Internet Week98 QoS : Int-serv Diff-serv QoS Int-serv RSVP Diff-serv

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1 Internet Week98 QoS : Int-serv Diff-serv kjc@csl.sony.co.jp QoS Int-serv RSVP Diff-serv

2 QoS

3 e.g., voice & data 10M/10 100M/100 --> FAX

4 LAN/WAN/ vs vs = heavy tail WWW CPU

5 ARPANET M/M/1 1 (2) N = T N: : T:

6 (3) Queueing Delay 0 0 Load 1.0 web server

7 Long-term: Day: Session: Round Trip Time: Packet Time: : Best-effort Best-effort

8 QoS Best-effort (ISP) QoS

9 QoS CoS QoS (Quality of Service) QoS) Int-serv model CoS (Class of Service) Diff-serv model QoS QoS CPU

10 Time required to send a 1KB packet Link (bps) 64K 512K 1.5M 10M 45M 100M time (usec) 125,000 15,625 5, QoS queue queue

11 QoS vs Over-provisioning QoS Over-Provisioning over-provisioning QoS QoS (admission control) (classifier) (packet scheduler) (shaper)

12 (signaling) IP src_addr, dst_addr, src_port, dst_port, proto TOS

13 Priority Queueing WFQ (Weighted Fair Queueing) CBQ (Class-Based Queueing) Drop-Tail/Drop-Head/Drop-Random RED (Random Early Detection) Priority Queueing priority queues packet classifier priority scheduler

14 WFQ (Weighted Fair Queueing) per-flow queues packet classifier packet scheduler Parekh s Model WFQ sender WFQ WFQ WFQ receiver token backet

15 Parekh + + D i b i g i (h - 1) l i g i i h m=1 l max r m D i b i g i h i l i r m delay bound for flow i token bucket size for flow i weighted rate for flow i hop count for flow i max packet length for flow i bandwidth at hop m Link 100% agency X 70% agency Y 30% ftp 40% telnet 30% ftp 20% telnet 10% class 0 class 1 class 3 class 4 pri: 2 pri: 3 pri: 2 pri: 3

16 CBQ (Class-Based Queueing) (set overlimit) packet default class estimator classifier class 1 packet scheduler (weighted-round robin) class 2 RED (Random Early Detection) TCP ECN (Explicit Congestion Notification) RED Penalty-box

17 RED 1.0 Packet Drop Probability mark prob 0 0 min thresh max thresh Average Queue Size Int-serv RSVP

18 Integrated Services QoS 89 IETF 94 (Interoperability Int-serv QoS RSVP - IETF - ISI ISSLL (Integrated Services over Specific Link Layers) Int-serv Guaranteed Service Controlled Load Service Best-effort

19 (isolation) Token Bucket TSpec [ r, b, p, m, M ] r: rate Token Buffer b: bucket size Data Packet Data Buffer p: peak rate m: min policed unit M: max packet size

20 RSVP RSVP IPv4 IPv6 RSVP (2) RSVP Fixed-Filter, Shared-Explicit, Wildcard-Filter RSVP RSVP

21 RSVP previous Hops Incoming Interfaces Outgoing Interfaces Next Hops A data Path a c data Path C Resv Router Resv B data Path b d data Path D B Resv Resv D RSVP Path Resv PathTear ResvTear Path Resv PathErr ResvErr Path Resv Confirm DiagReq DiagRep

22 Path Sender Path Sender Template: -- Filter Spec: (e.g., dst addr/port) Sender Tspec: Adspec: Router Adspec Resv Receiver Path Resv Flowspec: QoS -- Tspec: Tspec -- Rspec: Guaranteed QoS FilterSpec: Router Resv

23 Path S2 sender hosts receiver hosts path path path path path path path state path state path state S1 S2 R1 R2 R3 Resv R1 sender hosts receiver hosts path path path path path path path state path state path state resv resv resv resv state resv state S1 S2 R1 R2 R3

24 R2 sender hosts receiver hosts path path path path path path path state path state path state resv resv resv resv state resv state resv merge RSVP RSVP process Policy Cntrl Admis Cntrl Packet Schedulr Classifier Application RSVP process Policy Cntrl Admis Cntrl Packet Schedulr Classifier Routing process RSVP RSVP data data data HOST ROUTER

25 ISI RSVPD apps command mode rtap policy control RSRR mrouted (mcast routes) (vif info) (unicast routes) user space (if info) kernel space API admission admission routing socket classifier packet sched traffic control rsvpd rsvp proto control Raw/UDPencap IPv4/IPv6 (for all vifs/ifs) data control rsvpd state (Path, Resv) rsvpeep protocol tapping rstat rsvptrace DiagReq DiagRep rsvp protocols (Path, PathTear, Resv, ResvTear, Confirm, DiagReq, DiagRep) ISSLL (Integrated Services over Specific Link Layers) IS802 Subnet Bandwidth Manager (SBM) ISATM Int-serv ATM ISSLOW T1 (1500B / 28.8Kbps ~= 400msec)

26 RSVP RSVP over MPLS RSVP over diff-serv RSVP RSVP RSVP RSVP over diff-serv

27 Diff-serv Differentiated Services Int-serv/RSVP ISP ISP TOS

28 Diff-serv per flow TOS Classifier ISP Diff-serv 1997/08 Munich IETF Int-serv WG Diff-serv BOF Premium Service Model V. Jacobson (LBL) Drop preference Model D. Clark (MIT) Cisco s CoS F. Baker (Cisco) 1998/03 IETF Diff-serv WG ISP

29 IPv4 TOS DS 4-bit version 4bit header length 8-bit time to live (TTL) 8-bit type of service (TOS) 16-bit identification 8-bit protocol 3-bit flags 32-bit source IP address 32-bit source IP address 16-bit total length (in bytes) 13-bit fragment offset 16-bit header checksum options (if any) data TOS precedence low delay throughput reliability min cost DSCP (differentiated services codepoint) (currently unused) 2 ECN IPv6 Traffic Class

30 Diff-serv SLA: Service Level Agreement Diff-serv ISP A ISP B C SLA E B B SLA C SLA E B

31 marker classifier meter profile shaper dropper traffic conditioner at an edge node Forwarding Behavior Forwardig Behavior SLA(Service Level Agreement) forwarding behavior ISP: Behavior ISP ISP ISP-ISP SLA

32 PHB (Per Hop Behavior) (forwarding vs routing analogy) PHB PHB PHB Best-effort Guaranteed PHB PHB PHB PHB ISP Default PHB DSCP field in packet PHB 1 PHB 2 64 entry lookup table

33 Standard PHBs Default PHB codepoint "0": best-effort Class Selector PHBs IP precedence Assured Forwarding PHBs Drop preference Expedited Forwarding PHBs xxxxx0: Standard PHBs xxxx11: Experimental/Local Use xxxx01: Experimental/Local Use* : Default PHB xxx000: Class Selector PHBs : Assured Forwarding PHBs ( ) : Expedited Forwarding PHB AF Class Selector

34 Expedited Forwarding Jacobson Premium Service ISP Priority Queue WFQ CBQ ATM CBR Best-effort IETF Assured Forwarding Clark Drop Preference QoS PHB (RIO, WRED) OUT OUT IETF Class Selector PHB

35 RIO (RED with In and Out) IN OUT RED OUT 1.0 Packet Drop Probability mark prob OUT IN 0 0 OUTmin OUTmax INmin Average Queue Size INmax Diff-serv RSVP over Diff-serv RSVP Diff-serv over MPLS ISP (forwarding vs routing analogy)

36 Diff-serv PHB QoS Int-serv/RSVP QoS RSVP diff-serv Diff-serv RSVP QoS

37 < > IETF: IETF diffserv WG: IETF intserv WG: IETF issll WG: IETF rsvp WG: RSVP: Diffserv at MIT: CBQ: ALTQ: < > Quality of Service. P. Ferguson and G. Huston. Wiley. ISBN An Engineering Approach to Computer Networking. S. Keshav. Addison-Wesley. ISBN High-speed Networks: TCP/IP and ATM Design Principles. William Stallings. Prentice Hall. ISBN Gigabit Networking. Craig Partridge. Addison-Wesley. ISBN < > Queueing Systems vol. 1 and vol. 2. Leonard Kleinrock. Wiley-Interscience. ISBN , X

IP: TCP: QoS 90 QoS IP IP IP

InternetWeek99 QoS DiffServ kjc@csl.sony.co.jp DiffServ DiffServ DiffServ DiffServ IP: TCP: QoS 90 QoS IP IP IP QoS QoS (admission control) (classifier) (shaping)(policing) (packet scheduler) (signaling)