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Diff-Serv-aware Traffic Engineering draft-ietf-mpls-diff-te-reqts-00.txt

Diff-Serv-aware Traffic Engineering draft-ietf-mpls-diff-te-reqts-00.txt. IETF TE WG, Dec 2000, San Diego. Francois Le Faucheur, Cisco Systems Angela Chiu, AT&T William Townsend, Tenor Networks Darek Skalecki, Nortel Tom Nadeau, Cisco Systems Martin Tatham, BT. History. Pittsburgh.

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Diff-Serv-aware Traffic Engineering draft-ietf-mpls-diff-te-reqts-00.txt

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  1. Diff-Serv-aware Traffic Engineeringdraft-ietf-mpls-diff-te-reqts-00.txt IETF TE WG, Dec 2000, San Diego Francois Le Faucheur, Cisco Systems Angela Chiu, AT&T William Townsend, Tenor Networks Darek Skalecki, Nortel Tom Nadeau, Cisco Systems Martin Tatham, BT

  2. History Pittsburgh San Diego draft-lefaucheur-diff-te-reqts-00.txt draft-lefaucheur-diff-te-ext-00.txt draft-ietf-mpls-diff-te-reqts-00.txt draft-ietf-mpls-diff-te-ext-00.txt draft-lefaucheur-diff-te-ospf-00.txt draft-lefaucheur-diff-te-isis-00.txt made MPLS WG document

  3. Motivation • Current MPLS TE: • can be used simultaneously with Diff-Serv • performs constraint based routing (CBR) on a single BW constraint • this is sufficient for many environments

  4. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of linkeg: • link speed = 155 Mb/s • Max Reservable Bandwidth Aggregate = 155 • Max Reservable Bandwidth for EF/Voice= 70

  5. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C On link B-->D 40 + 30 < 70 40 + 30 + 40 < 155

  6. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of Voice?

  7. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of Voice? No, because 40 + 30 + 10> 70

  8. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of Voice? No, because 40 + 30 + 10> 70

  9. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of BE Data?

  10. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of BE Data? Yes, because 40+30+40 +10 < 155

  11. Motivation • Good EF behavior requires that aggregate EF traffic is less than “reasonable” % of link (for instance 50%) • BE behavior fine if aggregate traffic is 100% of link B Voice 40 Voice 30 155 155 BE Data 10 BE Data 40 A 155 D 155 C Can I use Link B->D to set up a new LSP A-->D for 10 Mb/s of BE Data? Yes, because 40+30+40 +10 < 155

  12. Motivation • CBR needs to include the link for BE and exclude the link for Voice/EF • current TE, IGP advertises single “unreserved Bw” value for all CoS ==> a link is either included or excluded by CBR for all CoSs • IGP needs to advertise a different “unreserved Bw” for BE and for Voice • RSVP-TE/ CR-LDP need to signal CT so that CAC is performed depending on CT

  13. Motivation • Only applies to some environments: • Distributed Route Computation • Voice traffic is significant compared to link speed • distribution of traffic across Classes is not consistent everywhere • Examples: • global ISPs (e.g., Concert), especially on transoceanic links • telco transporting very large Voice Trunks (e.g. AT&T)

  14. Motivation • Pre-standard implementations available today • tests/experimentation carried out by SPs(SPs to present at next IETF?) • need for a standard to allow future interoperability

  15. Principles • Class-Type (CT)= arbitrary set of DS Classes with same Bw constraints • eg. CT0=BE, CT1=AF1+AF2, CT2=EF • Configurable Max Reservable per CT • eg Max CT0=155, Max CT1=120, Max CT2=75 • IGP advertise “Unreserved Bw per CT” • CBR uses advertised “Unrsvd Bw” of relevant CT • RSVP-TE/CR-LDP signal CT

  16. Issue • How many CTs should we allow? • proposal: • 2 is the burning requirement • 4 is comfortable • remember one CT can comprise multiple classes • Examples: • SP1 only uses existing TE (single CT) • SP2 uses 2 CTs (Data,Voice) • SP3 uses 3 CTs (Voice, Low Loss data, BE)

  17. Issue • How does preemption play within and across CTs? • Proposal: • do not constrain how many, and which, preemption levels are used by each CT • preemption operate independently of CT:LSP1(P1) will preempt LSP2(P2) if P1<P2 regardless of LSP1’s CT and LSP2’s CT • Examples: • SP1 uses P0 for Voice, P1 for Data • SP2 uses P0&P1 for Voice, P2&P3&P4 for Data

  18. Issue • How to minimise IGP scalability impact? • Proposal: • no configuration required regarding which preemption level is used by which CT • IGP will not advertise Unrevd Bw for preemption levels which are not used(*) • Examples: • SP1 uses P0 for Voice, P1 for Data • IGP advertises existing 8 Bw values + 1 additional Bw value • SP2 uses P0&P1 for Voice, P2&P3&P4 for Data • IGP advertises existing 8 Bw values + 2 additional Bw values • SP3 uses P0 for Voice, P1for Low-loss Data, P2&P3 for BE • IGP advertises existing 8 Bw values + 3 additional Bw values (*) except P0 which is always advertised

  19. Max EF Unrsvd EF EF LSPs BE LSPs Unrsvd BE Max BE Issue • Bandwidth Reservation Scheme: • how to compute “unreserved Bw” for each CT? • proposal: one simple model (*) • Max Reservable CT1/EF=50 • Max Reservable CT0/BE=100 • Currently established CT1/EF LSPs= 20 • Currently established CT0/BE LSPs= 30 ==> Unresvd EF = 30 (= 50-20) Unresevd BE= 50 (= 100-30-20) (*) investigating potential enhancements

  20. Proposal • Should TEWG take ownership of “DS-TE Requirements” document?(currently owned by MPLS WG)

  21. Proposal • If yes, turn <draft-ietf-mpls-diff-te-reqts-00.txt> into a TEWG document instead of MPLS WG document.

  22. Proposal • Protocol extensions to satisfy DS-TE Requirements remain in the WG responsible for the protocol: • RSVP-TE/CR-LDP/MPLS MIBs ==> MPLS WG(draft-ietf-mpls-diff-te-ext-00.txt) • OSPF ==> OSPF WG(draft-lefaucheur-diff-te-ospf-00.txt) • ISIS ==> ISIS WG(draft-lefaucheur-diff-te-isis-00.txt)

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