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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)

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Outline

• Goals• Proposal• Discussion items• Advantages & Comparison• Backup

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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

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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)

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Proposal: ISCD & SCSI formats

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Proposal: SCSI format (ODUflex)

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ST=ODUflex |Bw Type| Flags | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available BW in bytes/sec at Prio 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ST=ODUflex |Bw Type| Flags | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Minimum LSP Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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Example – Muxing Hierarchy Coverage

ST BW Type Available ODUs at priority Pi

ODU4 (4) 0 (Max-Lsp-Bw ) 1

ODU3 (3) 0 (Max-Lsp-Bw ) 2

ODU0 (5) 0 (Max-Lsp-Bw ) 82

ODUflex(10) 0 (Max-Lsp-Bw) ( 80x1,301,709 )/8 bytes/sec

ODUflex(10) 2 (Min-Lsp-Bw) 1,301,709 /8 bytes/sec

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Discussion Items (1)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

2. 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

3. 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

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Discussion Items (2)4. 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

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Advantages & ComparisonAdvantages:• 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

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BACKUP SLIDES

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Comparison (1)Draft-Ashok Draft-Ceccarelli

Model •Simple extensions to RFC4202•Consistent with GMPLS model•Technology specific extensions in SCSI

•New BA similar to ISCD already defined

Hierarchy Handling

•Full mux capability taken care•No FA-LSPs required to address G.709-v3 mux layers•Smaller TE-DB & Scalable

•Addresses only one level•Requires Te-Link per Mux layer to support G.709-v3 hierarchy•Not a scalable solution

Backward Compatibility

Compatible with G.709-v1 deployments (RFC-4202/4203/4328)

Redefines G.709 ISCD. Invalidates RFC 4328. In general breaks away from existing GMPLS model for BW advertisement.

Scalable Model

• Compact sub-TLVs defined •Further optimization possibilities with priority bit-map use•Easy to deal with future extensions

• ServiceType repeated per priority per signal type• use of 4 words unnecessary for advertising #of ODU containers• Future extensions may force having SCSI in BA (duplication of 4202 ISCD)

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Comparison (2)Draft-Ashok Draft-Ceccarelli

Termination & Switching flags

•Don’t see the need•Not supported

•supported

VCAT Addressed using BW-Type=1 advertisement

Not addressed

Size1) OTU4 link with 7

signal types + 8 priorities

2) OTU4 link with 7 signal types + 5 priorities

Compact

1) 59 words

2) 50 words

Numbers are higher than draft-ashok model1) 114 words

2) 70 words

Simplicity Simple TLV structure, easy to encode/decode.

The unit of BW depends on M field. Depending on the value of M field, BW could be interpreted as simple unsigned integer or IEEE floating point number. Results in engineering complexity

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ISCD Size Comparison for an OTU4 Link

Draft-Ashok Draft-Ceccarelli

Number of Priority Levels Supported 8 8 5 3

ODU4 6 16 10 6

ODU3 6 16 10 6

ODU2 - 16 10 6ODU2e - 16 10 6ODU2_ANY 6 - - -ODU1 6 16 10 6ODU0 6 16 10 6ODUflex 10 32 20 12 Total Variable 40 128 80 48Total Fixed 12 1 1 1 Total ISCD Size(in words) 52 129 81 49

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

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Backwards Compatibility (1)

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

Node-A Node-B Node-C

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Backwards compatibility(2)Link A-B

(G.709-v1 Telink RF C 4203/4201)

Link B-C(G.709-v3 Telink

based on our draft)Old CSPF Compatible Compatible

( Ref to Note below)New CSPF Compatible Compatible

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)

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Options to address Backwards Compatibility

1. 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)

2. 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

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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 1.25GODU0 Service

TE-link#2

TE-link#1

TE-link#3

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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#1

TE-link#3

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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#2

TE-link#1

TE-link#3

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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#1

TE-link#3

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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#1

TE-link#3

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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#1

TE-link#3

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Issue with RFC4201Bundled Link with 5 component links, each with OTU2 rate and supports the following muxing capabilities:

ODU2/ODU0ODU2/ODU1ODU2/ODU1/ODU0

1. BW before any service is createdUnreserved 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 linkUnreserved 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.