Optimized Fast-handoff Scheme for Application Layer Mobility Management

1
Optimized Fast-handoff Scheme for Application
Layer Mobility Management

• Authors Ashutosh Dutta, Sunil Madhani, Wai Chen
• Telcordia Technologies
• Henning Schulzrinne
• Columbia University
• Onur Altintas
• Toyota InfoTechnology Center
• First author is also a student at Columbia
  University

2
Outline

• Motivation
• Intra-domain Mobility Management
• SIP based Mobility Management
• SIP and Mobile IP
• Fast-handoff for SIP Mobility
• Test-bed Realization
• Experimental results

3
IETF Multimedia Protocol Stack
Media Transport
media encap (H.261. MPEG)
Signaling
SAP
SDP
MGCP
DHCPP
Application Daemon
SIP
H.323
RTSP
RSVP
RTCP
RTP
DNS
LDAP
TCP
UDP
CIP
MIPv6
IDMP
Network
MIP
ICMP
IGMP
MIP-LR
IPv4, IPv6, IP Multicast
Kernel
PPP
AAL3/4
AAL5
PPP
Physical
CDMA 1XRTT /GPRS
SONET
ATM
Ethernet
802.11b
Heterogeneous Access
4
Motivation

• Objective Design and evaluate optimized
  techniques based on Application Layer Mobility
  Management Scheme
• Several Network Layer Scheme provide optimized
  handoff techniques for Intra-domain mobility
• Application Layer Mobility Management Scheme
  rules out the need for networking components
  such as Home Agent/Foreign Agent
• SIP based mobility is an application layer scheme
  supporting Real-Time traffic for Mobile Wireless
  Internet
• It is essential to reduce transient real-time
  traffic during frequent handoffs

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Network Layer fast-handoff approaches

• Intra-domain Mobility Management Protocol
• Use of Mobility Agent to limit the Intra-domain
  updates to within a domain
• Hierarchical Mobile IPv4/v6 Fast Hand-offs
• Foreign Agent Assisted Handoffs
• Intra-domain Mobility with buffering Agents

6
SIP Background

• SIP allows two or more participants to establish
  a session including multiple media streams
• audio, video, distributed games, shared
  applications, white boards, or any other
  Internet-based communication mechanism
• Standardized by the IETF RFC 2543
• Is being implemented by several vendors,
  primarily for Internet telephony
• e.g. Microsoft XP operating system includes SIP
  as part of its built-in protocol stack
• Recently being extended to provide presence,
  instant messaging and event notification
• Endpoints addressed by SIP URLs
• siponur_at_toyota-itc.com

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Why SIP Mobility ?

• SIP is an application layer signaling protocol
• it can keep mobility support independent of the
  underlying wireless technology and network layer
  elements
• 3GPP, 3GPP2, and MWIF have agreed upon SIP as the
  basis of the session management of the mobile
  Internet
• SIP will eventually be part of the mobile
  Internet so why not use its inherently present
  mobility support functions
• SIP can provide personal mobility, terminal
  mobility, session mobility and service mobility
• No requirement to modify (or add) capabilities to
  existing terminals operating system

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Types of SIP mobility

• SIP provides variety of mobility techniques
• Personal Mobility
• Allows users to be reachable in multiple
  locations using a unique URI
• Service Mobility
• Allows users to maintain access to their services
  while moving between service providers
• Session Mobility
• Allows a user to maintain a media session while
  changing between terminals
• Mid-session (terminal) mobility
• Allows a user to maintain a session while moving
  (support for real-time streaming applications for
  mobiles)

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SIP mobility Performance snapshot in 802.11
Environment

• Byte Sizes of SIP signaling Timing for Signaling
  messages
• INVITE - 455 bytes 100 msec processing time
  between msgs (OS dependent)
• Ringing - 223 bytes 5 msec for Invite to traverse
• OK - 381 bytes 70 msec for Re-Invite to traverse
  (mostly queuing delays)
• ACK - 261 bytes 150 msec for complete
  re-registration
• Bye - 150 bytes 300-400 msec for address
  acquisition without (SIP,MIP)
• De-Register - 370 bytes 3-4 sec for address
  acquisition with ARP (SIP,MIP)
• Re-Invite - 450 bytes
• Re-register - 425 bytes

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Handoff Delay Analysis (SIP-Mobility)
MH (IP1)
CH
MH (IP0)
Base Station
DHCP/PPP Server
SIP Signaling
Beacon
Beacon Interval
RTP Session
MH moves
Beacon
Binds
L2
Discover/Request
L3
Offer/IP address
Configuration Time
Re-Invite
L2 Layer 2
Media Redirection
RTP Session
L3 Layer 3
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SIPMM-MIP BW and Latency experimental evaluation
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Cellular IP
MIP registration
CIP update
Media
Home Agent
Correspondent Host
Internet (with Mobile IP)
Domain B
Domain A
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Hierarchical Foreign Agent
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HAWAII
Internet
Domain 2
Domain 1
Domain Root Router
Domain Root Router
R
R
R
R
R
R
R
R
R
BS
BS
BS
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TeleMIPs Architecture Layout
IDMP/TeleMIP Architecture
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Initial Domain-Based Registration Procedure
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Subsequent Intra-Domain Registration
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Mobility Proxy
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SIP fast-handoff mechanism -RTPtrans
Intra- Domain fast-handoff
Domain -D1
RT1,RT2,RT3 - RTP Translators
Mapping Database
IP2 -gt IPR1
Delay
IP3 -gt IPR2
Simulator
.
SIP
.
Server
.
(Media)
R
1
2 (Re-invite)
(Media in flight)
3
Register
2
IPR2
IPR3
IPR1
4
RT2
RT3
RT1
IP1p1
IP2p1
4
(Transient media)
IP1
IP2
IP3
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SIP fast-handoff RTPtrans - Protocol flow
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SIP fast-handoff with B2B SIP UA approach 1
Router
Delay
CH
Simulator
IPch
SIP MA (B2B)
Media
Invite B2B SDP
SIP
SIP
UAC
UAS
SIP
SIP
Media
UAS
UAC
Media
Media
Media
Invite
Re-Invite
Invite
IP3
IP1(Initial position before move)
IP2
Move
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Flow diagram B2B approach 1(Limits Re-invite to
B2B UA within a domain)
B2BUA
IP1
IP0
UA1
UA2
MH
MH
CH
Invite
Invite
ok
ok
ack
ack
RTP1
RTP2
Media Transl- ator
Re-Invite
RTP1 after the move
RTP2
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SIP fast-handoff with B2B SIP UA approach 2
Router
Delay
CH
Simulator
IPch
SIP MA (B2B)
Invite MH SDP
SIP
SIP
UAC
UAS
SIP
SIP
Media
UAS
UAC
Media
Media
Invite
Invite no SDP
Invite
IP3
IP1(Initial position before move)
IP2
Move
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Fast handoff with B2B UA approach 2 flow
diagram Re-invite from MH activates the
interceptor at B2BUA
B2BUA
IP0
IP1
UA1
UA2
MH
CH
MH
Invite (no SDP)
OK (MH SDP)
Invite MH SDP
OK
ACK
ACK CH SDP
RTP
Re-Invite
RTP1
(Interceptor)
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B2BUA- fast-handoff approach 3 multicast agent
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B2BUA- fast-handoff approach 3 multicast agent
-flow
B2BUA
IP0
IP1
CH
UA1
UA2
MH
MH
Invite (no SDP)
OK (MH SDP)
Invite MH SDP
OK
ACK
ACK CH SDP
RTP
Re-Invite
Re-Invite with Maddr
Transient data at M addr
RTP1
RTP
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SIP based Mobility in a Test-bed
Outer sphere CDMA/CDPD network
DMZ Network
Company Intranet
DomainSN1
DHCP
HUB
IGW
Ciscos NAT
DNS
Internet
CH
sun80
SIP Client
cisco80
PPP Server/ Wireless ISP
.21
DomainSN2
SIP Proxy
802.11b
DHCP
SIP Proxy
Private Subnet 2
MH
CH
sun90
CDMA
CDPD
cisco90
DHCP
DomainSN3
802.11b
Private Subnet 1
Private Subnet 3
802.11b
Outdoor
DMZ Network 802.11
MH
SIP Client
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Sample Packet Trace for Fast Handoff (see notes
page)
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Sample Packet Trace for Mobility Proxy-based
Handoff (see notes page)
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Issues

• Duplicate Packets Detection
• Aging of RTP translator
• Scalability
• Number of subnets is large
• Mobile is moving too rapidly between the subnets
• Mechanism to remove the virtual Interface
• Mapping of subnets and RTPtranslators

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Conclusions

• Application Layer fast-handoff mechanism
  discussed
• Test-bed Realization presented
• Results of the experiments analyzed
• RTP aging, scalability, effect of mobility rate
  are future
• Comparison with other network layer approaches is
  helpful.