Transcript Mobile VPN over WLAN a Teleservice of the UMTS

Mobile VPN over WLAN a Teleservice
of the UMTS
C. F. Grecas, I. S. Venieris
NTUA, July 2006
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VPN’s Structure
VPN
Sector1
VPN
Sector3
VPN
Sector2
Public
Network
VPN
Sectorn
The public nature of the facilities connecting the sectors of
the VPN is not perceived by the users
NTUA, July 2006
3
The Mobile VPN architecture
employing the UMTS’s core
network
WLAN1
WLAN2
SGSN1
SGSN2
SGSN4
SGSN3
WLAN4
WLAN3
NTUA, July 2006
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The WLAN’s basic architecture
Router
RADIUS
server
DS
AP1
AP2
AP3
BSA1
BSA2
BSA3
ESS
•
•
•
•
DS: Distribution System (Ethernet)
AP: Performs the wireless-to-wired bridging function
BSA: Basic Service Area covered by a single AR
ESS: Linkage of two or more BSAs belonging to the same DS
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The UMTS structure
Gr
SGSN
Uu
MN
HLR
Iu
UTRAN
Gc
SGSN
Public
Data
Network
GGSN
Gn
Gi
SGSN
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The protocol stack modification of the
SGSN
To/from UTRAN
GTP-U Relay GTP-U
Iu
GTP-U Relay GTP-U
UDP
UDP
UDP
IP
IP
IP
AAL5
L2
AAL5
ATM
L1
a
Gn
UDP
IP
IP
L2
WL2
ATM
SN L1
SG
m
/ fr o
To
WL1
b
To
/fro
m
Wi
-Fi
LA
N
L2
WL2
L1
WL1
c
For the requirements of the Mobile VPN the SGSN
degenerates into a typical layer 3 router
NTUA, July 2006
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The protocol stack modification of the GGSN
IP
IP
GTP-U
GTP-U
UDP
UDP
IP
IP
L2
L1
Gn
Gi
a
L2
WL2
T
T
WL1 o/fro L1 o/fro
m
m
Wi
SG
-Fi
SN
LA
N
b
Similar “horizontal” extension are made to
the GGSN protocol stack
NTUA, July 2006
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The VPN's subnets connected to the
UMTS Core Network.
ESS1
BSA1
BSA2
BSA3
AP
AP
AP
BSA1
ESS2
BSA2
AP
BSA3
AP
AP
IP Subnet2
IP Subnet1
Router1
RADIUS
server
Router 2
RADIUS
server
SGSN1
SGSN2
Internet
Internet
SGSN4
IP Subnet4
Router 4
RADIUS
server
RADIUS
server
Router 3
IP Subnet3
AP
BSA1
SGSN3
AP
BSA2
ESS4
AP
BSA3
AP
AP
BSA1
BSA2
AP
BSA3
ESS3
Every WLAN section constitutes an ESS
All the MSs are registered as members of every ESS
NTUA, July 2006
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The Location Update mechanism (IP layer)
Router 2
ICMP
ICMP
Router1
SGSN1
SGSN2
ICMP
ICMP
ICMP
SGSN3
ICMP
ICMP
SGSN4
RADIUS
server
Router 4
AP
AP
M
IC
P
AP
Router 3
M
S
Host-specific routes
ICMP packets
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Traffic Handling within the MPVN
ESS1
BSA1
BSA2
BSA3
AP
AP
AP
BSA1
ESS2
BSA2
AP
BSA3
AP
AP
IP Subnet2
IP Subnet1
Router1
RADIUS
server
Router 2
RADIUS
server
SGSN1
SGSN2
Internet
Internet
SGSN4
IP Subnet4
Router 4
RADIUS
server
RADIUS
server
Router 3
IP Subnet3
AP
BSA1
SGSN3
AP
BSA2
ESS4
AP
BSA3
AP
BSA1
AP
BSA2
AP
BSA3
ESS3
Within the same ESS (WLAN resources/techniques)
Between different ESSs (Section Router, PLMN platform )
To and from the public Internet (Section Router)
NTUA, July 2006
Cohabitation with the conventional
UMTS services
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• The coexistence with the rest of the UMTS services is to be
assured by the cell granularity of the UMTS cells
• The system specifications foresee even the employment of
pico-cells in the areas of heavy traffic
• A trade off should be adopted between the UMTS and
WLAN Mobile Station following the QoS guaranteed
NTUA, July 2006