extending the flexible routing tables (FRT) method such that network proximity is considered. Routing tables in FRT-and PFRT-based algorithms are updated according to the order of the set of all routing table patterns. FRT-based algorithms define a total order based on node identifiers, whereas PFRT-based algorithms define two total orders based on node identifiers and network proximity. Because PFRT is a simple extension of FRT, PFRT-based algorithms also have many of the advantageous features of FRT. We extended Chord to design PFRT-Chord, which is a PFRT-based algorithm. Experimental results showed that PFRT-Chord preserves the expected FRT-derived properties and it could take account of network proximity.