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Routing Extensions for G.709 OTN (draft-ashok-ccamp-gmpls-ospf-g709-02.txt)

Routing Extensions for G.709 OTN (draft-ashok-ccamp-gmpls-ospf-g709-02.txt). Rajan Rao ( rrao@infinera.com ) Ashok Kunjidhapatham ( akunjidhapatham@infinera.com ) Khuzema Pithewan ( kpithewan@infinera.com ) Snigdho Bardalai ( sbardalai@infinera.com ). Outline. Goals Proposal

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Routing Extensions for G.709 OTN (draft-ashok-ccamp-gmpls-ospf-g709-02.txt)

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  1. Routing Extensions for G.709 OTN (draft-ashok-ccamp-gmpls-ospf-g709-02.txt) Rajan Rao (rrao@infinera.com) Ashok Kunjidhapatham (akunjidhapatham@infinera.com) Khuzema Pithewan (kpithewan@infinera.com) Snigdho Bardalai (sbardalai@infinera.com)

  2. Outline • Goals • Proposal • Discussion items • Advantages & Comparison • Backup

  3. Goals A generic, scalable BW model that: • covers all OTN services including ODUflex, • covers potential evolution of OTN standards, • Hides complexities of TS disparities, • is Backwards compatible (to RFC 4203), • supports G.709-v3 complete muxing hierarchy, • is ready for VCAT services

  4. Proposal • Simple extensions to RFC-4202 • Retains main ISCD format • Consistent with RFC-4202, RFC-4203 & RFC-4201 • Switching type =TDM & Encoding type = ODUk • Max LSP BW in bytes/sec • Technology specific extensions in SCSI • Expands SCSI to carry G.709-v3 BW info • Advertise #of ODU containers for fixed rate ODUs • Advertise ODUflex BW in bytes/sec • Per Signal Type BW coverage • for Max-LSP & Unreserved BW types • Coverage for complete muxing hierarchy (G.709-v3)

  5. Proposal: ISCD & SCSI formats

  6. Proposal: SCSI format (ODUflex)

  7. Example – Muxing Hierarchy Coverage

  8. Discussion Items (1) • Question-1: Use of ISCD::Max-LSP-BW results in path computation failure when ODUflex is not supported (Danielle’s comment) • Authors agreed to the issue raised • Resolved by moving ODUflex BW advertisement to SCSI • Updated draft was sent out 10/28/10 • Question-2: Value for ISCD::TDM:Minimum-LSP-BW field (Pietro’s comment) • Authors agreed to the issue raised • The value is not restricted to TSG = {1.25, 2.5}. It is lowest switchable container • Previously this field was used for ODUflex. With ODUflex moved to SCSI this is not the case. There is no issue in setting the value to lowest switchable container. • Clarification will be provided in next draft update • Question-3: No backwards compatibility issues as no ODU adv defined in RFC 4202/4203/4328 (Danielle’s comment) • Authors believe backwards compatibility with G.709-v1 is required to comply with the above RFCs • The solution proposed addresses backwards compatibility fully (ref draft-ashok-02) • If WG agrees to not support backwards compatibility, we could use main ISCD for ODUflex • ref to backup slides 15-17 for details

  9. Discussion Items (2) • Question-4: Full muxing not a requirement (Fatai’s comment) • Authors didn’t agreed to the comment • Our interpretation of G.709-v3 is full hierarchy support is required • We agree with Deborah’s comments on NOT restricting GMPLS solution to a single stage

  10. Advantages & Comparison Advantages: • Re-using of existing ISCD definitions (RFC 4202) • Technology specific extensions consistent with GMPLS arch • Backwards compatible with G.709-v1 (RFC 4202, RFC 4203, RFC 4328) • without the use of multiple ISCDs • Coverage for complete muxing hierarchy (G.7090-v3 ) • Doesn’t require MLN to address muxing hierarchy • Doesn’t prevent MLN deployments • More compact encoding Comparison: • Not clear why we need a new technology agnostic ISCD for GMPLS as proposed by other draft • Creating a new ISCD will cause backwards compatibility issues for existing GMPLS/MPLS /MPLS-TP deployments (e.g. PSC, SONET/SDH, LSC) • Requires MLN to support muxing hierarchy • Don’t agree with Termination/Switching capability advertisement

  11. Backup Slides

  12. Comparison (1)

  13. Comparison (2)

  14. ISCD Size Comparison for an OTU4 Link Note: 1. Draft-Ashok uses signal type of ODU2_ANY for {ODU2 & ODU2e} 2. All units are in number of words (4 bytes).

  15. Backwards Compatibility (1) Node-A Node-B Node-C Link A-B: • G.709-v1 version compatible OTUk interface (2001) • Uses RFC 4328 for signaling • RFC 4203 & RFC 4201 based ISCD interpretation Link B-C: • G.709-v3 version compatible OTUk interface (12/09) • Uses ISCD + SCSI extensions as per our draft

  16. Backwards compatibility(2) Note: • The GOAL is to make TE-links with newer OTN capabilities compatible with CSPF in deployed networks • The ISCD format proposed in our draft allows Node-A • To interpret unReserved-BW, MaxLSP-BW and MinLSP-BW as per RFC4203 & RFC 4201 • Crank-back possibilities if muxing limitations exist • With or without Node-A going through software upgrade • Our BW model extended to support ODUflex • ODUflex a separate sub-TLV in SCSI • Addresses the case when ODUflex is not supported (the scenario highlighted in Daniele’s email)

  17. Options to address Backwards Compatibility • If backwards compatibility needs to be addressed: • Use main ISCD as per RFC 4202/4203/4201 • New sub-TLV for ODUflex in SCSI (BW in bytes/sec) • If backwards compatibility is not an issue: • Use main ISCD for ODUflex  BW advertisement • No need for a separate sub-TLV for ODUflex • Either option can be easily accommodated in our BW Model • Option#1 is preferred approach

  18. OTN example • The example below will be used where: • TE-link#1 is a link of type OTU2 supporting time-slot granularity of 2.5G • TE-link#2 is ODU1 supporting time-slot granularity of 1.25G • TE-link#3 is a link of type OTU2 supporting time-slot granularity of 1.25G ODU0 Service TE-link#2 TE-link#3 TE-link#1

  19. OTN example – first level • The advertisement for TE-link#1 (OTU2 with TS=2.5Gbps) would be: • Available ODU2s @Pi : 1 • Available ODU1s @Pi : 4 • Available ODU0s @Pi : 0 (not supported on this link, not included in the adv) • Max-LSP-BW = 10Gpbs • Min-LSP-BW = 2.5Gbps (ODU1 nominal rate) • The advertisement for TE-link#3 (OTU2 with TS=1.25Gbps) would be: • Available ODU2s @Pi : 1 • Available ODU1s @Pi : 4 • Available ODU0s @Pi : 8 (supported on this link) • Max-LSP-BW = 10Gpbs • Min-LSP-BW = 1.25Gbps (ODU0 nominal rate) TE-link#3 TE-link#1

  20. OTN example – second level • The advertisement for TE-link#2 (ODU1 FA-LSP) is: • Available ODU2s @Pi : 0 (not included in the adv) • Available ODU1s @Pi : 1 • Available ODU0s @Pi : 2 (supported on this link) • Max-LSP-BW = 2.5Gpbs • Min-LSP-BW = 1.25Gbps (ODU0 nominal rate) • The advertisement for TE-link#1 (OTU2) changes to: • Available ODU2s @Pi : 0 (not included in the adv) • Available ODU1s @Pi : 3 • Available ODU0s @Pi : 0 (not supported on this link, not included in the adv) • Max-LSP-BW = 7.5Gpbs • Min-LSP-BW = 2.5Gbps (ODU1 nominal rate) TE-link#3 TE-link#2 TE-link#1

  21. OTN example – third level • Establish ODU0 service. • The advertisement for TE-link#2 (ODU1) changes to: • Available ODU2s @Pi : 0 (not included in the adv) • Available ODU1s @Pi : 0 (not included in the adv) • Available ODU0s @Pi : 1 • Max-LSP-BW = 1.25Gpbs • Min-LSP-BW = 1.25Gbps (ODU0 nominal rate) • The advertisement for TE-link#3 (OTU2) changes to: • Available ODU2s @Pi : 0 (not included in the adv) • Available ODU1s @Pi : 3 • Available ODU0s @Pi : 7 • Max-LSP-BW = 8.75Gpbs • Min-LSP-BW = 1.25Gbps (ODU0 nominal rate) ODU0 service TE-link#2 TE-link#3 TE-link#1

  22. OTN example – Bundled links • Say TE-link#3 is a bundle of 3xOTU2s • The advertisement for TE-link#3 before ODU0 service is added: • Available ODU2s @Pi : 3 • Available ODU1s @Pi : 12 • Available ODU0s @Pi : 24 • Max-LSP-BW = 10.0Gpbs • Min-LSP-BW =1.25Gbps (ODU0 nominal rate) • The advertisement for TE-link#3 after ODU0 service is added: • Available ODU2s @Pi : 2 • Available ODU1s @Pi : 11 • Available ODU0s @Pi : 23 • Max-LSP-BW = 10.0Gpbs • Min-LSP-BW =1.25Gbps (ODU0 nominal rate) ODU0 Service TE-link#2 TE-link#3 TE-link#1

  23. OTN example – ODUflex • Add ODUflex connection of 5.0Gbps on TE-link#1 • The advertisement for TE-link#1 (OTU2) changes to: • Available ODU2s @Pi : 0 (not included in the adv) • Available ODU1s @Pi : 1 • Available ODU0s @Pi : 0 (not supported & not included in the adv) • SCSI::ODUflex:Max-LSP-BW = 2.5Gpbs (used for ODUflex) • SCSI::ODUflex:Min-LSP-BW = 2.5Gbps (ODU1 nominal rate used for ODUflex) TE-link#3 TE-link#1

  24. Issue with RFC4201 • Bundled Link with 5 component links, each with OTU2 rate and supports the following muxing capabilities: • ODU2/ODU0 • ODU2/ODU1 • ODU2/ODU1/ODU0 • 1. BW before any service is created • Unreserved BW = 50Gbps, Max-LSP-BW = 10G (ODU2), Min-LSP-BW = 1.25G (ODU0) • 2. BW After creating four ODU0 service and each using separate component link in the bundled link • Unreserved BW = ~45Gbps, Max-LSP-BW = 10G (ODU2), Min-LSP-BW = 1.25G (ODU0) • 3. The issue after step #2: • A node computing ODU2-4v path for a 40G client would select this link if per layer BW information is not available; results in a crank back.

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