Leopard: A Locality Aware Peer-to-Peer System with No Hot Spot

Abstract

Abstract. Recent research [7,12,2] has shown that Internet hosts can be efficiently (i.e., without excessive measurements) mapped to a virtual (Euclidean) coordinate system, where the geometric distance between any two nodes in this virtual space approximates their real IP network distance (latency). Based on this result, in this paper, we propose an alternative approach that inherently incorporates a virtual coordinate system into a P2P network. In our system, called Leopard, a node is assigned a coordinate in the so-called node geo space as it joins the network, and obtains neighbor relationships that reflects network proximity from the beginning. The object id space and the node geo space are then "weaved" together via a novel technique called geographically-scoped hashing. Through analysis and simulation, we show three major desirable properties of Leopard to exemplify the power of this paradigm shift: i) a constant routing stretch, i.e., IP level network latency of object look-up is proportional to the distance between a requesting node and the target object; ii) always locates a near-by copy when multiple copies exist; and iii) effectively handles "flash crowd" traffic with near optimal load balancing.

Underlay awareness in P2P systems: Techniques and challenges

“…In [33], Yinzhe et al apply this concept on a structured overlay. Both content identifiers and latency information are processed together using a special hashing function called Geographically Scoped Hashing to produce the final peer and content identifiers.…”

“…BNS [3], TSO [31] , Ono [5], LTM [21], CAT [32], Brocade [36], Plethora [9], Mithos [28], MBC [35] Latency gMeasure [34], Genius [23], eCAN [30], Leopard [33], Hop-based Proximity [8], Proximity in DHTs [4], Landmark-based proximity [ …”

Enabling resilient P2P video streaming: survey and analysis

“…Figure 10 presents how the concept of biased neighbor selection can help in reducing inter-AS traffic by limiting the number of overlay links across different ASs. In Leopard [61], which is a geolocation awareness approach, the system tries to achieve constant routing stretch and load balancing during flash crowds. In DagStream [62] a peer selects geographically close peers as neighbors and can, therefore, minimize the packet delay between itself and its parent peers.…”

Methods for Improving Resilience in Communication Networks and P2P Overlays

“…The path stretch, or dilation, is a good metric for the quality of the location awareness of an overlay network. A good overview of P2P substrates that follow this approach is given in [17] and specific approaches can be found in [108,109,16,104]. Including locality information in overlay construction is no direct measure to improve resilience.…”