1.0.0

morningbreadloafNetworking and Communications

Oct 30, 2013 (3 years and 11 months ago)

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林振緯

Department of Computer Science & Information Engineering,

Fun Jen Catholic University, Taipei, Taiwan

jwlin@csie.fju.edu.tw

Nov. 12, 2004



網際網路之沿革與趨勢




Outline


Introduction


Wireless LAN


GSM


GPRS


3G


Mobile IP

Networks
Today

IP based
Internet

The WWW

Other
Services

PSTN

Network

MPLS

Network

ATM

Network

Wireless

LAN

Modem, ADSL

Video
Server

Core Networks

(By Dr. Zheng da Wu)

Wireless

Network

Wireless Internet


New area


Diverse mobile devices


Wireless communication networks


Internet


Users can access various services, any time and
any where


Wireless LANs and WANs

LAN

WAN

100 m

2,500 m

Wireless LAN


Replace

the

wired

Ethernet

LANs

in

a

local

area


Provide

access

to

wired

LANs

and

the

Internet


Offer

high

data

rates



Currently,

up

to

54

Mbps


Major Standards for WLAN


HIPERLAN


High Performance Radio LAN


European standard


IEEE 802.11


US standard


Today, it holds the entire market

Two Modes of IEEE 802.11


Infrastructure Mode


Terminals communicate to an access point.



Ad Hoc Mode


Terminals communicate in a peer
-
to
-
peer basis
without any access point.

802.11
-

Infrastructure Mode

AP

AP

Distribution System

Portal

Internet

Wired IEEE
802.x LAN

IEEE 802.11 LAN

Basic Service Set
(BSS)


the
stations and AP
within the same
radio coverage.

BSS
-
1

BSS
-
2

Internetworking

Database for
location
management
and

Roaming

802.11


Ad Hoc mode

Internet

Mobile Ad
-
hoc Networks(MANET)


Ad
-
hoc On
-
demand Distance Vector (AODV)


Dynamic Source Routing (DSR)


A

layer

2

bridge

between

IEEE

802
.
11

and

Ethernet


A

switched

Ethernet

subnet

attached

to

the

layer

2

distributed

network



A

finite

range,

on

the

order

of

500

feet

indoor

and

1000

feet

outdoors


Access Point (AP)

WLAN

terminals

WLAN

terminals

WLAN

Radio interface

AP

AP

L2
distribution
networks

Access

Router

Access

Router

Local

Service

IP

backbone

network

DNS

DHCP

User DB

L2

distribution

network

Other WLAN APs

Billing

System

HTTP

server

Gateway

AAA

Server/Proxy

Interface to
external IP
networks
(Internet)

AAA

roaming

IP interface

WLAN, IP and Internet

Global System for

Mobile Communications (GSM)


Frequency Band


890



915
,

935
-
960

MHz


»
Channel

spacing
:

200

KHz


»
Total

channel

number
:

124


»
Number

of

slots

per

channel
:

8


Multiple

Access


TDMA

and

FDMA


Data services up to 9.6 kbps



Base
Transceiver
Station
(BTS
)

Mobile Service
Switching Center

(
MSC
)

PSTN, ISDN,
PSPDN, CSPDN

Home Location
Register,

(HLR)

Visitor Location
Register (
VLR
)

Mobile station
(
MS
) with smart
card, Subscriber
Identity Module
(
SIM
)

Equipment ID
register (
EIR
) and
Authentication
center (
AuC
)

cellular telephone system

Base Station
Controller (
BSC
)

Base Station
SubSystem

Network SubSystem

ISDN

(Integrated Services Digital Network)

PSTN

(Public Switched Telephone Network)

PSPDN

(Packet Switched Public Data Net.)

CSPDN

(Circuit Switched Public Data Net.)

Architecture of GSM

Mobile Station (MS)


Mobile Equipment


International Mobile Equipment Identity (IMEI)
number


Subscriber Identity Module (SIM)


Personal Identification Number (PIN)


International Mobile Subscriber Identity (IMSI)
number


Enables access to subscribed services


Base Station Subsystem



Base Transceiver Subsystem (BTS)



House the radio transceivers the radio link
protocols with mobile stations


Base Station Controller (BSC)


Manage the radio resources for one or more
BTSs


Handle radio
-
channel set up, frequency
hopping, and handovers

Network Subsystem


Mobile Switching Centre (MSC)


Home Location Register (HLR)


Visitor Location Register (VLR)


Authentication Center (AUC)


Equipment Identity Register (EIR)


Short Message Service (SMS)


Mobile Switching Centre (MSC)


Performs all switching/exchange functions


Handles

»
Registration

»
Authentication

»
Location updating


May connect to other networks

»
Gateway MSC (GMSC)


Home and Visitor Location Registers



Home

Location Register (HLR)


Administrative information for all subscribers

»
IMSI number

»
actual phone number

»
permitted supplementary services

»
current location i.e. which VLR subscriber is currently registered with

»
parameters for authentication and ciphering



One HLR per GSM PLMN


Visitor Location Register (VLR)


Local database for a subset of user data, including data about all user
currently in the domain of the VLR


Selected information from the HLR for all mobiles in MSC area


Often bundled with MSC (VLR domain tied in with MSC coverage)






Generate user specific authentication parameters
on request of a VLR


Authentication parameters used for authentication
of mobile terminals and encryption of user data on
the air interface

Authentication Center (AUC)


Register GSM mobile stations and user rights


Stolen or malfunctioning mobile stations can be
locked

Equipment Identity Register (EIR)

Short Message Service (SMS)


Use

“always

on”

data

channel

(i
.
e
.
,

independent

of

the

voice

traffic

channels)


Operate

independently

and

concurrently

with

voice

operations
.


Transfer

a

message

of

size

up

to

160

characters

to

and

from

the

mobile

station
.


A

SMS

Service

Centre

(SM
-
SC)

serves

as

the

message

switching

centre
.



An

external

short

message

entity

(ESME,

message

entity,)

sends

SMS

message

to

the

SM
-
SC

Short Message Service (SMS)





BTS

BSC

MSC

VLR

HLR

SMS
-
IWMSC

SMS
-
GMSC

PSDN

SM SC

PC

ESMEs

GSM Network Subsystem

SM
-
SC (Short Message Service Center): message switching centre

SMS
-
GMSC (Short Message Service Gateway MSC): SM
-
SC

MSC

IWMSC (Interworking MSC): MSC

SM
-
SC

ESME (external short message entity
): a
data terminal residing on
external network



Improve GSM’s data transmission capacities (Circuit
switching, low data rate 9.6 kbps)



2.5G data service overlaid on an existing GSM network


»
Mobile station uses up to 8 timeslots (channels) for GPRS data
connection from Mobile Station

»
Depending the coding, a transfer rate of up to 150 Kbps is possible,



GPRS provides packet mode transfer for applications with
a selection of QoS parameters for service request;


General Packet Radio Service
(GPRS)

Architecture of GPRS

Mobile Service
Switching Center
(MSC
)

Home Location
Register
, (HLR)

Visitor Location
Register
(VLR)

GPRS Mobile
station (
MS
)

Equipment ID
register
(EIR)

and
Authentication
center
(AuC)

Base Station
Controller
(BSC
)

Serving GPRS support
node,
SGSN

Gateway GPRS support
node
, GGSN

IP and

X.25

GR

GR:

GPRS register,


a part of HRL

GPRS Mobile Station


Three Classes


Class

A

-

simultaneous

circuit

switched

(GSM)

and

packet

switched

(GPRS)

traffic


Class

B
-

supports

both

GSM

and

GPRS

connections

but

not

both

at

the

same

time
.

One

call

is

suspended

for

the

duration

of

the

other


Class

C

-

handless

both

GPRS

or

GSM

but

can

only

be

connected

to

one

at

the

same

time

GPRS Network Subsystem


Two new nodes introduced for packet data



Serving GPRS Support Node (SGSN)

»
monitors GPRS users

»
handles security and access control

»
may be regarded as the packet switched equivalent of the circuit
-
switched MSC



Gateway GPRS Support Node (GGSN)

»
internetworking functionality

»
routes incoming data to correct SGSN

»
translates between different protocols and formats





GPRS

General Packet Radio Service

WWW

GPRS tunnel ON IP

IPSec


Forwards IP from mobile device to Internet or Intranet via
GPRS backbone network


IPSec

Logical link over RAN

Third
-
Generation

Mobile Communication System (3G)


Frequency Band


1885
~

2025
MHz

and

2110
~
2200
MHz


Capable of providing high
-
speed data
transmission


384kbps for mobile; 2Mbps for stationary


Multimedia Service



3G Standards


International Telecommunications Unit (ITU)


Two major 3G systems


Universal Mobile Telecommunications
System

(UMTS)


cdma2000

Gf

Gi

Iu

Gi

Mr

Gi

Ms

Gi

R

Uu

MGW

Gn

Gc

TE

MT

UTRAN

Gr

SGSN

GGSN

EIR

MGCF

R
-
SGW *)

MRF

Multimedia

IP Networks

PSTN/

Legacy/External

Applications &

Services *)

Mm

Mw

Legacy

mobile

signalling

Network

Mc

Cx

Alternative

Access

Network

Mh

CSCF

CSCF

Mg

T
-
SGW *)

T
-
SGW *)

HSS *)

HSS *)

Applications

& Services *)

MSC



server

GMSC server

Mc

Mc

D

C

SCP

CAP

MGW

Nb

Nc

Iu

Iu

R
-
SGW *)

Mh

CAP

CAP

R

Um

TE

MT

BSS/

GERAN

Gb

A

Iu

Circuit
-
Switched

Domain

Packet Domain

Multi
-
Media

Domain

UMTS Reference Model

UMTS
-

UTRA


UMTS Terrestrial Radio Access (UTRA)


Radio Network Subsystem


Air interface

»
W
-
CDMA


Node B

»
equivalent of a BTS


Radio Network Controller

»
supports a number of Node Bs

»
equivalent of a BSC





3G, 2.5G and 2G


GSM/GPRS BTS

UMTS BTS

BSC

MSC

RNC

SGSN

GGSN

Fixed

Telephone

Infrastructure

Packet

Data

Infrastructure


Different radio access
networks on the same core network

cdma2000

Circuit Domain

Radio Network

Packet Domain

BSC

BSC

BSC

RP Interface

BTS

BTS1

BTS1

BTS

BTS1

BTS1

BTS

A Interface

Packet Data

MSC/VLR

HLR

MSC/VLR

GMSC

SS7

IWF

PSTN

Private

IP Network

Public

Internet

Public

Internet

Public

Internet

PDN

AAA

PDSN/FA

IP Network

HA

Mobile IP functionality
-

Foreign agent (FA) and Home agent (HA)

Packet data service node (PDSN)


Equivalent of SSGN in GPRS

Authentication, Authorization, and Accounting (AAA)

Future of Wireless Networks

IP Backbone/

Internet

Multi
-
mode terminal

w/MobileIP client

& IPSec Client

Public

WLAN

802.11 Access
Points

Ethernet

WLAN

Gateway

& FA

802.11 Access Points

Ethernet

WLAN

Gateway,


HA, FA

Home AAA Server

Enterprise

Corporate

LAN

VPN

Firewall

PDSN/FA/HA/Fir
ewall

CDMA WSP

PCF

BS

BS

MSC/RNC

GGSN/FA/HA/

Firewall

GSM/UMTS

WSP

BS

BSC

SGSN

CGF

BS


Mobile devices can
connect to office networks
anytime from anywhere….


Current mobility is based on
single wireless technologies.


Future will allow automatic
configuration for seamless
roaming amongst various
wireless technologies…and,
hence, greater coverage
(ubiquitous).

Mobile IP


A standard proposed to solve the problem of
Internet mobility

1.0.0.1

1.0.0.2

1.0.0.254

3.0.0.254

a

a

a

c

3.0.0.253

3.0.0.252

c

c

2.0.0.253

2.0.0.3

b

2.0.0.4

4.0.0.5

4.0.0.252

b

b

b

b

Host 1

Host 2

Host 3

Host 4

Host 5

Router A

Router B

Router C

A Routing Example: 1.0.0.1


2.0.0.4

Target/Prefix
-
Length

Next Hop

Interface

1.0.0
.0 / 24


direct”

a

0.0.0.0 / 0

1.0.0.254

a

Host 1’s routing table

Ethernet A

Network Prefix = 1.0.0

High
-
Speed Fiber Backbone

Network Prefix = 3.0.0

Ethernet B

Network Prefix = 2.0.0

Ethernet C

Network Prefix = 4.0.0

1.0.0.1

1.0.0.2

1.0.0.254

3.0.0.254

a

a

a

c

3.0.0.253

3.0.0.252

c

c

2.0.0.253

2.0.0.3

b

2.0.0.4

4.0.0.5

4.0.0.252

b

b

b

b

Host 1

Host 2

Host 3

Host 4

Host 5

Router A

Router B

Router C

A Routing Example: 1.0.0.1


2.0.0.4

Target/Prefix
-
Length

Next Hop

Interface

1.0.0
.0 / 24


direct”

a

3.0.0
.0 / 24


direct”

c

2.0.0
.0 / 24

3.0.0.253

c

4.0.0
.0 / 24

3.0.0.252

c

Router A’s routing table

Ethernet A

Network Prefix = 1.0.0

High
-
Speed Fiber Backbone

Network Prefix = 3.0.0

Ethernet B

Network Prefix = 2.0.0

Ethernet C

Network Prefix = 4.0.0

1.0.0.1

1.0.0.2

1.0.0.254

3.0.0.254

a

a

a

c

3.0.0.253

3.0.0.252

c

c

2.0.0.253

2.0.0.3

b

2.0.0.4

4.0.0.5

4.0.0.252

b

b

b

b

Host 1

Host 2

Host 3

Host 4

Host 5

Router A

Router B

Router C

A Routing Example: 1.0.0.1


2.0.0.4

Target/Prefix
-
Length

Next Hop

Interface

1.0.0
.0 / 24

3.0.0.254

c

2.0.0
.0 / 24


direct”

b

3.0.0
.0 / 24


direct”

c

Router B’s routing table

Ethernet A

Network Prefix = 1.0.0

High
-
Speed Fiber Backbone

Network Prefix = 3.0.0

Ethernet B

Network Prefix = 2.0.0

Ethernet C

Network Prefix = 4.0.0

1.0.0.1

1.0.0.2

1.0.0.254

3.0.0.254

a

a

a

c

3.0.0.253

3.0.0.252

c

c

2.0.0.253

2.0.0.3

b

2.0.0.4

4.0.0.5

4.0.0.252

b

b

b

b

Host 1

Host 2

Host 3

Host 4

Host 5

Router A

Router B

Router C

A Routing Example: 1.0.0.1


2.0.0.4

Target/Prefix
-
Length

Next Hop

Interface

1.0.0
.0 / 24

3.0.0.254

c

2.0.0
.0 / 24


direct”

b

3.0.0
.0 / 24


direct”

c

Router B’s routing table

Ethernet A

Network Prefix = 1.0.0

High
-
Speed Fiber Backbone

Network Prefix = 3.0.0

Ethernet B

Network Prefix = 2.0.0

Ethernet C

Network Prefix = 4.0.0

?

Mobility Solution


Use two IP addresses:


a fixed home address


a care
-
of address that changes at each new point
of attachment


Entities and Relationships

Home Link


the
link having the
same network
prefix as the
node’s IP address

Mobile Node
“at home”

Home Agent


a
router on the
mobile node’s
home link.

Foreign
Agent

Foreign
Agent

Foreign Link

Foreign Link

Mobile Node
“visiting” a
foreign link

Care
-
of Address


Two conceptual types of care
-
of addresses


Foreign agent care
-
of address

»
IP address of the foreign agent


Collocated care
-
of address

»
An IP address temporarily assigned to a mobile node
.


Three Mechanisms


Agent Discovery


Registration


Routing

Agent Discovery


Periodically broadcasts Agent Advertisements


Move Detection


Fails to hear an advertisement from that agent
within the specified Lifetime


Assign a foreign agent or collocated care
-
of
-
address


Registration


Inform its home agent of its current care
-
of
address


Deregister when it returns to its home link

Registering Care
-
of Address

Foreign
Agent

Home
Agent

1

2

3

4

The mobile node, with the assistance of a foreign agent, sends
a Registration Request with the care
-
of address information.

When the home agent receives this request, it adds the
necessary information to its routing table, and sends a
Registration Reply back to the mobile node.

Mobile Node
“visiting” a
foreign link

Deregistration

Home
Agent

1. (de
-
)Registration Request

Mobile Node
returns to
its home link

2. (de
-
)Registration Reply

Routing

Different Scenarios


Mobile Node


Correspondent Node


Correspondent Node → Mobile Node

How to Send Packets to a
Correspondent Node?

Foreign
Agent

Home
Agent

Correspondent

Mobile
Node

Simply use the
Correspondent’s IP
address as the
destination address.

How to Send Packets to a
Mobile Node?

Foreign
Agent

Home
Agent

Correspondent

Mobile
Node

Source
address

Correspondent’s IP
address

Destination
address

Mobile’s IP address

Tunneling to the Care
-
of Address

Foreign
Agent

Home
Agent

Mobile Node
“visiting” a
foreign link

Tunnel

Home Agent intercepts packets destined to the mobile node’s
home address and tunnels them to the mobile node’s care
-
of
address.

Foreign Agent removes original packet from the tunnel
and delivers the original packet to the mobile node over
the foreign link.

IP in IP Encapsulation

Header

Payload

Original IP
packet

Ipsrc = Original Sender


Ipdes = Destination’s Home Address

Outer
Header

Outer Payload

Ipsrc = Home Agent


Ipdes = Mobile node’s Care
-
of Address

Encapsulating
IP packet

Header

Payload

The home agent inserts a new IP header, or tunnel header, in
front of the IP header of any datagram addressed to the mobile
node’s home address.

Triangle Routing

Mobile Node
“visiting” a
foreign link

Foreign
Agent

Home
Agent

Correspondent

Why doesn’t the mobile node
inform the correspondent of
its care
-
of address and have it
tunnel directly to the mobile
node?

Mobile IPv6


No Foreign Agent


Route Optimization


Use both tunneling and source routing to
deliver packets to mobile nodes.


No Foreign Agent


Enormous address space


Address size from 32 to 128 bits


Collocated care
-
of address

Routing in Mobile IPv6

Mobile Node
“visiting” a
foreign link

Home
Agent

Correspondent which
does not know the
care
-
of address

Correspondent which
knows the care
-
of
address

Source Routing

Tunneling

Source
-
Routed Packet

Conclusion


Wireless LAN


Wireless WAN


Mobile IP


Thank you for your attention



林振緯

jwlin@csie.fju.edu.tw