Internet2 QoS: Baby Steps and Big Lessons Ben Teitelbaum July 26 th, 2001 IBM Internet2 Day

IBM Internet2 Day (July 26 th, 2001)2 The Goal The Holy Grail of computer networking is to design a network that has the flexibility and low cost of the Internet, yet offers the end-to- end quality of service of the telephone network. - S. Keshav (An Engineering Approach to Computer Networking, Addison-Wesley, 1997.)

IBM Internet2 Day (July 26 th, 2001)3 The Environment Wavelength division multiplexing (WDM) lambdas are proliferating quicker than Moores Law, with total bandwidth per optical fiber increasing faster still-perhaps four times a year...[and] the rate of change is speeding up...The Law of Wasted Bandwidth tells us that the companies that exploit bandwidth recklessly, will win. - George Gilder (Gilder Technology Report, January 2001)

IBM Internet2 Day (July 26 th, 2001)4 architecture A Brief History of Internet2 QoS Began chanting: enable advanced applications, … Assessed requirements What do you want? What can you give us? •Recommended DiffServ and Jacobson-style Premium Service •Charted QBone initiative •Developed architecture and proceeded to implement it •Frustration and disillusionment •Refocusing on lighter-weight services (e.g. QBSS) and reëvaluation of application needs frustration deployment new approaches reëvaluation

IBM Internet2 Day (July 26 th, 2001)5 QBone Architecture A Service: QBone Premium Service •Built on Expedited Forwarding (EF) (RFC 2598) •Assurance: near-zero loss & low, bounded jitter for marked traffic conforming to a specified peak rate a.k.a. “virtual leased line”, “virtual wire” Reservation Setup Protocol •Now: long-lived, manual setup •Proposed: SIBBS protocol between QBone domains; RSVP end-to-end between hosts QBone Measurement Architecture •Uniform collection of QoS metrics •Uniform dissemination interface

IBM Internet2 Day (July 26 th, 2001)6 QBone Architecture (30 kilofoot view) •Architecture focuses on interdomain interfaces... –Edge-to-edge services –Signaling –Measurement GigaPoP A Campus A Campus C Campus D Backbone Campus B GigaPoP B •...and how edge-to-edge services concatenate to form an e2e service •Each domain needs to think in terms of provisioning edge-to-edge virtual trunks (policed on ingress / shaped on egress)

IBM Internet2 Day (July 26 th, 2001)7 QBone Architecture v2.0 Architecture under review by design team •Collaboration with TF-NGN Premium-IP group •Clarifying service assurance •Fixing known bugs in measurement architecture •Clarifying implications for operators and SLAs Big issues: •How to balance service ideal with need for incremental deployment? •Delay assurance? •Routing-based edge classification •Exactly what policers/shapers are needed? GigaPoP B Backbone ?

IBM Internet2 Day (July 26 th, 2001)8 QPS Status (Good News) The Good News: •With enough elbow grease, e2e services can be built •DiffServ building blocks increasingly available in modern routers •Many host OSs capable of QoS signaling (RSVP) •Numerous DiffServ testbed trials •Partial deployment in Internet2 backbones •Has enabled some networking research –On the Impact of Policing and Rate Guarantees in Diff-Serv Networks: A Video Streaming Application Perspective, R. Guerin et al. (to be presented at SIGCOMM 2001) –Aggregation and Scalable QoS: A Performance Study, H. Fu, E. Knightly (IWQoS 2001)

IBM Internet2 Day (July 26 th, 2001)9

10 QPS Status (Bad News) The Bad News: •Low demand for QPS (app/net chicken/egg dynamic) •Router support for DiffServ is spotty; E.g... –no PQ –DiffServ comes with a performance cost –limitations on token bucket depths –inflexible classification rules •Elbow grease in short supply in most campus IT shops •Building a QPS cloud requires upgrading the world

IBM Internet2 Day (July 26 th, 2001)11 QBone Scavenger Service Basic idea Voluntary marking hints to network that degraded service is OK (like Un*x nice for the network) •Scavenger traffic may be degraded at congestion points •Thin best-effort network that can expand to full capacity in absence of congestion Goals •A tool to preserve/extend uncongested BE experience for interactive applications

IBM Internet2 Day (July 26 th, 2001)12 Motivations 1/3 All traffic is not equal •Mix of critical/non-critical traffic •Since you may be competing with yourself for downstream resources, its in your interest to identify non-critical traffic to protect your critical traffic Most routers support multiple queues •Lets get some value and experience out of them! Internet2 utilization very low •Pro: interactive apps work fine; Con: what a waste •What new applications could be built if we werent shy about filling the pipes?

IBM Internet2 Day (July 26 th, 2001)13 Motivations 2/3 Congestion points •Yes Virginia, they do exist! •If Internet2 E2E-PI succeeds, they will continue to exist Fine-grained Netiquette •Self-policing users exist (bulk transfers run at night) –HEP community –Admin functionality (e.g. backups) •Lets let these folks run their flows all day long Pricing •Additional control over upstream commodity usage •Potential negotiation point with commodity providors

IBM Internet2 Day (July 26 th, 2001)14 Motivations 3/3 Policy •Users/institutions could mark non-mission traffic

IBM Internet2 Day (July 26 th, 2001)15 QBSS Service Definition Voluntary marking for QBSS •Packets indicated by DSCP= •Codepoint has global significance •Extra-semantics for class selector PHB Domain requirements •Must propagate QBSS DSCP •Router requirements –Forward independently giving it a lower probability of timely forwarding OR forward in same manner as BE –Offer a very small minimum departure rate (unlike BH PDB) –QBSS gets all un-used bandwidth

IBM Internet2 Day (July 26 th, 2001)16 Implications Very nice deployment story •On day one... –Near ubiquitous deployment –Should just work with multicast –Technology transfer begins •Incremental deployment at congestion points to restore uncongested best-effort service Policy? Pricing? Performance?

IBM Internet2 Day (July 26 th, 2001)17 Where is Growth Coming From? Current growth •From three university dorm nets Working with... •GRAPE / TRANSPAC •CERN •SLAC / Cosm library Applications now QBSS-enabled •wu-ftp •Apache •bbftp

IBM Internet2 Day (July 26 th, 2001)18 Summary QBone testbed architecture •Still makes sense •Some tweaks underway Working on deploying two services •QBSS (fast deployment path) •QPS (slow deployment path) How to participate •Join the mailing list •Join a QoS WG activity –Architecture DT –Scavenger DT – Application QoS Needs DT – Signaling DT

IBM Internet2 Day (July 26 th, 2001)19 For more information... Internet2 Home: • Internet2 QoS Working Group Home: • •(links to all WG design teams from here) QBone Home: • Abilene Premium Service Home: •

IBM Internet2 Day (July 26 th, 2001)20