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Policy-based QoS Management

Policy-based QoS Management. Outline. Terminologies Bandwidth Broker Policy Framework Policy Protocols Case studies Internet2 and Qbone. Why PBM?. New QoS architectures – Intserv, Diffserv Diverse application requirements and service levels End-end service over multiple domains

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Policy-based QoS Management

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  1. Policy-based QoS Management Engineering Internet QoS

  2. Outline • Terminologies • Bandwidth Broker • Policy Framework • Policy Protocols • Case studies • Internet2 and Qbone Engineering Internet QoS

  3. Why PBM? • New QoS architectures – Intserv, Diffserv • Diverse application requirements and service levels • End-end service over multiple domains • Needs contractual agreement • Agreements need to be translated into actions • Devices need to implement/enforce these actions Engineering Internet QoS

  4. Terminologies • Service-level Agreement (SLA) • Legal document • Levels of availability, serviceability and performance, …. • Service-level Objective (SLO) • Set of parameters and their values derived from SLA Engineering Internet QoS

  5. Terminologies (Contd) • Service-level Specification (SLS) • How to treat a customer’s traffic • e.g. for Diffserv DSCP and associated PHB • May be included in SLA and its SLO • Traffic Conditioning Agreement (TCA) • Diffserv specific [RFC 2475] • Classifier rules, traffic profiles and metering, marking, discarding and/or shaping rules Engineering Internet QoS

  6. Bandwidth Broker (BB) • Bandwidth Broker – a logical entity • Implementation may be domain specific • Functions of BB • Automate the process of SLS negotiation • Admission control • Resource management • Network management • Configuration of devices to provision QoS Engineering Internet QoS

  7. BB in Diffserv Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Engineering Internet QoS

  8. Bandwidth Signaling • No standard protocol so far • Simple interdomain bandwidth broker signaling protocol (SIBBS) under development[3] • Client-server oriented • TCP connection between peering BBs Engineering Internet QoS

  9. Policy Framework • IETF Resource Allocation Protocol (RAP) Working group responsible for developing PBM framework • Definition of protocols • Policy implementation on devices to support QoS enabled service • Policy definition • “Policy is used to denote the unified regulation of access to network resources and services based on administrative criteria” [5] Engineering Internet QoS

  10. 3-Tier Policy • Network Level • network wide resource utilization, topology and objectives • Node Level (network consists of nodes) • TCAs to meet specific QoS objectives of provisioned service • Device Level • Translation of node policy into classification rules, scheduling mechanisms … Engineering Internet QoS

  11. RAP WG terminologies • Policy Decision Point (PDP) • Determines what treatment a packet may receive when passing through a domain • Logical entity with global view of a domain • Interacts with PEPs • May use additional protocols (DIAMETER/RADIUS) for authentication/billing etc. • Policy Enforcement Point (PEP) • Enforce/implement policy • Router/switch forwarding packets Engineering Internet QoS

  12. Policy Architecture Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Engineering Internet QoS

  13. Policy Protocols • PDP and PEP communicate via Common Open Policy Service (COPS) protocol • COPS features • Exchange policy information between PDP and PEPs • Persistent TCP connection • Fault tolerance – uses keepalive messages • In case of failure Local PDP consulted Engineering Internet QoS

  14. COPS Message Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Engineering Internet QoS

  15. COPS Models • Outsourcing model • User contacts PEP which in turn contacts the PDP (PEP outsources the decision making) • Supported by Intserv/RSVP • Policy provisioning model (COPS-PR) • User contacts the PDP directly • Supported in Diffserv Engineering Internet QoS

  16. Policy Rules • Policy rules usually follow If, What, When and Then logic • Example: • If: The user is CEO of a company • What: The application is watching streaming video and • When: The time is 9:00 – 17:00 • Then: The user is entitled to a service-level premium that gives a throughput of 2 Mbps and an end-to-end latency of no more that 150 ms. Engineering Internet QoS

  17. Policy Representation • Policy Information Base (PIB) - RAP WG • Similar to Structure of management information (SMI) and Management Information Base (MIB) used in network management • A tree structure with branches representing types of policy rules or policy rule classes (PRCs) and leaves represent content of the policy rules or policy rule instances (PRIs) • Lightweight Directory Access Protocol (LDAP) • LDAP schema Engineering Internet QoS

  18. Policy and RSVP • End application may use RSVP • RSVP message reaches PEP • PEP contacts PDP for policy decision • PEP needs to interpret POLICY_DATA object in PATH/RESV messages • Policy object may carry list of Policy Elements (PEs) • Priority PE • Priority level to be used by the flow • Authentication PE • may contain information that identifies the source securely • PDP can verify this authentication PE before admitting the flow Engineering Internet QoS

  19. Bandwidth Broker Implementation Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Engineering Internet QoS

  20. Policy enforcement scenario-1 Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Domain A has a policy that during the peak hour, download Entertainment server mango should not exceed 2 Mbps Engineering Internet QoS

  21. Policy Scenario - 2 Reprinted with Permission from “Engineering Internet QoS - Jha & Hassan, Artech House Publishing, Norwood, MA, USA. www.artechhouse.com Gaming traffic is consuming substantial amount of bandwidth. Restrict gaming traffic to 2 Mbps. Engineering Internet QoS

  22. Internet-2 • Experimental backbone providing high-speed access called GigaPops • Membership: over 180 universities and 50 corporations • Research activities • Infrastructure for QoS experimentation such as Diffserv • Bandwidth broker • Interdomain signaling Engineering Internet QoS

  23. QBone • Key Internet2 project • Define architecture for participation in an interdomain Diffserv test bed • Deployment on new IP services • Measurement architecture • Collection of a set of QoS metrics at inter-domain peering points • Service Architecture • Currently only Qbone Premium service (QPS) • Similar to Diffserv Premium service – wire like communication Engineering Internet QoS

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