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Design and Analysis of Survivable Design and Analysis of Survivable Multipath Provisioning Multipath Provisioning

In Telecom Mesh NetworksIn Telecom Mesh Networks

Sheng HuangSheng Huang

PhD Exit SeminarDept. of Electrical and Computer Engineering,

University of California, Davis

Sheng Huang, UC DavisSheng Huang, UC Davis

OutlineOutline

• Introduction• Research Contributions

Survivable Multipath Provisioning with Differential Delay Constraint.

Adaptive Reliable Multipath Provisioning.

Survivable Traffic Grooming with Inverse Multiplexing.

A Multistate Multipath Provisioning Scheme for Differentiated Failures in Telecom Mesh Networks.

Telecommunication Network HierarchyTelecommunication Network Hierarchy

Long haul: 100s-1000s kmbackbone networks, Meshes

Metro: 10s kmRings

Access: a few km Hubbed Rings

Users

Multipath ProvisioningMultipath Provisioning

Courtesy: K. Zhu, et al. Traffic Grooming in Next-Generation SONET/SDH


• Next-generation SONET/SDH technologies: Virtual Concatenation (VCAT);

Link Capacity Adjustment Scheme (LCAS);

Generic Framing Procedure (GFP) -- GFP-F, GFP-T.

Issue: Differential Delay Constraint


• Advantages:

-- Scalability;

-- Efficiency;

-- Compatibility;

-- Resilience;

-- Bandwidth on Demand (with LCAS).

• Disadvantages:

-- Complexity;

-- Differential-Delay Constraint.

Network SurvivabilityNetwork Survivability

• Survivability is critical in telecom networks.

single fiber cut -- data and revenue loss.

• Survivable Multipath Provisioning Challenges:

Protect multiple primary paths; DDC-aware;

• Connection Availability, Service-Level-Agreement (SLA).

• Explore LCAS capability.

Survivable Multipath Provisioning Survivable Multipath Provisioning with Differential Delay Constraintwith Differential Delay Constraint

In Telecom Mesh NetworksIn Telecom Mesh Networks[1][1]

[1] S. Huang, B. Mukherjee, and C. Martel, “Survivable Multipath Provisioning with Differential Delay Constraint in Telecom Mesh Networks,” in Proc. of INFOCOM 2008, Phoenix, AZ, pages 191-195, Apr. 2008.

Introduction: Differential DelayIntroduction: Differential Delay

Route Dist.

(km)

Delay

(ms)

6-8-11 2000 10

6-5-10-11 3800 19

6-7-9-12-11 3900 19.5

Next-Generation SONET/SDH Technologies: GFP, VCAT and LCAS

Framer/Mapper Device:DD Compensation: Internal memory and SDRAM

( , ) *5 /i j i jP P P P i jDD D D L L s km

Differential Delay (DD) between path Pi and Pj is:

SMP Problem StatementSMP Problem Statement

Given:

Input Network

Sequence Request (s, d, B)

Goal:

Route the request and provide backup capacity such that we can still send B units of bandwidth even if there is a single link failure.

Optimizations: Short primary paths, reduce backup capacity used.

Survivable Multipath Provisioning IssuesSurvivable Multipath Provisioning Issues• Differential-Delay Constraint (DDC). - Operation, Administration, Maintenance & Provisioning. - Quality of Service. - Destination node compensation capability.

• Survivability: efficiency and fast fault-recovery.

• Route computation: low signaling-overhead; simple management; low complexity.

• Backup sharing: Backup path selection and sharable backup capacity calculation.

SMP: Solution ApproachSMP: Solution Approach

2wP

s d

.

.

.

1wP

KwP

bP

Request : <s, d, B, DDC> O-K-Paths & SPLIT O-K-Paths: Optimal K link-disjoint paths which satisfy DDC SPLIT: Shared Protection of Largest Individual Traversed link

Request (s, d, B); B is multiples of VCAT granularity gB: K primary paths carry B/K units eachBackup (Excess Capacity): B/K

DDC

s d

20

20

20

20

(s, d, 60)

example

The more paths the less capacity the backup path needs, but finding many link-disjoint paths meeting DDC is challenging (main result of this research).

Finding More SFinding More SD PathsD Paths

• Differential-Delay-Constrained K Link-Disjoint Paths SPLIT.

Basic Idea: Recombining sub-paths

KDP:S-a-b-D and S-c-b-d-D

DD = (4+5+6+2) - (1+2+3) = 11

S ba D

c d4

1 2 3

5 6 2

S ba D

c d4

1 2 3

5 6 2

Recombine Sub-paths:We can get : S-a-b-d-D and S-c-b-D

DD = (4+5+3) - (1+2+6+2) = 1

Heuristic AlgorithmsHeuristic Algorithms[1][1]

SPLIT-DDCKDP1. Find a set of k-shortest edge-disjoint paths s-d.

2. Define merge nodes. Build an auxiliary graph G’, whose vertices are merge nodes.

3. Generate all simple paths from s to d in G’.

4. Find the Largest disjoint path set meeting DDC (O-K-paths).

5. Select best backup path among O-K-paths and assign capacity.

SPLIT-KDP1. Find a set of k-shortest edge-disjoint paths s-d.

2. Find maximum of paths which meet DDC.

3. Select best backup path and assign capacity.

[1] S. Huang, B. Mukherjee, and C. Martel, “Survivable Multipath Provisioning with Differential Delay Constraint in Telecom Mesh Networks,” in Proc. of INFOCOM 2008, Phoenix, AZ, pages 191-195, Apr. 2008.

DDCKDP: Finding All Paths in Auxiliary GraphDDCKDP: Finding All Paths in Auxiliary Graph

• Looking at all combinations of paths in G’ is exponential worst case, but in practice never finds more than 64 paths.

• Simulated on two typical backbone networks one of which is significantly larger than the other.

DDCKDP Results: Example 6DDCKDP Results: Example 61111

Route Dist. (km) DDC:

6-8-11 2000 800 (4ms)

6-5-10-11 3800

6-7-9-12-11 3900

6-2-1-5-8-10-14-15-11 8550

Route Dist. (km) DDC:

6-5-8-11 3200 800 (4 ms)

6-8-10-11 3300

6-7-9-12-11 3900

Simulation Backbone Topology (link distance in km)

KDP

DDCKDP

DDCKDP Procedure: Example 6DDCKDP Procedure: Example 61111

From KDP Alg.:6-8-11, 20006-5-10-11, 38006-7-9-12-11, 39006-2-1-5-8-10-14-15-11, 8550

Get all set of disjoint paths from auxiliary graph: worst case exponential.Simulation records: the number of simple path & set are small (max path #32, set # 64 ).

Backup Sharing: Single Joint Path VCGsBackup Sharing: Single Joint Path VCGs

Non-Sharable

Sharable

Working

Backup

Free S1 D1

S2 D2

a b

If primary paths are disjoint, we can share backup capacity

Link capacity distribution

Backup capacity is shared on

Sub-path a b

Backup Sharing: Multiple Joint Paths VCGsBackup Sharing: Multiple Joint Paths VCGs

S1

x y

D1S2 D2

S1

x y

D1S2 D2

Non-Sharable

Sharable

Working

Backup

Free

(No Share)

Share

S2 — D2 : new connection

Backup Sharing: Calculate Backup CapacityBackup Sharing: Calculate Backup Capacity

• For each arc, keep track of the primary and backup paths it is currently participating in, and how long those connections will continue.

• Maintain limited number of conflict set for each arc.

• From the conflict set, calculate the maximum sharable capacity on the arc.

• Calculate the Potential Reserved Backup Resource (PRBR) on candidate path and pick the one with minimum PRBR.

Illustrative Numerical Results : Topology 1Illustrative Numerical Results : Topology 1

Arrival: Independent Holding time: a negative exp. dist.Connections: uniform distributed

16 wavelengths per linkOC-192 per wavelengthFull wavelength conversion

VCAT granularity: STS-1Experiments for several DDC’s: {5ms, 8ms, 10ms, 20ms, 50ms}

Performance Metrics:Bandwidth Blocking Ratio (BBR)Resource Overbuild (RO)

Requests bandwidth dist.: 50M:100M:150M:600M:1G:2.5G:5G:10G

=100:50:20:10:10:4:2:1

Topology 1: Bandwidth Blocking Ratio vs. DDCTopology 1: Bandwidth Blocking Ratio vs. DDC

T1: Bandwidth Blocking Ratio: DDCKDP vs. KDPT1: Bandwidth Blocking Ratio: DDCKDP vs. KDP

Topology 1: Resource Overbuild vs. DDCTopology 1: Resource Overbuild vs. DDC

T1: Resource Overbuild: DDCKDP vs. KDPT1: Resource Overbuild: DDCKDP vs. KDP

Illustrative Numerical Results: Topology 2Illustrative Numerical Results: Topology 2

Sample U.S. backbone network: 60 nodes, 91 bidirectional links

Topology 2: Bandwidth Blocking Ratio vs. DDCTopology 2: Bandwidth Blocking Ratio vs. DDC

T2: Bandwidth Blocking Ratio:

T2: Bandwidth Blocking Ratio: DDCKDP vs. KDPT2: Bandwidth Blocking Ratio: DDCKDP vs. KDP

Topology 2: Resource Overbuild vs. DDCTopology 2: Resource Overbuild vs. DDC

T2: Resource Overbuild: DDCKDP vs. KDPT2: Resource Overbuild: DDCKDP vs. KDP

DDCKDP In the Case of Null DDCDDCKDP In the Case of Null DDC

• DDCKDP is an efficient protection scheme even when DDC is not an issue.

• We compare our approach (with a large DDC) to one of the best multi-path protection schemes (not considering DDC) that also exploits shared backup resources.

DDCKDP vs. PIVM Ignoring DDCDDCKDP vs. PIVM Ignoring DDC

PIVM: Protecting Individual VCG Member2 (Non-DDC)

[2] C. Ou, L. Sahasabuddle, K. Zhu, C. Martel, and B. Mukherjee, “Survivable Virtual Concatenation for Data Over SONET/SDH in Optical Transport Networks,” IEEE/ACM Transactions on Networking, vol. 14, pp. 218-231, Feb. 2006.

ConclusionConclusion

• Exploiting O-K-paths and SPLIT are efficient approaches for SMP (Survivable Multipath Provisioning). DDCKDP outperforms KDP.

• The improvements of DDCKDP is substantial when DDC is small. With 8ms DDC, DDCKDP can achieve more than 50% improvements in BBR over KDP.

• SPLIT-DDCKDP is a resource-efficient, low-signaling-overhead, fast-fault-recovery approach for SMP with DDC.

• Just as a backup method (ignoring the DDC issue), DDCKDP improves on the best prior work for SMP.

Adaptive Reliable Multipath Adaptive Reliable Multipath Provisioning in Survivable Provisioning in Survivable WDM Mesh NetworksWDM Mesh Networks[3,4][3,4]

[3] S. Huang, B. Mukherjee, “Adaptive Reliable Multipath Provisioning in Survivable WDM Mesh Networks,” in Proc. of ICC 2008, Beijing, China, May 19-23, 2008.

[4] S. Huang, C. Martel, and B. Mukherjee, “Adaptive Reliable Multipath Provisioning in Survivable WDM Mesh Networks,” IEEE J. Sel. Areas Communication, to appear.

IntroductionIntroduction

• Network operators provide service based on service-level agreement (SLA).

• Differential-delay constraint (DDC) for MP.

• Multipath provisioning: pros and cons.

• Adaptive: Availability-Aware, DDC-Aware, Resource-Efficiency-Aware.

• Reliable: Availability (SLA) guaranteed service.


• Multipath Provisioning – M:N(m)

M: primary N: backup (m): multipath

3:0(m), 2:0(m) : DDC

s-d : 150 Mbps, consider all link availabilities to be 0.999, different SLA.Primary paths only

150 Mbps: 0.99100 Mbps: 0.999950 Mbps: 0.9999999

150 Mbps: 0.9975 Mbps: 0.99999

150 Mbps: 0.997


• Multipath Provisioning – M:N(m)

2:1(m): DDC

150 Mbps: 0.999975 Mbps: 0.9999999

s-d : 150 Mbps, consider all link availabilities to be 0.999, different SLA.Primary & Backup paths

150 Mbps: 0.99999 150 Mbps: 0.9999999


• M : N (m) two connection blocking situations:

Availability Blocking: Blocked because of no connection meet SLA. No M : N (m) connection between s-d pair is found that meets SLA.

Bandwidth Blocking: Blocked because of capacity limitation. A M : N (m) connection that meets SLA can be found. But it failed on bandwidth allocation (no enough free capacity).

Connection Availability AnalysisConnection Availability Analysis

Availability of any k out of M;Availability of any k out of N.

where:AR: connection availability;M: number of primary paths;N: the number of backup paths;

Bandwidth Migration with LCASBandwidth Migration with LCAS

• Type 1: Local bandwidth migration among primary paths.

(a) R2 blocked bottleneck link a-b, after migration (b) R2R2 accepted !accepted !

Reduce bandwidth blocking

(working, free, availability)

Bandwidth Migration with LCASBandwidth Migration with LCAS

• Type 2: Global bandwidth migration for lower backup capacity.

(a) Backup capacity 28 after migration (b) Backup capacity 24,

(working, free, availability)

Averaging

save 4!save 4!

Heuristic Algorithm: MPAG-BMHeuristic Algorithm: MPAG-BM[3][3]

• MPAG-BM: Multipath Provisioning with Availability Guarantee using Bandwidth Migration.

Input: Graph, Network State, Connection Request (s, d, B, DDC, SLA).

Output: M:N(m) provisioning meet B, SLA, and DDC.

1. Compute DDC-aware M link-disjoint paths between s-d pair.

2. Try no backup MP: M:0(m), (M-1):0(m), … 2:0(m).

3. Try single Meet-SLA-Path (cheapest path among several meet SLA paths).

4. Try MP with backup – overbuild low to high: e.g.,3:1(m), 2:1(m), etc.

5. Assign capacity and reserve backup. If necessary, perform Type-1 migration.

6. Accept, Allocate and Update. If necessary, perform Type-2 migration.

Heuristic Algorithm: MPAG-BMHeuristic Algorithm: MPAG-BMRequest Arrives

Request DepartsUpdate Network

State

No-Backup MPM : 0 (m)

M=MaxDP

M = M-1

AR ≥ SLA AR ≥ SLAAR ≥ SLA

Single Path MSP

Backup MPM:N(m)

(M=MaxDP-1,N=1) (N/M) +

Assign Capacity(M:N(m))

OK Type-2 BM

Type-1 BM OK Request Blocked

Request Accepted

Y

N

Y Y

N N (M > 1)

NN

N

N (M > 1)

Y

Y

Heuristic Algorithm: MPAGHeuristic Algorithm: MPAG

• MPAG: Multipath Provisioning with Availability Guarantee.

MPAG is MPAG-BM without Bandwidth Migration.

• MPAG-BM: Need LCAS support.

MPAG: In case of no LCAS support.

• Bandwidth Migration conditions:

Type 1: local, when bandwidth blocking.

Type 2: global, after network state changes ( e.g., connection departs).

Illustrative Numerical ExampleIllustrative Numerical Example

Sample U.S. topology (link distances in 1000 km).

Request bandwidth distribution:100M : 150M : 600M : 1G : 2.5G : 5G : 10G = 50 : 20 : 10 : 10 : 4 : 2 : 1SLA: uniform {0.99, 0.999, 0.9999}Link availability: uniform {0.999, 0.9999, 0.99999}

• DDC: {8ms, 18ms}• Wavelength convertible• 16 wavelength per fiber.• VCAT granularity: STS-1• Wavelength channel : STS-192• Request: uniform dist.• Arrival: Independent Poisson, • Holding time: neg. exp. dist.


Single, MPAG DDC = 8ms, MPAG-BM DDC = 8ms BBR Comparison

Illustrative Numerical ExampleIllustrative Numerical ExampleSingle, MPAG DDC = 8ms, MPAG-BM DDC = 18ms BBR Comparison


Single, MPAG DDC = 8ms, MPAG-BM DDC = 50ms BBR Comparison


• M : N (m) can meet ultra-high availability SLA.

• Both MPAG and MPAG-BM are significantly better

than single-path provisioning in all cases.

• DDC value impact the performance in both algorithms.

• With bandwidth migration, MPAG-BM performs better than MPAG with different load and DDC.

Survivable Traffic Grooming with Survivable Traffic Grooming with Inverse Multiplexing in Telecom Inverse Multiplexing in Telecom

Mesh NetworksMesh Networks[5][5]

[5] S. Huang, B. Mukherjee, “Survivable Multipath Traffic Grooming in Telecom Mesh Networks with Inverse Multiplexing,” in Optical Network Design and Modeling, 2009.ONDM 2009. International Conference on, Braunschweig, Germany, Feb. 2009, pp. 1–6.

Outline

• Introduction.• Node Architecture and Problem Statement.• f-lightpath, Analytical Model, Protection-at-

Connection (MP-PAC) Protection-at-Lightpath (MP-PAL).

• Heuristic Algorithm: MP-PAC, MP-PAL.• Illustrative Numerical Examples.• Conclusions.


• Features in Multipath Traffic GroomingFeatures in Multipath Traffic Grooming sub-connection grooming; a connection can be carried by multiple sub-connection grooming; a connection can be carried by multiple

wavelengths. Survivability is critical.wavelengths. Survivability is critical.

• Subject to Multiple ConstraintsSubject to Multiple Constraints

-- DDC: Differential-Delay Constraint-- DDC: Differential-Delay Constraint

-- IMF: Inverse-Multiplexing Factor-- IMF: Inverse-Multiplexing Factor

-- Grooming Ports: Grooming-Add/Drop, Bypass.-- Grooming Ports: Grooming-Add/Drop, Bypass.

• Enabling TechnologyEnabling Technology

-- VCAT: Virtual Concatenation; -- VCAT: Virtual Concatenation;

VCG: a group of VCAT for same connectionVCG: a group of VCAT for same connection

Constraints

• IMF:

• Grooming ports:

W-fabric

G-fabric adddrop

Simplified Node Architecture

Wavelength SwitchFabric

(W-Fabric)

Tx Rx

Grooming Fabric (G-Fabric)

buffer

Local Add Local Drop

Split: connection sub-connectionsAggregate: sub-connections connection

One connection can be carried by multiple wavelength channel

Grooming:Drop, Add, Pass-through

Buffer is used for differential-delay compensation

… …

… …

… …

… …

……Fiber In Fiber Out

Problem Statement

• Given:

Network G = (V, E, C, D, W, P, g, DDC, IMF)

Request R = <s, d, B, th>

• Task: Route each R, w.r.t. DDC, IMF.• Requirements:

Every R needs to be protected against single fiber link failure while minimizing the extra cost of working and backup paths.

• Note: Backup capacity can be shared (disjoint working

paths). A special case (IMF =1, DDC=∞) is NP-Complete. Heuristic algorithm is desired.

Multipath Grooming Issues

• Single-Primary-Path Grooming: Generic Graph Model -- λ layer, lightpath layer, access

layer, One Node Six-Vertices model

• Generic model cannot be adopted for multipath grooming directly.

• Lightpaths are set up over “constrained” link-disjoint paths.

• It requires new analytical model.

Layered Analytical Model

Connection

f-lightpath

Lightpath

Physical Topology

Backup Sharing

Routing

Setup connection:1) Calculate disjoint paths from physical topology2) Search or setup lightpath3) Build f-lightpath4) Select backup and assign capacity5) Find sharable backup capacity using conflict set model6) Reserve capacity7) Add f-lightpath and establish connection

Teardown: Reverse process.

setup teardown

Protect Methods, f-lightpath

• MP-PAL: protection-at-lightpath level

Save grooming ports for backup lightpath.

• MP-PAC: protection-at-connection level

both working and backup can use same wavelength channel.

• f-lightpath: a flow of lightpath containing one link-disjoint backup path and multiple disjoint primary paths. A path includes one or a sequence of lightpath.

Example:

f-lightpath Primary Backup

flp1( l1, l5 ) ( l2, l3, l8,)

flp2( l4, l5 ),

( l6 )

( l7, l7)

Provisioning Example

Illustrative Numerical Examples

Bandwidth distribution:STS −3c : STS −12c : STS −21c :STS−48c : STS−96c : STS−192c = 20 : 10 : 10 : 4 : 2 : 1

Assumptions:• Poisson arrival • Neg.-exp.–dist. holding time• Uniformly dist. node pair • 16 wavelength per unidir. link • Always select the shorter path as working paths• grooming ports parameter ∆• Full wavelength conversion

Main Performance Metrics:Bandwidth Blocking Ratio (BBR)Resource Overbuild (RO)

MP-PAC BBR and RO vs. IMFMP-PAC BBR and RO vs. IMF

MP-PAL BBR and RO vs. IMFMP-PAL BBR and RO vs. IMF

Comparison BBR: MP-PAC vs. MP-PALComparison BBR: MP-PAC vs. MP-PAL

Comparison RO: MP-PAC vs. MP-PALComparison RO: MP-PAC vs. MP-PAL

MP-PAC BBR and RO vs. Grooming PortMP-PAC BBR and RO vs. Grooming Port

MP-PAL BBR and RO vs. Grooming PortMP-PAL BBR and RO vs. Grooming Port

Comparison BBR: MP-PAC vs. MP-PAL

Comparison RO: MP-PAC vs. MP-PAL

Conclusions

• Network performance can be notably improved by exploiting inverse-multiplexing capability.

• Tight constraints have negative impact.• The four layered model is an efficient method

for studying multipath grooming problem.• In general, MP-PAC outperforms MP-PAL

unless grooming ports is moderate or small.

A Multistate Multipath Provisioning A Multistate Multipath Provisioning Scheme for DifferentiatedScheme for Differentiated Failures Failures

inin Telecom Mesh NetworksTelecom Mesh Networks[6][6]

[6] S. Huang, Ming Xia, Chip Martel, B. Mukherjee, “A Multistate Multipath Provisioning Scheme for Combating Node Failures in Telecom Mesh Networks,” in 2009 IEEE Military Communications (MILCOM 2009), Boston, USA, Oct. 18-21, 2009.

OutlineOutline

• Introduction

• Failure definition and protection

• Provisioning state and transition model

• Problem statement and solutions

• Illustrative numerical examples

• Conclusion

University of California, DavisUniversity of California, Davis


• Disaster failures have significant impact on communication Disaster failures have significant impact on communication networks (one node failure in a backbone network with a networks (one node failure in a backbone network with a large area of link failures).large area of link failures).

• Multipath Provisioning inherently provides better Multipath Provisioning inherently provides better survivability to deal with a disaster.survivability to deal with a disaster.

• A lot of network survivability research works assume A lot of network survivability research works assume network nodes are completely reliable, but in reality they are network nodes are completely reliable, but in reality they are subject to disaster failures, e.g., earthquake.subject to disaster failures, e.g., earthquake.

• New research area: survivability against Weapons of Mass New research area: survivability against Weapons of Mass Destruction (WMD) attack.Destruction (WMD) attack.


Introduction: A Simple ExampleIntroduction: A Simple Example

• Request (s-d): STS-24

• Failure at Node m : STS-12 (50% )

• β = 75% Pb=STS-18

1 1bSTS-12; STS-12; P STS-12w wP P

Single-link failure protection is not enough

to protect node failure !


Failure Definition and ProtectionFailure Definition and Protection

• Failure definition: SF: Single-link Failure MF: Multi-link Failure DF: Disaster Failure (node failure)

• Node failure in DF: Failure on source or destination node. Failure on an intermediate node.

Source and destination node failures are un-restorable. The connections losing their source/ destination node will be dropped (unless data replication).


Failure Definition and Protection (Cont.)Failure Definition and Protection (Cont.)

• SF: Primary/Backup. Multiple link-disjoint paths between s-d pair. Set one as backup.

• MF: Reprovisioning. Reassign capacity on remaining paths. Re-route a connection.

• DF: Degraded service. Proactive capacity assignment to meet the

degraded service requirements (β * B).University of California, DavisUniversity of California, Davis

DF (Single-node Failure) Protection


DF (Single-node Failure) Protection (Cont.)(Cont.)

Provisioning State and Transition Model

• Provisioning State (P-state): P0 : Provisioning without failure. P1 : Provisioning upon SF. P2 : Re-provisioning upon MF. P3 : Provisioning upon DF. Poff : Termination State (blocked, expired, dropped).

• Customer State (C-state): C0 : Guaranteed degraded service. C1 : Low priority, best effort degraded service.


State Transition Model

Request

RWA/CA

P0

P1 P2

P3Poff

Event State Transition

SF Arrival P0 P1;

Departure P1 P0;

MF Arrival P0P1; P0P1 P2;

P1 P2;

Departure P1P0; P2P0;

DF Arrival P0P1P2P3;

P0P1P2P3Poff;

P1P2P3;

P1P2P3Poff;

Departure P3P2P0;

• Define Provisioning States: P0 – NF; P1 – SF

P2 – MF; P3 – DF

Poff – Expire/Tear-Down P0, P1, P2 – B ; P3 – β*B

Block

Expire

Accept


Problem Statement

• Given: Network G = (V, E, W, g) Request R=<s, d, B, ht, β, βth, Cx>

• Task: Route each request using MP.• Objective:

SF, MF: protection with full bandwidth. DF: degraded service is guaranteed.

C0 : degraded-service guaranteed (β*B). C1: best-effort (βth) with lower priority.


Heuristic Algorithms

DREAM-MP-P0/P1:

1. Find Link-Disjoint Paths Set with DDC.

2. Assign Capacity with Node failure aware (disaster-aware).

3. Calculate Backup Share

4. Reserve working and backup capacity.

5. Switch to backup resource for SF protection.

DREAM-MP-P2 (MF):

Given MF information, re-provisioning (no backup).

DREAM-MP-P3 (DF):

1. Find impacted connections and switch to their degraded service in P3 state.

2. Reprovision all existing connections in C0 state (guaranteed level of partial service).

3. Reprovision all existing connections in C1 state (drop it if minimum threshold of original bandwidth can not be provided).


Illustrative Numerical Example

• Request Bandwidth distribution:50M : 100M : 600M : 1G : 2.5G : 5G :10G = 50 : 20 : 10 : 10 : 4 : 2 : 1

• Cx distribution: C0:C1=7:3. β (0.5,0.7,0.9) βth = 0.5, 16 wavelengths (STS-192 each).• Failures arrive following

independent memory-less process, and have negative exp. Distributed holding time with 0.01667 mean (12 hours).

• Failures begin to arrive after a total of 20,000 connections arrivals.

• Compare with SPLIT-MP (P0, P1 only).

BDR: Bandwidth Dropping RatioCDR: Connection Dropping RatioBBR: Bandwidth Blocking RatioRO: Resource Overbuild


DF Protection Performance StudyDF Protection Performance Study

DF Protection Performance Study (Cont.)DF Protection Performance Study (Cont.)

MF Performance StudyMF Performance Study


SF Performance StudySF Performance Study


Disaster-Protection-Zone (DPZ) ProtectionDisaster-Protection-Zone (DPZ) Protection

Link-failure SRG: r1, r2, r3; Node-failure SRG: n1 and n2;Disaster Protection Zone: DPZ0 and DPZ1


Comparison for Data ReplicationComparison for Data Replication



• A novel Multipath Provisioning scheme was devised for different failures.

• Connectivity can be significantly maintained even under disaster-failure (node failure) with demonstrated bandwidth efficiency.

• Our algorithm outperforms a generic node-disjoint algorithm.

• Multiple node failure and destination failure are also studied using SRG and data replication.


Thank You!

• http://networks.cs.ucdavis.edu/~sheng• Publications• Multipath routing source code• More to come… Makefile for latex, etc.

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