Supporting Mobile Wireless Internet Roaming Users in a SIP Environment An SAIC Company S. Baba &, J.-C. Chen +, A. Dutta +, N. Nakajima &, H. Schulzrinne *, Y. Shobatake &, and F. Vakil + + Telcordia Technologies & Toshiba America Research Inc. * Columbia University ITSUMO TM : Internet Technology Supporting Universal Mobile Operation

hmmp.ppt– 2 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Outline  Motivation  Objective  Background  End-to-end Architecture  HMMP (Host Mobility Management Protocol) –Built upon SIP signaling scheme  Related Work  Open Issues & Future work  Demo Clip (If time permits)  Discussion

hmmp.ppt– 3 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Motivation  Mobility is rapidly becoming the rule rather than exception.  SIP is gaining acceptance as the signaling protocol for multimedia conferences and Internet telephony. It is essential to support mobile users in a SIP signaling and control environment.  Current Wireless Efforts –3GPP –3G-IP –MWIF –3GPP2

hmmp.ppt– 4 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Objectives  Present a framework, i.e., host mobility management protocol (HMMP), for supporting roaming users in a mobile wireless Internet whose signaling system is built upon SIP.  Identify possible impacts of mobility on SIP and/or other protocols.  Propose “necessary extensions” for supporting mobility with SIP.

hmmp.ppt– 5 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Framework Requirements SIP based mobility management scheme for wireless IP networks would  support personal as well as terminal mobility  support global roaming  support functions such as –hand-off –registration –configuration –address binding – location management  be independent of underlying wireless technology  support real-time and non-real time multimedia applications (i.e., both TCP and RTP/UDP based application)  inter-work with today’s 1G/2G telephony smoothly

hmmp.ppt– 6 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Service Profile for all IP wireless network user

hmmp.ppt– 7 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. The Network Architecture MS: Mobile Station BS: Base Station ERC: Edge Router & Controller Control messages (i.e., signaling) Domain Control Agent Visited Network Domain Control Agent Wireline IP backbone network Home Network ERC Internet Regional IP network ERC Inter-Domain Control Agent Radio Access Network (RAN) Radio Access Network (RAN) BS DCA IDCA MS IP

hmmp.ppt– 8 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Network Signaling and Control Architecture Signaling: Wireline IP backbone network Internet Visiting Registrar 3G Access SIP 3G Access SIP Server MAAAQ SIP VR Regional IP network Visiting Network MS DCA Home Network 3G Access SIP 3G Access Regional IP network SIP Server MAAAQ SIP HR Home Registrar DCA Inter-Domain Registrar SIP Server MAAAQ IDR IDCA SIP UA in mobiles and hosts.

hmmp.ppt– 9 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Network Elements  Mobile Station (MS) –User terminal –Adaptive software radios, i.e., full flexibility in the frequency band –Control and management entity  Radio Access Network (RAN) –Provides MSs with access to the wireline infrastructure. –Set of base stations (BSs) and base station controllers (BSCs) –Adaptive software radios –May support IP routing and control functions at BSs  Open Issue under study.

hmmp.ppt– 10 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Network Elements (contd.)  Edge Router & Controller (ERC) –Comprises two elements  Edge Router (ER) with one or more interfaces to provide multiple subnets  Edge Control Agent (ECA): Control and management entity –Default router of all MSs behind it  Domain Control Agent (DCA) –connection/session management –means of interaction (i.e., signaling)  between users and network control system, and  among network control entities –MAAAQ, i.e.,  Mobility management,  Authentication, Authorization, and Accounting (AAA), and  QoS management

hmmp.ppt– 11 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. What is HMMP?  A protocol (framework) for supporting real-time and non-real- time multimedia applications on mobile terminals of all IP networks.  Is built on top of existing personal mobility feature of Session Initiation Protocol (SIP).  Supports –domain hand-off (i.e., roaming) and –subnet hand-off (i.e., macro mobility), and –cell hand-off (i.e., micro mobility).  If base stations are not IP based, cell hand-off details are technology dependent.  Supports both real-time and non-real-time application  Spoofs constant endpoints for TCP applications of roaming users and supports TCP as is.

hmmp.ppt– 12 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. HMMP Overview: Cell hand-off (A --> B) SIP Server MAAAQ SIP HR SIP SIP Server MAAAQ VR Internet Regional IP network Visiting NetworkHome Network BSC 1 BS ERC 1 BSC 2 BS ERC 2 ERC 3 BS BSC 3 A C B D Home RegistrarVisiting Registrar Corresponding Host SIP IP ch

hmmp.ppt– 13 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Cell hand-off (Micro Mobility)  Mobile moves from A to B, BSC 1 –Bind the mobile’s MAC address (or CDMA sequence) to port B –Update the label translation table in BSC 1. –Technology dependent and is done via the link layer control channels –SIP signaling may be involved to emulate soft hand-off

hmmp.ppt– 14 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. HMMP Overview: Subnet hand-off (B --> C) SIP Server MAAAQ HR INFO SIP Server MAAAQ VR Internet Visiting NetworkHome Network BSC 1 BS ERC 1 BSC 2 BS ERC 2 ERC 3 BS BSC 3 A C B D Home RegistrarVisiting Registrar Corresponding Host DHCP INVITE INFO method for address binding. DHCP updates the DNS. IP ch

hmmp.ppt– 15 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Subnet hand-off (Macro Mobility - Intra-Domain mobility)  Mobile moves further from B to C, and it is still registered with the network –The mobile asks a new temporary address from DHCP.  either directly or via a SIP registrar  The DHCP gives the mobile a temporary IP address, the address of its default gateway, and the subnet mask, nearest outbound SIP proxy server if needed –The DHCP updates the domain name system (DNS) simultaneously for the new inbound connections –mostly for mobile ftp/web applications  In public networks, the network may authenticate the mobile as a protection against fraud (Not a requirement).  The mobile or SIP server re-invites the corresponding host to the temporary address with new SDP parameters

hmmp.ppt– 16 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Subnet hand-off (Contd.) –SIP server and network resource reservation scheme should create a new route with adequate resources between the corresponding host and the mobile.  This new route with adequate resources is only created for real-time applications like voice.  The non-real-time applications are allowed to traverse the network hop- by-hop.  The mobile or SIP server creates a short-lived tunnel between ERC-1 and ERC-2 to reduce loss of the transient data due to hand-off. –Typically needed during hard hand-off – the mobile or SIP server informs ERC-1 to bind the previous address of the mobile to its current one for a time-out period.This requires  SIP user agents at all ERCs, and  the address of the most recent ERC which is the most recent default gateway. –Tunnel creation is faster when both the interfaces are part of the same ERC.

hmmp.ppt– 17 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. HMMP Overview: Domain Hand-off ( C --> D) SIP Server MAAAQ SIP HR SIP Server MAAAQ VR Internet Visiting NetworkHome Network BSC 1 BS ERC 1 BSC 2 BS ERC 2 ERC 3 BS BSC 3 A C B D Home RegistrarVisiting Registrar Corresponding Host SIP DHCP INFO INVITE Similar to Subnet hand-off plus AAA IP ch SLA/SA

hmmp.ppt– 18 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Domain Hand-off (Roaming)  Mobile moves further to D –The mobile requests for a temporary address and receives one from DHCP. The DHCP updates the DNS simultaneously. –The mobile re-registers with its temporary address in the new domain using the SIP REGISTER method.  The mobile profile is added to the visiting registrar (VR), i.e., –its profile is replicated either through interaction of the VR with the HR or –by pre-planned profile replications in the neighboring VRs. –The mobile or SIP server re-invites the corresponding host with the new temporary address –SIP server and network resource reservation scheme should create a new route with adequate resources between the corresponding host and the mobile.

hmmp.ppt– 19 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Domain Hand-off (Roaming), …, Continued  HMMP ensures that the transient data is forwarded to the new address –The mobile or SIP server informs ERC-2 to bind the previous address of the mobile to its current one for a time-out period. This requires  SIP user agents at all ERCs, and  the address of the most recent ERC which is the most recent default gateway.

hmmp.ppt– 20 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. A typical Protocol Map for Inter-Domain mobility DHCP Domain1Domain2 MT Local SIP Server Public AAA Database Local SIP Server Network registration/ configuration Service Profile Location Database LAAA Database LAAA Database User Profile User Profile User Profile Public SIP Server ” Location Database Service Profile 6’ Location Database Service Profile 10 DHCP+ client SIP client DHCP+ client Service Registration Location Update Mobile moves QoS SLA 2’ 7 8 Home Visitor

hmmp.ppt– 21 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Supporting TCP Applications with HMMP SIP Server MAAAQ SIP HR SIP Server MAAAQ VR Internet Visiting NetworkHome Network BSC 1 BS ERC 1 BSC 2 BS ERC 2 ERC 3 BS BSC 3 A C B D Home RegistrarVisiting Registrar Corresponding Host SIP DHCP SIP_EYE Ongoing TCP Connections INFO Equip MS with SIP_EYE. IP ch IP ch1

hmmp.ppt– 22 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Supporting TCP Applications with HMMP  A TCP connection is identified by a pair of endpoints, and each endpoint is identified by a pair of integers (host, port). –host is IP address of the endpoint, and port is the TCP port on the host.  TCP applications –ftp, telnet, irc, web  The underlying idea of HMMP support of TCP are –SIP-Eye keeps track of ongoing TCP end-points –The MS informs the corresponding TCP endpoints about its new address, –The corresponding host(s) bind (binds) the initial IP address of the MS with its temporary one, and – The CH uses encapsulation to send TCP packets bearing the initial source and destination addresses to the current location/address of the MS. –MS does the encapsulation of its previous IP address with the new one and sends to CH

hmmp.ppt– 23 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. State of the Art: Related Work

hmmp.ppt– 24 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Related Work: Related Work

hmmp.ppt– 25 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Why HMMP? Pros & Cons

hmmp.ppt– 26 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Possible Impact on other Protocols  It is desirable that –the SIP INFO method provides the means of profile verification and/or replication, and address binding, –SIP registrar interacts with the AAA entity for inter-domain case –the SIP user agent is either equipped with a SIP_EYE agent or interact with a SIP_EYE agent that maintains a record of ongoing TCP connections of the mobile, and –the SIP user agent understands address binding INFO messages and takes necessary actions, –Needs a faster configuration protocol (e.g., DRCP)  Either –the DHCP interacts with the DNS and updates it dynamically, or –a new protocol is developed to allow applications to use SIP registrar for name to address and address to name mappings.

hmmp.ppt– 27 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. Open Issues & Future Work  Proper use of the soft hand-off mechanism of the CDMA technologies.  Performance - complexity trade-off of the short-lived tunneling between current and previous ERCs. –Other possible alternatives being looked into (e.g., SIP multicast agent)  Detailed specifications of the SIP_EYE agent and its relation with the SIP UA. –Compare with other means of encapsulation method (e.g., closer to the base station)  Interaction of the SIP Registrar with the AAA, if necessary. –If a variant of DHCP (e.g., DRCP) is used, no interaction between AAA and Registrar is necessary.  Comparison with solutions that combines SIP & Mobile IP.  A prototype of HMMP is being implemented now.

hmmp.ppt– 28 Telcordia Technologies Proprietary - Internal use only. See proprietary restrictions on title page. References  M. Handley, H. Schulzrinne, E. Schooler, J. Rosenberg, “SIP: Session Initiation Protocol, RFC 2543 (Proposed Standard), IETF  E. Wedlund, and H. Schulzrinne, “Mobility Support using SIP” ACM WOWMOM workshop, Seattle, August 1999  F. Vakil, A. Dutta, J.-C. Chen, S. Baba, Y. Shobatake, H. Schulzrinne, “Mobility Management in a SIP Environment Requirements, Functions and Issues”, Internet Draft March 2000, Work in Progress  P. R. Calhoun, and J. Kempf, "Mobility Management and Authentication in an All-IP Network", mwif00.009, January  ITSUMO Group, “ITSUMO’s All IP Wireless Architecture”, mwif00.012, January 14,  A. McAuley, S. Das, and S. Baba, Y. Shobatake, “Dynamic Registration and Configuration Protocol for Mobile Hosts”,, work in progress, October  F. Vakil, A. Dutta, J.-C. Chen, S. Baba, and Y. Shobatake, “Host Mobility Management Protocol: Extending SIP to 3G-IP Networks”,, work in progress, October  S. Donavan, “ The SIP INFO Method”, March 2000, Work in Progress  RFC 2004, IETF, “Minimal Encapsulation within IP”  RFC 2002, IETF. “IP Mobility Support”  RFC 2131, “Dynamic Host Configuration Protocol”  Telcordia Technologies, “Voice Over Packet in Next Generation Networks: An Architectural Framework”, Bellcore SR-4717, Issue 1, January  ITSUMO Group, “Benchmarking of ITSUMO’s All IP Wireless Architecture”, mwif00.028, January 28,  ITSUMO Group, “A Reference Architecture for All IP Wireless Networks”, 3GPP2-S00 allip , January 6,  ITSUMO Group, “A Signaling Architecture for All IP Wireless Networks”, 3GPP2-S00allip , January 6,  ITSUMO Group, “Evolution of Wireless Telephony towards Voice over 3G-IP”, 3GPP2- P , to the August 23, 1999.