Transcript 1.0.0

網際網路之沿革與趨勢
林振緯
Department of Computer Science & Information Engineering,
Fun Jen Catholic University, Taipei, Taiwan
[email protected]
Nov. 12, 2004
Outline
Introduction
 Wireless LAN
 GSM
 GPRS
 3G
 Mobile IP

Networks
Today
Core Networks
The WWW
IP based
Internet
LAN
Modem, ADSL
PSTN
Wireless
MPLS
ATM
Network
Network
Network
Network
Other
Services
Wireless
Video
Server
(By Dr. Zheng da Wu)
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
100 m
LAN
2,500 m
WAN
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
IEEE 802.11 LAN
BSS-2
BSS-1
Basic Service Set
(BSS) – the
stations and AP
within the same
radio coverage.
AP
AP
Distribution System
Database for
location
management
and Roaming
Portal
Internet
Internetworking
Wired IEEE
802.x LAN
802.11 – Ad Hoc mode
Internet
Mobile Ad-hoc Networks(MANET)


Ad-hoc On-demand Distance Vector (AODV)
Dynamic Source Routing (DSR)
Access Point (AP)



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
WLAN, IP and Internet
Other WLAN APs
User DB
L2
distribution
network
Access
Router
WLAN
terminals
AP
WLAN
terminals
AAA
roaming
L2
distribution
networks
Local
Service
AAA
Server/Proxy
IP
backbone
network
HTTP
server
Access
Router
AP
WLAN
Radio interface
Billing
System
IP interface
Gateway
DNS
DHCP
Interface to
external IP
networks
(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 Station
SubSystem
Architecture of GSM
Base
Transceiver
Station (BTS)
cellular telephone system
Base Station
Controller (BSC)
Network SubSystem
Mobile station
(MS) with smart
card, Subscriber
Identity Module
(SIM)
Mobile Service
Switching Center
(MSC)
Home Location
Register, (HLR)
PSTN, ISDN,
PSPDN, CSPDN
ISDN (Integrated Services Digital Network)
PSTN (Public Switched Telephone Network)
PSPDN (Packet Switched Public Data Net.)
CSPDN (Circuit Switched Public Data Net.)
Visitor Location
Register (VLR)
Equipment ID
register (EIR) and
Authentication
center (AuC)
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)
Authentication Center (AUC)
– 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
Equipment Identity Register (EIR)
– Register GSM mobile stations and user rights
– Stolen or malfunctioning mobile stations can be
locked
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)
GSM Network Subsystem
SMS-GMSC
PSDN
SM SC
BTS
BSC
SMS-IWMSC
MSC
VLR
PC
ESMEs
HLR
SM-SC (Short Message Service Center): message switching centre
SMS-GMSC (Short Message Service Gateway MSC): SMSCMSC
IWMSC (Interworking MSC): MSCSM-SC
ESME (external short message entity): a data terminal residing on
external network
General Packet Radio Service
(GPRS)
– 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;
Architecture of GPRS
GPRS Mobile
station (MS)
IP and
X.25
Gateway GPRS support
node, GGSN
Serving GPRS support
node, SGSN
Base Station
Controller (BSC)
Mobile Service
Switching Center
Home Location
(MSC)
Register, (HLR)
GR
GR: GPRS register,
a part of HRL
Visitor Location
Register (VLR)
Equipment ID
register (EIR) and
Authentication
center (AuC)
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 circuitswitched 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

Forwards IP from mobile device to Internet or Intranet via
GPRS backbone network
IPSec
WWW
GPRS tunnel ON IP
Logical link over RAN
IPSec
Third-Generation
Mobile Communication System (3G)

Frequency Band
– 1885~ 2025MHz and 2110~2200MHz
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

UMTS Reference Model
Alternative
Access
Network
Legacy mobile
signallingNetwork
Applications &
Services *)
SCP
Mh
CAP
Packet Domain
TE
MT
R
Um
Iu
TE
UTRAN
MT
R
Uu
Gf
Gb
CSCF
Mr
Gi
EIR
BSS/
Iu
GERAN
Mm
Cx
HSS *)
Gr
Mg
MRF
Gi
Gc
Gi
MGCF
GGSN
SGSN
A
T-SGW *)
Mc
Gi
Gn
Iu
MGW
MGW
Nb
Iu
Multimedia
IP Networks
CSCF
R-SGW *)
Mw
Ms
Mc
PSTN/
Legacy/External
Mc
Nc
MSC server
Circuit-Switched
Domain
CAP
Applications
& Services *)
CAP
GMSC server
D
C
HSS *)
R-SGW *)
Mh
T-SGW *)
Multi-Media
Domain
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
BSC
RNC
MSC
SGSN
GGSN
UMTS BTS
Fixed
Telephone
Infrastructure
Packet
Data
Infrastructure
Different radio access networks on the same core network
cdma2000
Radio Network
SS7
BTS
BTS1
HLR
MSC/VLR
BSC
PSTN
GMSC
MSC/VLR
BTS
BTS1
Circuit Domain
IWF
BSC
Packet Domain
A Interface
BTS
IP Network
Public
PDN
Internet
RP Interface PDSN/FA
Packet Data
BSC
HA
AAA
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)
Private
IP Network
Future of Wireless Networks
• 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).
Enterprise
Home AAA Server
WLAN
Gateway,
HA, FA
Corporate LAN
Ethernet
VPN
Firewall
802.11 Access Points
IP Backbone/
Internet
GSM/UMTS
WSP
CDMA WSP
PDSN/FA/HA/Fir
ewall
WLAN
PCF
Public
WLAN
Gateway
& FA
GGSN/FA/HA/
Firewall
SGSN
Ethernet
MSC/RNC
BSC
BS
BS
Mobile devices can
connect to office networks
anytime from anywhere….
BS
802.11 Access
Points
Multi-mode terminal
w/MobileIP client
& IPSec Client
CGF
BS
Mobile IP

A standard proposed to solve the problem of
Internet mobility
A Routing Example: 1.0.0.1  2.0.0.4
Ethernet B
Network Prefix = 2.0.0
Ethernet A
High-Speed Fiber Backbone
Network Prefix = 1.0.0
Network Prefix = 3.0.0
Host 1
Router B
Host 2
3.0.0.253
a
Router A
a
1.0.0.1
c
Host 3
b
2.0.0.4
2.0.0.253
Host 5
1.0.0.2
1.0.0.254
b
b
2.0.0.3
c
a
Host 4
3.0.0.254
c
3.0.0.252
Router C
Host 1’s routing table
b
b
4.0.0.5
4.0.0.252
Target/Prefix-Length
Next Hop
Interface
1.0.0.0 / 24
“direct”
a
Ethernet C
0.0.0.0 / 0
1.0.0.254
a
Network Prefix = 4.0.0
A Routing Example: 1.0.0.1  2.0.0.4
Ethernet B
Network Prefix = 2.0.0
Ethernet A
High-Speed Fiber Backbone
Network Prefix = 1.0.0
Network Prefix = 3.0.0
Host 1
Router B
Host 2
3.0.0.253
a
a
1.0.0.1
Router A
c
Host 3
b
2.0.0.4
2.0.0.253
Host 5
1.0.0.2
1.0.0.254
Router A’s routing table
b
b
2.0.0.3
c
a
Host 4
3.0.0.254
c
3.0.0.252
Router C
b
b
4.0.0.5
Target/Prefix-Length
Next Hop
Interface
1.0.0.0 / 24
“direct”
a
3.0.0.0 / 24
“direct”
c
Ethernet C
2.0.0.0 / 24
3.0.0.253
c
Network Prefix = 4.0.0
4.0.0.0 / 24
3.0.0.252
c
4.0.0.252
A Routing Example: 1.0.0.1  2.0.0.4
Ethernet B
Network Prefix = 2.0.0
Ethernet A
High-Speed Fiber Backbone
Network Prefix = 1.0.0
Network Prefix = 3.0.0
Host 1
Router B
Host 2
3.0.0.253
a
Router A
a
1.0.0.1
c
Host 3
b
2.0.0.4
2.0.0.253
Host 5
1.0.0.2
1.0.0.254
b
b
2.0.0.3
c
a
Host 4
3.0.0.254
Router B’s routing table
c
3.0.0.252
Router C
b
b
4.0.0.5
Target/Prefix-Length
Next Hop
Interface
1.0.0.0 / 24
3.0.0.254
c
2.0.0.0 / 24
“direct”
b
Ethernet C
3.0.0.0 / 24
“direct”
c
Network Prefix = 4.0.0
4.0.0.252
A Routing Example: 1.0.0.1  2.0.0.4
Ethernet B
Network Prefix = 2.0.0
Ethernet A
High-Speed Fiber Backbone
Network Prefix = 1.0.0
Network Prefix = 3.0.0
Host 1
Router B
Host 2
3.0.0.253
a
Router A
a
1.0.0.1
c
Host 3
?
b
2.0.0.3
2.0.0.253
c
a
1.0.0.2
1.0.0.254
3.0.0.254
Router B’s routing table
c
3.0.0.252
Router C
b
b
Host 5
Host 4
b
b
4.0.0.5
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
Ethernet C
3.0.0.0 / 24
“direct”
c
Network Prefix = 4.0.0
4.0.0.252
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
Mobile Node
“visiting” a
foreign link
Mobile Node
“at home”
Foreign
Agent
Home Link – the
link having the
same network
prefix as the
node’s IP address
Home Agent – a
router on the
mobile node’s
home link.
Foreign
Agent
Foreign Link
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-ofaddress
Registration
Inform its home agent of its current care-of
address
 Deregister when it returns to its home link

Registering Care-of Address
The mobile node, with the assistance of a foreign agent, sends
a Registration Request with the care-of address information.
Mobile Node
“visiting” a
foreign link
2
1
4
Foreign
Agent
Home
Agent
3
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.
Deregistration
1. (de-)Registration Request
Home
Agent
2. (de-)Registration Reply
Mobile Node
returns to
its home link
Routing
Different Scenarios
 Mobile Node → Correspondent Node
 Correspondent Node → Mobile Node
How to Send Packets to a
Correspondent Node?
Mobile
Node
Foreign
Agent
Simply use the
Correspondent’s IP
address as the
destination address.
Home
Agent
Correspondent
How to Send Packets to a
Mobile Node?
Mobile
Node
Foreign
Agent
Source
address
Correspondent’s IP
address
Destination
address
Mobile’s IP address
Home
Agent
Correspondent
Tunneling to the Care-of Address
Home Agent intercepts packets destined to the mobile node’s
home address and tunnels them to the mobile node’s care-of
address.
Mobile Node
“visiting” a
foreign link
Foreign
Agent
Tunnel
Home
Agent
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
Ipsrc = Original Sender
Ipdes = Destination’s Home Address
Header
Payload
Original IP
packet
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.
Ipsrc = Home Agent
Ipdes = Mobile node’s Care-of Address
Outer
Payload
Header
Header
Outer Payload
Encapsulating
IP packet
Triangle Routing
Mobile Node
“visiting” a
foreign link
Foreign
Agent
Why doesn’t the mobile node
inform the correspondent of
its care-of address and have it
tunnel directly to the mobile
node?
Home
Agent
Correspondent
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
Correspondent which
knows the care-of
address
Mobile Node
“visiting” a
foreign link
Source Routing
Tunneling
Home
Agent
Correspondent which
does not know the
care-of address
Source-Routed Packet
Conclusion
Wireless LAN
 Wireless WAN
 Mobile IP

Thank you for your attention
林振緯
[email protected]