Policy-Based QoS Management Architecture in an Integrated UMTS and WLAN Environment 莊勝超 洪志宗 張永伸 蘇芳生 IEEE Communications Magazine November 2003 p.118

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

Introduction Why integrate WLAN and UMTS network? 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? What is the benefit for integrating WLAN and UMTS network? –High bandwidth for hotspot and seamless coverage for other place

Introduction (cont.) QoS (Quality of Service) 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 –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

Introduction (cont.) PDF/PDP (Policy Decision Function/Point) PDF/PDP (Policy Decision Function/Point) –MPDF (Master PDF) PEP (Policy Enforcement Point) PEP (Policy Enforcement Point) COPS (Common Open Policy Service) COPS (Common Open Policy Service)

Policy-based QoS architecture in WLAN (cont.) Tightly Coupled 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

Policy-based QoS architecture in WLAN (cont.) Loosely Coupled 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

Policy-based QoS architecture in WLAN

QoS Management in an integrated UMTS and WLAN environment One operator controls the UMTS network and WLANS One operator controls the UMTS network and WLANS Different UMTS operators share a WLAN Different UMTS operators share a WLAN An independent WLAN is interconnected to a UMTS operator ’ s network An independent WLAN is interconnected to a UMTS operator ’ s network

Scenario 1: UMTS and WLAN under one operator

Scenario 1

Scenario 1 (cont.) When encountered a conflict 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 After resolved the conflict –MPDF validate new policy with UMTS ’ PDF –Sends back new policy to WPDF and also writes to policy repository

Scenario 2: A WLAN network shared by multiple operators

Scenario 2 (cont.) WPDF is a child node in the policy hierarchies of operators A ’ s and B ’ s networks WPDF is a child node in the policy hierarchies of operators A ’ s and B ’ s networks It is serving two MPDFs that are peers. It is serving two MPDFs that are peers.

Scenario 2 (cont.) It is inevitable that the WPDF will encounter conflict policies provided by different MPDFs It is inevitable that the WPDF will encounter conflict policies provided by different MPDFs Way of resolving conflicts 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

The reason why solution 2 is better Operators of MPDFs does not have to worry about policies in shared WLAN infrastructure 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 New WLAN domains can easily be added without affecting policies implemented by the individual MPDFs

Scenario 2 (cont.)

When encountered conflicts 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

Scenario 2 (cont.) If there is a conflict between QoS parameters and policies installed by another MPDF 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 After MPDF creating new policy –MPDF validates them with PDF of the UMTS domain on the data path of the session

Scenario 3: Customers ’ s WLAN Interconnected to an operator ’ s UMTS network

Scenario 3 (cont.) This model allows the UMTS operator to provide wide-area mobile services to customers that have their own WLAN infrastructure 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 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) Network-level policies is determined by service level specifications (SLSs)

Scenario 3 (cont.) There are dynamic and static service requirements 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

Scenario 3 (cont.)

When encounter a network state change 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

Scenario 3 (cont.) Continued 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

Scenario 3 (cont.) If WPDF receieved a negative COPS message If WPDF receieved a negative COPS message –Modify SLS parameters and resend it –Retry until a upper limit

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