a survey of recent advances in network planning/traffic engineering (te) tools

A Survey of Recent Advances A Survey of Recent Advances in Network Planning/TE Toolsin Network Planning/TE Tools

Vishal Sharma, Ph.D.Metanoia, [email protected]://www.metanoia-inc.com

Metanoia, Inc.Critical Systems Thinking™

© Copyright 2006All Rights Reserved

APRICOT’06, Perth, Australia, 1-2 March 2006 2


Copyright 2006All Rights Reserved

Agenda

TE tools in network design process and tool workflow

Taxonomy of TE tools Architecture

Design

Functions/features

New enhancements (last 1-2 years)

A perspective on current carrier needs

Operation and key features of representative TE tools OPNET’s SP Guru and VNE Server

Cariden’s MATE

PARC’s Route Generator (now part of Cisco IPSC)




Traffic Engineering Tools in the Overall Network Design Process

SS7 SignalingNetwork Design

Optical Link Configuration

Bandwidth Requirements

Link Requirements

Switch NetworkDesign

ATM NetworkDesign

IP/MPLS NetworkDesign

SONET/SDHNetwork Design

Optical RingNetwork Design

Optical MeshNetwork Design

Traffic DemandGeneration/Estimation

SONET/SDHSynchronization

We are here

Note: In a combined multi-layer network design, this strict division may not hold




TE Tool Workflow: Control Exercised over Varying Timescales

Forecast traffic demandsTraffic requirements

Performance objectives

Traffic measurement dataObserved network statesForecast

Load

Load Uncertainties

Traffic Managementpkt. level processing,

routing control, congestionmanagement

Capacity Managementcapacity allocation, cap.planning, routing, design

management

Network Planning network dimensioning,modeling, perf. analysis,

what-if analysis

ms, sec, min

days, weeks

months, years

Controls(config/reconfig)

ActualLoad

Network

Datacollection

TE Tools




Taxonomy of Modern Tools: Architecture

Centralized or distributed?

Obtaining network topology &

utilization info?

Inputs

Their formats?

Interface with n/w elements?

Outputs

Their formats?

Installing routes/LSPs in n/w?

Path route computation

On-line, dynamic?

Off-line, global?

Combination of above?

Route computation trigger

User? Administrator?

New request(s)?

Scalability

# of links & nodes handled?

# of flows, LSPs, circuits?

# of constraints handled?




Taxonomy of Modern Tools: Design Philosophy

Control-centric

Long time scales

Large granularity flows

Verisimilitude-centric

Pkt. by pkt. sims. of elements & network

Traffic trace-based perf. simulations

Hybrids

Long time scale analysis for network perf.

Pkt. level sims. for element & flow performance




Taxonomy of Modern Tools: Functions/Features by Task

Operations Engineering/Architecture Planning

Network design + opt.

Flow analysis

Simulation &experimentation

Network planning

Multi-protocolmodeling

Survivability analysis

Economic analysis

Monitoring

Diagnostics

Validation




Taxonomy of Modern Tools: Recent Enhancements

IGP tuning – Layer 3 traffic engineering

Incorporation of FRR – bypass, detour

Routing of VoIP calls – with queueing delay and MOS

Diff-Serv aware TE – set pool boundaries

Coupling with physical layer topology

Multicast support – for multimedia apps.

Modeling new services – VPLS, PWs, L3 VPNs




Canonical Structure/Organization

H/w DeviceModels

User Interface/GUI/Command Line

Simulate

Analyze

Design

InternalEngine

ModulesIGP

MPLS-TE

Protection

RerouteOutputs

Config.Files

Inputs

Inputs

(Topo, Cap., Failure)Analysis

Reports

Eco. AnalysisForecasting

NMS

EMS EMS

Vendor Data Extraction

EquipmentInventory

Network

Data ExtractionData Conversion

Element DataElement State/Stats

Measurements/Probes




A Perspective on Some Current Carrier Requirements

Accurate planning models

IP n/w planning with peering

Useability and consistency

Obtain precise traffic matrices

Good interface with monitoring tools

Intelligent heuristics

Extensible architecture

Application-level performance monitoring

Multicasting for multi-media services support




OPNET Technologies

Founded 1986, ex MIT experts in communication system modeling

Intelligent network management software

OPNET Modeler, original flagship product

Comprehensive, comunication network modeling tool

Allows for modeling nodes, links, physical characteristics

In-built models for common communication protocols

Flexible extensions possible via C-like language

Solution suites

Service Providers: SP Guru, WDM Guru, CapEx Optimizer

System vendors: SP Guru, Modeler, NetBiz




OPNET SP Guru: Components & Features

ProcessInputs

Discovery via NMplatforms for topology

Simulate failure &overload to get:- Worst-case loading- % disrupted traffic- SLA violation

Config.Verification

FlowAnalysis

FailureAnalysis

NetworkDesign

NetworkSimulation

MPLSModule

Integrated topo.,config., util. datafrom VNE Server

Switch/routerconfig. filesTraffic & link util.

data from systems

Traffic matrix info. fromdata collection tools

- Family of design algos.- TE capability- Impact of new algos. ortechnologies, e.g. VPNs

- “What-if” scenarios- Reachability analysis- Arch. & cost for givenQos, delay, jitter, loss- Current n/w loading

- Distribution of trafficon network links

Network model: nodes, links,speeds, topology, metrics

Validate configs.Deploy validated config.

Export n/wconfig.

- Primary/sec. path layout- FRR backup tunnels

Network simulation and analysis




OPNET SP Guru: Internal Operation

Operates in 3 flavors

Fully-detailed, event-driven simulations

Partially event-driven simulations

Analytic simulations

OnlyPackets

OnlyFlows

Packets, Flows, Loads

Discrete EventSimulations

FlowAnalysis

Hybrid Simulations

Useful fortransient events

Micro-simulations viaspaced tracer packets

For iterative design& failure analysis




OPNET SP Guru: NetDoctor

Rule-based config. & performance verification component

Diagnoses problems from misconfigs. or protocol conflicts

NetDoctor

Series of specifiedconfig. changes

Near real-time n/wdata from VNE Server

Output of SP Gurusimulations

Verify networkoperation

Network levelconfig. verification

(150+ rules)

User-defined rule-basedconfig. verification




OPNET SP Guru: VNE Server

Collect data from multiple sources

Merge to create a unified picture, useful for planning, engg., ops.

VNE Engine

VNE reports

- Identify changes- Merge and synchronize

VNEDbase

Device config.-NM tools

PM tools

Tables

SNMP MIBs

Asset info.

Adapters(extensible)

Many user I/Fs: console, mgt. I/F,n/w browser for assets, link util.info., protocols run, ...

JDBC compliant

Networktopology

H/Wconfig.

S/Wconfig.

Topo.

Util. data

From n/wdevices




OPNET Solutions: Key Characteristics

NetDoctor for configuration & network operations analysis

VNE Server

Automated I/F to various network data components

Ability to build a complete network view

Hybrid simulation techniques

Provide balance between speed and resolution

Ability to add SP’s own rules, algorithms, modules

Facility to map actual IP addressing to internal network model




Cariden Technologies

Founded 2001, ex Stanford, experts in OR, statistics, software

MATE: suite of tools for TE-related tasks

Data gathering: integrated module or plug-in

Simulation: OSPF/IS-IS, BGP, MPLS multicast, Diffserv, ...

Optimization: Offline MPLS LSPs, IGP tuning (unique), chageover

Control-centric architecture

Does IGP planning for IP networks

Emphasis on ease-of-use




MATE TE Process

DataCollection

DemandEstimation

RoutingOptimization

ChangeoverPlanning

User-definedConstraints

ChangeoverExecution

UserMonitoring

MATE’s TE System Components




MATE IGP Traffic Engineering

Problems

Uneven link utilization

Heuristic/ad-hoc planning

Coarse capacity upgrade rules (e.g. at 50 or 75%)

Above 60% utilization expected in 6 mo!

Sample network with projected traffic growth in 6 months

Original network state




MATE Routing Optimization

[Reproduced with permission: Cariden Technologies]

Objectives

Max. headroom on failure

Max. normal headroom

Minimize latency

Constraints

Fixed intra-site metrics

Symmetric weights

Latency bounds

Results

Max. link util. 89% 59%

Max. link util. on failure 110% 92%

All links brought to below 60% utilization

under normal conditions




MATE Resilience Capabilities

Before (worst case) After (worst case)

>> 95% utilization

Max. utilization under 92%




MATE: Changeover ExampleExtract from a Changeover Plan

[Source: Cariden Technologies]

A step-by-step procedure to move network from current to new config.

Sequence of single metric changes to effect transition

At each step, continue to meet limits on latency, utilization




MATE: Key Distinguishing Characteristics

Demand estimation & characterization Estimate p2p demands from aggregate node/intf. demands & routing

Estimate effective b/w per queueing class to meet QoS for demands

Robust routing changeovers Sequence of moves to transition network from one routing/LSP pattern to

another via a series of “make-before-break” operations

IGP metric-tuning based optimization in IP networks

Practical BGP simulations – peering, load balancing

Fully cross-platform – supports client/server or client-only model




PARC Technologies1

Founded 1999, ex Imperial College, London, experts in OR and optimization

Funded March 2001, $23M from Cisco, CSFB, NTT

Acquired by Cisco circa July/Aug. 2004

Control-centric architecture

Had products in two areas

Network analysis: decision support for IP operators & planners

Route Generator: off-line tool for path computation in MPLS-TE n/ws

1 Now part of Cisco IPSC




PARC IP Network Analysis: Modules & Operation

Collection of modules for key analysis functions in IP networks

Traffic FlowAnalyzer

ForecastAnalyzer

ResilienceAnalyzer

NetworkOptimizer

NetworkAnalyzer

LSP + I/Fcounters

Router I/F thputmeasurements

Routerconfig. files

Knowledge ofVPN structure

E2E traffic flows

Futuredemands

Currenttraffic flows

Forecastdemands

Combine info. from flowanalyzer & forecasts

Produce future utilizationreport

Identify link/nodefailure that network isnot resilient to

Consider current and futuretraffic loads

Recommend changes to n/wtopology — add nodes/links

Derive e2e trafficflows in the SP n/w




PARC IP Network Analysis: Operation

Key idea

Observe SP network state ...

Predict how network reacts to a changed environment

Designed for

IP-only networks

IP/MPLS n/wks (with or w/o TE)

Network AnalysisModules

Classes of Change Analyzable

- Topology: link/node failure

- Planning: adding node/link

- Deltas to traffic matrix

Predictions

- Max. utilization under link/node failure

- Traffic flow change on adding a link(s)

- Impact of incremental TE in plain IP n/w

ObserveAnticipatedChange(s)

Carrier Network

Outputs




PARC Route Generator: Features & Operation

DemandAdmission

Constraints

RepairScenarios

NetworkGrooming

NetworkResilience

ProtectionAudit

Primary Tunnel Routing

FRR Backup TunnelRouting

- Bandwidth- Delay- Protected elements- Affinity

ObjectiveFunctions

Minimize- Utilization- Metrics- Disruption- Delay

Maximize- Routed b/w- Spare b/w- B/w sharingUse Cases




PARC Solution Performance: Bandwidth Sharing Efficiency

Average Shared Bandwidth per Link •

0

1

2

3

4

5

6

7

NET1 22

NET2

54

NET4

101

NET5

236

Network Size (Nodes)

Ave

rag

e S

har

ed

Ba

nd

wid

th

BRG

CSPF

NET3

38

Maximum Shared Bandwidth per Link

0

5

10

15

20

25

30

35

Network Size (Nodes)

Ma

x S

ha

red

Ba

nd

wid

th

BRG

CSPF

NET1 NET2

54

NET4

101

NET5

236

NET3

38

Same bandwidth reused across different failure cases

[Reproduced with permission: PARCTechnologies Ltd.]




Key Characteristics of PARC’s Solutions Interacts w/ routers, creates a full model of n/w routing

Uses measurements to implicitly derive traffic matrices

Leads to very accurate bounds on aggregate flows

Tool for intelligent probe placement for n/w data collection

RG allows provisioning of bandwidth-on-demand services

Accounts for session duration and CAC

Advances in algo. hybridization + constraint programming

Prove problem infeasibility or solution optimality

a survey of recent advances in network planning/traffic engineering (te) tools

Technology

network simulation

network perf

sample network

opnet sp guru

taxonomy of modern tools

traffic engineering

agenda te tools

overall network design