VoIP Best Practices for Fejlanalyse

transcript

Welcome toImplementing VoIP:

VoIP Network Best Practices

Implementing VoIP:VoIP Network Best Practices

Agenda Introductions From Hype to Adoption VoIP Myths Anatomy of a VoIP Call VoIP Metrics Lab 1: VoIP in ActionBreak The Three Phases of Successful VoIP Deployment

Phase 1: Site Survey and Testing Phase 2: Monitoring the Roll Out Phase 3: Ongoing Troubleshooting and Maintenance

Break Lab 2: VoIP Call Monitoring Best Practices Summary Network Instruments Solutions Set Q&A

First things first:Introductions

Douglas Smith

President and Co-Founder of Network Instruments Oversees

FinanceSalesMarketingProduction

Works closely on product design with company CEO, Roman Oliynyk

A part of the networking community since 1985 Awarded degrees in Math and Economics

from University of Wisconsin-Madison

Charles Thompson

Manager of Sales Engineering Works directly with the Network Instruments

sales team and partner channel to provide…Technical expertiseProfessional services In-depth product information for enterprise

accounts Travels throughout North America conducting

workshops and presentations on network analysis

Personally trained thousands of network managers on the Observer product line

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Network Instruments

Founded in 1994

40,000 licenses sold ~4K new customers

annually

12 offices worldwide

Sold in over 75 countries

2005 growth Overall: 24%

Celebrating 11 years of continued company growth

Network InstrumentsCompany Growth

History of Product Innovation 1st affordable Windows-based analyzer

1st distributed software-based protocol analyzer

1st to include SNMP for switched environments

1st 802.11 a/b/g wireless analyzer and remote probe

1st combined wired and wireless solution together

1st to support 64-bit Windows

1st to develop multi-session, multi-user probes

1st to integrate application analysis

1st to develop enterprise-ready VoIP Expert

Distributed Architecture Advantages

Distributed Network Analysis Architecture

NI-DNA™ - Distributed Network Analysis

NI-DNA provides Distributed and complete functionality for every type of Network topology in any location using the most intelligent Analysis tools

Unified Code Unified Code SetSet

Two key components: the console, which displays data and the probe, which is used for data collection and processing.

ScalabilityScalability

FlexibilityFlexibility

ModularityModularity

AffordabilitAffordabilit

Local/Remote Local/Remote VisibilityVisibility

Observer console includes a local probe for local analysis and connects to remote probes.

VisibilityVisibility

EfficiencyEfficiency

ProductivityProductivity

SecuritySecurity

Multi-Topology Multi-Topology SupportSupport

Observer’s single user interface can manage multiple Gigabit links, 802.11 connections, 10/100/1000 Ethernet and Wide Area networks.

AdaptabilityAdaptability

SimplicitySimplicity

TransparencyTransparency

ReliabilityReliability

Analysis OptionsSoftware

GigaStor

10/100/1000 Probe Appliance

WAN and Gigabit Probe Appliances

Top TalkersMultiHop Analysis

Connection Dynamics

Application Analysis

SNMP Management

VoIP Analysis

Gigabit and WANObserver Suite System

Snapshot of Customers

From Hype to Adoption

Market researchers expect the number of VoIP users worldwide to increase

from around five million in 2004 to 200 million subscribers in 2010

http://www.heise.de/english/newsticker/news/64129

“Ninety-nine percent of all VoIP network implementations that fail

do so because IT departments didn’t do their homework.”

-- William Stofega, VoIP research director, IDC

VoIP Monitoring and Analysis Challenges

Current, competing tools were designed for lab use No method of quickly determining status and health No mechanism for understanding aggregate call quality VoIP dependencies are not implemented properly Separate tools increase learning curve, reduce ROI

Other VoIP tools

Observer 11

Common VoIP Myths

VoIP Myths

Myth #1

Running VoIP without Quality of Service

is acceptable

Contention = Delay Why is Quality of Service important?

Managing VoIP means managing delay

Even a network with large bandwidth capabilities can have poor call quality due to network contention

QoS measures can help make VoIP traffic less susceptible to adverse network conditions

QoS offers VoIP traffic more consistent availability

VoIP Myths

Myth #2

No VoIP Site Survey is necessary

Site Surveys are Critical

With the decision to implement VoIP, one of two choices are usually made

IT managers keep network conditions the same and add VoIP traffic

IT managers upgrade their bandwidth capacity

Site Surveys are Critical Result

Does not solve or address potential VoIP problems

Network adjustments are made after deployment has begun

Deployment issues can cause user resistance to VoIP technology

Adding bandwidth may not be necessary or offer value

Common VoIP Myths

Myth #3

Voice conversations are secure

VoIP Conversations are a Security Risk

VoIP is another piece of network data

Tools are used to capture not only voice conversations but to also generate audio playback for later use

Higher-end VoIP systems may offer a way to encrypt data but many existing or lower-end systems do not

VoIP traffic is most vulnerable on the LAN since Internet WAN traffic is typically through VPNs

Consider wiretapping rules and regulations

Anatomy of a VoIP Call

How does VoIP work?

H ow VoIP phones send audio s tream s over a network

W A NLA N LA N

S e nd R e ce ive

01001101 01001101

E n cod e a nd pac ke t ize N e tw o rk d e la y, jitte r, & pa cke t los s J it te r sm o o th ing , de cod e , & p la yb ack

To ta l de la y b udg e t o f 1 50 m s o r le ss (one w a y)

How does VoIP work?

VoIP phones use codecs to translate analog sound streams into digital packets for transmission

On the receiving end, the codec translates the packets back to analog

To ensure normal conversations, all of this musthappen as close to real-time as possible

VoIP Metrics

VoIP Basics

What is VoIP?

Packetized voice traffic sent over an IP network

What challenges does it bring?

Competes with other traffic on the network

A new technology that needs real-time, consistent monitoring

Sensitive to delay

VoIP Basics Understanding VoIP begins with understanding

Normal trafficNot sensitive to delayExample: FTP, HTTP, e-mail, etc.

Tolerant trafficSensitive to delayLoss tolerantBuffered by receiverExample: streaming video, Internet radio,

Real-time trafficDelay and loss sensitiveExample: VoIP

VoIP Terms

Jitter

R-Factor / MOS

Burstiness / Gap / Gap Duration

QoS / TOS / Precedence

Compression Techniques (Codecs)

Jitter What is it?

Jitter is the variation in the time between packets transmitted and received

For example, if a packet stream leaves a device with 30 ms packet spacing and arrives with 50 ms packet spacing, the jitter is 20 ms

N etw orkIP P hone

010011011234

Jitte r buffer Codec

VoIP packets can arrive at the receiving phone out of sequence, late, early, or not at a ll. IP phones use a to reconstruct the packet stream at the receiving end, duplicating m issing packets or filling in with white when necessary.

jitter buffercomfort noise

Jitter buffe ring and packe t loss concea lm ent

Jitter Why measure it?

Understanding jitter gives hard facts to help improve call quality

Excessive jitter will confuse callers about who is speaking and who is listening

Adjusting jitter buffers can help at the expense of increased latency and thus, clipping. Jitter buffer overflow will introduce dropped packets.

Observer’s Jitter MeasurementIn aggregate…

and per call…

Call Quality Scoring

What is it?

Industry standard methodologies for associating a grade to a call

R-factor Identifies live call quality using a single

source of visibility Based on E-Model (ITU G.107)Scale: 1-100Typically the maximum value would be

93.2 after standard degradation Codec usedNetwork delay Jitter bufferPacket loss

MOS User satisfaction level with a callTakes into account a number of different factors

Handset qualityAmbient noiseNetwork performance

Scale: 1-54.0 and higher considered satisfied4.5 and higher extremely satisfied

On simulated calls, traffic is captured at the destination and compared to the originalsent data to identify degradation

Why measure Call Quality?Provides objective and subjective scores

to evaluate existing conditions to compare with historical conditions.

Observer’s Call Quality Scoring

In aggregate…

per call…

and Expert…

Burstiness and Burst Density What is it?

A burst is a period of time characterized by high rates of packet loss

Burst percentage is the % of time bursts are occurring Burst density is the rate of VoIP data packets lost

during a burst period

Why measure it?

Higher rates affect call quality, especially when coupled with long average burst duration times

Possible reason for packet loss include network congestion, media failure, and link failure

Gap Density and Duration What is it?

Gaps are the periods between bursts A gap is a period of time characterized by lower levels of

packet loss than the burst periods that bound it Gap density is the percent of packet loss during gaps Average gap duration is measured in time

Why measure it?

Knowing the gap helps define the burst In most cases, packet loss during gaps is rendered

insignificant by concealment techniques built into the VoIP infrastructure

Observer’s Burst and Gap Density

In aggregate…

and per call…

Settings for QoS / Precedence Support for multiple definitions of Quality of Service (QoS)

Also known as Precedence or Type Of Service (TOS)

What is it? QoS is a bit setting used by routers and switches to

prioritize packet flow

Why measure it? Incorrectly set QoS can

lead to VoIP or other network contention

Contention will lead to delays in packet delivery, reducing call quality

Observer’s QoS/TOS/Precedence

In aggregate…

per call…

and Decode…

Compression Techniques

Codec is a term for Coder/Decoder

Different compression techniques (codecs) G.711: 64kbps (no compression) G.729: 8kbps G.723: 6.3kbps, 5.3kbps

Higher compression reduces R-Factor and MOS but also reduces potential contention

Which Codecs Are Used?In aggregate…

per call…

and Decode…

How does VoIP work?

H ow VoIP phones send audio s tream s over a network

W A NLA N LA N

S e nd R e ce ive

01001101 01001101

E n cod e a nd pac ke t ize N e tw o rk d e la y, jitte r, & pa cke t los s J it te r sm o o th ing , de cod e , & p la yb ack

To ta l de la y b udg e t o f 1 50 m s o r le ss (one w a y)

Capture and Decode of a VoIP Call

Agenda Introductions From Hype to Adoption VoIP Myths Anatomy of a VoIP Call VoIP Metrics Lab 1: VoIP in ActionBreak The Three Phases of Successful VoIP Deployment

Phase 1: Site Survey and Testing Phase 2: Monitoring the Roll Out Phase 3: Ongoing Troubleshooting and Maintenance

Break Lab 2: VoIP Call Monitoring Best Practices Summary Network Instruments Solutions Set Q&A

Phase 1: Site Survey and Testing

Site Surveys are Critical

Conduct a Site Survey to review…WAN link bandwidth levelsCurrent traffic flowsView existing switches for bottlenecks and

choke pointsDetermine needs through testing and modelingPlacement of analysis tools

The more you know about your network the better prepared you are to properly integrate VoIP

WAN Link Bandwidth Levels

Summary

Port 1 Source DCE

Port 2 Source DTE

Port 2 Source DCE

Port 1 Source DTE

Long-Term Trending

Estimate VoIP Impact

How will VoIP traffic affect the network?

First, determine number of potential users Assume users spend 20% of their day on the phone

Includes active calls as well as VM retrievalVideo will add to utilization

Varies based on site

Determine the codec in use; for example: G.711: 64kbps (no compression) G.729: 8kbps G.723: 6.3kbps, 5.3kbps

Examples: VoIP Impact

100 users on site, 20% usage = 20 concurrent sessionsG.711 Codec: 1.28 MbpsG.729 Codec: 160 kbpsG.723 Codec: ~120 kbps

Bandwidth impact using a T1 at 1.54 MbpsG.711 Codec: 83%G.729 Codec: 10%G.723 Codec: 8%

Current Traffic Flows

Assuming one drop per user, evaluate connection speeds and current usage

If multiple network drops per user, not applicable

Find Bottlenecks and Choke Points

Determining switch, router, and device utilization Review uplinks and shared pipes

Testing and Modeling

Do a pilot test to generate sample calls in various network conditions

Capture live data and model hypothetical situations

Switch codecs to find optimal performance

Use Observer’s “What-If” Analysis to predict response

Here is an example using Observer…

Review Observer’s UDP Events to find live calls

1 User

100 SimultaneousUsers

1000 SimultaneousUsers

Placement of Analysis Tools

Where should you place your analyzer tools for maximum visibility?

Depends on what you’re wanting to seeEach call includes both client and server

communications

If you need access to all local conversations…Use a SPAN session on the access layerAssign all VoIP traffic to a dedicated VLAN

Points of Visibility Consider a sample network

VoIP ca llm anage r

C ore sw itch

A ccess layer

VoIP ca llm anage rC ore sw itch

A ccess layer

M PLSM esh

East CoastO ffice

W est CoastO ffice

Points of Visibility

Capturing local IP traffic shows

Phone’s communication with its local call manager

Both sides of the full-duplex connection between local phones

Both sides of the full-duplex connection between phones located across a WAN

VoIP C allM an ager

A ccess sw itch

VoIP C allM an ager

MPLSMesh

East CoastOffice

West CoastOffice

C onnection vis ible to ana lyzerC onnection h idden from ana lyzer

Need a more coherent view of calls across WAN links?

Use a SPAN session to mirror…

Both the uplink traffic between the core and MPLS mesh

All traffic flowing to and from the call manager

VoIP C allM an ager

A ccess sw itch

VoIP C allM an ager

MPLSMesh

East CoastOffice

West CoastOffice

C onnection vis ible to ana lyzerC onnection h idden from ana lyzer

C oreS w itch

For complete coverage, and complete visibility connect analysis probes to both the core and access layers at each site

Phase 2: Monitoring the Roll Out

Verifying VoIP Health

Cumulative VoIP MetricsSatisfaction Scoring Aggregate Jitter Total CallsCodec Verification

Network Configuration and PerformanceQuality of Service / PrecedenceVerifying VLAN ConfigurationReviewing Link Utilization

Monitoring Overall VoIP Health

Call Scoring

Aggregate Jitter

High jitter or low call scoring is an issue

If this is the case, go back and review your setups

Codecs Used

Total Calls

Is the network responding as expected with the total number of calls?

Is the right Codec being used?

Is Quality of Service / Precedence configured properly?

Verifying VLAN Setup

Identify VLAN setups and verify that VoIP traffic exists in its appropriate VLAN

Verifying VLAN Setup

Is the station in its appropriate VLAN?

Link Utilization

Verify utilization for each link

Ensure that what you see here coincides with information gathered from “What-If” Analysis in the testing phase

Phase 3: Troubleshooting and Ongoing Maintenance

When Problems Arise

TroubleshootingReal-time nature of the callCall flow analysisAutomated problem identification and resolutionCall mapping for jitter, lost packets, and

utilization spikesUse trending data to report on period in question

for traffic analysis

Ongoing MaintenanceProactive MonitoringSchedule Reporting

Real-Time Call Analysis

Review calls in real-time

Track for any inconsistencies

Call Flow Analysis

Identify call in question Track individual stream that comprise the call Drill down to Connection Dynamics

Connection Dynamics

Expert Help

Speed problem resolution by obtaining instant possibilities of network issues

Automate problem resolution

Call Mapping

Compare jitter to bandwidth utilization to understand RTP/RTCP response time

Is this a bandwidth issue?

Trending Obtain a snapshot of a

time period in question Check to see if current

conditions are deviating from historical data

Monitoring and Alerting

Select which VoIP characteristics should be continuously monitored

Determine what threshold levels are acceptable and set triggers accordingly

Customize the appropriate network action based on the event

Review Expert thresholds crossed or exceeded

Shows where thresholds

were exceeded

Scheduled Reporting Customize reports to provide the necessary insight for long-

term analysis and planning Schedule the reports for automatic delivery on a daily,

weekly, monthly, or even yearly basis

Sample Report

Choose from a variety of report options and types or create custom reports

Live VoIP Troubleshooting

Summary

Best Practice #1

Understand and measure the various components of call

quality

Best Practice #2

Implement Quality of Service

Prioritization

Best Practice #3

Conduct a Site Survey

Best Practice #4

Deploy analysis tools strategically for

maximum visibility

Best Practice #5

Implement VLANs to help isolate and

monitor VoIP issues

Best Practice #6

Monitor the rollout to ensure a positive user

experience

Best Practice #7

Compare jitter to overall network bandwidth utilization to understand response time

Best Practice #8

Set up your analyzer to proactively monitor

VoIP activity

Best Practice #9

Automate problem resolution

Best Practice #10

Baseline your network traffic

Network Instruments Solution Set

Analysis OptionsSoftware

GigaStor

10/100/1000 Probe Appliance

WAN and Gigabit Probe Appliances

Top TalkersMultiHop Analysis

Connection Dynamics

Application Analysis

SNMP Management

VoIP Analysis

Gigabit and WANObserver Suite System

Customer Feedback

“So far, Observer’s VoIP capabilities have helped cut down CI Travel’s

phone bill by about 25-30 percent.”

Paul Ingram, CI Travel

Solid Reviews and Testimonials

Observer continues to receive stellar reviews from industry pundits and our valued customers

“…it is the best packet analysis package we have tested .”

- Dave Bailey, IT Week, December 1, 2005

“Traffic statistics in Observer 11's VoIP Expert tool are more robust, with call summary, quality scoring and detailed per-call metrics such as call status, current jitter, call setup, duration, teardown, MOS/R-factor and QoS levels.”

- Dan Hong, Redmond, November 16, 2005

“Like all Observer features, VoIP Expert is based on the Network Instruments Distributed Network Analysis architecture, which means VOIP analysis is available across multiple topologies such as local-area network, wide-area network, Gigabit Ethernet and 802.11a/b/g.”

- Michelle Speir Hasse, Federal Computer Week, November 21, 2005

Recent Wins

Large-scale GigaStor deployment

Sniffer replacement For maintaining customer

networks

Large-scale 10/100/1000 appliance deployment for 90% of U.S. locations

Sniffer replacement For comprehensive visibility

Large-scale 10/100/1000 appliance deployment across U.S. locations

Sniffer replacement For distributed analysis

Large scale Expert probe deployment

For real-time network monitoring

Enterprise Pricing

VoIP Analysis included at no additional charge Shipped with a 64-bit Core, with support for 32-bit systems Gigabit and WAN Appliances are all 64-bit systems

Expert Observer Includes VoIP US$ 2,895

Observer Suite Includes VoIP US$ 3,995

10/100/1000 Probe Appliance Includes VoIP US$ 2,495

Gigabit Probe Appliance Includes VoIP US$ 11,995

2 TB GigaStor Includes VoIP US$ 19,995

Network Instruments continues to lead the analysis industry in performance and value

Thank You

For more information:Network Instruments, LLC

Chuck Oxleyphone: 416-285-9191

toll-free: 1-800-526-7919 x3897e-mail: coxley@networkinstruments.com

www.networkinstruments.com

VoIP Best Practices for Fejlanalyse

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