To reduce the searching cost is the key of improving the performance of P2P network. We propose a search algorithm for unstructured P2P network, which is based on query agent. The algorithm can adaptively control the scale of query by satisfactory degree. We carry out simulations under two query-replication modes and the simulation results show that the algorithm can effectively decrease the redundant cost. The mobility of query agent assures that the repeat messages are trivial.
Similar to conventional NAT gateways, NAT-PT gateways break traditional TCP/IP’s end-to-end argument property; hence, any IP-based applications protected by IPSec protocol cannot traverse NAT-PT gateways properly. The interworking issues between IPSec and NAT-PT gateways under IPv4/IPv6 co-existent environments were studied: this paper first pointed out the deficiency of current NAT-Traversal scheme when interworking with NAT-PT gateways and proposed an enhanced scheme, which enabled interworking between IPSec and NAT-PT gateways and served the following three scenarios: 1) secure communication between IPv6 hosts and IPv4 hosts; 2) secure communication between IPv6 subnets and IPv4 subnets; 3) secure communication between remote IPv6 hosts and legacy IPv4 subnets.
A mechanism, E-SDR is proposed to enhance salvaging performance for Dynamic Source Routing (DSR). In this mechanism, salvaging is processed not by only one node as in traditional DSR, but also its neighbor ones. Through this kind of co-operation among neighbor nodes, the probability of salvaging a packet can be increased. Hence, higher routing performance can be achieved. We implement the mechanism in NS-2 as a patch of DSR, and compare E-DSR to traditional DSR. The results show that, this mechanism can improve traditional DSR routing performance significantly, especially as nodes and traffic are accruing.