VoIP Voice Quality - Not There Yet But Not Too Far Away
By Michael Lemm
I have been hearing and reading about lots of complaining concerning the voice
quality of a VoIP connection....both residential and business Is this real or
memorex (so to speak). Just what are the REAL issues...and where may we
(especially businesses) be headed with the maturation of VoIP?
The issue is still that our IP networks are packet based. This is efficient for moving
data, but not so good for time and sequence sensitive traffic.
Over private networks, we can adjust the communications elements for session
versus packet centric performance. We make sure we have sufficient bandwidth
to allow a smooth stream of session traffic (VoIP for example), we adjust
prioritization so that session traffic has priority, we change our balancing and
routing to insure sessions follow a consistent symmetrical route. The result is a
less efficient use of our bandwidth capacity, but a higher quality session for the
users. In short, we move away from the purely packet delivery focus and towards a
channel like network.
Over the Internet, we lose the ability to optimize our session traffic. The Internet is
by design application neutral. The focus is on packet delivery, and each packet is
as important as every other packet. At each step in the communications path, the
devices are tuned to receive a packet, determine which port to send it out next,
and move it on its way. Load balancing across multiple paths, each packet to a
given destination may take a unique route. The criteria for success is the delivery
of packets error free.
So what is likely to happen? I expect prioritization of session traffic over the carrier
networks. They will implement it first for their own services, and the cost of doing
so will be recovered from that service revenue. It will be available to individuals,
companies, and competing service providers as a premium service. After all, it is a
level of delivery above what simple Internet access promises. To work, the carriers
will have to agree on respecting each others prioritization when traffic moves from
one carrier to another. This will probably be no different than their current method
of carrying each others traffic from business sense, and the engineers will quickly
work out the technical aspects. The VoIP service companies will scream that this
isn't fair, that their service is simply using bandwidth paid for by their customers'
access fees. However, session prioritization is not what their customers' have
contracted for, so their complaints will be ignored. A new level of access will
become common - possibly called Voice Assured or something along that line.
At some point, either a new startup carrier or an existing carrier will decide to
market session priority as part of their standard level of service. If sufficient
customers switch to get this, the other carriers will follow suit. By that time, most of
the networks will have become session prioritized as the standard build.
Big iron will not benefit from all of this.
Some session service providers will lose out to the carriers because their business
model relies on the performance of a competitor. Some will step up and pay for
session priority so that their customers do not. If they can survive with the reduced
margins until session priority becomes the norm, they will retain their customer
base.
(Q)Has anyone experienced poor call quality using VoIP?
Yes - of course most people have knowingly or unknowingly. VoIP traffic in all
methods of delivery- Skype, Vonage, Cable, IP-PBXs, Peer-2-Peer, softswitches
and COs... have varying degrees of voice quality issues in their experiences with
VoIP. At least for now.
(Q)Is this a case of poor equipment, poor software, bad connections, or what?
This is a very broad issue. Too many people expect to "just plug it in" and it's
going to work- whatever "it" is defined as. The same is true about VoIP due to
marketing, misfires, bad judgment, and inexperience.
There are many other reasons too - DSPs which are improving (Fact), software
gets fatter which patches the known existing issues and maybe creating a few new
unknowns still (My belief), connections- a few in the cables, connectors themselves
but everything is relevent to what is defined as VoIP which is just a protocol- what
about all those other things to access, control, and transport those packets?
Then - keep in mind that a significant majority of "telephone lines" are copper,
TDM based. Longer loops have boosted loop current levels and mixed with IP --
you get echo.
The "list" of issues or causes and effects is just mind boggling. It's not simple or
black and white - short answer is "it depends."
Once VoIP can meet those expectations of "just plug it in" then we will in doubt be
in a new world of telecom. It's a journey and it will be an adventure for those that
tough it out. It will be interesting to see and experience how it all plays out.
(Q)Do you think that less than toll quality voice will be a limit to the growth of VoIP?
No. Less than toll quality isn't a VoIP metric for enterprise or carriers (Big Iron) or
the softswitch world either. VoIP as a whole - is improving- at least so says the
media.
:) Call quality is moving away from what we do for example with software and an
appliance to watch voice packets, equipment, and other things... to embedded
monitoring call quality within the software itself reporting back across the network.
This is significant in when it becomes the norm--- then less expensive solutions to
monitor, packet shape, and direct voice packets to their final destinations on time
will notably change quality, MOS scores, etc. Who can afford the existing tools
other than Big Iron and L-Enterprise ?
(Q)If poor voice quality continues can this cause a backlash against VoIP and a
return to Big Iron for some companies?
Not likely. Too much is already invested and proven in the way of the carriers
successfully delivery VoIP traffic without the end-user knowing they are in fact on a
VoIP segment or call. Ethernet Layer 2 provides a slightly cheaper method of
delivery over TDM and since cost is always a factor and as "techniques" improve
so will delivery. It isn't likely that a "pull out" will occur.
(Q)What can be done to raise VoIP voice quality to toll grade?
It depends upon which audience is addressed. From where I sit:
1) Training - Certification - Field Experience by those implementing VoIP;
2) Metrics that measure not just MOS but the actual voice packets for jitter,
latency, etc and then accountability in the missions of those making the decisions-
did we achieve our objective and what were the true costs in doing so and how did
it impact us?
3) Timing - hardware isn't getting worse, it's getting better. (That's a fact) The
industry is in a learning curve- one that's not going to become stagnant because
delivering VoIP in any form factor is challenging- it's not for those faint of heart.
(Implementers)
4) User Expectations - this is one of the greatest failures not just in VoIP but
delivery of any telecom / IT service or solution. The expectations are not set and
there is a consistent failure of "the meeting of the minds."
5) Benchmarking vs. Hook-Line-Sinker - instead of ramping an entire effort for
VoIP cut-overs - organizations need to set some bench marking in place first. The
temptation to go big vs small because the leaders within the organization need to
score a big hit (cost savings).
6) QoS, access, transport, infrastructure - these all apply to any user of VoIP.
Before jumping in, catch up and get into more specifics about what is wanted,
methods of delivery, metrics, how VoIP is planned before inking a deal or making a
change with someone promising them something better, faster, cheaper - as with
anything.
VoIP is here to stay. Sink, swim, or paddle - it's rewarding, it's a beast to manage,
challenging and very rewarding for those who are prepared.
Michael is the owner of FreedomFire Communications....including
DS3-Bandwidth.com and Business-VoIP-Solution.com. Michael also
authors Broadband Nation where you're always welcome to drop in and catch up
on the latest BroadBand news, tips, insights, and ramblings for the masses.
By Michael Lemm
I have been hearing and reading about lots of complaining concerning the voice
quality of a VoIP connection....both residential and business Is this real or
memorex (so to speak). Just what are the REAL issues...and where may we
(especially businesses) be headed with the maturation of VoIP?
The issue is still that our IP networks are packet based. This is efficient for moving
data, but not so good for time and sequence sensitive traffic.
Over private networks, we can adjust the communications elements for session
versus packet centric performance. We make sure we have sufficient bandwidth
to allow a smooth stream of session traffic (VoIP for example), we adjust
prioritization so that session traffic has priority, we change our balancing and
routing to insure sessions follow a consistent symmetrical route. The result is a
less efficient use of our bandwidth capacity, but a higher quality session for the
users. In short, we move away from the purely packet delivery focus and towards a
channel like network.
Over the Internet, we lose the ability to optimize our session traffic. The Internet is
by design application neutral. The focus is on packet delivery, and each packet is
as important as every other packet. At each step in the communications path, the
devices are tuned to receive a packet, determine which port to send it out next,
and move it on its way. Load balancing across multiple paths, each packet to a
given destination may take a unique route. The criteria for success is the delivery
of packets error free.
So what is likely to happen? I expect prioritization of session traffic over the carrier
networks. They will implement it first for their own services, and the cost of doing
so will be recovered from that service revenue. It will be available to individuals,
companies, and competing service providers as a premium service. After all, it is a
level of delivery above what simple Internet access promises. To work, the carriers
will have to agree on respecting each others prioritization when traffic moves from
one carrier to another. This will probably be no different than their current method
of carrying each others traffic from business sense, and the engineers will quickly
work out the technical aspects. The VoIP service companies will scream that this
isn't fair, that their service is simply using bandwidth paid for by their customers'
access fees. However, session prioritization is not what their customers' have
contracted for, so their complaints will be ignored. A new level of access will
become common - possibly called Voice Assured or something along that line.
At some point, either a new startup carrier or an existing carrier will decide to
market session priority as part of their standard level of service. If sufficient
customers switch to get this, the other carriers will follow suit. By that time, most of
the networks will have become session prioritized as the standard build.
Big iron will not benefit from all of this.
Some session service providers will lose out to the carriers because their business
model relies on the performance of a competitor. Some will step up and pay for
session priority so that their customers do not. If they can survive with the reduced
margins until session priority becomes the norm, they will retain their customer
base.
(Q)Has anyone experienced poor call quality using VoIP?
Yes - of course most people have knowingly or unknowingly. VoIP traffic in all
methods of delivery- Skype, Vonage, Cable, IP-PBXs, Peer-2-Peer, softswitches
and COs... have varying degrees of voice quality issues in their experiences with
VoIP. At least for now.
(Q)Is this a case of poor equipment, poor software, bad connections, or what?
This is a very broad issue. Too many people expect to "just plug it in" and it's
going to work- whatever "it" is defined as. The same is true about VoIP due to
marketing, misfires, bad judgment, and inexperience.
There are many other reasons too - DSPs which are improving (Fact), software
gets fatter which patches the known existing issues and maybe creating a few new
unknowns still (My belief), connections- a few in the cables, connectors themselves
but everything is relevent to what is defined as VoIP which is just a protocol- what
about all those other things to access, control, and transport those packets?
Then - keep in mind that a significant majority of "telephone lines" are copper,
TDM based. Longer loops have boosted loop current levels and mixed with IP --
you get echo.
The "list" of issues or causes and effects is just mind boggling. It's not simple or
black and white - short answer is "it depends."
Once VoIP can meet those expectations of "just plug it in" then we will in doubt be
in a new world of telecom. It's a journey and it will be an adventure for those that
tough it out. It will be interesting to see and experience how it all plays out.
(Q)Do you think that less than toll quality voice will be a limit to the growth of VoIP?
No. Less than toll quality isn't a VoIP metric for enterprise or carriers (Big Iron) or
the softswitch world either. VoIP as a whole - is improving- at least so says the
media.
:) Call quality is moving away from what we do for example with software and an
appliance to watch voice packets, equipment, and other things... to embedded
monitoring call quality within the software itself reporting back across the network.
This is significant in when it becomes the norm--- then less expensive solutions to
monitor, packet shape, and direct voice packets to their final destinations on time
will notably change quality, MOS scores, etc. Who can afford the existing tools
other than Big Iron and L-Enterprise ?
(Q)If poor voice quality continues can this cause a backlash against VoIP and a
return to Big Iron for some companies?
Not likely. Too much is already invested and proven in the way of the carriers
successfully delivery VoIP traffic without the end-user knowing they are in fact on a
VoIP segment or call. Ethernet Layer 2 provides a slightly cheaper method of
delivery over TDM and since cost is always a factor and as "techniques" improve
so will delivery. It isn't likely that a "pull out" will occur.
(Q)What can be done to raise VoIP voice quality to toll grade?
It depends upon which audience is addressed. From where I sit:
1) Training - Certification - Field Experience by those implementing VoIP;
2) Metrics that measure not just MOS but the actual voice packets for jitter,
latency, etc and then accountability in the missions of those making the decisions-
did we achieve our objective and what were the true costs in doing so and how did
it impact us?
3) Timing - hardware isn't getting worse, it's getting better. (That's a fact) The
industry is in a learning curve- one that's not going to become stagnant because
delivering VoIP in any form factor is challenging- it's not for those faint of heart.
(Implementers)
4) User Expectations - this is one of the greatest failures not just in VoIP but
delivery of any telecom / IT service or solution. The expectations are not set and
there is a consistent failure of "the meeting of the minds."
5) Benchmarking vs. Hook-Line-Sinker - instead of ramping an entire effort for
VoIP cut-overs - organizations need to set some bench marking in place first. The
temptation to go big vs small because the leaders within the organization need to
score a big hit (cost savings).
6) QoS, access, transport, infrastructure - these all apply to any user of VoIP.
Before jumping in, catch up and get into more specifics about what is wanted,
methods of delivery, metrics, how VoIP is planned before inking a deal or making a
change with someone promising them something better, faster, cheaper - as with
anything.
VoIP is here to stay. Sink, swim, or paddle - it's rewarding, it's a beast to manage,
challenging and very rewarding for those who are prepared.
Michael is the owner of FreedomFire Communications....including
DS3-Bandwidth.com and Business-VoIP-Solution.com. Michael also
authors Broadband Nation where you're always welcome to drop in and catch up
on the latest BroadBand news, tips, insights, and ramblings for the masses.
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