Towards Service Differentiation on the Internet

Transcription

1 Towards Service Differentiation on the Internet from New Internet and Networking Technologies for Grids and High-Performance Computing, tutorial given at IEEE HOTI 2006, Stanford, California August 25th, 2006 C. Pham University of Pau, France LIUPPA laboratory

2 Revisiting the same service for all paradigm N E W C H A P T E R IP packet No delivery guarantee INTERNET Enhancing the best-effort service DiffServ IP packet Introduce Service Differentiation 2

3 Service Differentiation The real question is to choose which packets shall be dropped. The first definition of differential service is something like "not mine. -- Christian Huitema q Differentiated services provide a way to specify the relative priority of packets q Some data is more important than other q People who pay for better service get it! SLA DiffServ Service Level Agreement 3

4 Divide traffic into classes Differentiated IP Services Voice Platinum Class Low Latency Application Traffic , Web Browsing E-Commerce Traffic Classification Gold Silver Guaranteed: Latency and Delivery Guaranteed Delivery Voice Bronze Best Effort Delivery DiffServ Borrowed from Cisco 4

5 Design Goals/Challenges q Ability to charge differently for different services q No per flow state or per flow signaling q All policy decisions made at network boundaries q Boundary routers implement policy decisions by tagging packets with appropriate priority tag q Traffic policing at network boundaries q Deploy incrementally: build simple system at first, expand if needed in future DiffServ 5

6 IP implementation: DiffServ No per flow state in the core IP packet 10Gbps=2.4Mpps with 512-byte packets Flow 1 Flow 2 Flow 3 Flow 4 Stateful approaches are not scalable at gigabit rates! 6 bits used for Differentiated Service Code Point (DSCP) and determine PHB that the packet will receive IP header Ver Len Typ.Ser. TTL Ident Proto IP Data Area Source IP Address Destination IP Address Options RFC IP TOS Fl DiffServ IntServ/ RSVP Total Length Frag.Offset Header Checksum Padding DiffServ 6

7 DiffServ building blocks DIFFSERV TRAFFIC CONDITIONING SHAPING MARKING POLICY PER HOP BEHAVIOR TOKEN BUCKET INTRA-DOMAIN INTER-DOMAIN SCHEDULING (RR, WRR, FQ, WFQ) AQM (DT, RED, ) DiffServ 7

8 Traffic Conditioning q User declares traffic profile (eg, rate and burst size); traffic is metered and shaped if non-conforming 5Mbps SLA 2Mbps Service Level Agreement meter r tokens per second packets classifier marker Shaper/ dropper DiffServ drop forward <= C bps regulator b tokens 8

9 Token Bucket for traffic characterization q Given b=bucket size, C=link capacity and r=token generation rate bps bits slope r b*c/(c-r) Arrival curve slope C t 0 time t 0 time DiffServ 11

10 Differentiated Architecture Ingress Edge Router DiffServ Domain Egress Edge Router Interior Router r marking scheduling Marking: per-flow traffic management marks packets as in-profile and outprofile b. Per-Hop-Behavior (PHB): per class traffic management Ingress buffering and scheduling based on marking at edge preference given to in-profile packets DiffServ Egress 12

11 Pre-defined PHB q Expedited Forwarding (EF, premium): q departure rate of packets from a class equals or exceeds a specified rate (logical link with a minimum guaranteed rate) q Emulates leased-line behavior q Assured Forwarding (AF): q 4 classes, each guaranteed a minimum amount of bandwidth and buffering; each with three drop preference partitions q Emulates frame-relay behavior DiffServ 13

12 Premium Service Example Drop always 10Mbps Fixed Bandwidth DiffServ source Gordon Schaffee 14

13 Assured Service Example Drop if congested 10Mbps Uncongested Assured Service Congested DiffServ source Gordon Schaffee 15

14 Border Router Functionality Premium Service Token Bucket Packet Input Data Queue Wait for token Set P-bit Packet Output Assured Service Token Bucket Class 1 Class 2 Class 3 Class 4 Low drop probability Medium drop proba High drop proba No token DiffServ Packet Input Test if token Token Set A-bit Data Queue Packet Output source Gordon Schaffee, modified by C. Pham 16

15 Internal Router Functionality Packets In P-bit set? Yes High Priority Queue No Low Priority Queue Packets Out If A-bit set, a_cnt++ if congested If A-bit set, a_cnt-- RED In/Out Queue Management A DSCP codes aggregates, not individual flows No state in the core Should scale to millions of flows DiffServ source Gordon Schaffee, modified by C. Pham 17

16 Scheduling q DiffServ PHB relies mainly on scheduling q choose the next packet for transmission q FIFO: in order of arrival to the queue; packets that arrive to a full buffer are either discarded, or a discard policy is defined. q More complex policies: FCFS, PRIORITY, EDD DiffServ 18

17 Putting it together! 1 Drop probalility 0 1 WRED Queue 0 WRED Queue 1 0 1/4 1/2 3/4 Queue filling Prec. 0 BE + AF UDP out profile 30 % Queue 0 Prec. 1 AF UDP in profile Prec. 2 AF TCP out profile 30 % 30 % Queue 1 Queue 2 Classifier Prec. 3 AF TCP in profile Prec. 4 Prec. 5 EF Prec. 6 Control DiffServ 10 % Queue 3 Prec. 7 Control Source VTHD 28

18 DiffServ for grids Wide-area interactive simulations display computer-based plane simulator FTP airport simulator INTERNET (x,y,z,t) scheduling Interactive applications require low latencies human in the loop flight simulator marking r Ingress/Ingress Egress Egress. b Egress Egress Assured Forwarding Premium 29

19 DiffServ for grids (con t) Wide-area interactive simulations display airport simulator INTERNET Interactive applications require low latencies computer-based plane simulator (x,y,z,t) human in the loop flight simulator FTP Ingress/Ingress FTP scheduling. Egress Egress Egress Egress A DSCP codes aggregates, not individual flows No state in the core Should scale to millions of flows Assured Forwarding Premium 30

20 Bandwidth provisioning N E W C H A P T E R q DWDM-based optical fibers have made bandwidth very cheap in the backbone q On the other hand, dynamic provisioning is difficult because of the complexity of the network control plane: q Distinct technologies q Many protocols layers q Many control software IP ATM SONET/SDH DWDM 31

21 The telephone circuit view SW SW Trunk lines SW SW SW SW PABX PABX SW 36

22 Advantages of circuits q Provides the same path for information of the same connection: less out-of-order delivery q Easier provisioning/reservation of network s resources: planning and management features 37

23 Back to virtual circuits q Virtual circuit refers to a connection oriented network/link layer: e.g. X.25, Frame Relay, ATM Virtual Circuit Switching: a path is defined for each connection A B C R3 R1 R2 R4 R5 But IP is connectionless! D F E 39

24 Why virtual circuit? q Initially to speed up router s forwarding tasks: X.25, Frame Relay, ATM. We re fast enough! Now: Virtual circuits for traffic engineering! 43

25 Virtual circuits in IP networks q Multi-Protocol Label Switching q Fast: use label switchingè LSR q Multi-Protocol: above link layer, below network layer q Facilitate traffic engineering IP LINK PPP Header(Packet over SONET/SDH) PPP Header Header Layer 3 Header Ethernet Ethernet Hdr Header Layer 3 Header Frame Relay FR Hdr Header Layer 3 Header 44

26 Label structure Label Exp S TTL Label = 20 bits Exp = Experimental, 3 bits S = Bottom of stack, 1bit TTL = Time to live, 8 bits q More than one label is allowed -> Label Stack q LSRs always forward packets based on the value of the label at the top of the stack 45

27 From multilayer networks FR access ATM SONET/SDH ring SONET/SDH ring 46

28 to IP/ networks Multi-access Label Switch Router IP/ link 1 Multi-access U N I V E R S I T Y 47

29 operation 1a. Routing protocols (e.g. OSPF-TE, IS-IS-TE) exchange reachability to destination networks 1b. Label Distribution Protocol (LDP) establishes label mappings to destination network Label Switch Router 4. LSR at egress removes label and delivers packet IP link 1 IP 10 IP 20 IP src dest out * /16 1/10 * /16 1/26 2. Ingress LSR receives packet and label s packets Source Yi Lin, modified C. Pham 3. LSR forwards packets using label switching

30 Label Distribution In In dest out out Link label link label / Label Switch Router In In dest out out Link label link label / Label Switch Router link 1 Use label 20 for! /16! Use label 40 for! /16! Use label 10 for! /16! In In dest out out Link label link label In In dest out out Link label link label / / Unsolicited downstream label distribution 49

31 Label Distribution (con t) In In dest out out Link label link label / !? Label Switch Router In In dest out out Link label link label / Label Switch Router Use label 10 for! /16! link 1 Use label 20 for! /16! Use label 40 for! /16! request label for! /16! request label request for! label for! /16! /16! In In dest out out Link label link label In In dest out out Link label link label / / On-demand downstream label distribution 50

32 Dynamic circuits for grids E B C I need 2.5 Gbps between: A & B B & C D & C E & A A D 51

33 Forwarding Equivalent Class: high-level forwarding criteria Table A L6: (FEC F) D, L11 L8: (FEC X) A, pop (FEC Y) D, L12 (FEC Z) B, L5 Table B L4: (FEC E) C, L6 (FEC F) D, L7 L3: (FEC X) A, L8 (FEC Y) D, L9 L5: (FEC Z) C, L10 L5 LSR B L10 LSR C Table C L24:(FEC X) B, L3 L25:(FEC Y) F, pop L10:(FEC Z) E, pop L14:(FEC Z) E, pop L19:(FEC Z) E, pop LSR E Z X LSR A L14 L19 Table E (FEC D) C, L22 (FEC F) C, L23 (FEC X) C, L24 (FEC Y) C, L25 Table D L7: (FEC F) F, pop L11:(FEC F) F, pop L18:(FEC X) A, pop L9: (FEC Y) F, pop L12:(FEC Y) F, pop (FEC Z) C, L14 LSR D LSR F Y Table F (FEC D) D, pop (FEC E) C, L17 (FEC X) D, L18 (FEC Z) C, L19 52

34 Forwarding Equivalent Class Table A L6: (FEC F) D, L11 L8: (FEC X) A, pop (FEC Y) D, L12 (FEC Z) B, L5 X LSR A A FEC aggregates a number of individual flows with the same characteristics: IP prefix, router ID, delay or bandwidth constraints Table B L4: (FEC E) C, L6 (FEC F) D, L7 L3: (FEC X) A, L8 (FEC Y) D, L9 L5: (FEC Z) C, L10 One possible utilization of FEC L10 Pre-defined FEC establish preferential paths in the backbone network, thus allowing some form of traffic engineering/control. LSR C LSR B L5 FTP Application Traffic Table D L7: (FEC F) F, pop L11:(FEC Web F) F, pop L18:(FEC X) A, pop L9: Browsing (FEC Y) F, pop L12:(FEC Y) F, pop (FEC Voice Z) C, L14 LSR D L14 FEC Classification Ingress LSR L19 Table C L24:(FEC X) B, L3 L25:(FEC Y) F, pop L10:(FEC Z) E, pop L14:(FEC Z) E, pop L19:(FEC Z) E, pop LSR F Y FEC A L34 LSR E Z Table E (FEC D) C, L22 (FEC F) C, L23 (FEC X) C, L24 (FEC Y) C, L25 FEC B L45 FEC C L07 Table F (FEC D) D, pop (FEC E) C, L17 (FEC X) D, L18 (FEC Z) C, L19 53

35 FEC for the grid Wide-area interactive simulations computer-based display plane simulator FTP (x,y,z,t) INTERNET airport simulator human in the loop flight simulator Egress Egress Egress Egress Egress Egress FEC A: time constraint applications FEC B: best effort traffic 54

36 Label & FEC q Independent LSP control q An LSR binds a label to a FEC, whether or not the LSR has received a label from the next-hop for the FEC q The LSR then advertises the label to its neighbor q Ordered LSP control q An LSR only binds and advertises a label for a particular FEC if: it is the egress LSR for that FEC or it has already received a label binding from its next-hop 55

37 Label Distribution Protocols q LDP Maps unicast IP destinations into labels q RSVP-TE, CR-LDP Used in traffic engineering q BGP External labels (VPN) q PIM For multicast states label mapping 56

38 for resiliency FastReroute q Intended to provide SONET/SDHlike healing capabilities q Selects an alternate route in tenth of ms, provides path protection q Traditional routing protocols need minutes to converge! q FastReroute is performed by maintaining backup LSPs 57

39 for resiliency, con t Backup LSPs q One-to-one q Many-to-one: more efficient but needs more configurations C G A D F H B E One LSP from A to H 3 backup LSPs 58

40 for resiliency, con t Recovery on failures q Suppose E or link B-E is down q B uses detour around E with backup LSP C G A D F H B E 59

41 for VPN (Virtual Private Networks) q Virtual Private Networks: build a secure, confidential communication on a public network infrastructure using routing, encryption technologies and controlled accesses Shared network 60

42 for VPN, con t The traditional way of VPN q Uses leases lines, Frame Relay/ATM infrastructures 61

43 134.13/16 VPN B for VPN, con t VPN over IP/ q IP/ replace dedicated networks q reduces VPN complexity by reducing routing information needed at provider s routers /16 VPN B Know only attached VPNs /16 S /16 s /8 s1 Do not know VPNs at all VPN A VPN A Ingress LSR IP backbone Egress LSR IP VPN B /8 62

44 for optical networks Before Application Application Transport Transport Network Network Network Network Link WDM WDM Link Terminals IP router IP router Terminals Source J. Wang, B. Mukherjee, B. Yoo! 63

45 for ON, con t MPλS=+λ lightpath Application Application Transport Transport Network Link Network(IP) λ is MPλS viewed WDM as a label Network(IP) MPλS WDM Network Link Terminals MPλS enabled LSR MPλS enabled LSR Terminals Source J. Wang, B. Mukherjee, B. Yoo! 64

46 for ON, con t G q G stands for Generalized Multi- Protocol Label Switching q Extends the concept of beyond data networks to address legacy transport networks q Reduce OPEX cost for operators q A suite of protocols that provides a common set of control functions for disparate transport technologies (IP, ATM, SONET/SDH, DWDM) q Hot issue at IETF! 65

47 for ON, con t G control plane Source S. Kinoshita, R. Rabbat, APNOMS 2005! 66

48 Ex: Service Provisioning CLIENT Typical service provisioning Contract With G Signaling SALES Contract handling UNI ADMINISTRATION PROJECT MNGT NETWORK OPERATION LOCAL DOMAIN NETWORK OPERATION LOCAL DOMAIN EXTERNAL SUPPLIER Create work packages Knowledge of each technology domain! Plan Install Configure Provisioing of each layer! Plan Install Configure Separate mngt of perdomain operations functions! Plan Install Configure PATH Call control Call control RSVP signaling RSVP signaling OK? RESERV From Pascalini et al., IEEE Comm. Mag. July

49 DiffServ over (G) map DiffServ class on FEC Source Yong-Tak Kim! 68

50 Some words on inter-domain Source Yong-Tak Kim! 69

51 Summary Towards IP/(G)/DWDM From cisco 70

52 Summary Technology scope Source Alcatel 71

53 Want to know more? q G: IEEE Comm. Mag., Vol. 43(7), July 2005 q Optical Control Plane for the Grid Community: IEEE Comm. Mag., Vol. 44(3), March q Optical Transport Systems/Networks by S. Kinoshita & R. Rabbat, APNOMS q «Inter-domain Traffic Engineering for QoSguaranteed DiffServ Provisioning», Young-Tak Kim, APNOMS %203.pdf q See Tutorial IV of HOTI 2006: Dynamic Optimal Networks for Grid Computing 72

54 End of part 1, go to part 2 73