policy-based qos management

Engineering Internet QoS 1

Policy-based QoS Management

Engineering Internet QoS 2

Outline

oTerminologiesoBandwidth BrokeroPolicy FrameworkoPolicy ProtocolsoCase studieso Internet2 and Qbone

Engineering Internet QoS 3

Why PBM?

o New QoS architectures – Intserv, Diffservo Diverse application requirements and

service levelso End-end service over multiple domains

Needs contractual agreement

o Agreements need to be translated into actions Devices need to implement/enforce these

actions

Engineering Internet QoS 4

Terminologies

o Service-level Agreement (SLA) Legal document Levels of availability, serviceability and

performance, ….

o Service-level Objective (SLO) Set of parameters and their values

derived from SLA

Engineering Internet QoS 5

Terminologies (Contd)

o 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

o 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)

o Bandwidth Broker – a logical entity Implementation may be domain specific

o 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

o No standard protocol so faro Simple interdomain bandwidth

broker signaling protocol (SIBBS) under development[3] Client-server oriented TCP connection between peering BBs

Engineering Internet QoS 9

Policy Framework

o IETF Resource Allocation Protocol (RAP) Working group responsible for developing PBM framework Definition of protocols

• Policy implementation on devices to support QoS enabled service

o 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

o Network Level network wide resource utilization,

topology and objectiveso Node Level (network consists of nodes)

TCAs to meet specific QoS objectives of provisioned service

o Device Level Translation of node policy into

classification rules, scheduling mechanisms …

Engineering Internet QoS 11

RAP WG terminologies

o 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.

o 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

o PDP and PEP communicate via Common Open Policy Service (COPS) protocol

o 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

o Outsourcing model User contacts PEP which in turn

contacts the PDP (PEP outsources the decision making)

Supported by Intserv/RSVP

o Policy provisioning model (COPS-PR) User contacts the PDP directly Supported in Diffserv

Engineering Internet QoS 16

Policy Rules

o Policy rules usually follow If, What, When and Then logic

o 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

o 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)

o Lightweight Directory Access Protocol (LDAP) LDAP schema

Engineering Internet QoS 18

Policy and RSVP

o End application may use RSVPo 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

Domain A has a policy that during the peak hour, downloadEntertainment server mango should not exceed 2 Mbps

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

Engineering Internet QoS 21

Policy Scenario - 2

Gaming traffic is consuming substantial amount of bandwidth. Restrict gaming traffic to 2 Mbps.

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

Engineering Internet QoS 22

Internet-2

o Experimental backbone providing high-speed access called GigaPops Membership: over 180 universities and

50 corporationso Research activities

Infrastructure for QoS experimentation such as Diffserv

Bandwidth broker Interdomain signaling

Engineering Internet QoS 23

QBone

o Key Internet2 project Define architecture for participation in an

interdomain Diffserv test bed Deployment on new IP services

o Measurement architecture Collection of a set of QoS metrics at inter-

domain peering points

o Service Architecture Currently only Qbone Premium service (QPS)

• Similar to Diffserv Premium service – wire like communication