Transcript Quality of Service Provisioning within IMS

Higher Institute of Industry
Postgraduate Department
Quality of Service Provisioning
within IMS-WLAN Interworking
Prepared by:
Asma Abdalla Mustafa Elmangosh
Supervisors:
Dr. Majdi Ali Altomi Ashibani
Dr. Fathi Hamad Ben-Shatwan
Thursday, 12 July 2007
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Outline
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Next Generation Networks.
IP QoS Models.
IP Multimedia Subsystem.
Policy-based Quality of Service in IMS.
Wireless LANs & WLAN-IMS Interworking.
The Proposed QoS Architecture.
Performance Evaluation of Proposed Architecture.
Published Work.
Conclusions.
Further Work.
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The NGN Motivation:
Any where, any time, any device
Integrated
Services
Access
Independent
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Mobility
and QoS
enabled
IP core
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Next Generation Networks (NGN)
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A Next Generation Network (NGN) is a
[ITU]:
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A packet-based network
provide telecommunication services
make use of multiple broadband, QoS-enabled
transport technologies.
service-related functions are independent from
underlying transport-related technologies.
offers unrestricted access by users to different
service providers.
It supports generalized mobility.
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Next Generation Networks (NGN)
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Advantage:
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
Save costs (ONLY one network to handle).
Increase revenues (easy to add more service).
Consequences:

Network operators will be degraded to “bit
pipes”.
IP Multimedia Subsystem
A Global Service Delivery Platform
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NGN Architecture
Application Plane
Open APIs & Protocols (JAIN, Parlay, SIP)
Service Control Plane
PSTN/ISDN emulation
Management
Plane
IP Multimedia Subsystem
Other Multimedia Components
Transport Plane
Access
Functions
Access Transport
Functions
Edge
Functions
Core Transport
Function
Subscriber &
Service
Provisioning,
Network
Management,
Operational
support, Billing
Support
Gateway
Functions
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IP Quality of Service Models
Best Effort Internet
(No QoS)
Signaling: Resources
reservation per flow end-to-end.
The Internet only makes a Best
Effort attempt to deliver packets
Full QoS Network
(IntServ)
Lack of scalability
Simple core /intelligent edges
Differentiated queuing/scheduling
(per class)
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Traffic Classes Network
(DiffServ)
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IP Multimedia Subsystem (IMS)
Standard
by
the
3rd
Generation
Partnership Project (3GPP).
 IMS is a global, access-independent and
standard based IP connectivity and service
control architecture that enables various
types of multimedia services to end-users
using common Internet-based protocols.
 IMS is expected to provide the basic
architecture framework for the NGN.

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IMS Architecture
Application
Servers
Legacy
SCPs
Application
server
Layer
CAMEL, ANSI-41
INAP, TCAP
Non-Telephony
Services
Telephony
Services (TAS)
IM-SSF
Supplemental
Telephony
Services
Parlay API
OSA-GW
SIP-ISC
Session
Control
Layer
CSCF
HSS
DAL, 802.11,
GPRS, CDMA
Transport
&
Endpoint
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Layer 12 July 2007
MRFC
MGCF
Media
Server
Media
Gateway
SIP
PST9
N
IMS Components
The AS provides
value-added
Applications services to
Servers
subscribers.
CSCFs are the IMS entities
responsible of the call control:
there are 3 types of CSCFs
depending on their role:
IMS
• P-CSCF (Proxy CSCF)
• S-CSCF (Serving CSCF)
• I-CSCF (Interrogating CSCF)
Other IP/
IMS
networks
S-CSCF
The PS domain
provides the IP
bearer to access
to the IMS.
HSS
P-CSCF
The HSS holds the
IMS service profile of
the subscribers.
I-CSCF
MGW/
MGCF
PS Domain
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Provides
Legacy /
connectivity
PSTN
to external
CS networks.
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So, Why IMS in NGN?
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IMS provides several of the fundamental
characteristics of the NGN.
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IMS uses IETF standard protocols.
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Open interfaces allow for a wider choice of
suppliers.
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Session Setup
routes the SIP invite to
the called party’s home
domain
Home Network
(Originating)
HSS
Home Network
(Terminating)
HSS
S-CSCF
I-CSCF
HSS acts as a location
server to assist on
locating the S-CSCF
S-CSCF
I-CSCF
P-CSCF routes the SIP
invite to the user’s home
domain (I-CSCF)
I-CSCF proxies
the SIP invite to
the user’s serving
S-CSCF
Visited Network
(Originating)
Visited Network
(Terminating)
P-CSCF
P-CSCF
IPCAN
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S-CSCF potentially
invokes service profile,
but normally forward the
SIP invite to the P-CSCF
Bearer established directly between user
client following successfully signaling
IPCAN
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Policy-based Quality of Service in
IMS
IMS
2) Request for QoS
resources (Service
Information )
P-CSCF
PDF
(Policy Decision
Function)
3) Request for QoS
resources (Authorized
IP QoS parameters)
Resource
Reservation
Data
UE
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Policy decision:
Check QoS request
allowed according to
local policy rules
Policy enforcement
GGSN
PEF (Policy
Enforcement Function)
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Wireless LANs
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Provide LAN functionality
without fixed infrastructure
using
wireless
radio
technology.
WLAN can ONLY be a
complementary technology
to 3G.
Two major WLAN
standards:
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IEEE 802.11: The de facto
WLAN standard worldwide.
HiperLAN.
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MAC
802.11d {International roaming}
802.11e {QoS/efficiency enhancements}
802.11h {5GHz regulatory extensions}
802.11i {Security enhancements}
PHY
802.11a {5GHz OFDM PHY}
802.11b {2.4GHz CCK PHY}
802.11g {2.4GHz OFDM PHY}
IEEE 802.11 standards
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IEEE 802.11e
Required for
Prioritized QoS
services
Required for
parameterized
services
HCF
Contention
Access
HCF
Controlled
Access
(EDCF)
(HCCA)
Hybrid
Coordination
Function
Distributed Coordination Function
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WLAN-3GPP Interworking
Architecture
WLAN
UE
Wg
WLAN Access Network
3GPP AAA
Server
Ww
Wn
WAG
Wo
Wm
OCS
Wz
Wa
Wx
Dw
SLF
Wy
Intranet / Internet
Authentication,
3GPP Authorization
Home Network and
Accounting
HSS
HLR server
• Terminates all AAA
Offline in
signaling
originated
r'
Charging
/ G WLAN that
the
pertains
'
System
D
Wf
to the WLAN UE
Wp
PDG
Wi
WLAN 3GPP IP Access
Wu
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WLAN Access Gateway
• Charging data
generation
• Routing enforcement
Packet Data Gateway
•Charging data
generation,
• IP address management
• Tunnel termination 16
• QoS handling
The Proposed QoS Architecture for
WLAN IMS Access
WLAN
UE
WLAN
AN
WAG
TE
PDG
End-to-End Service
3GPPIP
IP Access
BearerRCF2475
Service
DiffServ
External Bearer
Service
WLAN Bearer
Service
IEEE
802.11e
Remote IP
Remote IP
Tunneling
layer
Tunneling
layer
Transport
IP
Transport
IP
Transport
IP
Transport
IP
Transport
IP
Transport
IP
L2/L1
L2/L1
L2/L1
L2/L1
L2/L1
L2/L1
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Remote IP
L2/L1
L2/L1
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PDG implementation re-using GGSN
functionality
PDG
Tunnel
Termination
Gateway
WLAN UE
WLAN UE
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end-to-end
tunnel
Subset of
GGSN
functions
Gi / Wi
IMS
GTP tunnel
GPRS mobile operators can reuse existing infrastructure
and functionality for a user accessing from a WLAN UE.
By using this existing standardized reference point,
interoperability towards the Gateway GPRS Support Nodes
(GGSN) is assured.
Mapping between E2E IP tunnel and GTP tunnel is required.
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Implementing PDG by reusing
GGSN
UE
P-CSCF
SIP/SDP
Application
PDG
IP BS Manager
WLAN AN
TTG
GGSN
IP BS Manager
IP BS Manager
IP BS Manager
Gq
Go
PDF
PEF
Translation /
Mapping
function
Translation /
Mapping
function
WLAN BS
Manager
WLAN BS
Manager
WLAN QoS
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Translation /
Mapping
function
Translation /
Mapping
function
UMTS BS
Manager
UMTS BS
Manager
DiffServ QoS
PDP context
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QoS mapping between DiffServ PHBs,
UMTS QoS class and EDCA ACs
Costly in term of the required signaling.
 Could cause inconsistency in the delivered
QoS level to the end user.
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Using a stand-alone PDG
UE
SIP/SDP
Application
IP BS Manager
P-CSCF
WLAN AN
PDG
IP BS Manager
IP BS Manager
PEF
Translation /
Mapping
function
Translation /
Mapping
function
WLAN BS
Manager
WLAN BS
Manager
Gq
Go
PDF
DiffServ QoS
WLAN QoS
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QoS mapping between DiffServ PHBs
and EDCA ACs
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This mapping scheme has been evaluated
in our previous work.
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Performance Evaluation
of Proposed Framework
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QoS Parameters
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Delay:
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Jitter:
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Jitter is the variation in delay over time experienced by
consecutive packets that are part of the same flow.
Throughput:
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The delay (or latency) is the amount of time that it takes for a
packet to be transmitted from one point in a network to
another point in the network.
Throughput is the amount of data that can be transferred in a
given amount of time.
Packet Loss Rate:
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Loss rate as a QoS measure determines the maximum number
of packets expected to be lost within a specified transfer time.
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Scenario 1: Evaluation of WLAN
EDCA 802.11e
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Reveals the performance of the legacy 802.11
DCF and the 802.11e EDCA.
Using NS-2 Network Simulation.
0
4
1
5
2
6
AP
7
3
Source Nodes
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Destination
Nodes
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Scenario 1: Evaluation of WLAN
EDCA 802.11e
Legacy DCF 802.11 throughput
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EDCF 802.11e throughput
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Scenario 2: evaluation of WLAN EDCA
802.11e interworking with DiffServ
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Simulation was used to evaluate the proposed
framework and the mapping between the
DiffServ architecture in core network and EDCA
802.11e WLAN.
Core Network
IP router
WLAN UE
Server
Access Point
End-to-End User Bearer Service
RFC 2475 IP DiffServ
IEEE 802.11e
Radio Bearer Service
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Wireline Bearer Service
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Traffic Throughput with CN
background load of 20%
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Traffic Throughput with CN
background load of 70%
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Lack of QoS impact on the voice
throughput.
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Lack of QoS impact on the video
throughput.
Lack of QoS impact on the
background throughput
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Scenario 3: IMS Multimedia Telephony Evaluation
on WLAN-3GPP/IMS Interworking End-to-End
IMS
PDG
PDG
DiffServ Domain
WAG
WAG
IPSec Tunnel
AP1
IPSec Tunnel
AP2
UE
WLAN AN1
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UE
WLAN AN2
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Published work
This thesis has contributed with the following
research papers:
 A. Elmangosh, M. Ashibani, F. Ben-Shatwan, “The
Interworking between EDCA 802.11e and
DiffServ”, IEEE eSCO-Wi 2007 Proceedings of
IEEE IPCCC 2007, New Orleans, Louisiana, USA,
April 2007.
 A. Elmangosh, M. Ashibani, F. Ben-Shatwan,
”Quality of Service Provisioning Issue of
Accessing IP Multimedia Subsystem via Wireless
LANs”, The first International Conference on New
Technologies, Mobility and Security (NTMS) 2007,
Paris, France, May 2007.
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Conclusion
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The (NGN) is foreseen as being an IP-based network that
supports a wide variety of services through fixed-mobile
environment.
This converged environment requires the support of
interworking methods between different QoS technologies,
in order to guarantee end-to-end QoS for multimedia
sessions in heterogeneous networks.
It is expected that the Differentiated Service module
(DiffServ) will become a key QoS assurance mechanism in
the upcoming All-IP NGN.
While multimedia services can be delivered to end-users
without the IMS framework, however the deploy of IMS will
benefits both users and operators
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Conclusion
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The performance evaluation of our proposed interworking
framework between 802.11e WLAN and DiffServ
architecture shows the necessity of providing end-to-end
QoS in heterogeneous networks.
The results show also that 802.11e EDCA is QoS capable to
conform with DiffServ PHBs QoS requirements.
In this work extra functionalities have been introduced to
the existing WLAN QSTAs (packet classification and
conditioning) in order to support DiffServ architecture.

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extra cost and delay to the traffic flows.
could be easily neglected with the high computation terminals
available now-days.
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Further Work
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In our work we considered only the EDCA access method of
the IEEE 802.11e MAC layer because of its expected widely
deployment in the near future. Further work need to be
done considering the HCCA access method.
The IMS was defined as an access-independent platform,
however further work need to be done in this prospect to
study the interworking of IMS with other access networks
such as Wi-MAX and xDSL.
In this work we depend mainly on the simulation method to
evaluate the proposed framework. In further work the same
evaluation can be implemented by using the NGN Test-bed
currently under constructing at the Higher Institute of
Industry.
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Thank you
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