M OBILE IP vs. SIP

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(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

no s

h s

smooth

no s

t t

t

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

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

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 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.)

(33)

Case 2

„

MN and CN are close; distance MN and it’s home network varies. ( t

h

varies.)

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 t

T

2 2

4

3 2 4

2 2

+ +

=

+ +

+

=

+

=

+

=

(34)

Case 3

„

Wireless link delay varies. ( t s , t mc varies.)

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 t

T

2 2

4

3 2 4

2 2

+ +

=

+ +

+

=

+

=

+

=

(35)

Disruption with Shadow Registration

mc f

arp s

shadow sip_inter_

mc

f arp

s

mc hc

h no

f

mc hc

s h no

s f

s shadow

mip_inter_

mc hc

s h no

s f s

t t

t t T

t

t t

t

t t

t t

t

t t

t t t

t t t

T

t t

t t t

t t t

2 2

4

2 : msg INVITE

sending by

CN reinvites

MN

2 : VR and

AAAF local

the in processed is

msg REGISTER

4 : ARP and

P DHC SIP

2

) )

( (

) 2

( 2

) (

: on optimizati route

2 : FA current in

handled is

msg on

registrati s

MN'

2 : connection Internet

of initiation

IP Mobile

+ +

+

=

+

+ +

+ +

=

+ +

− +

+

− +

=

+ +

− +

(36)

The Effect of Shadow Registration

mc f

arp s

sip_inter

mc hc

no f

shadow mip_inter

mc h

arp s

sip_inter

mc hc

no h

mip_inter

t t

t t

T

t t

t t

T

t t

t t

T

t t

t t

T

2 2

4

2

on registrati Shadow

With

2 2

4 3

on Registrati Shadow

Without

_

+ +

+

=

+ +

+

=

+ +

+

=

+ +

+

=

Figure

Updating...

References

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