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 usage
Formula: 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
– 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 narrative
Interdevice communication
Device properties
Routing and addressing
If applicable: SNMP management and conferencing
addressing
Passwords (if requested)
Start the argument early, and everybody wins.

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Network Readiness - Summary
– Service Level Agreements
– Service Targets
– Ports and Protocols
• Questions?

Assessing Network Readiness

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