PolicyBased QoS Management Architecture in an Integrated UMTS and WLAN Environment

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Policy-Based QoS Management Architecture in an
Integrated UMTS and WLAN Environment

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• IEEE Communications Magazine November 2003 p.118

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Outline

• Introduction
• Policy-Based QoS architecture in WLAN Networks
• Policy-Based QoS management in an integrated
  environment (Scenarios)
• Conclusion

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Introduction

• Why integrate WLAN and UMTS network?
• UMTS s bandwidth is not sufficient for public
  wireless broadband service
• WLAN acts as an complementary broadband access in
  hotspots
• What is the benefit for integrating WLAN and UMTS
  network?
• High bandwidth for hotspot and seamless coverage
  for other place

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Introduction (cont.)

• QoS (Quality of Service)
• QoS is an industry-wide initiative to provide
  preferential treatment to certain subsets of
  data, enabling that data to traverse the Internet
  or intranet with higher quality transmission
  service
• Policy-based
• Policy-based management is an administrative
  approach that is used to simplify the management
  of a given endeavor by establishing policies to
  deal with situations that are likely to occur

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Introduction (cont.)

• PDF/PDP (Policy Decision Function/Point)
• MPDF (Master PDF)
• PEP (Policy Enforcement Point)
• COPS (Common Open Policy Service)

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Policy-based QoS architecture in WLAN (cont.)

• Tightly Coupled
• WLAN devices is treated as if they are normal
  UMTS UE (User Equipment)
• PDF can enforce the network-level policies at the
  WR directly
• PDF is reused (WLAN and UMTS)
• No effect on the 3GPP access control and
  billing/charging entities

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Policy-based QoS architecture in WLAN (cont.)

• Loosely Coupled
• WLAN is considered as a peer UMTS network
• Constitutes a distinct policy domain with its own
  PDF (WPDF)
• Standalone WPDF to perform service-level policy
  control for the WLAN domain
• Is not expected to affect the access control and
  billing/charging reference model

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Policy-based QoS architecture in WLAN
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QoS Management in an integrated UMTS and WLAN
environment

• One operator controls the UMTS network and WLANS
• Different UMTS operators share a WLAN
• An independent WLAN is interconnected to a UMTS
  operators network

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Scenario 1 UMTS and WLAN under one operator
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Scenario 1
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Scenario 1 (cont.)

• When encountered a conflict
• WPDF asks the MPDF to resolve the policy conflict
  (by sending QoS parameters)
• MPDF resolves conflicts by creating new
  network-level policies based on the network-wide
  policies
• After resolved the conflict
• MPDF validate new policy with UMTS PDF
• Sends back new policy to WPDF and also writes to
  policy repository

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Scenario 2 A WLAN network shared by multiple
operators
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Scenario 2 (cont.)

• WPDF is a child node in the policy hierarchies of
  operators As and Bs networks
• It is serving two MPDFs that are peers.

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Scenario 2 (cont.)

• It is inevitable that the WPDF will encounter
  conflict policies provided by different MPDFs
• Way of resolving conflicts
• MPDFs soles responsible for negotiating new
  policies that will replace the old policies
• Additional policies known as overriding policies
  are preset in the WPDF and are used to resolve
  the conflicting policies

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The reason why solution 2 is better

• Operators of MPDFs does not have to worry about
  policies in shared WLAN infrastructure
• New WLAN domains can easily be added without
  affecting policies implemented by the individual
  MPDFs

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Scenario 2 (cont.)
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Scenario 2 (cont.)

• When encountered conflicts
• First, WPDF must verify that they do not conflict
  with policies installed by another MPDF
• Second, WPDF asks the MPDF to resolve the
  conflicts by sending QoS parameters

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Scenario 2 (cont.)

• If there is a conflict between QoS parameters and
  policies installed by another MPDF
• WPDF resolve the conflict by applying overriding
  policies (modify QoS parameters)
• Send overriding policies to MPDF
• After MPDF creating new policy
• MPDF validates them with PDF of the UMTS domain
  on the data path of the session

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Scenario 3 Customerss WLAN Interconnected to an
operators UMTS network
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Scenario 3 (cont.)

• This model allows the UMTS operator to provide
  wide-area mobile services to customers that have
  their own WLAN infrastructure
• WPDF in the WLAN domain is a peer of the MPDF in
  the UMTS network
• Network-level policies is determined by service
  level specifications (SLSs)

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Scenario 3 (cont.)

• There are dynamic and static service requirements
• Static service can be directly translated into
  enforceable netowrk level policies
• Dynamic services are dependent on the state of
  the UMTS/WLAN network
• Dynamic services can only be translated into
  network-level policies after negotiating with the
  connecting networks

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Scenario 3 (cont.)
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Scenario 3 (cont.)

• When encounter a network state change
• WLAN send revised SLS parameter encapsulated in
  COPS) to IPA2
• IPA2 check if the requested SLS parameters is
  supportable
• If supportable, return a positive COPS message
• If not supportable, forward SLS parameters to
  IPA3 after translate into network-level policies
  for verification purpose
• If translate failed, return negative COPS
  decision message to WLAN

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Scenario 3 (cont.)

• Continued
• IPA3 will repeat IPA2's action
• If updated SLS parameters can be implemented,
  IPA3 will return a positive COPS message, or it
  will return a negative COPS message to IPA2
• After IPA2 received positive COPS message, it
  will also return a positive COPS message to WLAN

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Scenario 3 (cont.)

• If WPDF receieved a negative COPS message
• Modify SLS parameters and resend it
• Retry until a upper limit

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Conclusion

• Todos
• Standarlize COPS message
• Enhance security of communications channel
  between the interconnected policy entities
• Quicken the process of policy negotiation in
  peering architecture
• Problem
• Depth of the hierarchical architecture affects
  the policy provisioning time in an operator's
  network