应用前景分析-

Contents1What

is

IMSThe

Need

for

IMSAnalysis

of

the

Benefits

of

IMSApplications

DevelopmentFixed-to-Mobile

ConvergenceFrom

call

to

SessionImplications

and

ConclusionIMS

is

a

core

network

architecture

based

on

IP

standards2IMS

will

create

much

more

flexibility3Status

of

IMS

Today4

The

IMS

specificationsare

detailed

in

two

standards:

3GPPR4

and

R5.

Both

have

been

ratified

and

products

areavailable

from

a

number

of

vendors.

Despite

the

many

advantages

which

IMS

promises

thereare

still

some

significantquestions

hanging

over

it.

SIP

stacks

are

available

on

a

number

of

devices,

and

arebecomingincreasingly

available,

particularly

in

3G

devices.Carriers

and

vendors

also

claim

that

IMS

can

be

used

to

enable

applications

for

GPRS

devices.Contents5What

is

IMSThe

Need

for

IMSAnalysis

of

the

Benefits

of

IMSApplications

DevelopmentFixed-to-Mobile

ConvergenceFrom

call

to

SessionImplications

and

ConclusionThe

Need

for

IMSQuestionsBenefitsIt

is

less

clear

if

therearealternatives

which

providesimilar

advantages

as

IMSprovides.There

is

also

a

question

overthe

degree

of

cost

efficiencyto

be

gained.VoIP

service

providers

such

asSkype

are

or

could

enablemany

of

the

applications

andbenefits

madepossibleby

IMS.IMS

is

a

way

for

the

operatorsto

retain

control.

By

integratingaccess

and

services,

theoperators

keep

control

of

thecustomer,

and

make

it

moredifficult

for

them

to

simply

usethem

for

network

access.Interoperability

is

also

a

keyIMS

benefit.

Because

it

isbased

on

industry

standards,

itwill

be

much

easier

for

differentcarriers

to

interconnect

andinteroperate,

enabling

theirsubscribers

to

benefit

from

IMSservices.6IMS

Drivers

&

Restraints7The

drivers

and

restraints

for

the

adoption

of

IMS

differ

for

different

types

of

carrier.

Manyofthe

drivers

are

long

term,

while

manyof

the

restraints

are

shorter

term.

Therefore

weexpect

that

the

implementation

of

IMS

will

take

some

time,

but

once

established,

it

willbecome

a

fundamental

part

oftelecommunications

networks.Contents8What

is

IMSThe

Need

for

IMSAnalysis

of

the

Benefits

of

IMSApplications

DevelopmentFixed-to-Mobile

ConvergenceFrom

call

to

SessionImplications

and

ConclusionIMS

and

Applications

Development9IMS

Applications

by

Market

Segment10IMS

and

FMC11The

Importance

of

IMS

and

FMC12Access

networks

and

applications

are

separate,

and

so

all

applicationsare

available

through

all

access

networks.IMS

will

change

the

nature

of

telecommunications.

Instead

of

calls,

sessionswill

be

initiated

which

can

use

different

mediafor

different,

simultaneousservices.

Additional

users

can

be

brought

into

or

join

in

the

session.

Thenature

of

the

session

can

change

from

one

type

of

communication

toanother.13From

Telephone

Call

to

“Device

Session”Combinational

services

will

be

important

for

several

reasons:They

increasethe

value

of

a

session,

and

so

can

induce

higher

charges.

Voice

is

still

and

will

remain

the

major

telecommunications

application.

Enabling

differentapplications

in

addition

will

not

requiresignificant

changes

in

user

behaviour.This

will

be

a

powerful

way

of

introducing

new

services

to

less

advanced

usersThe

Power

of

Combinational

Services14Contents15What

is

IMSThe

Need

for

IMSAnalysis

of

the

Benefits

of

IMSApplications

DevelopmentFixed-to-Mobile

ConvergenceFrom

call

to

SessionImplications

and

ConclusionClearly

the

deployments

of

IMSwillhave

a

number

ofpowerful

implications.One

of

the

major

conclusions

is

the

importance

of

theorganisationalstructureof

the

operator.The

increasing

importance

of

operation

segmentation.Operators

must

also

be