Mobile Routers moving in a heterogeneous network environment can take advantage of the different, often complementing, characteristics of the various wireless network technologies. Satellite and cellular networks can provide wide coverage outside urban areas. However, the cost of communications for these technologies is often significant. Shorter range, high bandwidth wireless technologies, such as IEEE 802.11 WLAN and WiMax can provide high data rates at a low price but cover only hot spots (WLAN) or urban areas (WiMax). For a Mobile Router to provide cost effective high bandwidth communication services to Mobile Network Nodes, it needs to be able to switch between the different technologies and between different providers networks frequently to provide connectivity via the best available
Keyword: Heterogenous Network, Mobility, IEEE 802.11, WLAN, Wimax
[...] providing passengers in a train with Internet access, the high costs and relatively low speeds of the high coverage technologies make it preferable to use multiple network technologies. Thus, the link layer approach to mobility management can not provide a general solution to network mobility management. Network layer approaches or to be more accurate mobility management protocols sitting between the network layer and the transport layer enable the use of a single mobility management protocol with multiple link types and multiple applications and transport protocols. [...]
[...] The server acts a SIP proxy for the SIP hosts inside the mobile network enabling a NEMO like operation Application adaptation and content delivery In a heterogeneous network environment, handoffs often result in changes to the availability of network resources for an application. Typically in vertical handoffs, the available bandwidth and delay will change dramatically when moving between WLAN and WWAN technologies. Even in horizontal handoffs the available bandwidth may differ markedly due to differences in network loads or the received signal strength. [...]
[...] NEMO protocol treats both in the same way by hiding the mobility of the Mobile Router from them. If the Visiting Mobile Nodes are using a mobility management protocol there will be two layers of mobility management which may create additional overheads as discussed in more detail in the following subsection. An extension to Session Initiation Protocol (SIP) has been proposed for network mobility management. It uses a SIP Network Mobility Server to manage the mobility of the SIP nodes in a mobile network. [...]
[...] To do so without disrupting the connectivity and reachability of the Mobile Network Nodes, the Mobile Router needs to run a mobility management protocol Mobility protocols management Mobility management is used in this dissertation to refer to the task of handling the mobility to ensure reachability and session continuity of the mobile devices. Mobility management has been traditionally handled at the link layer. These approaches have the advantage of hiding the mobility both from the applications and the TCP/IP protocol stack. [...]
[...] Hosei Matsuoka, Takeshi Yoshimura, and Tomoyuki Ohya. A robust method for soft ip handover. IEEE Internet Computing J. McNair and F. Zhu. "vertical handoffs in fourth-generation multinetwork environments". IEEE Wireless Communications, 15, jun 2004. Internet Engineering Task Force, Mobility for IPv6 working group. Conclusion High speed mobility within the heterogeneous network environment would result in frequent handoffs. These frequent handoffs could disrupt the communications of the Mobile Network Nodes, if not handled carefully. Seamless handoffs, i.e. the ability to switch [...]
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