M OBILE IP vs. SIP

(1)

M ^OBILITY M ANAGEMENT FOR

VoIP S ^ERVICE :

M ^OBILE IP vs. SIP

Ted Taekyoung Kwon, Mario Gerla, Sajal Das, Subir Das IEEE Wireless Communications‧October 2002

B91902004 資訊系三年級許雅婷 B91902005 資訊系三年級奚光瑩 B91902035 資訊系三年級林彥涵

(2)

Outline

Introduction

Network Layer Solution: Mobile IP

Application Layer Approach: SIP

Shadow Registration

Delay / Disruption Analysis

Conclusion

(3)

Introduction (1/4)

Wireless technologies convergence

way to support seamless mobility to mobile nodes

Emergence of VoIP service and growth

the amount of disruption time to process

the handoff of an ongoing VoIP call (or

session)

(4)

Introduction (2/4)

Three types of mobility

Roaming － in absence of the Internet connectivity

Macromobility － from one administrative domain to another

Micromobility － inside a given domain

Mobility management framework

Two basic approaches to support mobility in VoIP services

Network layer － Mobile IP

Application layer － H.323 and SIP

(5)

Introduction (3/4)

Authentication, Authorization, Accounting (AAA)

user moves into the visited network

user initiates Internet connectivity in the home network

Problem: the mobile node should resolve the AAA issue whenever it hands off

between different administration domains

(6)

Introduction (4/4)

Minimize delay/disruption in dealing with macromobility and micromobility

noticeable disruption during a voice conversation make VoIP service users unhappy

Shadow registration

Reduce the time to process interdomain handoff

Establish a registration status in the neighboring

administrative domains a priori anticipating possible handoffs when the user registers in the given

wireless/mobile network

(7)

Network layer solution:

Mobile IP (1/3)

Mobile IPv4 Overview

Home address

A mobile node (MN) is reachable by its invariant home address when it stays connected in its home network

Care-of-address (CoA)

Only valid for the time the MN stay connected to a foreign network

Two mobility agent

The foreign agent (FA) and the home agent (HA)

Registration: whenever the MN obtains the CoA from the FA, it must inform its HA of the obtained CoA

Tunneling: After registration, the HA can forward the packets to the FA

(8)

Network Layer Solution:

Mobile IP (2/3)

Basic working of Mobile IP

Packets from the correspondent node (CN) to the MN are first captured by the HA and tunneled to the MN, while the MN sends packets to the CN directly.

Optimization － Mobility binding

Allows the CN to encapsulate packets directly to the current CoA of the MN

CN maintains a binding cache to store the mobility bindings for one or more MNs

The Binding Update message is used for the HA to inform the CN that the MN has changed its CoA

(9)

Network Layer Solution:

Mobile IP (3/3)

Optimization－Mobility binding (cont.)

Binding Warning message: sent by FA to inform HA of the MN and retunnel the packet to the CoA in the cache entry when the FA receives a tunneled packet for an MN that is not in its visitor list.

If the FA has no binding cache entry for that MN?

The FA sends the packet to the home addr of the MN and the packet will be trapped by the HA -> current CoA of the MN.

Smooth Handoff

: the old FA and the new FA exchange the

Binding Update/Acknowledgment

message when the MN obtains a new CoA.

(10)

Regional Registration

Regional registration

When a MN first arrives at a visited domain, it performs a registration with its HA.

The home network of the MN generates a

registration key and distributes it to the MN and visited domain.

The CoA will not change when the MN changes FA under the same GFA (gateway foreign agent)

Two new message types: Regional Registration

Request and Regional Registration Reply

(11)

The entities of

Mobile IP-based approach

RFA (regional foreign agent): the local FA that accommodates the MN in the subnet

AAAF (the AAA server in the foreign network)

AAAH (the AAA server in the home network)

(12)

Message flow

—initial registration

Message flow for initial registration at a foreign network

• MN: mobile node

• RFA: regional foreign agent

• GFA: gateway foreign agent

• AAAF: AAA server in foreign network

• AAAH: AAA server in home network

• HA: home agent

• AMR: AA-Mobile-Node-Request

• HAR: home agent request

• HAA: home agent answer

• AMA: AA-Mobile-Node-Answer

(13)

Message flow

— intradomain handoff

Message flow in the intradomain handoff

When the MN changes the point of attachment between FAs, it sends the

Registration Request

message to the new RFA (NFA)

When the NFA receives this message, it modifies the message into the

Regional Registration Request

message

The NFA sends the

Binding Update

message to the old RFA (OFA)

The OFA replies with

Binding Acknowledgment

message to confirm the update of binding cache entry on the MN

The

Binding Update

message to the CN is not necessary

The addr of GFA is registered in the HA of the MN

(14)

Message flow

— interdomain handoff

MN is authenticated Diameter-compliant messages that contains Binding

Update/Acknowledgment information

Normal Binding

Update/Acknowledgment messages

Binding Warning message Binding Update message AAAO: the AAA server of the old foreign network to which the OFA belongs

AAAF: the AAA server of the new foreign network to which the NFA belongs

(15)

Application Layer Approach:

SIP(1/4)

SIP overview

Establish and tear down multimedia sessions, both unicast and multicast

SIP user agent

Listen to incoming SIP messages

Send SIP messages

SIP redirect server

Return location of the host

(16)

Application Layer Approach:

SIP(2/4)

SIP overview

SIP proxy server

Use domain name to find a user

Hide the location of the user

Message exchange delay is shorter

Handle firewall and network address translation

(NAT)

(17)

Application Layer Approach:

SIP(3/4)

SIP architecture

Visit registrar (VR)

Home registrar (HR)

MN : user agent client

(18)

Application Layer Approach:

SIP(4/4)

Personal mobility

Maintain connectivity during SIP session

Fast handoff : RTP translator

(19)

SIP Message Flow(1/3)

Acquire IP address:

1.

MN broadcasts DHCP_DISCOVER

2.

Several DHCP server offer IP address via DHCP_OFFER

3.

MN select one server DHCP_REQUEST

4.

DHCP server sends DHCP_ACK

(20)

SIP Message Flow(2/3)

SIP registration :

MN : mobile node VR : visited registrar HR : home registrar AAAF: AAA server in foreign network

AAAH: AAA server in home network HR :

(21)

SIP Message Flow(3/3)

Signaling message flow

Micromobility

No need to verify the user’s credentials via AAA server

MN sends SIP-REGISTER message with new address

VR update its list

Macromobility

Same as SIP registration

(22)

Shadow Registration

— Mobile IP case

The AAAF appends the information about all of its neighboring AAA servers to the AMR message

AAAH checks out which neighboring AAA servers are available to the MN and sends the AMA message to those AAA servers for

shadow Registration

Signaling message flows for the interdomain handoff in the presence of the Shadow

Registration

(23)

Shadow Registration

— SIP case

SIP interdomain handoff with Shadow Registration :

Add one more message :

ANSWER from AAAH to AAAFn for Shadow Registration

AAAFn :

relevant neighboring AAA servers

(24)

Delay/Disruption Analysis

Assumption:

Simple VoIP

application (SVA) with SIP operates on top of Mobile IP.

Home address of CN is cached in MN’s SVA.

(SVA is mobility- unaware)

CN and network home

s MN' between delay

:

CN and MN between delay

:

general In

network home

to message send

to time :

network foreign

over message

send to time :

link wireless via

time :

hc mc

h f s h

f s

t t

t t t t

t t

<

(25)

Initial Registration and Session Setup (Mobile IP)

MN: mobile node

RFA: regional foereign agent GFA: gateway foreign agent AAAF: AAA of foreign network AAAH: AAA of home network HA: home agent

mc h

s init

mip

mc

h s

t t

t T

t

t t

2 2

2

2 : CN to INVITE sends

SVA

2 : (HA) network

home on to

registrati

2 : connection Internet

of initiation

_ = + +

(26)

Initial Registration and Session Setup (SIP)

MN: mobile node VR: visited registrar

AAAF: AAA of foreign network AAAH: AAA of home network HR: home registrar

mc h

arp s init sip

mc

h arp

s

t t t

t T

t

t t

t

2 2 4

2 : CN with ent establishm call

SIP

2 : (HR) network

home s

MN' to REGISTER SIP

: addresses duplicate

detects ARP

4 : n interactio message

DHCP

_ = + + +

(27)

Intradomain Handoff

f arp

s sip_intra

f arp s

f s

mip_intra

f s

t t

t T

t t t

t t

T

t t

2 4

2 : VR to

REGISTER sends

MN

: addresses duplicate

detects ARP

4 : n interactio DHCP

: SIP

2 2

2 : handoff n

intradomai in

on registrati

2 : connection Internet

of initiation

: IP Mobile

+ +

=

+

=

(28)

Interdomain Handoff (Mobile IP)

Two signaling flow (almost parallel):

Smooth handoff

Route optimization

MN: mobile node NFA: new RFA OFA: old RFA

GFA: gateway foreign agent AAAF: AAA of foreign network AAAH: AAA of home network AAAO: AAA of old foreign network

HA: home agent

CN: correspondent node

OFA and NFA between time

:

: OFA to

msg sends

NFA

2 : HA from

msg catches

NFA

2 : connection Internet

of initiation

tno

no

s h

s

t

t t

t

−

(29)

Interdomain Handoff

(Mobile IP)

MN: mobile node NFA: new RFA OFA: old RFA

GFA: gateway foreign agent AAAF: AAA of foreign network AAAH: AAA of home network AAAO: AAA of old foreign network

HA: home agent

CN: correspondent node

mc hc

h no

mip_inter

t t t t

T = + 3 + +

no h

s

no s

h s

smooth

no s

t t

t

t t t

T

t t

2 2

2

) (

) 2

( 2

: MN to

packets forwards

OFA

Handoff Smooth

+ +

=

+ +

+

− +

=

+

mc hc h no

mc hc s

h no s

h s

route

mc hc

s h

t t t t

t t t t t

t t t

T

t t

+ + +

=

+ +

− + +

− +

=

−

3

) (

) 2

( 2

: NFA via

MN to packets sends

CN

: CN to msg sends HA

: HA to msg sends OFA

on Optimizati Route

(30)

Interdomain Handoff (SIP)

mc h

arp s

sip_inter

mc h

arp s

t t

T

t t

2 2

4 2 : INVITE sending

by CN

reinvites MN

2 : HR to

REGISTER sends

MN

: addresses duplicate

detects ARP

4 : n interactio DHCP

+ +

+

=

(31)

Numerical Results

Assumption:

Delay in the wired foreign network is relatively short in comparison with wireless link.

MN, CN are connected to the Internet via wireless link.

Processing time in each entity is negligible.

t

^arp is negligible.

Three cases:

MN in it’s home network; distance between MN and CN varies.

MN and CN are close; distance MN and it’s home network varies.

Wireless link delay varies.

(32)

In MIP interdomain handoff, the forwarding of data between OFA to MN via NFA (smooth handoff) can make better performance than that in SIP interdomain handoff case.

Case 1

mc h

s sip_inter

mc hc

h no

mip_inter

f s

sip_intra

f s

mip_intra

t t

t T

t t

T

t t

T

t t

T

2 2

4 3 2 4

2 2

+ +

=

+ +

+

=

+

=

+

=

►

►MN in itMN in it’s home network; distance between MN and CN varies. (’s home network; distance between MN and CN varies. (ttmcmc varies.)varies.)

M OBILE IP vs. SIP

M OBILITY M ANAGEMENT FOR

VoIP S ERVICE :

M OBILE IP vs. SIP

Outline

Introduction

Network Layer Solution: Mobile IP

Application Layer Approach: SIP

Shadow Registration

Delay / Disruption Analysis

Conclusion

Introduction (1/4)

 Wireless technologies convergence

way to support seamless mobility to mobile nodes

 Emergence of VoIP service and growth

the amount of disruption time to process

the handoff of an ongoing VoIP call (or

session)

Introduction (2/4)

Three types of mobility

Mobility management framework

Two basic approaches to support mobility in VoIP services

Network layer － Mobile IP

Application layer － H.323 and SIP

Introduction (3/4)

Authentication, Authorization, Accounting (AAA)

user moves into the visited network

user initiates Internet connectivity in the home network

Problem: the mobile node should resolve the AAA issue whenever it hands off

between different administration domains

Introduction (4/4)

Minimize delay/disruption in dealing with macromobility and micromobility

Shadow registration

Reduce the time to process interdomain handoff

Establish a registration status in the neighboring

administrative domains a priori anticipating possible handoffs when the user registers in the given

wireless/mobile network

Network layer solution:

Mobile IP (1/3)

Mobile IPv4 Overview

Home address

Care-of-address (CoA)

Two mobility agent

Network Layer Solution:

Mobile IP (2/3)

Basic working of Mobile IP

Network Layer Solution:

Mobile IP (3/3)

Optimization－Mobility binding (cont.)

Smooth Handoff

Binding Update/Acknowledgment

Regional Registration

Regional registration

When a MN first arrives at a visited domain, it performs a registration with its HA.

The home network of the MN generates a

registration key and distributes it to the MN and visited domain.

The CoA will not change when the MN changes FA under the same GFA (gateway foreign agent)

Two new message types: Regional Registration

Request and Regional Registration Reply

The entities of

Mobile IP-based approach

Message flow

—initial registration

Message flow for initial registration at a foreign network

Message flow

— intradomain handoff

Message flow in the intradomain handoff

Registration Request

Regional Registration Request

Binding Update

Binding Acknowledgment

Binding Update

Message flow

— interdomain handoff

Application Layer Approach:

SIP(1/4)

SIP overview

Establish and tear down multimedia sessions, both unicast and multicast

SIP user agent

Listen to incoming SIP messages

M ^OBILITY M ANAGEMENT FOR

VoIP S ^ERVICE :

M ^OBILE IP vs. SIP

Wireless technologies convergence

Emergence of VoIP service and growth