Transcript sip-fast-handoff - Columbia University

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]
Outline
• Motivation
• Intra-domain Mobility Management
• SIP based Mobility Management
– SIP and Mobile IP
– Fast-handoff for SIP Mobility
• Test-bed Realization
• Experimental results
SAP
SDP
MGCP
DHCPP
H.323
SIP
RTSP
RSVP
Network
TCP
Physical
PPP
SONET
RTCP
RTP
DNS
LDAP
CIP
MIP
(H.261. MPEG)
UDP
IDMP
MIP-LR
MIPv6
IPv4, IPv6, IP Multicast ICMP
AAL3/4
ATM
AAL5
IGMP
PPP
802.11b
Heterogeneous
Access
Ethernet CDMA 1XRTT
/GPRS
Kernel
Signaling
Media Transport
media encap
Application Daemon
IETF Multimedia Protocol Stack
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
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
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 Internetbased 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
– sip:[email protected]
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 terminal’s operating system
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)
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
• OK - 381 bytes
5 msec for Invite to traverse
70 msec for Re-Invite to traverse
(mostly queuing delays)
150 msec for complete re-registration
300-400 msec for address acquisition witho
• ACK - 261 bytes
• Bye - 150 bytes
(SIP,MIP)
• De-Register - 370 bytes
(SIP,MIP)
• Re-Invite - 450 bytes
• Re-register - 425 bytes
3-4 sec for address acquisition with ARP
Handoff Delay Analysis (SIPMobility)
MH (IP0)
CH
MH (IP1)
SIP Signaling
RTP Session
Base Station
DHCP/PPP Server
Beacon
Beacon Interval
MH moves
Beacon
Binds
Discover/Request
L2
L3
Configuration
Time
Re-Invite
RTP Session
Media
Redirection
L2 = Layer 2
L3 = Layer 3
SIPMM-MIP BW and
Latency experimental
evaluation
SIP vs MIP Utilization Gain (Experiment)
SIP vs. MIP Latency (Experiment)
40
Latency in msec
35
0.5
27 msec
~50%
latency
improvement
SIP B/W Gain
30
SIP B/W Gain
0.4
25
SIP
20
15
0.3
16 msec
10
5
0.2
0
100 200 300 400 500 600 700 800 900 1000 1100
Bytes per packet
0
100 200 300 400 500 600 700 800 90010001100
Packet Size in bytes
MIP
CIP update MIP
registration
Media
Cellular IP
Home
Agent
Correspondent
Host
Internet
(with Mobile IP)
Gateway B
Gateway A
Cellular IP
Node
CIP
Node
CIP
Node
Cellular IP
Node
Cellular IP
Node
CIP
Node
CIP
Node
CIP
Node
CIP
Node
Cellular IP
Node
CIP
Node
CIP
Node
Domain B
Domain A
Hierarchical Foreign Agent
HA
HA
4
IP-based network
GFA 2
IP-based network
3
GFA 1
GFA
2
2
5
3
FA3
FA1
FA2
FA4
FA1
FA2
4
6
1
1
HAWAII
Domain 2
Internet
Domain 1
Domain Root
Router
Domain Root
Router
R
R
R
R
R
BS
R
BS
R
R
R
BS
IDMP/TeleMIP Architecture
TeleMIP’s Architecture Layout
Initial Domain-Based Registration Procedure
Subsequent Intra-Domain
Registration
Mobility Proxy
SIP fast-handoff mechanism -RTPtrans
Intra- Domain fast-handoff
Domain -D1
RT1,RT2,RT3 - RTP Translators
Mapping Database
IP2 -> IPR1
IP3 -> IPR2
.
.
.
Delay
Simulator
SIP
Server
R
CH
1
3
Register
2’
IPR3
IPR2
RT3
RT2
IPR1
IP2:p1 RT1 IP1:p1
4’
MH
MH
MH
IP3
IP2
IP1
4
SIP fast-handoff RTPtrans - Protocol flow
Fast-handoff Flow diagram
MH
IP1
SIP
Server
CH
RT1
RT2
RT3
Media (1)
First move
Re-Invite (2)
Re-register 2’
IP2
SIP-CGI (3)
Transient
Traffic during
the move
IP2
Second move
Forward
traffic
(IP1:p1 ---> IP2:p1)
New traffic
Re-Invite
IP3
Re-register
SIP-CGI
Transient
Traffic during
the move
Forward
traffic
(IP2:p1 ---> IP3:p1)
SIP fast-handoff with B2B SIP UA – approach 1
Delay
Simulator
Router
CH
IPch
SIP MA (B2B)
SIP SIP
UAC UAS
SIP SIP
UAS UAC
MH
IP3
MH
MH
IP2
Move
IP1(Initial position before move)
Flow diagram B2B approach –1
(Limits Re-invite to B2B UA within a domain)
IP1
MH
B2BUA
IP0
UA1
MH
UA2
CH
Invite
Invite
ok
ok
ack
ack
RTP1
RTP2
Media
Translator
Re-Invite
RTP1 after the move
RTP2
SIP fast-handoff with B2B SIP UA – approach 2
Delay
Simulator
Router
CH
IPch
SIP MA (B2B)
SIP SIP
UAC UAS
SIP SIP
UAS UAC
MH
IP3
MH
IP2
MH
Move
IP1(Initial position before move)
Fast handoff with B2B UA – approach 2 – flow diagram
Re-invite from MH activates the interceptor at B2BUA
IP1
IP0
MH
MH
B2BUA
UA1
UA2
CH
Invite (no SDP)
OK (MH SDP)
Invite MH SDP
OK
ACK
RTP
Re-Invite
RTP1
(Interceptor)
B2BUA- fast-handoff – approach 3 multicast agent
Internet /Delay
CH
Box
SIP B2B UA
Re-Invite
(SDP wit
h maddr)
ite
v
n
i
ReM1 - local scoped multicast address
(duration limited multicast)
Subnet 1
Subnet 0
MH
MH
Exis
ting
med
ia
Multicast
Agent
B2BUA- fast-handoff – approach 3 multicast agent flow
B2BUA
IP1
IP0
MH
MH
UA1
CH
UA2
Invite (no SDP)
OK (MH SDP)
Invite MH SDP
OK
ACK
RTP
Re-Invite
Re-Invite with Maddr
RTP1
Transient data at M addr
RTP
SIP based Mobility in a Test-bed
Outer sphere
CDMA/CDPD network
DMZ Network
Company
Intranet
Domain:SN1
DHCP
HUB
Cisco’s NAT
IGW
DNS
Internet
CH
cisco80
sun80
.21
SIP Client
PPP Server/
Wireless ISP
Domain:SN2
SIP Proxy
802.11b
MH
DHCP
SIP Proxy
CH
Private Subnet 2
sun90
Domain:SN3
cisco90
DHCP
802.11b
Private Subnet 3
Private Subnet 1
802.11b
“Outdoor”
DMZ
Network
802.11
MH
SIP Client
CDPD
CDMA
Sample Packet Trace for Fast Handoff
(see notes page)
Sample Packet Trace for Mobility Proxy-based
Handoff (see notes page)
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
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.