12 vo ip-t-hutchinson-11feb2011
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Carleton University
February 11th, 2011
Voice over IP
Presenter: Tony Hutchinson
System Engineering Manager
February 11th, 2011 Slide 2
Voice over IPCarleton University
Biographical Information
Tony Hutchison
Expertise:
VoIP and network design
PBX Design, TDM, ISDN, Ethernet, PSTN (PRI, BRI and Analogue), EMC, Safety
Telephony and data, TDM and PDH design
Current Position - 1998 to Present
System Engineer Manager – Mitel Networks (Canada)
VoIP design, PBX, Hosted Services, Network Design
Technical interface with RnD and customer facing Sales/System Engineers
Previous Positions (UK)
Telecom Sciences – SME PBX System Engineer
Philips – SME ISDN PBX System Designer (for the global market)
GEC – Transmission and Multiplex system (analogue and digital design)
Education
Birmingham University (UK): Electronic and Computer Engineering (Hons.)
February 11th, 2011 Slide 3
Voice over IPCarleton University
Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 4
Voice over IPCarleton University
Executive Summary
Business Case
VoIP
Toll Quality
?
Security?
Not In
tern
et
Convergence
of cabling
Moves, Adds,
Changes
Business Expansion
Enterprise/Branch office
Distributed BusinessHot DeskingResilie
ncy
Toll Bypass
Cut acrossgeographies
WorldCom
TDM Backup
Two towers NY
IP-Trunks
Cost ofdedicated
links Cost ofinfrastructure
Traffic rates
Line cardsVs L2
switches
Structurdwiring
Convergence
Voice/Data
Video
Conference
CTI
InteractivePresentation/
Passive
Services
Dial Tone
Hook Switch
Soft Phone
Teleworker
Road warrior
VPN
Voice Mail
UnifiedMessaging
PDA integration
BusinessApplications
Hotel
Security
Video/Cable
Infrastructure
SIP
Megaco
Signalling
ProprietaryFeatures
ManagedNetwork
SLA
VPN
ISP Access
MPLS
MAN
WAN
Fixed link
FrameRelayHistory
Lots Learnt
Lots
Forgotten
Signalling
Protocols
2W/4W
Echo
Sidetone
Acoustics
Ergonomics TransmissionLevels
LocalInternational
Challenges
Internet
Local
ISP
ManagedNetwork
OSI 7 Laye
rVoice
Quality
Toll
MOS
PESQ,PSQM
Maintaining
Guarantee
Bandw
idth
CODEC
G.711
G.729
G.726
WidebandVAD
VLAN
PriorityTOS
Diffserv
E911
Hybrid
Echo
Delay
Security
DOS NAT
Firewall
Encryption
PacketSize
Overhead Traffic
Delay
Jitter BufferConnectionless
PowerNetwork
impairments
Packet Loss
Culture
DataWorld Telecom
World
Training
NewStandards
Demarcation
Clock Sync
FAXIn-BandData
MODEM
POS
H.323
24/7
24/7
Agents
Presence
Real Internet
CableTV
Telephone
Numbers
GeographicIndependence
IPTDM
February 11th, 2011 Slide 5
Voice over IPCarleton University
Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 6
Voice over IPCarleton University
History
There has been much experience learnt in 100 years
Some is so common place, it has been forgotten
With IP some of these lessons need to be re-learnt
Echo was previously just louder side-tone
Added delays now affect conversation quality
Network Clocks were previously well defined
Data path wasn’t lossy, with potential gaps in speech
February 11th, 2011 Slide 7
Voice over IPCarleton University
Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 8
Voice over IPCarleton University
Business Case
So why all this interest in IP? Isn’t it just another transport medium?
Yes
Connectionless
Not constrained to a physical location
Path between two user points is not pre-defined, can change dynamically
Bandwidth is only consumed when needed
Cost Alternative
The long haul carriers (e.g. AT&T) are already carrying data traffic in their large networks (at a lower cost)
So, send voice as data and pay less!
Why Now?
Moore’s Law
Cheaper Processing
More readily available
February 11th, 2011 Slide 9
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Business Case
So why deploy IP rather than TDM?
Easier and cheaper maintenance: Integration of data and voice onto one network
Consolidation of trunk access to a central SIP gateway (IP) across the business
Lower operating costs: Integration of remote offices over a common corporate data network, rather than through PSTN. Single Dial Plan.
Access from anywhere: Power users such as Teleworker and sales ‘Road Warrior’. Global Access
Lower product costs: Integration of a voice application onto a central server, e.g. voice mail, means reduced number of devices. The remote sites no longer need their own local VM.
Security, Resiliency and Availability: In NY (September 11th) the IP infrastructure kept running; the PSTN didn’t
Future applications will be data centric, e.g. “Presence”
Displacement of current TDM systems and businesses
February 11th, 2011 Slide 10
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Business Case
There are still reasons for both IP and TDM to live together
Legacy devices are still going to be around (for some time) and people will still use these, e.g. FAX, remote MODEM
TDM is still likely to be the connection to the PSTN
Most businesses have a directory number via the PSTN. Not all have a fixed IP address.
By 2017, expected that most new PSTN core installations will be IP only
Mobile and 4G will increase VoIP uptake in the next 7-10 years.
By 2014 expected ratio is 5 mobile to 1 land-line connection
Existing landlines are being bundled with IP access for “last mile” access
~50% of mobile connections by 2020 expected via IP = $345Billion!
~30% of mobile IP connections expected through Google, Facebook, Yahoo
Largest growth area (mobile/smart phones) expected to be Asia Pacific
February 11th, 2011 Slide 11
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Business Case
In the Business PBX space three main tiers are emerging:
Managed Hosted Centrex
Globally the uptake is increasing, with predictions beyond $16billion
That’s a big market, and competition is fierce!
Hosting offers opportunity for VoIP without local “boxes”. High growth sector, but still early adopter cycle
Wireless connections and new data modes allow IP connections to be provisioned much easier in countries where it has traditionally been difficult to provide standard telephone cables and wires.
Global Service Revenues
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
2007 2008 2009 2010 2011 2012
Year
Rev
enue
s ($
mill
ion)
IP centrex service rental
Hosted IP PBX service rental
Managed IP PBX service rental
Total service revenues
February 11th, 2011 Slide 12
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Business Case
Largest revenue split today (Business Phones)
Americas Europe
Largest growth sectors:
Latin America Eastern Europe MEA Many smaller countries just
adding IP infrastructure
Slowest growth sectors:
North America Western Europe But it’s still growth!
Revenue Split 2011
NA
LA
W.Euro
E.Euro
MEA
Asia-Pac
ROW
February 11th, 2011 Slide 13
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Agenda
Executive Summary
History
Business Case
Services/Content
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 14
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Services/Content
What services are people looking for?
Basic hook-switch and dial tone
Call handling features
Advance features such as call centres, agents
Remote location, e.g. Teleworker, Remote Agent
Networking between sites
Virtual Private Networks
New features such as voice recognition
Integration with current applications such as customer accounts, hotel registration, etc.
Business Process Improvements
Unified Communications and mobility, including Fixed Mobile Convergence
February 11th, 2011 Slide 15
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Services/Content
Today the industry is comfortable at the level of V1 applications
Biggest features are Toll Bypass and Networking
Early adopters are now taking V2 and V3 applications
Remote workers and Applications that don’t require access to the office
Remote ACD, help desks, etc
“Road Warriors” - Sales
Service Personnel
Mobility integration
Common access number for all connections
By 2011 it is expected that in the US, 41% of companies will be IP only, using SIP trunks in favour of TDM
Aff
ect
on
b
usin
ess
February 11th, 2011 Slide 16
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Services/Content
Centralized Unified Messaging
Globally Accessible
Integrates with E-mail and mobile services
Presence and call routing
Redirection of calls based on time, availability and caller to different end points
Integration with Microsoft, e.g. Lync™ 2010, or LCS and existing user databases, e.g. Active Directory
Fixed Mobile Convergence
One number - able to pick up calls at desk and mobile, or alternative number
Switchover between mobile carrier and in-house Wireless LAN
ACD and call routing
Service is handled by same agent to give more personalized service
Agents located globally - full language support
Speech Recognition
Redirection of calls based on user spoken words
E-Business
Workforce is distributed, and mobile.
Inventory tracking, e.g. RFID tagging
On phone Advertising, e.g. hotel
Business Process ImprovementBusiness Process Improvement
February 11th, 2011 Slide 17
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Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 18
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Convergence
What do we mean by convergence?
Combining of different worlds
Different mindsets and cultures
Different set of standards
And why now?
Processing power is cheaper - Moore’s law!
Phones have more power today than early PCs
PCs and phones are standard desktop tools
Voice and data networks can be combined to ONE
Phones can now interact directly with data devices
February 11th, 2011 Slide 19
Voice over IPCarleton University
PSTN, Mobile/CellCircuit Switched
$455B
Internet, IP DataConnectionless
$18B
FR, ATM, PrivateLine
ConnectionOriented
$18B
Cable TV$75B
VoIP VoDSL
Convergence
Four main business areas are converging
Voice, TV, VPN and Data
Triple Play
Broadcast TV - 100% users
Telephony - 100% users
Internet - 40% users and up
Voice is still the biggest revenue earner
Incumbents need to grow and expand
Many Cable TV providers now offer IP connectivity, many also voice.
New IP providers: Hosted VoIP, SIP Trunks
Courtesy: ATM Forum
February 11th, 2011 Slide 20
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Convergence
Business A Business B
Replacement of Local Loop for Voice
LANLAN
Long Distance PSTNe.g. AT&T
CO,E.g. Verizon CO,
E.g. Bell
IP Network 1
SIP Trunk Gateway
SIP Trunk Gateway
SIP Trunk Gateway
Existing TDM
IP Network 2
SoftSwitch
Peer2Peer BGP Router
Existing IP
Usage
Migration
February 11th, 2011 Slide 21
Voice over IPCarleton University
Convergence
Convergence in the network is unseen by the user.
What does the user see at the access point?
Two line jacks into ONE?
In reality, once installed, building wiring isn’t removed
On new installations, it’s cheaper to pull too many wires, than not enough
Integration of ServicesIntegration of Services
February 11th, 2011 Slide 22
Voice over IPCarleton University
Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 23
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Infrastructure
What are the building blocks of the system and how are these connected?
Common Architectures and voice media paths
Signalling Protocols
Network Interconnections
February 11th, 2011 Slide 24
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Infrastructure
The voice media paths and switching define the type of system. Three main types are defined:
IP Enabled PBX Here a line card is simply replaced by an Ethernet card. Voice switching
is done in TDM. This is not scalable and adds unnecessary delay.
Hybrid PBX TDM and IP are handled equally, only traversing a gateway when IP and
TDM devices need to connect.
Typical in an SME/Enterprise environment
IP-PBX (Hosted) All switching is done in IP. TDM connections are generally only to the
PSTN via external gateway, which may be off-site.
Model used for Hosted services
G/W
IPPhone
IPPhone
TDMPhone
TDMPhone
Hybrid
G/W
IPPhone
IPPhone
TDMPhone
TDMPhone
IP-Enabled
G/W
IPPhone
IPPhone
IP-PBX
February 11th, 2011 Slide 25
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Infrastructure
Basic VoIP system building blocks
Gateway between IP and TDM
Media Gateway Controller
Call Control
Features and Services
End users
Different protocols use different names, but functions are essentially the same
Peer to Peer or Central Control?
Central is good at resolving resource conflicts
Peer to peer is resilient to network failure
SIP can handle both aspects
MediaGateway
MediaGatewayController
FeatureServer, e.g.Voice Mail
CallControl/MediaServer
IPPhone
IP
PSTN
IPPhone
MediaStreaming
Signalling
February 11th, 2011 Slide 26
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Infrastructure
Signalling Protocols are numerous and include:
H.323
MGCP/Megaco
SIP
Proprietary
Why so many Signalling protocols?
Different starting perspectives of the requirements
They all offer some advantage for different users
Most are evolving as new features start to roll out
February 11th, 2011 Slide 27
Voice over IPCarleton University
Infrastructure
H.323
Overview specification and includes: H.225 - Signalling H.245 - Media streaming TCP/IP and RTP/UDP/IP
One of the early protocols Standards based, uses current ISDN technology, works well for
interoperability between vendors Features are basic, but well proven Well proven ground rules about interoperability Centralised call control, based on known proven techniques, call state aware Slow to evolve Difficult to scale to millions of users Central call control = single point of failure Telephone routing biased rather than at application level
February 11th, 2011 Slide 28
Voice over IPCarleton University
Infrastructure
MGCP/MEGACO
MGCP was initially a proposal to IETF for a stateless gateway protocol, it has similarities to H.323, and has the ability to evolve
Combined forces with ITU to create MEdia GAteway COntrol
Similar to H.323 in content, but reduced messaging
New standard and evolving
Allows central and distributed call control access to a gateway
Was thought to be the front runner with Enterprise business but little is heard
Difficulties again in scaling from a global view. Different gateways need different controllers which need to intercommunicate.
February 11th, 2011 Slide 29
Voice over IPCarleton University
SIP (Session Initiation Protocol), RFC2543
More Client Server based and allowing Peer to Peer interaction. Call control can be distributed End devices need to be more intelligent than simple phones Has the ability to evolve quickly, and scale to large numbers Simple protocol, but lacks certain PBX capabilities Vendor specific options provide features Inter-vendor working is usually determined through “bake-off” but improving
as more vendors implement agreed solutions Networking features low, but improving Open Standards through IETF, agreed by many established industry leaders Continual proposal of new features and extensions SIP Extensions to include “proprietary” features to make them more
mainstream
SIP is the Internet Phone signalling protocol of choice
Infrastructure
February 11th, 2011 Slide 30
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Infrastructure
Business 1
Business 1
Service Provider 1
Internet
Service Provider 2
Business 2
Local Network Global Network
Local Network Management , one point of contact
Global Network Management, many points of contact
Common single private address space
Mixture of local private and public address spaces with overlapped addresses
Local QoS control No Guarantee of Qos or Service Level
Limited protocols Many protocols
February 11th, 2011 Slide 31
Voice over IPCarleton University
NAT
ALG
Private IP Address Space
Public IP Address Space
Infrastructure
Firewalls
Used to keep out unwanted access
Restricts flow of data both ways, including voice
Network Address Translation (NAT)
Maps many internal private addresses to limited number of public IP addresses
NAT is typically not application aware
VoIP media and signalling may include private IP addresses in messages which will be confusing externally in public IP space
Application Level Gateway (ALG)
Stateful and knowledgeable of protocol, e.g. SIP
Can translate private/public addresses within messages
NAT and IPv6
NAT and ALG will not be needed
Any device can access any other device in both public and private address space
Truly global access- one large address space
February 11th, 2011 Slide 32
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VoIP
Infrastructure
Carrier/SP
PSTN
LAN
LAN
SIP Trunk Gateway
Internet
SIP ALGLAN
Carrier2
Border Gateway
Architecture of SIP in a large carrier deployment
• SIP ALG provides IPv4 NAT and firewall functions for SIP (a.k.a. Session Border Controller (SBC))
Hosted
SIP ALG
SoftSwitch
Public IP
Private IPPrivate IP
Private IP
Public IP
Public IP
February 11th, 2011 Slide 33
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Industry Trends
SIP Trunks
SIP User
Network SP provides phones
Network SP provides end-end IP
IPv6 provides everyone with a global address
SPs compete on a global scale
Infrastructure
With IPv6 all devices can be addressed globally
Removes need for NAT and SIP Proxies (ALG), making global connections possible
For example: call control in NA, gateway in Asia, IP phone in Europe!
SIP is becoming an accepted global standard for IP media device signalling
SIP and IPv6 have the potential to become disruptive technologies in displacing the current (TDM) telephone network systems
Today
February 11th, 2011 Slide 34
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Agenda
Executive Summary
History
Business Case
Services
Convergence
Infrastructure
Challenges
February 11th, 2011 Slide 35
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The ChallengesMany!
There are many…
Voice Quality
Delay, lost data, jitter, echo
Network issues, non deterministic, connectionless
Bandwidth, packet overhead, queue delays
Clock synchronisation
NAT and ALG for “off-net” connections
Security
Emergency Location E911
IP address space AND translation
End points need to use the same media format, or CODEC
February 11th, 2011 Slide 36
Voice over IPCarleton University
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The ChallengesVoice Quality - Metrics
To a User - It’s a Phone!
Voice Quality Metrics
Toll Quality
Mean Opinion Score (MOS) of 4.0 or better
E-Model with R=80 or better
Output based on many inputs:
Delay
Levels
Echo
Background noise
CODECR=88
Continued Voice Quality is expected Continued Voice Quality is expected
February 11th, 2011 Slide 37
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The ChallengesVoice Quality- Delay and Loss
Voice Quality
With good echo cancellation techniques
End to end delays of ~150ms are tolerable
1% packet loss with good Packet Loss Concealment is also tolerable
Jitter only becomes significant when it results in packet loss
Jitter buffer balance between adding delay and introducing packet loss
G.711 - QoS Versus Delay and % Packet Loss
40
50
60
70
80
90
0 100 200 300 400 500
Total One Way Delay (ms)
QoSR Value
0% PL
1% PL
2% PL
3% PL
1% PLC
2% PLC
3% PLC
Satisfied
Some User Dissatisfied
Many Users Dissatisfied
Nearly All Users Dissatisfied
Not Recommended
55 dB
Far EndEcho Loss
Note: Above 200ms an additional 20ms delay is worse than 1% packet loss with PLC.
Some Delay is tolerable Some Delay is tolerable
February 11th, 2011 Slide 38
Voice over IPCarleton University
The ChallengesVoice Quality - Echo
De-packetisation
Packetisation
SpeechDecode
SpeechEncode
Jitter Bufferand Packet
LossConcealment
Echo Canceller
NLP
EchoPrediction
D / A
A / D
Electrical Coupling
IP Gateway End Point
De-packetisation
Packetisation
SpeechDecode
SpeechEncode
Jitter Bufferand Packet
LossConcealment
Echo Canceller
NLP
EchoPrediction
D / A
A / D
Acoustic Coupling
IP-Phone End Point
Echo is always present, even in TDM
Delays in IP make this more noticeable
IP
IP
Control of Echo is importantControl of Echo is important
February 11th, 2011 Slide 39
Voice over IPCarleton University
The ChallengesVoice Quality - Delay
Let’s look at where delay occurs
Fixed Delays in CODECs and filters
Packet size delays to build a packet
Jitter Buffer
Network (which also introduces jitter)
End to End Delay = 79ms, but with 10ms jitter (router)
3ms
CODECFilters
2ms
20msPacket Creation
40msJitter Buffer
2ms
L2Switch
2ms
1-10ms
RouterQueue
1-10ms
2ms
L2Switch
2ms
2ms
CODECFilters
3ms40ms
Jitter Buffer20ms
Packet Creation
Network
Control of Delay is importantControl of Delay is important
February 11th, 2011 Slide 40
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The ChallengesNetwork Jitter
Where does jitter come from?
Serialization delay: Waiting for larger packets to transfer
Lack of Priority means all data is treated equally - First in First out
Apply priority queues for voice and set MTU to cut large packetsVoice 1 Voice 2 Voice 3 Voice 1 Voice 2 Voice 3
Data
Input
O/Pw/o
MTU
Voice 1 Voice 2 Voice 3 Data Voice 1
Delay x ms
O/PwithMTU
Voice 1 Voice 2 Voice 3 Data1 Voice 1 Voice 2 Voice 3Data2 Data3
MTU Breaks up large packets
Priority mechanism to get voice into gap first
Use QoS settings to prioritize voice and minimize jitterUse QoS settings to prioritize voice and minimize jitter
February 11th, 2011 Slide 41
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The ChallengesNetwork Jitter
Removal of jitter
Voice CODECs run at a constant rate
Too much or too little will result in a gap
Small gaps in voice are not discernable <60ms
Small gaps in tones are discernable
Jitter Buffer needed = Leaky Bucket
Packet Loss Concealment hides loss
Fill gaps with noise, silence
Remove data in fixed size, during silence
Packet Arrival
Buffer Fill
Jitter Range
Jitter Buffer = ‘Leaky Bucket’
PLC Hides lost packets
Jitter Buffer = ‘Leaky Bucket’
PLC Hides lost packets
February 11th, 2011 Slide 42
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The ChallengesClock Slip
Clock Slip
The CODEC at each end may run at 64kbits/s, but they have a tolerance
No clock synchronization, therefore need to add or drop data
Example of packet drop due to slip Suppose two device, each at 50ppm (TDM tolerance)
That’s 100 bits drift in 1 million bits, or
8 bits in 80,000 bits which = 1 bit every 1.25 seconds @ 64kbits/s, or
1 packet (160 bytes) every 3 minutes, 20 seconds
Clock slip buffer needs to consider this drift up and down
Often, slip correction is included with jitter buffer control to minimize media delays and complexity of multiple buffers
Clock Slip
Fast Clock
Slow Clock
Clock Slip needs to be consideredClock Slip needs to be considered
February 11th, 2011 Slide 43
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The ChallengesTransmitting Tones
Transferring tones is problematic if jitter buffer discards
A DTMF tone need only be 75ms long. Losing 20ms from this is significant, results in
No digit being detected, or double digits
Big deal? ‘91’ gets you out of a PBX, double digits get you ‘9911’, I.e. emergency services!
DTMF information can be sent ‘in-band’ as an RTP datagram using RFC4733
Call Progression tones can also be sent as descriptions using RFC4733
New standards RFC4733 and RFC4734 supercede RFC2833
RFC4733 ensures DTMF tones are transferred correctlyRFC4733 ensures DTMF tones are transferred correctly
February 11th, 2011 Slide 44
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The ChallengesFAX and Modem
In band tone transmission
Other devices use in band tones, such as:
FAX and MODEM
FAX will work, but only under very controlled network conditions, such as packet loss
MODEMs will work, but again under controlled conditions such as echo cancellation
Alternative CODEC for FAX is T.38 (and less often T.37)
Alternative CODEC for MODEM (V.150) is under investigation
Proposals have been made, but due to complexity there is currently little enthusiasm to include this in gateways.
Limited (proprietary) solutions are available.
FAX and MODEM need alternative CODECsFAX and MODEM need alternative CODECs
February 11th, 2011 Slide 45
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The ChallengesPacket Size
How big a packet should be used?
Consider bandwidth use with different payload size and overhead
10 to 50ms is a good size to use for voice
Below 10ms: more bandwidth for payload is needed
Above 50ms: voice delays cause quality issues
Good compromise is 20-30ms, many people fixing on 20ms.
Some administrations using 10ms to decrease user-user delay
Other issues also appear:
Smaller packets mean more Packets Per Second (PPS)
Wireless connections, especially WiFi, have difficulty with high PPS rates
Preference is for larger packets, but this adds more voice delay
20ms Packets - Good Compromise20ms Packets - Good Compromise
February 11th, 2011 Slide 46
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The ChallengesCODEC
So many CODECs, which one to choose?
G.711
This is the base level, so must be in (defined in H.323, and defacto)
G.726
Good voice quality, but limited bandwidth reduction
G.729, G.729a, G.729ab
Good reduction in bandwidth, with good voice quality
729a is reduced MIPS in conversion
729ab only sends with voice activity, so even less bandwidth, but voice may be clipped
Wideband (G.722 and others)
Works especially well for conferences, offering 8kHz voice Bandwidth
Balance of Voice Quality and Bandwidth usageBalance of Voice Quality and Bandwidth usage
February 11th, 2011 Slide 47
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The ChallengesBandwidth
How much bandwidth needed?
Payload
G.711: 160 Bytes (64kbps)
G.729: 20 Bytes (8kbps)
8:1 compression in payload
Overhead: RTP, UDP, IP, MAC and Ethernet + interpacket gaps (dead space that can’t be used)
With overhead only 5:2 ratio
CODEC Type Bytes per Packet BandwidthG.711 242 96.8kbits/sG.726/32k 162 64.8kbits/sG.729 102 40.8kbits/s
G.711 ~ 100kbits/s
G.729 ~ 40kbits/s
G.711 ~ 100kbits/s
G.729 ~ 40kbits/s
February 11th, 2011 Slide 48
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WAN/InternetLAN
The ChallengesNAT and ALG (Off network connections)
Private IP Address Space Public IP
Address Space
NAT (Translates header addresses between Private and Public networks)
ALG (Protocol Aware and translates messages as well)
10.10.1.1
2.3.4.55.6.7.8
SA DA Message10.10.1.1 5.6.7.8 Send Voice to 10.10.1.1
SA DA Message2.3.4.5 5.6.7.8 Send Voice to 10.10.1.1
SA DA Message2.3.4.5 5.6.7.8 Send Voice to 2.3.4.5
NAT Only
NAT and ALG
February 11th, 2011 Slide 49
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The ChallengesSecurity
Security:
How accessible is the equipment
Put a lock on the door!
How robust is the system to attack, DOS?
Harden system to cater for fault conditions as well as normal operation.
Authentication (Who is this?)
Authorization (Is this action allowed?)
Encryption (You can’t see this, well not easily)
Integrity (Did someone tamper with this?)
Phreakers gaining access for free calls, or charging others
Provide separate access, e.g. separate physical connection
Remove ‘backdoors’
Ring-back on MODEM
Lock the Door! Lock the Door!
February 11th, 2011 Slide 50
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The ChallengesSecurity
Security
Monitoring and substitution of voice
UDP has no ACK/NACK, can be substituted, redirected
Encryption, use of public and private keys
DES, DES-3, RC-4, AES, SSH, SSL, IP-SEC, etc.
Legal issues and Intellectual Property in distribution and use of encryption
Access through firewalls
Open up ports, but this makes it ‘look like a pin cushion’
Use a Session Border Controller, or Application Level Gateway, dynamically opens ports as needed.
VPN between sites, but not to Internet direct
Understand where data may be public and safeguard access and read rights
Understand where data may be public and safeguard access and read rights
February 11th, 2011 Slide 51
Voice over IPCarleton University
The ChallengesRules and Regulations
Emergency Location (E911)
Emergency Location (E911) requires that a person making an emergency call can be physically located within a pre-defined area
IP phones can move and be located globally
These requirements are potentially in conflict
New global standards and regulations are evolving to maintain this capability
IETF-ECRIT : “Framework for Emergency Calling using Internet Multimedia”
CALEA
Call Tracing, Malicious call handling
Wire-tapping
Charging for services
Who pays? The Internet is ‘free’ But, is it?
Local and Global rules need to be
applied
Local and Global rules need to be
applied
February 11th, 2011 Slide 52
Voice over IPCarleton University
The ChallengesIPv6
IPv4 Public Address
The current public address range is running out
Main users are NA and Europe
Insufficient for ROW
Exhaustion Prediction:
IANA allocation: Feb 2011
Regional Internet Regions: Nov 2011
IPv6 Public Address
Driver: 3G/4G wireless, internet connected appliances
Already being deployed in a number of countries IPv6 is here! IPv4 is
running out
IPv6 is here! IPv4 is running out
February 11th, 2011 Slide 53
Voice over IPCarleton University
Finale
VoIP is mainstream Business Process Improvement, rather than networking and toll bypass Mobility and Unified Communications
Technical challenges for voice quality are being overcome
The large Telecos are changing to embrace the IP changes, e.g. BT 21CN
SIP is becoming a common communication method and feature interaction between vendors is improving
IPv6 is being implemented to provide truly global communications
SIP and IPv6 are disruptive communication technologies Many business and global changes expected because of these Many carriers providing voice, data and now IP Voice services
Thank You