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OSPF Traffic Engineering (TE) Express Path draft-giacalone-ospf-te-express-path-00.txt

OSPF Traffic Engineering (TE) Express Path draft-giacalone-ospf-te-express-path-00.txt. Spencer Giacalone, Alia Atlas, John Drake, Dave Ward. Agenda. Introduction to OSPF TE Express Path Background Problem Protocol overview Encodings Next steps Questions. The Scenario.

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OSPF Traffic Engineering (TE) Express Path draft-giacalone-ospf-te-express-path-00.txt

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  1. OSPFTraffic Engineering (TE) Express Pathdraft-giacalone-ospf-te-express-path-00.txt Spencer Giacalone, Alia Atlas, John Drake, Dave Ward

  2. Agenda • Introduction to OSPF TE Express Path • Background • Problem • Protocol overview • Encodings • Next steps • Questions IETF 80

  3. The Scenario • Financial networks have changed: • Orientation towards machine (“algo”) trading • Arbitrage • Real time data: Low latency (LL) and ultra low latency (ULL) • Milliseconds and (increasingly) microseconds count • High rate flows • Not able to gap (drop) packets • Out of SLA is out of service! IETF 80

  4. Problem • We need to guarantee delivery of large quantities of data with the lowest latency- not lowest cost, etc • In certain richly interconnected networks, interface cost is becoming generally irrelevant. Performance Is King. This is a real and current need. • We have high redundancy and bandwidth, but managing performance flows is difficult: • Overall path lengths vary • We act as a service provider, but are not one in the classical sense • Dependant on underlying transport services • Segments not always dark fiber • Full transport service “stack” not visible IETF 80

  5. Static Costing Is A Problem • Difficult to capture latency, loss, and bandwidth in single static metric • Performance changes- latency, loss, etc • Path protection • Flaps, drops, etc • I need to know the current values at LSP compute time • Complicated, error prone, time consuming IETF 80

  6. Overview • OSPF TE Express Path simplifies these issues • Automatically distributes performance data • Allows control plane manipulation • To permit MPLS tunnel setup, failover, fail back • Based on network performance • Intentionally independent from measurement protocols • E.g. MPLS TP, PTP, etc • Also, intentionally independent from “applications” • Routing/MPLS enhancements • Weighted ECMP • Others • Modular and extensible IETF 80

  7. What About Stability?? • Aimed at MPLS TE • Averaged values • Controlled announcement • Does not define how control plane reacts- just distributes data • Not having a déjà vu IETF 80

  8. Protocol Architecture • Extends RFC 3630 • Two Main Types of Sub-TLV • Nominal (Routine) Sub-TLVs • Steady state path selection according to performance • Initial tunnel build • Fail over path selection and monitoring (Non SLA compliant best path may not be desirable for fail over use) • Possibly also general monitoring • Alternative method- topology database • Link by link or path • Anomalous (Significant) Sub-TLVs • Can trigger re-computation when performance SLAs are violated • Fail back • Different announcement scheduling and averaging periods • Individually configured • Intentionally kept separate to simplify implementations IETF 80

  9. Sub-TLVs • Five New Sub-TLVs (Currently) • Nominal Unidirectional Link Delay • Nominal Unidirectional Delay Variation • Nominal Unidirectional Link Loss • Anomalous Unidirectional Link Delay • Anomalous Unidirectional Link Loss • Next version will include additional sub-TLVs for items like residual bandwidth IETF 80

  10. Encoding • Types: TBD • Length: 4 Bytes • Values: • Latency or jitter as rolling average, to remote peer, floating point • Loss as packet percentage • Sent when threshold exceeded • Different thresholds for different sub-TLVs • Configurable • And when reuse threshold passed (Anomalous sub-TLVs only at this time) IETF 80

  11. Simple MPLS TE Example • Nominal TLVs used to calculate CSPF- Initial state for path selection • Upon SLA violation, Anomalous sub-TLV prompts CSPF • And fail over to secondary • CSPF uses Nominal sub-TLVs ensure secondary path is conformant IETF 80

  12. Next Steps- Short/Mid Term • Propose OSPFWG adoption • Will also be presented in RTGWG for cross pollination • Revise draft • New Sub-TLVs aimed at weighted ECMP • Residual bandwidth • Available bandwidth • Modifications based on feedback • Modeling • Interworking/requirements with MPLS TP Loss/Delay IETF 80

  13. Next Steps- Longer Term Longer term plans include IS-IS TE Express Path, and drafts related to “applications” such as MPLS TE control plan Express Path, Weighted ECMP, and possibly others IETF 80

  14. Questions IETF 80

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