Mobility and Streaming Architecture

1. Ashutosh Dutta, Henning Schulzrinne, Yechiam Yemini, "MarconiNet: An Architecture for Internet Radio and TV. 9th International Workshop on Network Support for Digital Audio Video Systems (NOSSDAV 99), New Jersey, 23-25th June.

MarconiNet is an architecture for IP-based radio and TV networks, built upon standard Internet protocols including RTP, RTSP, SAP, and SDP. It allows to build virtual radio networks, similar to traditional AM/FM radio and TV networks. It addresses some of the practical problems of building Internet radio networks including the insertion of local content and advertising.

2. Ashutosh Dutta, Henning Schulzrinne, A Streaming Architecture for Next Generation Internet ICC 2001, Helsinki, Finland, June 11-14, 2001

With the influx of multi-media streaming content over the Internet, building a streaming infrastructure that would support flexible Next Generation Internet application in a scalable way on heterogenous access technology is most desirable. This paper presents a streaming architecture which provides some innovative methods and technique that would help build an IP based radio/TV network. This would provide tools for E-commerce and would benefit the broadcasting stations, local affilates, ISPs, and end users. Additionally this paper highlights the mechanism behind some of the components associated with this architecture such as local content, global content, program management with local control, payment model, security, advertisement insertion, seamless mobility within a domain.

3. Ashutosh Dutta, Faramak Vakil, J.C Chen, Miriam Tauil, Shinichi Baba and Henning Schulzrinne, "Application Layer Mobility Management Scheme for Wireless Internet," in 3Gwireless 2001,(San Francisco), pp. 7, May 2001

This paper discuses an application layer framework that uses a set of standard IETF protocols for supporting real-time and non-real-time multimedia applications on mobile terminals of next generation wireless [3G/4G] networks. It describes a 3G-IP architecture and brings out the requirements and issues which are essential for supporting roaming users in the wireless Internet in a ubiquitous way. In addition it highlights ways of achieving end-to-end mobility by means of signaling instead of using any agent in the middle of the network as often done currently.

4. Kaushik Chakrabarty, Archan Misra, Subir Das, Anthony McAuley, Ashutosh Dutta and Sajal Das, "Implementation and Performance Evaluation of TeleMIP," in icc, (Helsinki), pp. 6, May 2001.

In this paper, we present our implementation of TeleMIP, a two-level architecture for IP-based mobility management. TeleMIP essentially uses an Intra-Domain Mobility Management Protocol (IDMP) for managing mobility within a domain, and Mobile IP for supporting inter-domain (global) mobility. Unlike other proposed schemes for intra-domain mobility management, IDMP uses two care-of-addresses for mobility management. Th eglobal care-of address is relatively stable an didentifies the mobie node's current domain, while th elocal care-of-address changes every time th emobile changes subnets and identifies th emobile's current point of attachment. The paper describes our TelemIP implementation based on enahancements to the Stanford University Mobile IP Linux code and presents performance results obtained through experiments on our test-bed. Finally, we use analysis to accurately quantify the savings in signaling overhead abtained when TeleMIP is used in environments where mobiles change subnets relatively rapidly.

5. Archan Misra, Subir Das, Ashutosh Dutta, Anthony McAuley and Sajal Das, "IDMP-based Fast handoffs and paging in ip-based cellular Networks," in 3GWireless 2001, (San Francisco), pp. 6, May 2001.

In this paper, we consider the use of the recently proposed Intra-Domain Mobility Management Protocol (IDMP) in 3rd and 4th generation (3G/4G) wireless cellular networks to reduce the latency of intra-domain location updates and the mobility of signaling traffic. We first present enehancements to basic IDMP that provides fast intra-domain handoffs by using a duration-limited, proactive packet multicasting scheme. We quantify the expected buffering requirements of our proposed multicasting scheme for typical 3/4G characteristics and compare it with alternative IP-based fast handoff solutions. We also present a paging scheme under IDMP that replicates the current cellular paging structure. Our paging mechanism supports generic paging strategies and can significantly reduce the mobility-related IP signaling load.

6. Subir Das, Archan Misra, Anthony McAuley, Ashutosh Dutta and Sajal Das, "A generalized mobility solution using a dynamic tunneling," in ICCCD2000, (Kharagpur, India), pp. 4, Dec. 2000.

This paper presents a tunneling agent-based mobility architecture which supports routing of datagrams to mobile nodes inside a mobility domain. The novelty of this architecture is that it allows users the flexibility to choose their own mobility protocols. It essentially uses the recently proposed base TeleMIP's two-level management framework with a new logical entity, called the Dynamic Tunneling Agent (DTA). The architecture manages mobility by using two care-of addresses. While the global care-of address identifies the mobile's current point of attachment. By using DTA dynamically, this approach also offers several advantages over existing approaches.

7. Archan Misra, Subir Das, Anthony McAuley, Ashutosh Dutta and Sajal Das, Integrating QoS Support in TeleMIP's Mobility Architecture," in ICPWC, (Hyderabad, India), pp. 8, Dec. 2000.

The paper describes a Differentiated Services-based QoS architecture for next-generation wireless networks. The architecture is based on the two-level TeleMIP hierarchical mobility management scheme and integrates Bandwidth Broker-based admission control and resource provisioning for mobile nodes. The TeleMIP architecture is extended to satisfy the QoS requirements of a mobile node, while rquiring it to specify its traffic profile only when it first moves to a new domain. The paper explores alternative approaches for dynamically assigning Mobility Agents to a mobile node and evaluates their suitability for different service differentiation models.

8. Ashutosh Dutta, Onur Altintas, Henning Schulzrinne, Wai Chen Multimedia SIP sessions in a Mobile Heterogeneous Access Environment Accepted for 3G Wireless 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, 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 or different one. In this case 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 signaling and media flow in a Local Area Network and Wide Area Network environment.

9. Jasmine Chennikara, Wai Chen, Ashutosh Dutta, Onur Altintas Application Layer Multicast for Mobile Users in Diverse Networks, Globecom 2002

As multicast services become prevalent, it is important to find viable solutions for multicasting to mobile nodes. This problem is complicated by the necessity to support multicast services over existing backbone and access networks which may have varying network and/or link layer multicasting capabilities. While most work on supporting multicast services focuses on the IP layer solution, we propose an application-layer approach to providing multicast services to mobile users traversing networks with diverse multicast capabilities. We propose placing multicast proxies in the backbone and access networks to provide several multicast-related functions at the application layer including creating virtual application-layer multicast trees for dynamically tunneling through non-multicast-capable networks. In this paper, we describe our proposed application-layer multicast architecture and its advantages to third-party service providers for multicasting to mobile users in diverse networks.

10. Subir Das, Ashutosh Dutta, Anthony McAuley, Archan Misra and Sajal Das, IDMP: An Intra-Domain Mobility Management Protocol for Next Generation, Wireless Networks, IEEE Wireless Magazine, October 2002 - SAIC Best Paper

This paper describes a lightweight Intra-domain Management Protocol} (IDMP) for managing mobility within a domain, commonly known as micro-mobility management, for next generation wireless networks. IDMP is modular and simple because it leverages existing protocols, such as Mobile IP or SIP (Session Initiated Protocol) as global mobility management, for locating roaming nodes. Unlike other proposed intra-domain mobility management schemes, IDMP uses two dynamically autoconfigured care-of addresses (CoAs) for routing the packets destined to mobile nodes.The global care-of address (GCoA) is relatively stable and identifies the mobile node's attachment to the current domain, while the local care-of address (LCoA) changes every time the mobile changes subnets and identifies the mobile's attachment to the subnet level granularity. After describing the lightweight base protocol, we discuss possible enhancements to reduce the latency of intra-domain updates during handoffs, which are critical for real-time applications both for wide area cellular networks and enterprise wireless LANs. We also discuss mechanisms to incorporate paging support in IDMP and hence reduce the mobility-related signaling load on a mobile node. Detailed implementation and performance results from experiments on our testbed are also presented.

11. T.Chiba, H.Yokota, A.Idoue, A.Dutta, S.Das, Fuchun J. Lin, H.Schulzrinne Mobility Management Schemes for Heterogeneity Support in Next Generation Wireless Networks, NGI 2007 Seamless mobility support in a heterogeneous roaming environment poses several challenging issues in the choice of network architecture design and mobility protocol. Several standards organizations are designing next generation wireless network architectures with a suite of new network elements and protocols that provide service continuity for intraand inter-provider roaming. However, each of these mobility solutions provides its own set of signaling mechanisms and methods of interaction with different functional network elements. Thus, it becomes a challenging task for the network operators and service providers to support roaming to the visited networks with diverse capabilities while supporting service continuity. In this paper, we first highlight some of the next generation standards and then describe the main functional components of a generic next generation wireless architecture as described in several evolving standards. We then focus on the operational usage of network layer mobility protocols such as Client Mobile IP, Proxy Mobile IP and application layer mobility protocol for next generation networks, and address the operational issues associated with roaming and service continuity. Finally, we propose comprehensive mobility solutions that support the heterogeneity associated with the intra- and inter-provider roaming.

12. Ashutosh Dutta, Henning Schulzrinne, Wai Chen and Onur Altintas, "Mobility support for wireless streaming multimedia in MarconiNet," in IEEE Broadband Wireless Summit, Interop 2001, (Las Vegas), pp. 7, May 2001.

Real-time streaming content (audio and video) is mostly RTP/UDP based application which has stringent delay and loss requirements. Mobility affects the delay and loss factors for the multimedia stream delivery to a great extent, because of associated continuous handoff. This paper describes novel methods for supporting continuity of multimedia stream for the mobile clients in MarconiNet environment. In MarconiNet environment the end hosts could be (auto)mobile and these move from one cell to another, where each cell may belong to the same subnet or different subnet and different domain while receiving continuous multimedia stream content from several sources proxied via different local servers. Multimedia stream delivery to an end-host in MarconiNet's mobile environment depends upon the delay which is a composite of several factors such as cell/subnet detection, registration/configuration with new address, join/leave latency for the multicast streams. While movement detection, registration and configuration delays are similar to unicast stream delivery, join/leave latencies play an important role for delivery of multicast stream. This paper touches upon the latency factors associated, focuses on how media delivery due to mobility is affected by the join/leave latency and devises ways to improve that.

13. Ashutosh Dutta, Henning Schulzrinne, Subir Das, Anthony McAuley, Wai Chen, Onur Altintas MarconiNet supporting Streaming Media over Localized Wireless Multicast, M-Commerce 2002 Workshop, Atlanta September 28th, 2002

Flexible multi-media streaming such as advertisment insertion, location based services, mobility and wireless access are vital components that make existing Internet Radio and TV networks more attractive for the roaming users. All of these applications also provide added value to telematics, and military usage including coordination, education, situation awareness, distributed simulation, battlefield communication and multi-player games. While content distribution over a wired network can be realized by instituting proxies and gateways at several parts of the access network, providing mobility over heterogeneous wireless access need to consider many operational issues such as handoff, join and leave latency and desired level of quality of service for the mobile clients. This paper discusses some novel application layer techniques that provide a platform for Mobile E-Commerce with a multi-tiered payment and security scheme that supports a business model for a global streaming network.The proposed streaming network called MarconiNet is based on standard IETF protocols such as SIP, SAP and SDP for signaling, RTSP for stream control and RTP/RTCP for media delivery and feedback control.

14. Ashutosh Dutta, Ravi Jain, K. Daniel Wong, James Burns, Ken Young, Henning Schulzrinne Multilayerd Mobility Management for Survivable Network, to appear in Milcom Proceedings, October 2001

A variety of mobility management scheme have been developed for commercial networks ranging from Mobile IP (network layer support), to the Session Initiation Protocol (SIP) based on application layer components such as DNS and SMTP, and Micro-Mobility approaches like Cellular IP, HAWAII. There are significant challenges, however, with regard to the robustness, management overhead requirements and latency in each of these approaches, especially in military environments where the network is very dynamic. It is desirable to provide continuous connectivity between the nodes for real-time and non-real-time traffic.We propose to dramatically improve mobility management of the terrestrial networks to provide support for dynamic military networks by developing an integrated mobility management approach that both meets the needs of end-user applications and deals with the harsh networking environment. This approach is based on the concept of dynamic servers, provided on the airborne nodes, that enhance the mobility of nodes on the ground. Unlike in the fixed Internet, where such servers are always present, our approach requires the development of robust mechanisms that allow the servers to advertise their existence to terrestrial nodes and to synchronize with each other and with their terrestrial peers to ensure coherency.Proposed approach provides a multi-layered mobility management solution. It provides personal and terminal mobility for real-time traffic such as voice-over-IP or video streaming through deployment of dynamic SIP and DNS servers on the ACN. It provides network layer support through the use of Mobile IP with Location Registers (MIP-LR) for non-real-time applications. Local mobility management is achieved through the use of micro-mobility management protocol (MMP) that reduces the need to update the SIP, DNS and MIP-LR servers when end nodes move locally within a domain.

15. Y.Ohba, S. Das, A. Dutta Kerberized Handover Keying: A Media-Independent Handover Key Management Architecture, Mobiarch 2007

This paper proposes a media-independent handover key management architecture that uses Kerberos for secure key distribution among a server, an authenticator, and a mobile node. With the proposed architecture, signaling for key distribution is based on re-keying and is decoupled from re-authentication that requires EAP (Extensible Authentication Protocol) and AAA (Authentication, Authorization and Accounting) signaling similar to initial network access authentication. In this framework, the mobile node is able to obtain master session keys required for dynamically establishing the security associations with a set of authenticators without communicating with them before handover. By separating re-key operation from re-authentication, the proposed architecture is more optimized for proactive mode of operation. It is also optimized for reactive mode of operation by reversing the key distribution roles between the mobile node and the target access node. This paper discusses how the proposed architecture is applicable to the existing link-layer technologies including IEEE 802.11 and 802.16 and across multiple AAA domains. This paper also describes how Kerberos is bootstrapped from initial access authentication using an EAP method.

16. K. Taniuchi, Y.Ohba, S. Das, M. Tauil, Y-H Chang, A.Dutta, D. Baker, M. Yajnik, D. Famolari "IEEE 802.21: Media Independent Handover: Features, Applicability, Realization, IEEE Communciation Magazine, January 2009

This paper proposes a media-independent handover key management architecture that uses Kerberos for secure key distribution among a server, an authenticator, and a mobile node. With the proposed architecture, signaling for key distribution is based on re-keying and is decoupled from re-authentication that requires EAP (Extensible Authentication Protocol) and AAA (Authentication, Authorization and Accounting) signaling similar to initial network access authentication. In this framework, the mobile node is able to obtain master session keys required for dynamically establishing the security associations with a set of authenticators without communicating with them before handover. By separating re-key operation from re-authentication, the proposed architecture is more optimized for proactive mode of operation. It is also optimized for reactive mode of operation by reversing the key distribution roles between the mobile node and the target access node. This paper discusses how the proposed architecture is applicable to the existing link-layer technologies including IEEE 802.11 and 802.16 and across multiple AAA domains. This paper also describes how Kerberos is bootstrapped from initial access authentication using an EAP method.

Testbed - Mobility

1. Ashutosh Dutta, J.C Chen, S. Das, S. Madhani, A. McAuley, S. Baba, N. Nakajima, Y. Ohba, Henning Schulzrinne, "Implementing a Testbed for Mobile Multimedia, Globecom 2001

In an effort to realize wireless Internet telephony and multimedia streaming in a highly mobile environment a testbed emulating a wireless Internet has been built. This would allow setting up multi-media calls between IP mobiles and integration between IP and PSTN end-points in a wireless environment. Different functionalities and components involved with the wireless Internet streaming multimedia have been prototyped and experimented in the testbed. These include signaling, registration, dynamic binding, location mangamenet while supporting the QoS features for the mobile users. This paper describes some of the components of the testbed and highlights the experiences while building this testbed which could be beneficial to some who plan to build a similar testbed to realize several features and capabilities of Mobile Wireless Internet, before actually bringing to the market.

2. Ashutosh Dutta, Daniel Wong, James Burns, Ravi Jain, Henning Schulzrinne, A. McAuley Realization of Integrated Mobility Management for Ad-Hoc Networks, accepted for MILCOM 2002

A multi-layer mobility management architecture has been designed to take care of real-time and non-real-time traffic for intra-domain and inter-domain mobility in a survivable network. It consists of three components based on functionality. SIP based mobility management is used for real-time communication, and MIP-LR is used for non-real-time communication when nodes move between two different domains while MMP takes care of movement within a domain. A testbed has been implemented using the features of each mobility management approach in an integrated manner.In this paper we present our implementation and integration experience of these three mobility management protocols and evaulate their performance under simulated military environment while interacting with Dynamic DNS, DRCP/DCDP and coordinating among themselves based on the application type and domain being served.

3. Ashutosh Dutta, Prathima Agrawal, Subir Das, Moncef Elaoud, David Famolari, Henning Schulzrinne et al Realizing Mobile Wireless Internet Telephony and Streaming Multimedia Testbed Accepted Elsevier Journal for Computer and Communication

Streaming real-time multimedia content over the Internet is gaining momentum in the communications, entertainment, music and interactive game industries as well as in the military. In general, streaming applications include IP telephony, multimedia broadcasts and various interactive applications such as multi-party conferences, collaborations and multiplayer games. Successfully realizing such applications in a highly mobile environment, however, presents many research challenges. In order to investigate such challenges and demonstrate viable solutions, we have developed an experimental indoor and outdoor testbed laboratory. By implementing standard IETF protocols into this testbed, we have demonstrated the basic functionalities required of the mobile wireless Internet to successfully support mobile multimedia access. These requirements include signaling, registration, dynamic configuration, mobility binding, location management, Authentication Authorization and Accounting (AAA), and quality of service (QoS) over a variety of radio access network (RAN) technologies (e.g. 802.11b, CDMA/GPRS). In this paper, we describe this testbed and discuss important design issues and tradeoffs. We detail the incorporation and inter-relation of a wide catalog of IETF protocols - such as SIP, SAP, SDP, RTP/RTCP/RTSP, MGCP, variants of Mobile-IP, DRCP, HMMP PANA, and DSNP - to achieve our goals. We believe that the results and experiences obtained from this experimental testbed will advance the understanding of the pertinent deployment issues for a Mobile Wireless Internet.

4. A.Dutta, K. Manousakis, S. Das, F.J Lin, T.Chiba, H.Yokota, A.Idoue, H.Schulzrinne Mobility Testbed for 3GPP2-based MMD Networks, IEEE Communication Magazine, July, 2007

Wireless service providers strive to preserve the quality of service and user experience for mobile users. Several standards bodies are defining architecture that can be used as a platform to provide secured and seamless services to these mobile users. These architectures aim to provide several required functions such as signaling, configuration, security association, encryption, and billing. However, placement of several functional components and their interaction at several layers contribute to the operational complexities and thus affect the optimal results. Testbed realization of any standardized architecture can help investigate the underlying networking issues. In this paper, we describe a mobility testbed implementation based on one of the architecture alternatives of 3GPP2, where the outbound signaling servers are distributed around the edges of the network. We experiment with three different handoff techniques and analyze the associated experimental results. Analysis of these experimental results and experiences obtained from the testbed implementation can be helpful to any service provider that plans to deploy a version of the MMD (Multimedia Domain) architecture with distributed signaling servers.

5. M.Tauil, A.Dutta, Y. Cheng, S. Das, D. Baker, Y. Ohba, K.Taniuchi, H.Schulzrinne Realization of IEEE 802.21 services and preauthentication framework, Tridentcom 2009, Washington DC

Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies together with increasing use of real time multimedia applications is creating strong demand for handover solutions that can seamlessly and securely transfer user sessions across different access technologies. In this paper, we discuss how the IEEE 802.21 standard and its services address the challenges of seamless mobility for multi-interface devices. We focus on a proof-of-concept implementation that integrates IEEE 802.21 services and a pre-authentication framework, realizing different possible usage scenarios to optimize handover performance. We describe the implementation of two handover scenarios using the 802.21 Services: the first one is initiated by the mobile node and the second one is initiated by the operator network. We compare the two scenarios and discuss their respective benefits. Finally, we describe the implementation challenges and lessons learned through this exercise.


Survey Paper - Mobility

1. Ashutosh Dutta, Onur Altintas, Wai Chen, Henning Schulzrinne Mobility Approaches for All IP Wireless Networks, SCI 2002, Orlando, Florida

Several protocols and mechanisms have been developed to support inter-domain mobility and intra-domain mobility for multimedia services in the Internet. However choosing the right kind of mobility management which would meet the requirements and parameters suitable for a particular kind of application is of utmost impotance. We review these approaches from the viewpoint of protocol layers at which they operate and their applicability. We categorize them under the groups of network layer approaches and application layer approaches and compare each method qualitatively from various viewpoints. The motivation in doing such a classification is to indentify mobility support methods that require significant network dependence and those that do not rely on knowledge of network elements. Each of these mobility management approaches is appropriate for different set of real-time and non-real-time services such as VoIP, multimedia streaming and file transfer.

2. T.Chiba, H.Yokota, A.Idoue, A.Dutta, S.Das, Fuchun J. Lin Gap Analysis and Deployment Architectures for 3GPP2 MMD Networks, IEEE VT Magazine 2007

In recent years, mobile and fixed operators are offering broadband access to the Internet by either adding wireless access to their existing core networks (e.g., CDMA 1xEVDO, GPRS, and WiFi) or continuing to evolve existing broadband infrastructures (e.g., DSL, Cable and FTTx). Consequently, IMS and MMD architectures as defined by 3GPP and 3GPP2 are becoming increasingly important to network operators, in particular, for offering ubiquitous service and seamless mobility to end users, along with management and control. Although 3GPP2 MMD architecture has adopted most of the 3GPP IMS core functionalities and interfaces, it added several other unique functional components and interfaces to fit the specific need of CDMA2000 access networks. Therefore, it is important to understand the gaps and issues associated with 3GPP2 MMD architecture with regard to 3GPP IMS architecture. In this paper, we first analyze the functional and protocol level differences between IMS and MMD architectures. Based on our analysis, we then articulate several deployment architectural alternatives for 3GPP2 MMD networks and finally analyze the pros and cons of each architecture.

3. A.Dutta, S.Das, T.Chiba, H.Yokota, A.Idoue,H.Schulzrinne Comparative Analysis of Network Layer and Application Layer IP Mobility Protocols for IPv6 Networks, IEEE WPMC 2006

In order to provide seamless connectivity to the roaming users several mobility protocols have been developed at different layers. All of these mobility protocols exhibit certain common properties and demonstrate abstract mobility functions. But in order to achieve the desired functions, these implement signaling in different ways. In this paper we analyze two different mobility protocols that operate at different layers such as network layer and application layer. We describe each of the atomic operations and describe how these functional properties are carried out with some experimental results. We also illustrate the applicability of these two mobility protocols for IP Multimedia Subsystem (IMS) architecture.


Performance - Mobility

1. K. Daniel Wong, Hung-Yu Wei, Ashutosh Dutta, Kenneth Young, Henning Schulzrinne "Performance of IP Micro-Mobility Management Scehemes using Host Based Routing.", WPMC 01

Global IP mobility solutions using protocols like Mobile IP ( MIP) and SIP are not optimized to handle micro-mobility management, where low-latency handoffs are essential, to avoid inefficiencies and performance degradation. Host based routing (HBR) schemes, such as HAWAII, Cellular IP and MMP are one of the two main classes of schemes for IP micro-mobility management, the other being hierarchical Mobile IP - derived schemes. We look at the performance issues of HBR schemes, both qualitatively and quantitatively. Various simulation results and prototype system measurements demonstrate the superiority of HBR schemes over both MIP and hierarchical MIP-derived micro-mobility schemes in terms of fewer packets dropped per handoff for UDP traffic and better TCP throughput under varierty of scenarios.

2. F. Anjum, M. Elaoud, D. Famolari, A. Ghosh, R. Vaidyanathan, A.Dutta, P. Agrawal Voice Performance in WLAN Networks - An Experimental Study, Globecom 2003, San Francisco

In this work, we measure Wireless Local Area Network (WLAN) voice performance and capacity. While most WLAN applications today are data centric, the growing popularity of Voice over IP (VoIP) applications and the trend towards convergence with cellular networks will catalyze increased voice traffic. Since voice applications compete not only with each other, but also with data applications for WLAN bandwidth, quantifying voice performance and capacity in the presence of simultaneous data traffic is an important issue. We offer a practical investigation of the 802.11b MAC layers ability to support simultaneous voice and data applications. We quantify VoIP capacity for standard WLAN networks, indicative of those already in the field, as well as evaluate the practical benefits of implementing backoff control and priority queuing at the access point. Conclusions are drawn based on an extensive set of real-world measurements conducted using off-theshelf equipment in an experimental testbed.

3. A.Dutta, J.Burns, R.Jain, K. Daniel Wong, K. Young, H. Schulzrinne Implementation and Performance Evaluation of Application layer MIP-LR, to appear in IEEE Wirelesscom 2005

In order to avoid triangular routing and kernel dependency associated with the basic Mobile IP, an application layer solution based on Mobile-IP with Location Registers (MIP-LR) has been designed and prototyped in a laboratory environment. Application Layer MIP-LR augments the basic MIP-LR scheme with some application layer techniques that enable capturing and mangling of packets and thus provides kernel independecne from deployment perspective. Results from analysis and laboratory prototype demonstrate that one can attain up to 50 percent reduction in management overhead and 40 percent improvement on latency compared to standard Mobile IP in co-located mode. In addition to bandwidth efficiency gain it also provides survivability features in an ad hoc environment.

4. A.Dutta, B.Kim, T.Zhang, S.Baba, K.Taniuchi, Y.Ohba, H.Schulzrinne Experimental Analysis of Multi Interface Mobility Management with SIP and MIP, IEEE Wirelesscom 2005

We provide an experimental analysis of MIMM (Multi-Interface Mobility Management) demonstrated in a heterogeneous network involving 802.11b and CDMA access technologies. We have experimented WAN-LAN handoff for real-time service (voice and video) in the testbed. The subnet handoff managed by MIMM was done seamlessly in this evironment and is proved to support real-time application effectively. Both application layer and network layer mobility managementwere used in the experiment and their results were analyzed for real-time traffic.

5. T.Chiba, H.Yokota, A.Dutta, D.Chee, H.Schulzrinne Performance Analysis of Next Generation Mobility Protocols for IMS/MMD Networks IEEE IWCMC 2008

In an effort to provide seamless mobility support in IMS/MMD networks, operators need to choose a specific IP-based mobility protocol. However, there are several micro- and macro-mobility protocols available that the operators can choose from. Operators often face the challenge of selecting the most appropriate mobility protocol that can provide the most cost effective solution. Thus, it is important to analyze the effectiveness of these protocols before they are actually deployed in the IMS/MMD networks. In this paper, we analyze a number of candidate mobility protocols and conduct a performance analysis of some of them using a prototype implementation in an IPv6-based IMS/MMD testbed. These analyses provide us with some guidelines in terms of the applicability of these protocols when operators plan to deploy their IMS/MMD networks.

Mobility Fast-Handoff - Techniques, Systems prototype and Experimental

1. Ashutosh Dutta, Sunil Madhani, H. Schulzrinne, Onur Altintas, Wai Chen Optimized Fast-handoff Schemes for Application Layer Mobility Management MC2R November 2002

In order to ensure proper quality of service for real-time communication in a mobile wireless Internet environment it is essential to minimize the transient packet loss when the mobile host (MH) is moving between different cells (subnets) within a domain. This paper introduces application layer techniques to achieve fast handoff for real-time (RTP/UDP) multimedia traffic in a SIP-based signaling environment. These techniques are nased on standard SIP components such as user agents and proxies and provide a network independent solution suitable for application service providers.

2. N. Nakajima, A. Dutta, Subir Das, Henning Schulzrinne Handoff Delay Analysis for SIP Mobility in IPv6 Testbed, Accepted for for ICC 2003

This paper presents some experimental results on the performance of real-time mobile communication in an IPv6 testbed. For real-time multimedia communication, we adopt Session Initiation Protocol (SIP) as signaling protocol and Mobile IPv6 (MIPv6) to support seamless connectivity. While performance measurement of real-time mobile communication consists of several factors, we focus here on the handoff delay due to a node configuration in a typical IPv6 environment. In particular, we measure the delay incurred when a mobile node moves to a new location and performs Stateless Address Autoconfiguration and Duplicate Address Detection (DAD) during configuration. We also present a detailed analysis and delay measurements with and without DAD for real-time communication.

3. Ping-yu Hsieh, Ashutosh Dutta, Henning Schulzrinne Application Layer Mobility Proxy for Real-time communication Accepted for for 3G Wireless 2003

By configuring some of the application layer tools such as Linux IPCHAINS, IP Masquerading, RTPtrans and IP Aliasing, we build the mobility proxy, cooperation with SIP registrar, to forward data from the correspondent hosts to the new location of the mobile hosts as the mobile keeps on changing its IP address. It not only provides continuous connectivity of both TCP/IP and RTP/UDP traffic for the mobile hosts, but also offers the flexibility to build a mobility proxy in a mobile and wireless networking environment independent of the underlying networking technology. In this paper we present some of the mechanisms involved and experiments conducted to build this mobility proxy in a laboratory environment.

4. Archan Misra, Subir Das, Ashutosh Dutta, Anthony McAuley and Sajal Das, IDMP based\ Fast-handoff and Paging in IP based 4G Mobile Networks," in to appear in IEEE Communication Magazine, March 2002.

In this paper, we consider the use of our recently proposed Intra-Domain Mobility Management Protocol (IDMP) in generation (4G) mobile networks. On evaluating the heterogeneous access technologies, cellular layouts and application characteristics of 4G environments, we realize a need to reduce both the handoff latency and the frequency of mobility-related signaling. We first present IDMP's fast intra-domain handoff mechanism that uses a duration-limited, proactive packet `multicasting' solution. We quantify the expected buffering requirements of our proposed multicasting scheme for typical 4G network characteristics and compare it with alternative IP-based fast handoff solutions. We also present a paging scheme under IDMP that replicates the current cellular paging structure. Our paging mechanism supports generic paging strategies and can significantly reduce the mobility-related IP signaling load.

5. K. Daniel Wong, Ashutosh Dutta, Ken Young, Henning Schulzrinne Managing Simultaneous Mobility of IP Hosts, MILCOM 2003, Boston

Since triangular routing in Mobile IP (MIP) is undesirable, MIP with Route Optimization (MIP-RO) and MIP with Location Registers (MIP-LR), all use binding updates that are sent directly to a Correspondent Host. Session Initiation Protocol (SIP) based mobility management also uses direct binding updates between a Mobile Host and a Correspondent Host. However, this makes these protocols (except the basic MIP) vulnerable to the simultaneous mobility problem, i.e. the special case when both end hosts are mobile and move at about the same time. In this paper, we analyze the simultaneous mobility problem and propose new ways for MIP-LR and SIP to handle simultaneous mobility using a common approach stemming from a generalized solution.

6. Ashutosh Dutta, Jasmine Chennikara, Wai Chen, Onur Altintas, Henning Schulzrinne Multicasting streaming media to mobile users, IEEE Communication Magazine, October 2003 Issue

Content distribution in general, and multicasting in particular, over a wired network to static hosts can be realized by placing proxies and gateways at several parts of the network. However, if the end hosts are mobile over heterogeneous wireless access networks, one needs to consider many operational issue such as network detection, handoff, join and leave latency, and desired level of quality of service, as well as caching and load balancing. This article surveys a set of protocols and technologies that offer multicast-based services for streaming multi-media in a mobile environment. It also brings forth some issues related to mobile content distribution in the wireless Internet that may be helpful during its deployment by application service providers.

7. Daniel Wong, Ashutosh Dutta, Jim Burns, Ravi Jain, Ken Young, Henning Schulzrinne A multilayered mobility management scheme for autoconfigured wireless networks, IEEE Wireless Communication, October 2003 Issue

The convergence of wireless and IP has led to the need for IP to handle mobility. The Mobile IP protocol was developed to facilitate IP mobility. However it has a number of shortcomings for dynamically auto-configured networks. Mobility protocols like Mobile IP with Location registers (MIP-LR) and Session Initiation Protocol (SIP) have been developed to address some of its shortcomings. Micro-mobility protcols like Cellular IP have been developed to address other shortcomings of Mobile IP. In this article we present a new integrated mobility management scheme that advantageously combines the strengths of SIP and MIP-LR with the benefits of a micromobility management protcol similar to Cellular IP. A prototype implementation of our scheme is explained, and lessons learnt in the prototyping process are presented.

8. Ashutosh Dutta, Sunil Madhani, Wai Chen, Onur Altintas,Henning Schulzrinne GPS-assisted Fast-handoff for Real-time communication, IEEE Sarnoff Symposium 2006

Reducing transient data loss during a mobile's frequent subnet handoff depends upon several factors such as layer 2 handoff detection, faster IP address discovery, and registration and media re-direction. We present a new methodology that can provide faster IP address discovery using GPS coordinate of the mobile. This mechanism provides a suitable approach for high-speed vehicular users. It discusses several issues involved with this handoff process such as layer 2 detection, IP address assignment, and duplicate address detection. It also describes the experiment carried out in an external testbed.

9. Ashutosh Dutta, Subir Das, Peter Li, Anthony McAuley, Yoshihiro Ohba, Shinichi Baba, Henning Schulzrinne Secured Mobile Multimedia Communication for Wireless Internet, ICNSC 2004, Taipei, Taiwan

Wireless Internet roaming may include several radio access networks involving different layer 2 technologies such as 802.11b, CDMA and GPRS. As a mobile user moves around and switches between wireless cells, subnets and domains, it needs to maintain the session continuity. At the same time security of signaling and transport media should not be compromised. A multi-layer security framework involving user authentication, packet based encryption and access control mechanism can provide the desired level of security to the mobile users. Architecture, implementation and performance of a similar framework in a mobile environment is presented here. Results and performance analysis of the implementation will be of immense value for wireless Internet service providers, before it is actually deployed in a wide scale manner.

10. Ashutosh Dutta, Henning Schulzrinne MarconiNet:Overlay Mobile Content Distribution Network, IEEE Communication Magazine February 2004

Flexible multimedia streaming such as advertisement insertion, location-based services, mobility, and wireless access are vital components that make existing Internet radio and TV networks more attractive to roaming users. All of these applications also provide added value to telematics and military usage, including coordination, education, situation awareness, distributed simulation, battlefield communication, and multiplayer games. While content distribution over a wired network can be realized by instituting proxies and gateways at several parts of the access network, to provide mobility over heterogeneous wireless access we need to consider many operational issues such as handoff, join and leave latency, and desired QoS level for mobile clients. This article discusses some application layer techniques that help build a flexible mobile content distribution overlay type network supporting a multitiered payment and security scheme. The proposed streaming network, called MarconiNet, is based on standard IETF protocols (e.g., SIP, SAP, SDP, RTSP, and RTP/RTCP) that help provide signaling, session announcement, session description, stream control, media delivery, and feedback control, respectively.

11. Ashutosh Dutta, Sunil Madhani, Wai Chen, Onur Altintas, Henning Schulzrinne Fast-handoff Schemes for Application Layer Mobility Management, PIMRC 2004, Spain

In order to ensure proper quality of service for real-time communication in a mobile wireless Internet environment it is essential to minimize the transient packet loss when the mobile is moving between different cells (subnets) within a domain. Network layer mobility management schemes have been proposed to provide optimized fast-handoff for multimedia streams during a client's frequent movement within a domain. This paper introduces application layer techniques to achieve fast-handoff for real-time RTP/UDP based multimedia traffic in a SIP signaling environment. These techniques are based on standard SIP components such as user agent and proxy which usually participate to set up and tear down the multimedia sessions between the mobiles. Unlike network layer techniques, application layer techniques do not have to depend upon any additional components such as home agent and foreign agent. It thus provides a network access independent solution suitable for application service providers.

12. Ashutosh Dutta, Tao Zhang, Sunil Madhani, Kenichi Taniuchi, Kensaku Fujimoto, Y. Katsube, Y. Ohba, H. Schulzrinne Secure Universal Mobility for Wireless Internet, WMASH 2004, Philadelphia

The advent of the mobile wireless Internet has created the need for seamless and secure communication over heterogeneous access networks such as IEEE 802.11, WCDMA, cdma2000, and GPRS. An enterprise user desires to be reachable while outside ones enterprise networks and requires minimum interruption while ensuring that the signaling and data traffic is not compromised during ones movement within the enterprise and between enterprise and external networks. We describe the design, implementation and performance of a Secure Universal Mobility (SUM) architecture. It uses standard protocols, such as SIP and Mobile IP, to support mobility and uses standard virtual private network (VPN) technologies (e.g., IPsec) to support security (authentication and encryption). It uses pre-processing and make-before-break handoff techniques to achieve seamless mobility (i.e., with little interruption to users and user applications) across heterogeneous radio systems. It separates the handlings of initial mobility management and user application signaling messages from user application traffic so that VPNs can be established only when needed, thus reducing the interruptions to users.

13. K.Daniel Wong, A.Dutta, H. Schulzrinne, K. Young , Simultanous Mobility: Solutions and Analysis, Journal of Wireless Communications and Mobile Computing, Wiley series

The original Mobile IP (MIP) protocol does not perform route optimization but uses Home Agents to forward traffic. Thus, it does not have problems with simultaneous mobility, i.e., the special case when both end hosts are mobile and move at about the same time. However, MIP for IPv6 (MIPv6) promotes the use of MIP with Route Optimization (MIP-RO). MIP-RO uses binding updates that are sent directly to a Correspondent Host. Session Initiation Protocol based mobility management (SIPMM) and MIP with Location Registers (MIP-LR) also use direct binding updates between a Mobile Host and a Correspondent Host. Thus, MIP-RO, MIP-LR, and SIPMM are vulnerable to the simultaneous mobility problem. In this paper, we analyze the simultaneous mobility problem and propose new ways for MIP-RO, MIP-LR and SIPMM to handle simultaneous mobility through particular solutions of a common generalized solution.

14. D. Wong, A.Dutta, Simultaneous Mobility in MIPv6, IEEE, EIT 2005, Nebraska. Best Paper Award

Mobile IP for IPv6 (MIPv6) includes a procedure for route optimization, which allows packets from the correspondent host to go directly to the mobile host. However, the way route optimization is implemented makes it vulnerable to problems with simultaneous mobility, which can occur when two mobile hosts are communicating with each other. In this paper, we suggest ways to change MIPv6 to reduce its vulnerability to the simultaneous mobility problem.

15. A.Dutta, T.Zhang, S. Madhani, K. Taniuchi, K. Fujimoto, Y. Katsube, Y.Ohba, H. Schulzrinne Secure Universal Mobility for Wireless Internet, (Extended version) ACM MC2R

The advent of the mobile wireless Internet has created the need for seamless and secure communication over heterogeneous access networks such as IEEE 802.11, WCDMA, cdma2000, and GPRS. An enterprise user desires to be reachable while outside ones enterprise networks and requires minimum interruption while ensuring that the signaling and data traffic is not compromised during ones movement within the enterprise and between enterprise and external networks. We describe the design, implementation and performance of a Secure Universal Mobility (SUM) architecture. It uses standard protocols, such as SIP and Mobile IP, to support mobility and uses standard virtual private network (VPN) technologies (e.g., IPsec) to support security (authentication and encryption). It uses pre-processing and make-before-break handoff techniques to achieve seamless mobility across heterogeneous radio systems. It separates the handlings of initial mobility management and user application signaling messages from user application traffic so that VPNs can be established only when needed, thus reducing the interruptions to users.

16. A.Dutta, T.Zhang, K. Taniuchi, Y.ohba, H. Schulzrinne MPA assisted Optimizd Proacive Handoff Scheme, ACM Mobiquitous 2005

In order to support session-based real-time communication in a highly mobile environment it is desirable to limit end-to-end delay, jitter and packet loss at a certain threshold level. This paper describes a framework of Media-independent Pre-Authentication (MPA), a new handover optimization mechanism that has a potential to address issues on existing mobility management protocols and mobility optimization mechanisms to achieve these values. MPA is a mobile-assisted, secure handover optimization scheme that works over any link-layer and with any mobility management protocol. This paper also presents an initial implementation of MPA and performance results to show how existing protocols could be leveraged to realize the functionalities of MPA and provide the desired results.

17. A.Dutta, S.Das, D. Famolari, Y.Ohba, K.Taniuchi, T.Kodama, H.Schulzrinne Seamless Handoff across Heterogeneous Networks - An 802.21 Centric Approach IEEE WPMC 2005

Supporting seamless handover across heterogeneous access networks requires several functionalities to be taken into account such as service continuity, application class, quality of service, network discovery and selection, security and power management of the mobile. In this paper we present seamless handover techniques based on IEEE 802.21 framework that defines a Media Independent Handover Function consisting of event service, command service and information service. We also discuss how such services and primitives can help provide optimized handover between heterogeneous access networks such as 802.11, 802.16, CDMA and GPRS while interfacing with policy and higher layer mobility protocols.

18. K.D Wong, A.Dutta, H.Schulzrinne, K. Young Simultaneous Mobility: Analysis Framework, Theorems and Solutions, Wiley Wireless Communications and Mobile Computing Journal

The original Mobile IP (MIP) protocol does not perform route optimisation but uses Home Agents to forward traffic. Thus, it does not have problems with simultaneous mobility, i.e., the special case when both end hosts are mobile and move at about the same time. However, MIP for IPv6 (MIPv6) uses binding updates that are sent directly to a correspondent node. Session Initiation Protocol based mobility management (SIPMM) and MIP with Location Registers (MIP-LR) also use direct binding updates between a Mobile Host and a correspondent node. Thus, MIPv6, MIP-LR, and SIPMM are vulnerable to the simultaneous mobility problem. In this paper, we analyse the simultaneous mobility problem and solution mechanisms, and propose new ways for MIPv6, MIP-LR and SIPMM to handle simultaneous mobility.

19. A.Dutta, S.Das, D.Famolari,Y.Ohba,K.Taniuchi,V.Fajardo,T.Kodama,H.Schulzrinne Secured Seamless Convergence across Heterogeneous Access Networks, World Telecommunication Congress 2006, Budapest, Hungary,

Dual-mode handsets and multimode terminals are generating demand for solutions that enable convergence and seamless handover across heterogeneous access networks. The IEEE 802.21 working group is creating a framework that defines a Media Independent Handover Function (MIHF), facilitates the handover across heterogeneous access networks and help mobile users to experience a better performance during seamless handover. We also summarize a Media-independent Pre-Authentication (MPA) mechanism currently under discussion within the IETF and can be used to optimize handover performance. We present the 802.21 framework and the MPA technique and show how they can be integrated to improve the handover performance. We also describe a test-bed implementation and discuss experimental handover performance results of an 802.21-based approach in conjunction with MPA.

20. A.Dutta, H.Schulzrinne, K.D Wong Supporting Continuous Services to Roaming Clients, The Handbook of Mobile Middleware, CRC Press

Evolution of heterogeneous wireless access technologies such as Bluetooth, 802.11, CDMA, GPRS and 802.16 has helped usher the era for ubiquitous roaming. Ubiquitous roaming is meant to allow a mobile user to roam seamlessly between heterogeneous access networks. However, any Wireless Internet Service Provider is poised with a set of challenges while supporting continuous services to the roaming users. In order to be able to provide continuous services to the roaming users one needs to design a framework that can provide seamless mobility support for real-time communication such as VoIP and streaming content, guarantee quality of service and ensure security at the same time. In this chapter we describe a comprehensive framework that uses an application layer mobility management approach to support the roaming users in the wireless Internet involving heterogeneous access technologies.

21. A.Dutta, S.Madhani, T.Zhang,Y.Ohba,K.Taniuchi,H.Schulzrinne Network Discovery Mechanism for Fast-handoff, IEEE Broadnets 2006, San Jose.

Proactive handoff mechanisms involving secure pre-authentication and proactive configuration help reduce the delay and transient data loss for real-time communication during movement between homogeneous or heterogeneous access networks. Pre-authentication is meant to perform authentication with a network before a mobile moves into the network. To achieve secure pre-authentication with a target neighboring network, a mobile needs to obtain an IP address of the authentication server from the target network when the mobile is still outside the target network and then to establish a security association with the authentication agent in the target network. This requires the mobile to discover the parameters of various network elements in the target network ahead of time so that the mobile can communicate with these network elements to establish proactive security associations. We describe several approaches for a mobile to discover the network elements in target networks before moving into these target networks. We also describe how network discovery can help provide fast-handoff using secure pre-authentication and proactive IP address acquisition during handover between different access networks.

22. A.Dutta, E. Van den Berg, D. Famolari, V. Fajardo, Y.Ohba, K. Taniuchi, T.Kodama, H.Schulzrinne Dynamic Buffering Control Scheme for Mobile Handoff, IEEE PIMRC 2006

In a mobile environment, as a mobile node moves from one point of attachment to another during an ongoing application session it is subjected to packet loss due to network and link layer transition. Such packet loss affects the quality of ongoing communication session such as interactive VoIP traffic and streaming media. We provide a solution to this scenario by buffering packets for the mobile node at an access router or network node near the edge of the network where mobile may be moving away from or moving towards. The buffered packets are then forwarded to the mobile node once the handoff process completes. The buffering scheme is used in conjunction with existing mobility protocols, access protocols or as an independent network or link layer mechanism. Ability to control the buffer dynamically provides a reasonable trade-off between delay and packet loss which is within the threshold limit for real-time communication. The overview and mechanisms of such schemes are described and comparisons on existing buffering schemes are also provided.

23. T.Chiba, H.Yokota, A.Idoue, A.Dutta, K.Manousakis, S.Das, H.Schulzrinne Trombone Routing Mitigation Techniques for IMS/MMD Networks, IEEE WCNC 2007

Real-time services such as VoIP and multimedia streaming are affected during a mobiles rapid handoff due to the associated delay resulting from associated handoff operations of discovery, detection, configuration, registration, media redirection, and processing at different network nodes. Redundant communication path of any signaling and media adds to the delay during session setup and media delivery. This paper highlights the overall problem associated with redundant routing in a 3GPP2-based MMD (Multimedia Domain) environment and proposes several mechanisms to mitigate these problems. We also compare these mechanisms and select one for existing IMS/MMD networks that use MIPv4 as the mobility protocol. We present the implementation details of the selected redundant routing mitigation technique in the experimental MMD environment and verify the effectiveness by analyzing the measurement results.

24. Rafa M. Lopez, A.Dutta, Y.Ohba,H.Schulzrinne, A.F Gomez Skarmeta Network-Layer Assisted Mechanism to Optimize Authentication Delay Handoff in 802.11 Networks, ACM Mobiquitous, 2007

Secured and seamless mobility across heterogeneous access networks needs optimization at all layers. Authentication and security association at the link layer is one of the major components of delay during handoff. We propose a network layer assisted proactive handoff scheme that helps to optimize the handoff process involving link-layer security across multiple subnets. We demonstrate this proactive scheme and analyze the results for IEEE 802.11-based networks for both roaming and non-roaming scenarios. We then compare these results with the pre-authentication techniques offered by IEEE 802.11i.

25. A.Dutta, S.Das, D.Famolari, Y.Ohba, K. Taniuchi, V. Fajardo, R. M. Lopez, T. Kodama, H. Schulzrinne Seamless proactive handover across heterogeneous access networks, Springer Journal

Dual-mode handsets and multimode terminals are generating demand for solutions that enable convergence and seamless handover across heterogeneous access networks. The IEEE 802.21 working group is creating a framework that defines a Media Independent Handover Function (MIHF),facilitates handover across heterogeneous access networks and helps mobile users experience better performance during mobility events. In this paper, we describe this 802.21 framework and also summarize a Media-independent Pre-Authentication (MPA) mechanism currently under discussion within the IRTF that can further optimize handover performance.We discuss how the 802.21 framework and the MPA technique can be integrated to improve handover performance. Finally, we describe a test-bed implementation and validate experimental performance results of the combined mobility technique.

26. A.Dutta, S.Chakravarty, K.Taniuchi, V.Fajardo, Y.Ohba, D. Famolari, H. Schulzrinne An Experimental Study of Location Assisted Proactive Hanodver, Globecom 2007, Internet Protocol Symposium

Traditionally, signal-to-noise ratio of a mobile determines the handoff dynamics of the mobile. But in certain cases, precise location of the mobile augmented by information services, such as IEEE 802.21 MIS, can expedite the handoff with similar performance results. We illustrate an experimental system that takes advantage of the mobiles relative location with the neighboring access point to perform proactive handoff. It keeps track of the current location of the mobile and then uses the information from the neighboring networks to help perform the proactive handoff. Proactive handover technique helps the mobile to communicate with these networks before the handover is complete thereby reducing the delay and packet loss. In some cases, location-assisted handover could prove to be more useful compared to the handover technique based on signal-noise-ratio.

26. T.Chiba, H.Yokota, A.Dutta, D.Chee, H.Schulzrinne Route Optimization for Proxy Mobile IPv6 in IMS Network, IEEE ICSPC2008

Localized mobility protocols are designed to address many of the drawbacks such as additional signaling and over-the-air tunnel overhead associated with global mobility protocols like Mobile IPv4 and Mobile IPv6. Proxy Mobile IPv6 is one such network controlled localized protocol defined in the IETF. Although Proxy Mobile IPv6 can resolve longer binding update and tunnel overhead related issues when a mobile nodes movement is confined to a specific domain, some of the handoff-related functions and data paths between two communicating nodes still need to be optimized. The data path reduction between the communicating nodes helps to reduce one way packet delay when both nodes are under the same localized domain and the local mobility anchor point is away. The process of reducing the data path is often referred to as route optimization. Route optimization helps to reduce the delay due to media delivery that is critical for real-time application. We propose several route optimization techniques that can be applied to Proxy Mobile IPv6 to improve the efficiency of media delivery for both intra- and inter-domain movements. We select one of these proposed route optimization mechanisms and then describe the implementation details and analyze the experimental results.

27. A.Dutta, D. Famolari, S. Das, Y.Ohba, V. Fajardo, K. Taniuchi, R. Lopez, H.Schulzrinne Media-Independent Pre-authentication Supporting Secure Interdomain Handover Optimization, IEEE Wireless Magazine, April 2008

Handovers may cause delays and packet losses that affect real-time communication performance. Mobility protocols at several layers are designed to support handover, but they need to be optimized to ensure high-quality application performance. Existing optimization techniques are not sufficient to take care of interdomain and intertechnology handovers involving different access technologies, such as Wi-Fi, GSM, CDMA, and WiMAX. We categorize several types of handover, describe handover delay components, and propose a handover optimization framework called Media Independent Pre-Authentication that can provide optimizations for interdomain and intertechnology handover in a manner that is transparent to mobility management protocols. In addition, we also present experimental results demonstrating that this framework can achieve a significant reduction in handover delays for both network-layer and application-layer mobility management protocols.


Mobility Fast-Handoff - Modeling

1. A. Dutta, B. Lyles ,H. Schulzrinne, T. Chiba, H. Yokota, A. Idoue Generalized Modeling Framework for Handoff Analysis, PIMRC, 2007

A mobility event is the result of one network connection path being replaced by another via the rebinding of common system properties. The rebinding is a sequential process that may potentially involve multiple protocol layers of the mobile and require multiple network interactions. This overall process results in a period of time in which network service is degraded by transient data loss and increased end-to-end delay. Optimizations of the handover process mitigating these service degradations have been developed without a formal or systematic framework for mobility solutions. We develop a systematic systems model of the basic properties associated with a mobility event and design a framework around these properties that can provide methodologies for optimizing the handoff components. We then summarize the experimental results from a 3GPP2-based mobility testbed and highlight the delays associated with the functional components of the handoff event. We apply two types of optimization techniques and compare the results.

1. A. Dutta, B. Lyles ,H. Schulzrinne, J. Wang Systems Modeling for IP-based Handoff Using Timed Petri Nets, HICSS 2009

The mechanisms and design principles needed for building optimized handoff in the context of mobile Internet services are poorly understood and need better analysis. This paper contributes to the general theory of optimized handoff and has addressed the need for a formal model that can characterize a mobility event and the associated mobility optimization methodologies. It provides a systematic and formal approach to analyzing a mobility event. After a thorough analysis of the abstract operations associated with several mobility protocols, it determines that these basic handoff operations form a set of discrete events that can be modeled as Discrete Event Dynamic System (DEDS). It then uses Deterministic Timed Petri net to model the mobility event and evaluate the performance under different scheduling schemes. This model also helps to validate certain optimization methodologies that could lead to a set of design principles for any new mobility protocol as well as evaluate its effectiveness.


Potpourri

1. Ashutosh Dutta, Yechiam Yemini, " Power Management of LEOs under bursty broadband traffic. AIAA's 17th International Conference on Satellite Systems and Communication. AIAA, 1998 February, Yokohama, Japan

Reliable operation of LEO (Low Earth Orbit) communication satellites with Guaranteed Quality of Service (QoS) for real-time broadband multimedia traffic mostly depends upon its electrical power system. Broadband multi-media traffic is typically bursty and self-similar in nature. Integral part of the Electrical power system is its battery. Battery supplies the power to the LEOs during the eclipse period and it also augments the solar power during the solar period, when there is not enough solar power to take care of the communication load. Varying communication traffic that a satellite is subjected to for its on board processing and routing act as a varying load on the battery which is subjected to many thermal and power cycles during its operation in the orbit. So th etraffic patterns affect the charging and discharging regime and the amount of traffic determines the Depth of Discharge level of the battery. In this paper we describe and model the battery characteristics under varying communication traffic, analyze how it affects the battery lifetime, battery mass, thus leading to satellite life-time and cost of operation respectively, and suggests few different approaches of power mamanegement staretegies of LEOs which will increase th ebattery life, decrease the cost of the operation, and guarantee Quality of Services of broadband communication.

2. Sumit Khurana, Ashutosh Dutta, Provin Gurung, Henning Schulzrinne XML based Wide Area Communication with Networked Appliances, IEEE Sarnoff 2004

A variety of technologies are available to network appliances that provide home automation and control. However, these do not support wide-area access control and interworking of these Networked Appliances (NA). This paper describes an XML based data format for conveying information pertaining to control, query and event notification functionality to Networked Appliances.

3. Jasmine Chennikara, Ashutosh Dutta, Tony McAuley, Daniel Wong, Moncef Elaoud, Aileen Cheng, Maya Yajnik, Isil Sebuktekin, Ken Young, H. Schulzrinne Integrated Networking Technologies for Survivable Network, WCNC 2005, New Orleans

The Integrated Networking Technology prototype demonstrates the capability of several emerging networking technologies to operate together seamlessly to enhance the network services targeted for dynamic mobile environments such as those found in the battlefield. The prototype consists of four technologies: 1) Autoconfiguration technology supports autonomous and rapid network deployment and configuration; 2) Self-Managed Virtual Network (SMVN) technology provides virtual networking capabilities for networks which do not natively support these functions; 3) Integrated Mobility Management technology supports session continuity in the presence of node mobility; 4) Assured IP Quality of Service (QoS) technology supports service quality guarantees for mission-critical applications. The prototype is capable of operating over the various types of equipment and protocols to be utilized in battlefield networks. The prototype is designed such that network services and functions are survivable and reconfigurable. In this paper, we describe the four technologies as well as the integrated prototype in the laboratory environment.

4. T.Zhang, S. Madhani, A. Dutta, E. Van den Berg, Y.Ohba, K.Taniuchi,S.Mohanty Implementation and Evaluation of Autonomous Collaborative Discovery of Neighboring Networks, ITRE 2005

Emerging mobile devices often want to discover neighboring networks in real time. For example, a mobile may want to know the capabilities of the surrounding WiFi networks so that it can intelligently determine which one to use next and avoid wasting scarce battery power to attempt to connect the wrong networks. Knowing the address of the authentication server in a neighboring network may allow a mobile device to authenticate with the neighboring network while the device is still using the current network to transport its user traffic, even before the device detects the radio signal from the neighboring network. The Internet Engineering Task Force (IETF) is developing a Candidate Access Router Discovery (CARD) protocol for a mobile device to discover the address and capabilities of access routers in a neighboring network. However, it requires all neighboring access routers to implement CARD and to dynamically exchange network information with each other and with the mobiles, which is difficult to implement especially when neighboring networks belong to different network providers. Furthermore, CARD can only allow a mobile to obtain the information a local network provider configures its CARD protocol to provide, making it difficult to provide consistent information from network to network and to support mobile devices that may need different information depending on their different networking capabilities and user applications. This paper proposes and evaluates a new approach for real time discovery of neighboring network information: Autonomous Collaborative Discovery (ACD). It is autonomous because regular mobile users and their devices act autonomously to collect information and make the information available to other mobile users and devices. It is collaborative as the autonomous actions of the mobile users and devices help each other to discover the information they want.

5. A.Dutta, H.Cheng, S.Madahani, K.D. Wong, J. Chennikara, K. Young, H.Schulzrinne, A. Patel Flexible Call Control Framework for Supporting Multi-party Service IEEE MILCOM 2005

In order to manage two-party and multi-party multimedia calls, a flexible call control framework is essential. The framework helps to control calls between IP end-points and non-IP devices supporting AM, FM, and GSM waveforms over an IP-based core network. Such a mechanism is more useful in a military environment where third-party control or operator-assisted calls are widely used to bridge the traditional non-IP-based end-devices with multimedia-capable IP-based terminals. This mechanism has been implemented by using a call control framework consisting of standard-based protocols such as SIP, SDP, RTP, and HTTP, entities such as B2BUA for third party call control and MCU or multicast for multi-party conferencing. This paper introduces the framework, discusses some of the functional components and explains the operational aspects of this framework.

6. A.Dutta, J.Alberi, A.Cheng, B.Horgan, A. McAuley, D. Chee,B.Lyles IPv6 Transition Techniques for Legacy Application, MILCOM 2006, Washington DC

As part of Armys IPv6 transition initiative there are several deployment issues that need to be solved. These include transition at several layers of the protocol stack. Army has a suite of legacy applications that currently work on IPv4 systems. Before Army moves to an all IPv6 network, it will need to go through a period of transition where both IPv4 and IPv6 networks, applications will need to co-exist and interoperate. While the IETF has proposed several ways the transition can take place, we have focused our discussion on application transition. As part of this effort we choose the Armys heavily used legacy application MCS-L (Maneuver Control System-Lite) and applied several transition technologies. We took advantage of Telcordias Dynamic Slicing Tool to study the MCS-L code and made appropriate changes to make MCS-L IPv6 compatible. We tested several transition technologies such as dual stacking, Application Layer Gateway (ALG), Tunnel Broker and NAT-PT with MCS-L application. Both multicast and unicast mode of communication associated with MCS-L were also tested.

7. B.Falchuk, K.Sinkar, S.Loeb, A.Dutta, Mobile Contextual Mashup Service for IMS, IMSAA 2008, Bangalore, India

The Web 2.0 paradigm is all about the development of applications and content at the edge of the network by anyone. This wisdom of the crowd type of activity resulted in a large number of applications being introduced in short time frames utilizing the telecom network as a dumb pipe. However, IMS may open up the business opportunities for the cellular operators where they can take advantage of the openness of APIs offered by Web 2.0 dot-coms and still offer the flexible call control features of IMS. Thus, convergence of Web 2.0, mashups and IMS call control features have suddenly become a viable business model that will benefit the end users, cellular operators and application service providers at the same time. Rapid deployment of IMS can certainly be enhanced by successful blending of mashups and built-in features of IMS such as security, authentication, and quality of service. However, there is a lack of existing use case scenarios and experimental validation of supporting various web 2.0 applications over IMS. In this paper, we provide such a framework that helps to blend these two and highlight the lessons learned from the prototyping effort. We believe this framework and analysis of the results obtained from this experiment will be illuminating to cellular operators who plan to deploy IMS infrastructure and offer mash-up type services as well. A new type of service called contextual mashup is also described.

8. A.Dutta, C.Makaya, D. Chee, S.Das, J. Lin, S. Komorita, T.Chiba, H. Schulzrinne, Self Organizing IP Multimedia Subsystem, IMSAA 2009, Bangalore, India

While there have been tremendous efforts to develop the architecture and protocols to support advanced Internet-based services over 3G and 4G networks, IMS is far from being deployed in a wide scale manner. Effort to create an operator controlled signaling infrastructure using IP-based protocols has resulted in a large number of functional components and interactions between those components. Thus, the carriers are trying to explore alternative ways to deploy IMS that will allow them to manage their network in a cost effective manner while offering the value-added services. One of such approaches is self organization of IMS. The self organizing IMS can enable the IMS functional components and corresponding nodes to adapt them dynamically based on the features like network load, number of users and available system resources. This paper introduces such a self organizing and adaptive IMS architecture, describes the advanced functions and demonstrates the initial results from the prototype test-bed. In particular, we show how all IMS functional components can be merged and split among different nodes as the network demand and environment change without disrupting the ongoing sessions or calls. Although it is too early to conclude the effectiveness of self organizing IMS, initial results are encouraging and it may provide additional incentives to the operators for network evolution.

9. S. Komorita, T.Chiba, H.Yokota, A.Dutta, D. Chee, C. Makaya, S. Das, J. Lin, H. Schulzrinne, Evaluation of Service Continuity in a Self-organizing IMS, accepted for ICCT 2010

The NGN (Next Generation Network), which can provide advanced multimedia services over an all-IP based network, has been the subject of much attention for years. While there have been tremendous efforts to develop its architecture and protocols, especially for IMS, which is a key technology of the NGN, it is far from being widely deployed. However, efforts to create an advanced signaling infrastructure realizing many requirements have resulted in a large number of functional components and interactions between those components. Thus, the carriers are trying to explore effective ways to deploy IMS while offering value-added services. As one such approach, we have proposed a self-organizing IMS. A self-organizing IMS enables IMS functional components and corresponding physical nodes to adapt dynamically and automatically based on situation such as network load and available system resources while continuing IMS operation. To realize this, service continuity for users is an important requirement when a reconfiguration occurs during operation. In this paper, we propose a mechanism that will provide service continuity to users and focus on the implementation and describe performance evaluation in terms of number of control signaling and processing time during reconfiguration.

10. C.Makaya, A.Dutta, D. Chee, S.Das, J. Lin, S. Komorita, T.Chiba, H.Yokota, H. Schulzrinne, Load Balancing Support for Self-Organizing IMS Networks, Wireless VITAE 2011

With the increasing interest in deploying 4G/LTE network, IMS has a potential to be deployed in wide scale in order to support mobile Internet and value-added services over next-generation networks. Moreover, the effort to create an operator-controlled signaling infrastructure using IP-based protocols has resulted in a large number of functional components and interactions between core networks elements. Thus, the carriers are trying to explore alternative ways to deploy IMS that will allow them to manage their network in a cost effective manner while offering rich communications services. One of such approaches is self-organization of IMS (SOIMS). The self-organizing IMS can enable the IMS functional components to adapt dynamically based on the features like network load, number of users, node failures and available system resources. This paper proposes different mechanisms to handle self-organizing IMS using load balancing approach where the users are unaware of changes. The proposed solution enables topology hiding, recovery from IMS nodes failure, session continuity, and scaling.

Papers in submission:

Technical Reports:

1. A. Dutta, Tao Zhang, Joel Gannett, IP/SONET vs. IP/ATM/SONET for High-Speed Data Transport

2. S. Mohan, Tom Chapuran, A. Dutta, "Session Control Protocol Attributes for Flexible Multimedia Support and Transport Independence"

3. A. Dutta,S. Mohan, Tom Chapuran, "Paths for Industry Convergence on Session Management"

4. S. Mohan, Stuart Wagner et al., "CPE Evolution and Distributed Service Intelligence"

5. Tony Mcauley, A. Dutta, Rajesh Talpade, Deborah Bakin, "Scalable Multicast Routing"

6. S. Mohan, A. Dutta, Stu Wagner, Tom Chapuran, "Evolutionary Approaches to Implementing Session Control in Emerging Broadband Networks"

7. A. Dutta, S. Mohan, "Industry Progress towards Multi-service session control protocol"

8. A. Dutta, Teshima Shigeru, "Communications Service Evolution and Evaluation of Access Network Alternatives for the 10X Network Era"

9. A. Dutta, Vegard Masdal, "Business-Driven Evolution from Multiplatform to Multiservice Networks"

10. A. Dutta, Tao Zhang, "Capacity Planning for IP/SONET, IP/ATM/SONET and DPT architecture"