DiffServ-aware-MPLS Networking: a Promising Traffic Engineering for Next Generation Internet (NGI)

1. DiffServ-aware-MPLS Networking:a Promising Traffic Engineering forNext Generation Internet (NGI) 2002. 9. 25. Youngtak Kim Advanced Networking Technology Lab. (ANT Lab.) Dept. of Information & Communication Engineering, YeungNam University, Korea (ytkim@yu.ac.kr)

2. Outline • Networking Model and Traffic Engineering of NGI • Differentiated Service (DiffServ) • MPLS (Multi-protocol Label Switching) • Traffic Engineering with DiffServ-over-MPLS • Internet Traffic Engineering Measurement, Performance Monitoring • MPLS Fault Restoration • DiffServ-aware-MPLS TE of Commercial Routers • Summary and Discussions

3. Networking Model and Traffic Engineering ofNext Generation Internet (NGI)

4. Required Features of Next Generation Internet • Guaranteed Bandwidth & QoS • Bandwidth: • peak information rate (PIR), committed information rate (CIR), minimum information rate • Peak Burst Size (PBS), Committed Burst Size (CBS), Excess Burst Size (EBS) • End-to-end packet transfer delay • Jitter (delay variation) • Packet loss ratio • Differentiated Service provisioning with different priority/weight • Premium service, time-critical real-time service, controlled service, best effort service • Efficient Traffic Engineering for WDM optical lambda/fiber channels

5. IP Layer network GMPLS/PSC Layer network IP Router IP Router GMPLS/OXC layer Network IP Router IP Router LSP IP Router IP Router IP Router GMPLS PSC-LSR IP Router IP Router GMPLS OXC-LSR NGI with IP, MPLS and WDM Optical Network

6. Internet control & management protocols (RIP, OSPF, BGP, DVMRP, MOSPF) Traffic engineering with fault management & performance management for Internet Transit Network GMPLS-Signaling + OAM/LMP GMPLS-Signaling for optical network Application TCP/UDP IP IP LSP MPLS MPLS OXC OXC IP O-NIC (WDM) O-NIC (WDM) O-NIC (WDM) NIC O-NIC (WDM) O-NIC (WDM) O-NIC (WDM) fiber bundle NIC PSC-LSR (Optional Core) OXC-LSR (Core) Host A IP Router PSC-LSR (Edge) OXC-LSR (Core) Inter-networking with GMPLS-based WDM Optical Network

7. Application/Session Layer network (Node : aggregated traffic generator, Link : session connectivity) IP Layer network (Node : IP router, Link : IP transit connectivity) MPLS Layer network (Node : MPLS LSR (Label Switching Router), Link : Label Switched Path (LSP)) Hierarchical Multiplexing, Traffic Grooming at Extended Optical-UNI (ATM, Frame Relay, SONET/SDH, Ethernet) Optical network (Node : OADM, OXC Link : Optical WDM/ DWDM link) Packet Switch network (Node : ATM, FR EX Link : ATM VP/VC) TDM Network (Node : SONET ADM, MUX Link : SONET VC) Protocol Layers of Optical Internet

8. IP Routing Protocol (RIP, OSPF, BGP) Control Plane in a node IP Routing agent MPLS OAM IP Routing Table OAM message MPLS Signaling (CR-LDP, RSVP-TE) MPLS Signaling agent IP/Label forwarding table updates Data Plane in a node Incoming IP Packets Outgoing IP Packets IP Forwarding (Edge node only) FEC Incoming Labeled Packets MPLS Label Forwarding Outgoing Labeled Packets MPLS LSR (Label Switching Router)

9. OSPF-TE, BGP IP Routing Protocols for control channel setup Link Management Protocol (LMP) IP Routing Table LMP message GMPLS Signaling Protocol for Optical Network (Wavelength allocation, optical path setup & release) CR-LDP, RSVP-TE Control Plane in a node Link Management switching table updates Data Plane in a node Lambda 0 Lambda 0 port 1 port 1 Lambda / Fiber Switching Table Lambda 1 Lambda 1 • Lambda Add-drop • Wavelength routing • Wavelength translating • Fiber switching • • • • • • Lambda N Lambda N port 2 port 2 • • • • • • port n port n Optical Lambda Switching and Fiber Switching

10. Generalized MPLS Control function Packet Router(Routing) TDM Channel control function Lambda control function Fiber control function PSC cloud TDM cloud LSC cloud FSC cloud FA-PSCs (LSPPSC) FA-TDMs (LSPTDM) FA-LSCs (LSPLSC) FA-FSCs (LSPFSC) Lambda 1 Fiber 1 Fiber Bundle/Trunk Lambda n Fiber n Hierarchical Traffic Grooming in GMPLS Network

11. Traffic Engineering • Traffic Engineering • Performance evaluation and optimization of operational networks • Encompasses the technologies of measurement, modeling, characterization, and control of traffic • Goal of Internet Traffic Engineering • Facilitate efficient and reliable network operations while simultaneously optimizing network resource utilization and traffic performance • Enhance and guarantee the QoS delivered to end users • Optimize the resource utilization by optimized routing, efficient capacity management and traffic management • Traffic oriented performance measures: delay, delay variation, packet loss, and throughput • Enhanced network integrity with network survivability

12. Internet Traffic Engineering • Capacity Management • Capacity planning, routing control, resource management • Network resources: link bandwidth, buffer space, computational resource • Traffic Management • Nodal traffic control: traffic conditioning, queue management, scheduling • Regulating traffic flow: traffic shaping, arbitration of access to network resources • Traffic-oriented performance measures • Delay, delay variation • Packet loss • Throughput

13. Response Time Capacity Planning, Resource provisioning Re-configuration of logical topology (traffic trunk) Network Load re-balancing Long term (weeks, months) Call/connection admission control Connection duration (sec, min, hour) Call/connection routing (constraint-based) Dynamic source coding Feedback Flow Control Traffic parameter adjusting Round-trip delay (msec) Adaptive windows Adaptive rate control Explicit Notification Traffic shaping Excess traffic marking Packet Processing Time (usec) Traffic policing Selective discarding Reactive control Preventive control Traffic Control and Management Functions

14. User-Network Interface (UNI) Network A SB TB - CAC - RM - PC - Others B-TE B-NT2 B-NT1 UPC Optional Traffic Shaping Inter-Network (NNI) Network B TB SB - CAC - RM - PC - Others NPC B-TE B-NT2 B-NT1 ITU-T I.371 Traffic Management Framework UPC: Usage Parameter Control CAC: Connection Admission Control PC: Priority Control NPC: Network Parameter Control RM: Resource Management Others: Spacing, Framing, Shaping, etc

15. Service Level Agreement (SLA) / Service Level Specification (SLS) Traffic Level Agreement (TLA) / Traffic Level Specification(TLS) Internet Traffic Engineering with DiffServ or IntServ • DiffServ • DiffServ Code Points (DSCPs) • PHB (Per-Hop Behavior) • IntServ • Guaranteed Service • Controlled service • Best effort service DiffServ-to-CR-LSP mapping DiffServ-aware MPLS Traffic Engineering - CR-LSP traffic/QoS parameters ISP 1 ISP 2 User A User B GMPLS Network GMPLS Network OXC/WDM Optical Backbone Network OXC/WDM Optical Backbone Network Internet Traffic Engineering with DiffServ and GMPLS

16. Traffic Engineering with DiffServ-aware-MPLS • Differentiated Service (DiffServ) • 7 differentiated class-types (traffic aggregates) • QoS and traffic parameters are specified for each class-type • Priority or Weight is assigned for each class-type • Per-class level fine-grained optimization by DiffServ; Aggregated level optimization by MPLS LSP • MPLS-based Traffic Engineering • MPLS LSP provides constraint-based routing for traffic trunk provisioning • Connection-oriented traffic trunk (CR-LSP) planning and provisioning • Network load-balancing is possible by controlling the traffic trunk • By using EXP (CoS) fields in MPLS LSP Shim header, differentiated packet processing (DiffServ-aware) is possible • Efficient & flexible resource utilization with bandwidth borrowing among LSPs (traffic trunks)

17. Service Level Agreement (SLA) • Service Level Agreement (SLA) ? • A contract between a service provider and a customer • Specifies, usually in measurable terms, what QoS the service provider will provide • Generic QoS parameters • Availability • Delivery • Latency • Bandwidth • Mean Time Between Failures (MTBF) • Mean Time to Restoration of Service (MTRS)

18. Example of Service Level Specification • Service Level Specification in TEQUILA • Scope: the geographical/topological region over which the QoS is to be enforced; (possible topology: 1-to-1, 1-to-N, 1-to-all, N-to-1, all-to-1) • Flow Identification: DSCP, Source, Destination, Application • Traffic Conformance Testing: in-profile, out-profile with peak rate (P), token bucket rate (R ), bucket depth (B), Minimum packet size (M), Maximum transfer Unit (MTU) • Marking and Shaping services prior to conformance testing • Excess traffic treatment • Performance parameters: delay, jitter, packet loss, throughput • Service schedule: time of the day range, day of the week range, month of the year range, year range • Reliability: mean down time, maximum time to repair

19. Traffic / QoS Parameters of Bearer Service among IP Routers • Traffic parameters • Peak Data Rate (PDR) • Average Data Rate, Sustainable Data Rate with burst tolerance • Minimum Data Rate • Frame rate with max. frame size • QoS Parameters • End-to-end transfer Delay • Delay variance (Jitter) tolerance • Bit/Packet/Frame loss ratio

20. Long-term optimization Network Provisioning Mid-term optimization (Re-) configuration of logical topology (traffic trunk) Router parameter setting (Bandwidth allocation, Queuing, packet scheduling) Real-time per-flow optimization DiffServ-aware-MPLS DiffServ-aware-MPLS End system A End system B Collect & Analysis Measurement results Node performance monitoring End-to-end performance measurement Closed-loop Control in Traffic Engineering

21. Differentiated Service (DiffServ)

22. Differentiated Service • Goal of DiffServ • Service differentiation without scalability problem • A scalable mechanism for categorization of traffic flow into behavior aggregates • Each behavior aggregate is defined as a class-type by DS field in IP header • Each class-type is treated differently by its Per-Hop Behavior (PHB) using different classification, policing, shaping, and scheduling rules. • End user of differentiated network service should have a Service Level Agreement (SLA) with Traffic Conditioning Agreement (TCA) • TCA defines classifier rules as well as metering, marking, discarding, and shaping rules • Packets are classified, and possibly policed and shaped at the ingress to a DiffServ Network • When a packet traverses the DiffSev Domain boundaries, the DS field may be re-marked

23. Packet Classification • BA (Behavior Aggregate) Classifier • Classifies packets based on the DS code-point only • MF (Multi-field) Classifier • Selects packets based on the value of a combination of one or more header fields • IP packet header fields: • Source address, destination address • DS field • Protocol ID • Source Port, Destination port • Other information, such as incoming interface

24. Per Hop Behavior (PHB) • Per-Hop Behavior (PHB) • The externally observable forwarding behavior applied at a DS-compliant node to a DS behavior aggregate • The means by which a node allocates resources to behavior aggregates • Defines hop-by-hop resource allocation mechanism • Example of PHB • Guarantee minimal bandwidth allocation ( x % of a link or tunnel) • Guarantee minimal bandwidth allocation (x % of a link or tunnel) with proportional fair sharing of any excess link capacity • Buffer allocation • Priority relative to other PHBs • PHBs are specified as a group (PHB group) for consistency • PHBs are implemented in nodes by means of some buffer management and packet scheduling mechanisms

25. Example of DiffServ Class-type (Note : a) U : undefined, b) Drop precedence of AF4~AF1 : 010, 100, 110)

26. Smoothing (averaging) Buffer depth NCT (Network Control Traffic) Packet Scheduling Traffic Shaping IP Packet flow input Expedited Forwarding (EF) Metering, Action, Algorithmic Dropping Packet Classifier Assured Forwarding (AF) Packet Transmission with Link Speed X (LSP : PDR/PBS, CDR/CBS+EBS) Best Effort Forwarding (BEF) Packet Discarding (algorithmic dropping) Differentiated Packet Processing

27. Packet Classification Scheduling/ shaping Metering/Marking Per-Class-Queues count drop ? Single Rate TCM (CIR/CBS+EBS) count drop ? Single Rate TCM (CIR/CBS+EBS) NCT0 NCT1 AF 3 AF 4 AF 2 AF 1 EF Single Rate TCM (CIR/CBS+EBS) count drop ? IP Packet Stream count drop ? Packet Classifier Priority-based Scheduler Two Rate TCM (PIR/PBS, CIR/CBS+EBS) Two Rate TCM (PIR/PBS, CIR/CBS+EBS) Two Rate TCM (PIR/PBS, CIR/CBS+EBS) Two Rate TCM (PIR/PBS, CIR/CBS+EBS) count drop ? Rate-based Scheduler count drop ? count drop ? BF drop ? count DiffServ Traffic Handler

28. Meter Packets Marker Shaper/ Scheduler Classifier Packet Classifier and Traffic Conditioner

29. Traffic Policing, Metering / Marking and Re-marking (Note: B: arrived packet size, TE(t): token count of excess rate token bucket, TC(t): token count of committed rate token bucket, TP(t): token count of peak rate token bucket)

30. Buffer level 0 packet drop at buffer-full Drop Probability 1 Queue Length Buffer Limit Per Class-Type Queuing (1) : Tail-Drop Q

31. Buffer level TH min TH max 0 Discard with increasing probability Pa Discard Do not discard Probabilistic packet drop Drop Probability 1 Pmax Pmin THmax THmin Average Queue Length Per Class-Type Queuing (2): RED (Random Early Detection) Queue

32. Drop Probability 1 (Note: THmin(i) = (1/2 + i/8)*THmax Pmax (0..7) Average Queue Length THmin(0) THmax(0…7) THmin(7) (a) Default WRED Drop Probability Configuration Drop Probability Drop Probability 1 1 Pmax(0) Pmax(0) Pmax(7) Average Queue Length Pmax(7) Average Queue Length THmax(0…7) THmin(0) THmin(7) THmin(0) THmax(0) THmax(7) THmin(7) (b) WRED case 1 (c) WRED case 2 Per Class-Type Queuing (3): WRED (Weighted Random Early Detection) Queue

33. Buffer level (average In_profile) 0 Avg_in In-Profile (Green) Out-Profile (Red) Avg_total Buffer level (average_Total) Drop Probability Probabilistic packet drop 1 Pmax_out Pmax_in Pmin_in Pmin_out min_out min_in max_out max_in Average Queue Length Per Class-Type Queuing (4): RIO (RED with In/Out-Profile) Queuing

34. priority weight Priority Scheduler priority weight priority weight priority weight Rate-based scheduler (WRR or WFQ) DiffServ Packet Scheduler (1) • Priority-based, Weight-based Packet Scheduler (b) Weight-based Scheduler (a) Priority-based Scheduler (c) Hierarchical Packet Scheduler

35. NCT1 NCT0 EF AF4 priority Priority Scheduler priority AF3 shaping rate (PDR/PBS, CDR/CBS+EBS) priority AF2 Min rate Traffic Shaper Min rate Rate-based scheduler (WRR or WFQ) priority AF1 Min rate Min rate BF priority DiffServ Packet Scheduler (2) • Hierarchical Packet Scheduler

36. Committed rate Token bucket Outgoing packets WFQ/FIFO Incoming packets Configured rate Packet Scheduler Classify Measure No match Queuing method Traffic Shaping

37. Multi-Protocol Label Switching (MPLS)

38. Ingress Node label i IP datagram label j source A IP datagram label k label m Egress Node destination B MPLS Domain Network MPLS (Multi-Protocol Label Switching)

39. Ru Rd Downstream LSR Upstream LSR label distribution Bind <label, FEC> Packet Label assign outgoing label assign outgoing label check incoming label check incoming label Label Distribution Protocol (LDP) • Labels - short fixed identifier, meaningful only at the segment between LSR pair - assigned according to FEC (Forwarding Equivalent Class) • Label assignment & distribution - assigning label(s) to a FEC : binding a label L to a particular FEC F by down stream LSR switch - Label distribution by i) upstream node, ii) down stream node, or iii)downstream-on-demand

40. Packet P level (m+k) Packet P, level (m) Packet P level (m-1) Packet P level (m-1) LSP ingress (push a label) LSP egress (pop the label) swapping swapping R1 R2 Rn-1 Rn             Ri Ri+1 LSP ingress (push a label) LSP egress (pop the label) Hierarchical Label Stacking

41. MPLS Traffic Engineering • Connection-oriented LSP (Label Switched Path) • Constraint-based Routing • Traffic Engineering (TE) requirements of LSP • Constraint-based Shortest Path First (CSPF) • Forwarding Equivalent Class (FEC): multiple • source IP address range : min, max • destination IP address range : min, max • source port range : min, max • destination port range : min, max • service type • MPLS FEC-to-NHLFE (FTN) structure • FEC : Forwarding Equivalent Class • NHLFE : Next Hop Label Forwarding Entity

42. Constraint-based Routing in MPLS • Traffic parameters of the constraint-based routing for LSP • bandwidth of LSP : peak data rate, committed data rate • Modification of Link State Database for constraint-based routing • traffic parameter • available bandwidth at each link : number of lambda channels, bandwidth of each lambda channels • Additional QoS parameter • propagation delay • Combined cost metric • Modification of OSPF shortest path routing • constraint-based routing with traffic parameters: bandwidth, QoS, resource class, class of failure protection • SRLG (Shared Risk Link Group)

43. OSPF-TE/ BGP OSPF-TE/ BGP OSPF-TE/ BGP OSPF-TE/ BGP CR-LDP CR-LDP CR-LDP CR-LDP OAM OAM OAM OAM TCP/UDP TCP/UDP TCP/UDP TCP/UDP IP IP IP IP WDM WDM WDM NIA(ONIC) NIA(ONIC) NIA(ONIC) NIA(ONIC) O-NIC O-NIC O-NIC O-NIC MPLS-LSR (ingress) MPLS-LSR (egress) MPLS-LSR (intermediate) MPLS-LSR (intermediate) CR-LDP (label request) CR-LDP (label request) connection request from TE manager CR-LDP (label request) CR-LDP (label mapping) CR-LDP (label mapping) CR-LDP (label mapping) Constraint-Routed LDP (CR-LDP)

44. CR-LDP Traffic Parameters

45. Sender A Receiver C Resv Path Data Path Data Path Path Path Data Data Data Router R2 Router R1 Resv Resv Sender B Receiver D Resv RSVP-TE • RSVP-TE Message • Path, Resv • PathTear, ResvTear • PathErr, ResvErr • ResvConf, Hello, Notify

46. Traffic Policing for CR-LSP • Three token buckets : Peak Rate, Committed Rate, Excess • When a packet of size B bytes arrives at time t, • if TP(t) – B  0, the packet is not in excess of the PDR => TP(t) = TP(t) – B else the packet is in excess of the PDR => Packet Marking (and optionally discarding) • if TC(t) – B  0, the packet is not in excess of the CDR => TC(t) = TC(t) – B else if TE(t) – B  0, the packet is in excess of the CDR but is not in excess of the EBS => TE(t) = TE(t) – B else : the packet is in excess of both the CDR and EBS => Packet Marking (and optionally discarding)

47. Discarding Options of Marked Packet • Simple packet discarding policy (example) • if any packet is in excess of the PDR, then discard the packet • if any packet is in excess of both the CDR and EBS, then mark the packet and discard considering the relative “packet drop precedence” of the packet • Other considerations • relative packet drop precedence of Assured Forwarding (AF) • relative share (defined by weight) of the possible excess bandwidth above its committed rate among CR-LSPs • Packet scheduling for EF (Expedited Forwarding) packet to minimize delay & jitter • optional traffic shaping

48. MPLS OAM • IETF draft document : “OAM Functionality for MPLS Networks (Neil Harrison et. al, Expr. date : Aug. 2001)” • OAM (Operation and Maintenance) for the user-plane in MPLS network • CV (connectivity verification) OAM Function • used to detect defects related to misrouting of LSPs as well as link and nodal failure • if connectivity error is detected, it may trigger protection switching of the working path to the pre-established protection path • Performance OAM Function • FDI (Forward Defect Indicator)/ BDI (Backward Defect Indicator) OAM Function  triggers fault management function & LSP restoration/rerouting

49. 1 1 2 2 3 3 0 0 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 0 0 1 1 OAM Type OAM Type OAM Function OAM Function PDU Length PDU Length Ingress LSR Identifier Loop-back start LSR Identifier Loop-back end LSR Identifier Egress LSR Identifier LSP Identifier LSP Identifier Loop-back operation mode Sequence Number Time Stamp Optional data Number of Total Transmitted Packets Total Transmitted Data Size [Byte] Optional Information (b) Loopback Test OAM (a) Performance Management OAM MPLS OAM Packets (Example)

50. IP Performance Measurements • Connectivity (RFC 2678) • Instantaneous unidirectional connectivity • Instantaneous bi-directional connectivity • Interval unidirectional connectivity • Interval bi-directional connectivity • Interval temporal connectivity • Delay metric for IPPM (RFC 2679) • One-way delay Poisson stream • Packet loss metric for IPPM (RFC 2680) • One-way packet loss Poisson stream