Transcript 投影片 1 - NTUT

Adviser: Ho-Ting Wu
1
Presenter: Chi-Fong Yang
Institute of Computer Science and Information
Engineering
National Taipei University of Technology
2015/7/18
CROSS LAYER ASSISTED SIP
HANDOVER
BASE ON WIMAX
OUTLINE
Introduction
 Media Independent Handover Service
 Layer 2 Handover Schemes
 Layer 3 Handover Schemes
 Layer 3+ Handover Schemes
 QoS Supported in 802.16e
 Hidden Problem of SIP Handover on WiMAX
 Reference

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INTRODUCTION
Internet telephony uses SIP to establish and tear
down multimedia sessions
 Multimedia sessions are mostly based on
RTP/RTCP
 Layer 2 handover



Layer 3 handover


mobility solution for 802.16e MAC handover
mobility solution for acquiring a new IP address in a
newly connected network
Layer 3+(Upper Layer) handover

mobility solution for real-time traffic.
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PROBLEMS DEFINITION

Layer 2 handover


Link layer handover delay
Layer 3 handover
Address allocation delay(Dynamic Host
Configuration Protocol ,DHCP)
 Router Advertisement delay


Layer 3+(Upper Layer) handover
SIP re-INVITE process delay, consists of the Round
Trip Time (RTT)
 RTP packet transmission delay

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MEDIA INDEPENDENT HANDOVER
SERVICE
The standard IEEE 802.21
 The standard defines an abstraction layer,
providing Media Independent Handover(MIH)
Functions
 The goal of simplifying the management of
handovers to and from Ethernet, GSM, GPRS,
UMTS, WiFi, Bluetooth and 802.16 networks.
 Provide a common interface for managing events
and control messages exchanged between
network devices

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IEEE 802.21 ARCHITECTURE
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PRIMARY SERVICES OF MIH

MIES - Media Independent Event Service



The MIES provides support for both local and remote events
notification to the upper layers of a mobile host
Common events provided through MIHF are: “Link UP”,
“Link DOWN”, “Link Parameters Change”, “Link Going
DOWN” and “L2 Handover Imminent”
MICS - Media Independent Command Service
The MICS is used to gather information about the status of
connected links and to execute mobility and connectivity
decisions
 Typical examples of commands are: “MIH Poll” and “MIH
Configure” to poll connected links asking for their status and
to configure new links, respectively.


MIIS - Media Independent Information Service

The MIIS extends further the services of IEEE 802.21 with a
framework and corresponding mechanisms supporting the
discovery and distribution of network information within a
geographic area
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HANDOVER MANAGER
Goals
 service
continuity
 mobility policies
 adaptation support at the
application level
 common interface(Media
Independent Handover, MIH)
 Software Module
 Running in user space
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HANDOVER MANAGER STRUCTURE
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MOBILITY MANAGER




Link quality module
 in charge of storing the information related to the
available links and dispatching notifications about
changes in link quality
Handover decision module
 in charge of performing handoff decisions according to
user’s preferences
Power management module
 in charge of switching on or off the interfaces according
to user’s preferences
User policies module

contains description of policies about security, cost, and access
networks priorities
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MOBILITY MANAGER STRUCTURE
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APPLICATION MOBILITY
INTERFACE (AMI)
Goals
 AMI
receives the notifications from
the MM (Mobility Manager)
 AMI is in charge of performing
adaptation of application sessions
and/or issuing configuration
commands to the legacy
application.
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LAYER 2 HANDOVER SCHEMES
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The standard IEEE 802.16e-2005
 Support SS(subscriber stations) moving at
vehicular speeds and thereby specifies a system
for combined fixed and mobile broadband
wireless access.
 License-exempt frequencies below 11 GHz
(primarily 5–6 GHz)

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SOFT HANDOVER AND HARD
HANDOVER

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The process in which an mobile Host(MH)
migrates from the air-interface provided by one
Base Station(BS) to the air-interface provided by
another Base Station(BS)
 break-before-make handover(hard handover)

A handover where service with the target BS(Base
Station) starts after a disconnection of service with
the previous serving BS
make-before-break handover(soft handover)

A handover where service with the target BS starts
before disconnection of the service with the previous
serving BS.
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MACRO DIVERSITY HANDOVER AND
FAST BS SWITCHING



802.16e-2005 Page 250
Two optional HO(Handover) modes
 Macro Diversity Handover(MDHO)
 Fast BS Switching(FBSS)
The MDHO or FBSS capability can be enabled or disabled in
the REG-REQ/RSP message exchange
MDHO Decision
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
A MDHO begins with a decision for an MH(Mobile Host) to transmit
to and receive from multiple BSs(Base Station) at the same time
 A MDHO can start with either MOB_MSHO-REQ or MOB_BSHOREQ messages


FBSS HO Decision
A FBSS handover begins with a decision for an mobile host to
receive/transmit data from/to the Anchor BS
 A FBSS handover can be triggered by either MOB_MSHO-REQ or
MOB_BSHO-REQ messages

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MAC LAYER HANDOVER
PROCEDURES
Cell reselection


MH(Mobile Host) may use Neighbor BS(Base Station) information
acquired from a decoded MOB_NBR-ADV message, or may make a
request to schedule scanning intervals or sleep-intervals to scan, and
possibly range
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
Handover decision and initiation
A handover begins with a decision for an MH(Mobile Host) to
handover from a serving BS(Base Station) to a target BS(Base Station)
 The decision may originate either at the MH(Mobile Host) or the
serving BS(Base Station)
 Decision consummates with a notification of MH(Mobile Host) intent
to handover through MOB_MSHO-REQ or MOB_BSHO-REQ
message


Synchronization to target BS


MH(Mobile Host) shall synchronize to downlink transmissions of
Target BS(Base Station) and obtain downlink and uplink
transmission parameters
Ranging

Ranging is collection of processes by witch SS and BS maintain the
quality of RF commutation link between them
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MAC MANAGEMENT MESSAGES
802.16e MAC handover messages

Page 44, Table 14-MAC Management Messages
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
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CELL RESELECTION
Scanning procedure
using the MOB_SCN-REQ and MOB_SCN-RSP message
for scanning intervals
 The mobile host indicates in this message the estimated
duration of time it requires for the scanning


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
Association procedure
Association is an optional initial ranging procedure
occurring during scanning interval with respect to one of
the neighbor BSs(Base Stations)
 There are three levels of association as follows





Association Level 0(Scan/Association without coordination)
Association Level 1(Association with coordination)
Association Level 2(Network assisted association reporting)
802.16e-2005 Page 236
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EXAMPLE OF CELL SELECTION
WITH RANGING
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HANDOVER DECISION AND
INITIATION
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A handover begins with a decision for an
MH(Mobile Host) to handover from a serving
BS(Base Station) to a target BS(Base Station)
 The decision may originate either at the mobile
host
 proceed with a notification through either
MOB_MSHO-REQ or MOB_BSHO-REQ
messages
 mobile host actual pursuit of handover to one of
BSs(Base Stations) specified in MOB_BSHO-RSP
is recommended

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EXAMPLE OF MOBILE STATION
HANDOVER
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EXAMPLE OF BASE STATION
HANDOVER
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LAYER 3 HANDOVER SCHEMES
802.16e establish IP connectivity
MH(Mobile Host) using IPv4 and not using mobile IP, they
shall invoke DHCP mechanisms [IETF RFC 2131]
 MH(Mobile Host) using IPv6, they shall either invoke
DHCPv6 [IETF RFC 3315] or IPv6 Stateless Address
Autoconfiguration [IETF RFC 2462]



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
Once the L3 handoff has occurred, the MH(Mobile
Host) has to wait for some time in order to
acquire a new IP address for that subnet via
DHCP(Dynamic Host Configuration Protocol)
Mobile IP supported
IP Mobility Support for IPv4(IETF RFC-3344)
 Fast Handoffs for Mobile IPv6(IETF RFC-4068)



predictive fast handover
reactive fast handover
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DHCP IP ADDRESS ALLOCATION
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DEFINITION OF FAST HANDOFFS
FOR MOBILE IPV6
Access Router(AR)


Previous Access Router(PAR)


The mobile host's default router subsequent to its handover
Previous CoA(PCoA)


The mobile host's default router prior to its handover.
New Access Router(NAR)


The mobile host's default router
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The mobile host's Care of Address valid on PAR's subnet
New CoA(NCoA)

The mobile host's Care of Address valid on NAR's subnet
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MESSAGE FORMATS FOR FAST HANDOFFS
FOR MOBILE IPV6
Router Solicitation for Proxy Advertisement(RtSolPr)


Proxy Router Advertisement(PrRtAdv)


A message from the NAR to the PAR as a response to HI
Fast Binding Acknowledgment(FBAck)


A message from the PAR to the NAR regarding an mobile host’s handover
Handover Acknowledge(HAck)


A message from the mobile host instructing its PAR to redirect its
traffic(toward NAR)
Handover Initiate(HI)


A message from the PAR to the mobile host that provides information
about neighboring links facilitating expedited movement detection. The
message also acts as a trigger for network- initiated handover.
Fast Binding Update(FBU)


A message from the mobile host to the PAR requesting information for a
potential handover
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A message from the PAR in response to an FBU
Fast Neighbor Advertisement(FNA)

A message from the mobile host to the NAR to announce attachment, and
to confirm the use of NCoA when the MN has not received an FBACK
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PREDICTIVE FAST HANDOVER
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LAYER 3+ HANDOVER SCHEMES
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Mobile Host(MH) will have to inform of its IP
address change the Correspondent Node(CN)
 Mobile Host(MH) will have to update its SIP
session with the Correspondent Node(CN)
 Only at this point the L3 handoff can be
considered done
 SIP outbound proxy supported

SIP proxy in the visited network, namely the SIP
outbound proxy
 SIP outbound proxy can also support fast handoff

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SIP HANDOVER WITH 802.16E MAC
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FAST SIP HANDOVER WITH 802.16E
MAC(CASE 1)
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FAST SIP HANDOVER WITH 802.16E
MAC(CASE 2)
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QOS SUPPORTED IN 802.16E
Service flows




service flow is a unidirectional flow of packets that is provided
a particular QoS
an SFID(Service Flows Identify) is assigned to each existing
service flow, it is uniquely identified by a 32-bits
the relationship between SFID and transport CID, when
present, is unique(An SFID shall never be associated with
more than one transport CID)
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
Service classes
mobile networks require common definitions of service class
names and associated AuthorizedQoSParamSets in order to
facilitate operation across a distributed topology.
 global service class names are employed as a baseline
convention for communicating AuthorizedQoSParamSet or
AdmittedQoSParamSet


Scheduling Services

Each connection is associated with a single scheduling type
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SERVICE CLASSES

Std 802.16e–2005 page 211
Service class names are a rules-based naming system
whereby the global service class name itself contains
referential QoS Parameter codes.
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
Traffic/Burst Value
Max Latency Value
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SCHEDULING SERVICES
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Std 802.16e-2005 page 183
 Unsolicited Grant Service (UGS)
 Real-Time Polling Service (rtPS)
 Extended Real-Time Polling Service (ertPS)
 Non-Real-Time Polling Service (nrtPS)
 Best Effort ( BE)

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MANDATORY QOS PARAMETERS FOR UGS
Unsolicited Grant Service (UGS)
support real-time uplink service flows that transport
fixed-size data packets on a periodic basis, such as
T1/E1 and Voice over IP without silence suppression
 The BS shall provide Data Grant Burst IEs to the SS at
periodic intervals based upon the Maximum
Sustained Traffic Rate of the service flow.
 The mandatory QoS parameters

maximum sustained traffic rate
 maximum latency
 tolerated jitter
 uplink grant scheduling type
 request/transmission policy
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

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MANDATORY QOS PARAMETERS FOR RTPS
Real-Time Polling Service (rtPS)
support real-time uplink service flows that generate
transport variable size data packets on a periodic basis,
such as MPEG video
 allow the SS to specify the size of the desired
grant(offers real-time,periodic, unicast request
opportunities)
 The mandatory QoS parameters

Minimum reserved traffic rate
 maximum sustained traffic rate
 maximum latency
 uplink grant scheduling type
 request/transmission policy
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

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MANDATORY QOS PARAMETERS FOR
ERTPS
Extended Real-Time Polling Service (ertPS)
scheduling mechanism which builds on the efficiency of
both UGS and rtPS.
 BS shall provide unicast grants in an unsolicited
manner like in UGS, saving the latency of a bandwidth
request
 UGS allocations are fixed in size, ertPS allocations are
dynamic
 The mandatory QoS parameters

Minimum reserved traffic rate
 maximum sustained traffic rate
 maximum latency
 request/transmission policy
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

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MANDATORY QOS PARAMETERS FOR RTPS
Non-Real-Time Polling Service (nrtPS)
support non-real-time uplink service flows that generate
transport variable size data
 The BS shall provide timely unicast request
opportunities, The BS typically polls nrtPS CIDs on an
interval on the order of one second or less
 The mandatory QoS parameters

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
Minimum reserved traffic rate
 maximum sustained traffic rate
 traffic priority
 uplink grant scheduling type
 request/transmission policy

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MANDATORY QOS PARAMETERS FOR BE
Best Effort ( BE)
provide efficient service for best effort traffic in the
uplink
 the Request/Transmission Policy setting shall be set
such that the SS is allowed to use contention request
opportunities

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
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HIDDEN PROBLEM OF SIP
HANDOVER ON WIMAX
Scheduling type of 802.16
SIP is the traffic of BE(Best Erroft)
 RTP is the traffic of UGS/rtPS/ertPS(Unsolicited Grant
Service / Real-Time Polling Service /Extended Real-Time
Polling Service )

The bandwidth request of RTP is not reserved
in a duration of SIP session of call setup(reINVITE), even the SIP session of call setup is
successfully
 Actually the time of RTP transmission has long
delay
 For real time applications is unacceptable
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
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EXAMPLE OF HIDDEN PROBLEM
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BANDWIDTH OF RTP RESERVATION
SIP outbound proxy use re-INVITE to configure
the RTP transmission
 SIP outbound proxy usually has access to the
Session Description Protocol(SDP) information
containing the mobile host media address and
port
 SIP outbound proxy use Application Mobility
Interface(AMI) to negotiate with MAC
 SIP outbound proxy send the RTP bandwidth
request(release) through AMI to MAC

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BANDWIDTH OF RTP RESERVATION
FLOW
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BANDWIDTH OF RTP RELEASE
FLOW
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CONCLUSION
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Propose predictive handover with SIP to reduces
the handover latency
 Provide SIP proxy to fast configure the RTP
transmission
 Challenge

Bandwidth reservation for RTP transmission
 Admission Control(AC) and Bandwidth Allocation(BA)
for mobility network

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REFERENCE

[1].Jared Stein,Survey of IEEE802.21 Media
Independent Handover Services ,
http://www.cs.wustl.edu/~jain/cse574-06/ftp/handover/index.html




[2].Filippo Cacace, Luca Vollero, Managing Mobility and
Adaptation in Upcoming 802.21Enabled Devices
[3].IEEE Standard for Local and metropolitan area
networks
Part 16:Air Interface for Fixed Broadband Wireless
Access Systems, IEEE Std 802.16-2004, 2004.
[4].IEEE Standard for Local and metropolitan area networks
Part 16:Air Interface for Fixed and Mobile Broadband
Wireless Access Systems Amendment 2: Physical and
Medium Access Control Layers for Combined Fixed and
Mobile Operation in
Licensed Bands IEEE Std 802.16e2005
[5]. Wooseong Kim, Kyounghee Lee, Chansu Yu, Ben Lee, Link
Layer Assisted Mobility Support Using SIP for Realtime Multimedia Communications
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REFERENCE
[6]. R.Koodli,Ed,Fast Handoffs for Mobile
IPv6,IETF RFC-4068,July 2005
 [7]. C.Perkins,Ed,IP Mobility Support for
IPv4,IETF RFC-3344,August 2002。
 [8]. Session Initiation Protocol(SIP),IETF RFC3344, June 2002
 [9]. Henning Schulzrinne, Computer Science
Department, Columbia University, New York,
NY 10027,Optimized Fast-Handoff
Schemes for
Application Layer Mobility
Management

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ANNEX A(1) – LINK EVENTS
Back
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ANNEX A(2) – MIH LINK EVENTS
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Back
ANNEX A(3) – MIH AND LINK
COMMANDS
Back
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ANNEX A(4) – INFORMATION
ELEMENT TYPE
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Back
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ANNEX B(1) –TRAFFIC RATE AND
BURST VALUES
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Back
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ANNEX B(2) –MAXIMUM LATENCY
VALUES
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