[2] describes a global mobility solution that provides host mobility management for a diverse array of applications and devices on the Internet. In Internet (IP) environments, when a mobile node moves and attaches itself to another network, it needs to obtain a new IP address. This changing of the IP address requires all existing IP connections to the mobile node be terminated and then re-connected. This is necessary as the IP routing mechanisms rely on the topological information embedded in the IP address to deliver the data to the correct end-point. Mobile IP overcomes this by introducing a level of indirection at the network (IP) layer. This indirection is provided with the use of network agents and does not require any modification to the existing routers or end correspondent nodes. With MIP, each mobile node is identified by a static home network address from its home

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Handoff latency results in packet losses and severe End-to-End TCP performance degradation as TCP, perceiving these losses as congestion, causes source throttling or retransmission. In order to mitigate these effects, various Mobile IP(v6) extensions have been designed to augment the base Mobile IP with hierarchical registration management, address pre-fetching and local retransmission mechanisms. While these methods have reduced the impact of losses on TCP goodput and improved handoff latency, no comparative studies have been done regarding the relative performance amongst them. In this paper, we comprehensively evaluated the impact of layer-3 handoff latency on End-to-End TCP for various Mobile IP(v6) extensions. Five such frameworks are compared with the base Mobile IPv6 framework, namely, i) Hierarchical Mobile IPv6, ii) Hierarchical Mobile IPv6 with Fast-handover, iii) (Flat) Mobile IPv6 with Fast-handover, iv) Simultaneous Bindings, and v) Seamless handoff architecture for Mobile IP (S-MIP). We propose an evaluation model examining the effect of linear and ping-pong movement on handoff latency and TCP goodput, for all above frameworks. Our results show that S-MIP performs best under both ping-pong and linear movements during a handoff, with latency comparable to a layer-2 (access layer) handoff. All other frameworks suffer from packet losses and performance degradation of some sort. We also proposed an optimization for S-MIP which improves the performance by further eliminating the possibility of packets out of order, caused by the local packet forwarding mechanisms of S-MIP.

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The use of response function modeling, conjunction analysis, and high-field imaging reveals dissociable regional responses to a tonic aching electrical pain. Most specifically, the primary somatosensory cortex and insula seem to encode stimulus intensity information, whereas the secondary somatosensory cortex encodes pain intensity information. The cingulate findings are consistent with its proposed role in processing affective-motivational aspects of pain.