assessing network readiness

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Assessing Network Readiness

Copyright 2012 by InfoComm International®

Network Readiness - Introduction

• This session includes the following topics:• Service Level Agreements• Service Target Levels• Ports and Protocols

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Service Level Agreements


The Importance of Documentation

When you install a new service or system:

– How often does the system need to work perfectly?

– How long should the system last?

– Whose fault is it if it stops working?

– How soon does it need to be fixed?

Revolutionary idea: the customer is NOT always right.

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Needs Analysis

• Operational Needs• Determines the

Applications• Determines the Tasks that

can be done• Determines the Functions

and Features

Needs

Applications

Tasks

Functions and Features


Equipment List

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Service Level Agreement - Definition

• AV needs analysis - usually captured in Program Report

Based on needs analysis/program meeting

Comes from the architectural field

Focused on physical space

• IT service requirements - usually captured in SLA

Defined by the ITIL

Not tied to user's physical location

Focused on network requirements


Service Level Agreement Definition

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Service Level Agreement Definition

It’s a contract!


Types of Service Level Agreements

– Service-based SLAs cover one service for everyone that uses it

– Customer-Based SLAs cover all services provided to a group

– Multi-Level SLAs include a customer SLA for the enterprise, customer SLAs for groups, and service SLAs

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Service-Based SLA

• A fixed level of service offered to a wide range of users

• Standardized services offered at standardized prices


Customer-Based

• Services specific to the individual customer’s needs

• Not necessarily transferrable to a class of customers

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SLA Use Guidelines

All types of service providers should use SLAs.

Any time a new service is added to the network, an SLA is updated or created.

SLAs can exist in hierarchies.

SLAs thoroughly document system limitations.

SLAs evolve over time.


Service Level Agreement Components

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The SLA Lifecycle

1.Needs analysis - just like a program report.

2.Service targets - must be measurable.

3.Roles and Responsibilities - could include pricing.

4.Measure and Enforce - weekly measurements at first.

5.Review - service providers and customers are held accountable.


AV's Role in the SLA

• Roles with respect to the SLA differ according to project.As an end user help identify service targets

As a customer define the need and sign the SLA

SLA As a service provider write and sign the SLA

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Service Targets


Service Targets - Introduction

• This section includes the following topics:– Bandwidth

– Latency

– Packet Loss

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Bandwidth Usage Target Factors

Traffic is bursty.

You cant specify the whole capacity for use.

How much can you specify? 70%? 50%?

Using VLANs, QoS, and traffic shaping, more bandwidth can be specd for use.

Consult the network manager.


LAN to WAN Bottlenecks

LANs are exponentially faster than WANs

"Bottlenecks" can occur, like a six-lane highway merging to two lanes

Determine the speed of the WAN

Optimize design to keep high bit-rate traffic within LAN

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Quality of Service

Applications will take as much bandwidth as they can.

Insufficient bandwidth mean lost packets and/or long delays.

QoS prioritizes data and/or reserves bandwidth.


Bandwidth: Matching Content to the Network

70% of the rated network capacity is really available (or what network manager says)

Rated capacity is based on bottleneck point speed

Allows for collision avoidance, even in a switched network

30% of available network can be used for streaming media.

Otherwise other traffic has to wait

QoS (Quality of Service) is required

Bandwidth management (throttling)

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Streaming and QoS

Has QoS been implemented?

Existing differentiated service classes

Resource Reservation Protocol (RSVP)

Policy-based QoS rules

Traffic shaping


Conferencing and Bandwidth

– QoS is required – videoconferencing should have its own class of service

– Bandwidth is only relevant in terms of network segment

• 4 Mbps on one segment + 4 Mbps on another segment = 4 Mbps total

– Your goal is to find per segment usageFormula: Bandwidth per Segment for an MCU Call

(Bit Rate + 20% overhead ) * Number of Simultaneous Calls = Bandwidth Required

Each endpoint = simultaneous call.

If IPSec VPN is being used add an additional 5% of overhead.

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Common Videoconferencing Bit Rates

Endpoint Type Rate

Mobile/Software‐based 192 kbps

384 kbps

Desktop/Room‐based 512 Kbps

768 Kbps

HD Desktop/Room‐based 1024 Kbps

1472 Kbps

Immersive 1920 Kbps

3840 Kbps

4096 Kbps


Videoconferencing Bandwidth Example

Multipoint call with 6 endpoints

MCU and one endpoint at hub

Two 768 kbps streams from one site

1.9 Mbps streams from all others

How much bandwidth is required?

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• Hub Site LAN• [(0.768 + (0.768 * 0.2)) * 2] + [(1.9 + (1.9 * 0.2)) * 4] = • [(0.768 + 0.154) * 2] + [(1.9 + 0.4) * 4] = • [(0.922) * 2] + [(2.3) * 4] = • 1.844 + 9.2 = • 11 Mbps



Branch to Hub WAN Spokes[0.768 + (0.768 * 0.2)] * 2 = (0.768 + 0.154) * 2 = 0.922 * 2 = 1.844 Mbps

[1.9 + (1.9 * 0.2)] * 1 = [1.9 + (0.4)] * 1 = 2.3 * 1 = 2.3 Mbps

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Dedicated Network Links for Videoconferencing

Video can use up to 70% of a dedicated link

Audio can use even more

If MPLS is used, make sure dedicated links have their own access link to the MPLS provider


Latency Target Factors

Network response time

Is there QoS?

Is there packet shaping?

Presentation layer latency

Application specific factors

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Latency

How much latency is inherent? o Internal speed test server

o www.speedtest.net

o www.speakeasy.net

o www.dslreports.com

How much latency is acceptable? o Videoconferencing: 200 msec

o High fidelity audio: approx 50 sec

o Desktop video (streaming): 1 sec!

Will data be encrypted?


Videoconferencing Latency

Manufacturers claim to tolerate up to 200 ms

IEEE 401 recommends no more than 100 ms

Test inherent latency - provide dedicated links as necessary

Encryption will introduce additional latency

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Packet Loss Target Factors

How many packets can your application can be expected to drop?

Calculate peak and average bandwidth consumption

Compare to peak and average available throughput

Assess impact of dropped packets

Reserve bandwidth or reduce scale if necessary

Ports and Protocols

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Ports and Protocols - Introduction

• This section includes the following topics:– Ports and Protocols

– Firewalls

– Ports and Protocols Document


Ports

• Port number - indicates the application that sent/will use the data

System ports (0 - 1023) - assigned to standards track protocols

User ports (1024 - 49151) - assigned to application upon request

Dynamic ports (49152 - 65535) - cannot be assigned

• Socket – combination of Port and IP address; identifies a unique session

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Common Ports for AV

Protocol TCP Port(s) UDP Ports

HHTP 80

Secure HTTP (HTTPS) 443

File Transfer Protocol (FTP) 20 (data), 21 (control)

Secure Shell (SSH) 22 22

Telnet 23

Simple Network Management Protocol (SNMP) 161 161

Domain Name System 53 53


Identifying Ports and Protocols

Opening a port is a security concern.

Required ports should be documented for the network manager.

Required ports should be listed in manufacturer specs.

Verify specs using a network analyzer.

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Firewall

Firewall: any technology that protects from intrusion/regulates traffic

May allow all traffic except what’s forbidden

May forbid all traffic except what’s allowed

Either way: document and coordinate!


Ports and Protocols Document

Communicates and documents device connectivity needs.Device narrativeInterdevice communicationDevice propertiesRouting and addressingIf applicable: SNMP management and conferencing addressingPasswords (if requested)

Start the argument early, and everybody wins.

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Network Readiness - Summary

• This section includes the following topics:– Service Level Agreements

– Service Targets

– Ports and Protocols

• Questions?

assessing network readiness

Technology

service slas

service targets copyright

infocomm international

service requirements

new service

class of service bandwidth

fixed level of service

qos quality of service