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2008, IEEE/ACM Transactions on Networking
This paper introduces a new paging technique to track and wake up a mobile node (MN) attached to an access point (AP) in a wireless LAN network after a session initiation protocol (SIP) INVITE message is initiated by a caller. A tracking agent (TA) keeps track of the mobiles' handoffs between the APs. A paging agent (PA) triggers the TA to page the mobile when a SIP INVITE is received for one of its users. The context transfer feature of our paging protocol allows the paging messages to deliver the station context in order to enable faster session reestablishment. The AP then does onlink paging in a wireless link. SIP extensions are needed to trigger the PA to start paging MNs to notify their dormant status using an extended SIP REGISTER method. Tracking protocol is analyzed to compare soft-and hard-state approaches for state inconsistency ratio, message rate, and the overall cost. The simulation model we developed enables us to evaluate the traffic introduced by the tracking protocol and the cache (state) size. Paging protocol is analyzed for CPU processing times and the transmission delays in the SIP session setup with paging. Simulation of the paging with context transfer is used to show the gains in reauthentication. Index Terms-Context transfer, fluid flow and random walk mobility model, onlink paging, paging agent (PA), session initiation protocol (SIP), tracking agent (TA).
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 2003
In this paper we present results, which have obtained by extensive simulations for Mobile IP and Session Initiation Protocol from the perspective of VoIP service in wireless Internet access. After illustrating the problem in these two protocols for diverse cases of mobility management, we propose an integrated model, to reduce the handover latency and packet loss during handover. This combination of network and application layer mobility management model reduces the global signaling load and provides fast handoff for ongoing conversations. The proposed approach needs no modification to the existing SIP message set and Mobile IP. Simulation results presented in this paper are based on the NS2 Mobility Software[12]. However, since the current version of NS2 does not include SIP model for VoIP service, we add a suite of new features and procedures that are specific to this paper. The simulations results show that our proposed mechanisms achieve better performance than other protocols.
2009
Session mobility is the transfer of media of an ongoing communication session from one device to another. This document describes the basic approaches and shows the signaling and media flow examples for providing this service using the Session Initiation Protocol (SIP). Service discovery is essential to locate targets for session transfer and is discussed using the Service Location Protocol (SLP) as an example. This document is an informational document. Status of This Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
Mobile Computing and Communications Review, 2000
Supporting mobile Internet multimedia applications requires more than just the ability to maintain connectivity across subnet changes. We describe how the Session Initiation Protocol (SIP) can help provide terminal, personal, session and service mobility to applications ranging from Internet telephony to presence and instant messaging. We also briefly discuss application-layer mobility for streaming multimedia applications initiated by RTSP.
Bell Labs Technical Journal, 2004
In the emerging data networks, session initiation protocol (SIP)-based voice over IP (VoIP) is gaining wide-scale acceptance as a means of transporting voice over the packet data networks. With the emergence of interoperability between various third-generation (3G) cellular technologies such as 1xEV, 1xEV-DO, 1xEV-DV, and the Universal Mobile Telecommunications System (UMTS) on one hand and wireless LAN (WLAN) technologies such as 802.11a/b/g, HiperLAN/2, and Bluetooth* on the other, multimedia applications would have to interoperate seamlessly among several air interfaces. Mobile IP, a layer 3 protocol, maintains the data session across heterogeneous air interfaces but does not guarantee minimal or no packet loss when handing over a mobile node from one air interface to another. This paper first discusses a network architecture that supports seamless interoperability between 3G and WLAN and proposes autonomous layer 2 enhancements at the client side to support SIP-based multimedia applications in general and voice applications in particular. Finally, it discusses some other network issues that pose a challenge to providing VoIP in commercial networks in general, such as using SIP with network address translation (NAT) over mobile IP, and it specifically addresses the problem of performing VoIP in CDMA2000* 1XRTT.
Journal of Networks, 2008
This paper proposes a network-initiated terminal mobility mechanism (NITM) to facilitate handover with the session initiation protocol (SIP) in 3GPP Voice over WLAN (3GPP VoWLAN). We design the E2E tunnel state model running on the packet data gateway (PDG) using the CAMEL concept, and introduce the mobility server (MS) as a SIP application server to re-establish sessions with third party call control (3PCC). The MS is triggered to provide the terminal mobility service from the PDG by detecting the state transition of the E2E tunnel state model that represents the occurrence of a handover. This mechanism can advance the time to re-establish sessions. That is, our approach can provide smaller handover delay than mobileinitiated terminal mobility; moreover, it can handle mobility without additional support from the mobile host (MH). In addition, the handover missing problem (messages lost) might happen when the MH moves under communication. With the help of the MS, the lost messages are re-sent, and the handover missing problem, including simultaneous movement, is therefore solved.
2006 3rd Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services, MobiQuitous, 2006
Internet-based communication is currently in a hype. People utilize Internet services more and more to communicate with each other, e.g., via VoIP or chat. The next step would be to reutilize the same applications to achieve ubiquitous communication, anytime and anywhere, also where network support is not available, such as in ad-hoc networks. Existing Internet protocols must be modified for working in the ad-hoc serverless environment. The Session Initiation Protocol (SIP) is a fundamental element in the Internet for establishing multimedia communication sessions. However, SIP cannot be used in ad-hoc networks, as it relies on the support of SIP servers in the network; e.g, in ad-hoc networks it is not possible to locate SIP users since the assistance of a dedicated SIP server is missing. A solution for this problem is presented in this paper, which describes and evaluates a fully decentralized mechanism for locating SIP users in ad-hoc networks.
2002
Maintaining multimedia sessions by means of SIP signaling has often been termed as application layer mobility management scheme. There have been numerous proposals to support different types of mobility using SIP signaling which is generally used to set up and tear down the multimedia stream. Mobility management in heterogeneous networks plays a very important role since the user could be moving between multiple types of access networks involving many service providers during a multimedia session. These access networks could be 802.11b, CDPD, CDMA or GPRS based network supporting DHCP or PPP servers in the networks. The movement of the mobile host can be between the access networks where each access network may belong to the same subnet, same domain but different subnets or different different domain altogether. In most cases the end-client would have access to both the networks at the same time, but connectivity to the network would be determined by any local policy defined in the client itself such as signal strength or any other measurement based on QoS parameter of the traffic. This paper discusses various issues associated with SIP signaling for maintaining continuity of both signaling and media flow in a Local Area Network and Wide Area Network environment and presents the experimental results associated carried out in the testbed.
recent years. In the future, operators will need to enable users to use communication' services independently of access technologies, so they will have to support seamless handovers in heterogeneous networks. In this paper, we focus on building the simulation model for testing advanced handover procedures. Simulation model based on real operator network measurements was presented, verified and validated. In addition, advanced procedure for SIP based seamless handover in heterogeneous network using congestion detection was described. Its performance was evaluated using the described simulation model. The results have shown that, by using the CAHP C procedure, we can significantly improve the user experience for VoIP application when performing seamless handover in heterogeneous networks.
2003
SIP is evolving as the dominant protocol for multimedia call control in IP networks and is expected to be widely deployed in the near future. Using SIP for supporting mobility in SIP-based networks appears as a very attractive alternative to mobile IP, taking advantage of existing SIP infrastructure and signaling, while avoiding duplication of functionality. However, existing proposals for supporting mobility with SIP are not efficient in handling micro-mobility and do not cater for all types of traffic. In this paper, we introduce hierarchical mobile SIP (HMSIP), for efficient micro-mobility management in SIP environments. HMSIP is a SIP-based scheme that builds on existing IP mobility protocols, aiming at integrating their key concepts in the most beneficial way. Our proposed scheme minimizes the handoff latency and the backbone signaling overhead, while catering for all types of traffic. Moreover, HMSIP can be effectively combined with micro-mobility schemes for QoS flows, producing, thus, a complete micro-mobility solution for SIP flows with QoS guarantees.
Proceedings of the second international workshop on Mobility management & wireless access protocols - MobiWac '04, 2004
Session Initiation Protocol (SIP) was standardized for real-time applications and extended to support terminal mobility by Internet Expert Task Force (IETF). However, SIP terminal mobility suffers from the considerable handoff latency which is unsuitable for the real-time communications. In this paper, we propose Predictive Address Reservation with SIP (PAR-SIP) which decreases handoff delay by proactively processing the address allocation and session update using link layer information of wireless networks.
1999
Enabling mobility in IP networks is an important issue for making use of the many light-weight devices appearing at the market. The IP mobility support being standardized in the IETF uses tunnelling of IP packets from a Home Agent to a Foreign Agent to make the mobility transparent to the higher layer. There are a number of problems associated with Mobile IP, such as triangular routing, each host needing a home IP address, tunnelling management, etc. In this paper, we propose to use mobility support in the application layer protocol SIP where applicable, in order to support real-time communication in a more efficient way.
2004
Providing seamless mobility support is one of the most challenging problems towards the system integration of fourth generation (4G) wireless networks. Because of the transparency to the lower layer characteristics, application-layer mobility management protocol like the Session Initiation Protocol (SIP) has been considered as the right candidate for handling mobility in the heterogeneous 4G wireless networks. SIP is capable of providing support for not only terminal mobility but also for session mobility, personal mobility and service mobility. However, the performance of SIP, operating at the highest layer of the protocol stack, is only as good as the performance of the underlying transport layers in such a heterogeneous environment. In this paper we analyze the handoff performance of SIP in a IP-based 4G network with Universal Mobile Telecommunication System (UMTS) and Wireless LAN (WLAN) access networks. Analytical results show that the handoff to a UMTS access network introduces a minimum delay of 1.4048 s for 128 kbps channel, while for handoff to a WLAN access network the minimum delay is 0.2 ms. In the former case the minimum delay is unacceptable for streaming multimedia traffic and requires the deployment of soft-handoff techniques in order to reduce the handoff delay to a desirable maximum limit of 100 ms.
IEEE Wireless Communications, 2006
In the all-IP wireless networks beyond the third generation, mobility management can be effectively achieved by applying mobile IP (MIP) and the session initiation protocol (SIP) jointly. Nevertheless, an efficient combination of both protocols remains an open research issue. Conventional hybrid MIP-SIP mobility architectures operate MIP and SIP almost independently, resulting in significant redundant costs. This article investigates the representative hybrid MIP-SIP architectures and explores the joint optimizations between MIP and SIP for a more cost-efficient mobility support whilst utilizing their complementary power. Two novel design approaches are presented. The first approach culminates in a tightly integrated architecture, which merges the redundant mobility entities in MIP and SIP to yield maximum system efficiency. The other approach leads to a loosely integrated architecture, where necessary interactions are introduced between MIP and SIP mobility servers while their physical entities are kept intact. Major mobility procedures, including location update, session setup and handoff, are discussed in these architectures. The analytical results demonstrate that both proposed architectures outperform typical hybrid MIP-SIP architectures in terms of clear-cut reduced signaling costs
IJCSNS, 2009
The Session Initiation Protocol (SIP) is one of the most widely used protocols for Voice over Internet Protocol (VoIP). Mobility is a very sophisticated service in VoIP. VoIP mobility performance depends on the handoff delay in the Data Link layer. As VoIP is application layer application, application layer mobility support has a vital role in supporting VoIP mobility. This paper presents an overview of different modes of VoIP mobility at both the application layer and data link layer. Different aspects of these modes are explored.
The growing demand for seamless invocation of different multimedia services from handheld devices anytime anywhere is the main driving force for drawing attention in the area of mobility management. Although Session Initiation Protocol (SIP) based mobility solution is very efficient for real-time services, Mobile IP is required to handle mobility of the mobile node (MN) at the network layer. We have extensively studied and explored some existing mobility management methods integrating the functionalities of Mobile IP and SIP in this paper. These schemes require support of IP encapsulation at the protocol stack of correspondent node (CN). To address the above problem, we have proposed in this paper, certain modification at the IP layer of Base Station (BS) that also reduces the bandwidth consumption. Moreover, service provisioning in a continuous way in public places like airport, university campus etc., requires to integrate some micro-mobility protocol with the existing mobility management methods to reduce the handoff disruption time in case of intradomain handoff. Thus, in this paper, we have proposed two new hybrid mobility management schemes that integrate two existing Mobile IP and SIP-based schemes where the proposed modification in the IP layer of BS is incorporated separately with the micromobility protocol Hierarchical Mobile IP (HMIP). The numerical results show that the integration of HMIP into the existing methods reduces both the signaling cost and the delay, mainly the active handoff disruption time. Simulation results on NS-2 demonstrate the performance improvement of the proposed mobility management schemes over the existing methods in terms of handoff delay.
This paper presents results of the implementation of HTTP Session Mobility Service using SIP. The results are based on HTTP session mobility test on some notable websites. More precisely, web session hand-off between two web browsers was carried out. A loosely-coupled approach whereby an extension was developed and integrated into a web browser was used. This implementation leverages Session Initiation Protocol (SIP) Transportation and Mobility to transfer web sessions between two web browsers. Results showed that the service could not work on all websites, most notably websites based on FRAME/IFRAME HTML Tags, AJAX and other Web 2.0 technologies. The service, however, can work in a Peer-to-Peer environment. It can also be commercialized if the privacy and security of session data can be assured by the implementers. Some recommendations are made for the implementers of this service. Most important of all, it offers more Personal Mobility to web surfers, and SIP functionalities such as voice call can be achieved via a web browser.
Journal of Computer Science, 2007
Lately, the proliferation of small portable devices has driven the introduction of a new mobility concept called service mobility. In order to support service mobility, we introduce a new architecture implementing mechanisms to access end user's personalized services regardless of his physical location. The proposed architecture leverages on mobile agent technology to transport and move services to the end user's registered terminals and the Session Initiation Protocol (SIP) for user location signaling. A decentralized approach purely based on mobile agents is compared with a centralized approach. The performance measurement results show that mobile agents are worth being used for realizing service mobility but in specific conditions.