电子科技大学：《先进计算机网络技术》课程教学资源（课件讲稿）Unit 7 IntServ/RSVP and DiffServ

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Unit 7 IntServ/RSVP and DiffServ 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.1

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.1 Unit 7 IntServ/RSVP and DiffServ

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Outline Overview of QoS in IP networks 。 Integrated Service model(IntServ) Resource Reservation Protocol(RSVP) 。 Differentiated Services model (DiffServ) 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.2

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.2 Outline • Overview of QoS in IP networks • Integrated Service model (IntServ) • Resource Reservation Protocol (RSVP) • Differentiated Services model (DiffServ)

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Improving QOS in IP Networks IETF groups are working on proposals to provide better QOS control in IP networks,i.e.,going beyond best effort to provide some assurance for QOS 。 Work in Progress includes RSVP,Differentiated Services,and Integrated Services 。 Simple model for sharing and 1.5 Mbps link congestion H1 H3 studies: R1 R2 H2 R1 output H4 interface queue 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.3

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.3 Improving QOS in IP Networks • IETF groups are working on proposals to provide better QOS control in IP networks, i.e., going beyond best effort to provide some assurance for QOS • Work in Progress includes RSVP, Differentiated Services, and Integrated Services • Simple model for sharing and congestion studies:

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Principles for QOS Guarantees Consider a phone application at 1Mbps and an FTP application sharing a 1.5 Mbps link. bursts of FTP can congest the router and cause audio packets to be dropped. want to give priority to audio over FTP PRINCIPLE 1:Marking of packets is needed for router to distinguish between different classes;and new router policy to treat packets accordingly 1 Mbps H1 R1 1.5 Mbps R2 H2 H4 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.4

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.4 Principles for QOS Guarantees • Consider a phone application at 1Mbps and an FTP application sharing a 1.5 Mbps link. - bursts of FTP can congest the router and cause audio packets to be dropped. - want to give priority to audio over FTP • PRINCIPLE 1: Marking of packets is needed for router to distinguish between different classes; and new router policy to treat packets accordingly

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Principles for QOS Guarantees (more) Applications misbehave (audio sends packets at a rate higher than 1Mbps assumed above); PRINCIPLE 2:provide protection (isolation)for one class from other classes 。 Require Policing Mechanisms to ensure sources adhere to bandwidth requirements;Marking and Policing need to be done at the edges: 1 Mbps packet marking and policing H3 R1 1.5 Mbps R2 H2 H4 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.5

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.5 Principles for QOS Guarantees (more) • Applications misbehave (audio sends packets at a rate higher than 1Mbps assumed above); • PRINCIPLE 2: provide protection (isolation) for one class from other classes • Require Policing Mechanisms to ensure sources adhere to bandwidth requirements; Marking and Policing need to be done at the edges:

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Principles for QOS Guarantees (more) Alternative to Marking and Policing:allocate a set portion of bandwidth to each application flow;can lead to inefficient use of bandwidth if one of the flows does not use its allocation 。 PRINCIPLE 3:While providing isolation,it is desirable to use resources as efficiently as possible packet marking 1 Mbps 1 Mbps logical link H3 R1 R2 1.5 Mbps H2 5 Mbps logical link H4 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.6

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.6 Principles for QOS Guarantees (more) • Alternative to Marking and Policing: allocate a set portion of bandwidth to each application flow; can lead to inefficient use of bandwidth if one of the flows does not use its allocation • PRINCIPLE 3: While providing isolation, it is desirable to use resources as efficiently as possible

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Principles for QOS Guarantees (more) 。 Cannot support traffic beyond link capacity PRINCIPLE 4:Need a Call Admission Process;application flow declares its needs,network may block call if it cannot satisfy the needs 1Mbps 1.5 Mbps R2 H2 H4 1 Mbps 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.7

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.7 Principles for QOS Guarantees (more) • Cannot support traffic beyond link capacity • PRINCIPLE 4: Need a Call Admission Process; application flow declares its needs, network may block call if it cannot satisfy the needs

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Summary QoS for networked applications nnnn aunosa yy 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.8

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.8 Summary

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Outline Overview of QoS in IP networks Integrated Service model (IntServ) Resource Reservation Protocol (RSVP) Differentiated Services model (DiffServ) 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.9

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.9 Outline • Overview of QoS in IP networks • Integrated Service model (IntServ) • Resource Reservation Protocol (RSVP) • Differentiated Services model (DiffServ)

Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Integrated Service (Intserv) The Integrated Services model(RFC1633)was introduced to guarantee a predictable behavior of the network for applications requiring QoS guarantee applications signal to the network that they require special QoS data flows among applications,with flow recording at each router SP ISP 3 ISP4 ISP 2 2616009:Network Traffic Engineering 7:IntServ and DiffServ Page.10

2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 7: IntServ and DiffServ Page.10 - The Integrated Services model (RFC1633) was introduced to guarantee a predictable behavior of the network for applications requiring QoS guarantee - applications signal to the network that they require special QoS - data flows among applications, with flow recording at each router Integrated Service (Intserv) ISP 1 ISP 2 ISP 3 ISP 4