In the last few years tremendous development in the area of wireless and mobile network has been observed. Internet Engineering Task Force (IETF) proposed Mobile IPv6 to provide mobility in wireless networks. In Mobile IPv6, a Mobile Node directly updates its current location information to a Correspondent Node using a Route optimization technique. However, Route Optimization suffers from handover delays derived from the signaling message exchange. Handover latency in Mobile IPv6 plays an importantrole in the performance of a network scenario. It results in packet losses and severe End-to-End performance degradation. This paper analyzes and also compares some of the existing mechanismsthat are used for reducing handover latency and packet loss problem in the current mobile IPv6 Route Optimization environment and gives the overview of this area.

Mobile IPv6 is a very important part in the mobile computing for global Internet. However, there are some security threats in the current mobile IPv6 such as threats against binding update, Route Optimization and Tunneling. Therefore, strong security mechanism is required to provide authentication as well as address verification with better handover latency and efficient performance. This paper studies the security threats in the current mobile IPv6; meanwhile, summarize and analyze the existing Security Mechanism, infrastructures in the current mobile IPv6 and give the overview of this area.

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Any error-concealment technique can be applied at the decoder, it is necessary first to find out whether and where a transmission error has occurred. Error detection can be performed at the transport coder/decoder and at the image decoder. One way to perform error detection at the transport coder is by adding header information containing a sequence number. At the transport decoder, the sequence number can be used for packet-loss detection. Another method at the transport level is to use a forward error correction (FEC). There are also methods that can exploit the characteristics of natural image signals where the differences of pixel values between two neighboring lines are used for detecting transmission errors. When the difference is greater than a threshold, the current image segment is declared to be damaged. When VLC is used in the source code, any damage to a single bit can cause resynchronization, resulting in the subsequent bits being undecodable. However, this property can be used as a means to detect transmission errors. In addition, the syntax embedded in the bit stream can also be used for error detection.Index Terms-Forward Error Concealment, interpolation, joint source channel coding, robust image transmission, image system model.