Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Joly MacFie]

On Sun, Nov 27, 2016 at 9:47 PM, Jay R. Ashworth  wrote:

> That is congruent with my understanding of how cableco voice is
> provisioned;
> it has different rules WRT VoN -- specifically about 911 -- because the
> cable
> company segregates it and handles it differently (your cablemodem is
> expected
> to be tied to your service address -- or whatever terminal device does the
> voice).
>

​I've seen some telco types refer to this as VuIP  i.e. "under IP" to
differentiate​ from VoIP such as Skype , Vonage, etc

Not sure if this applies to LTE.

j





-- 

Joly MacFie
President - Internet Society New York Chapter (ISOC-NY)
http://isoc-ny.org  218 565 9365

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Jay R. Ashworth]

- Original Message -
> From: "Luke Guillory" <lguill...@reservetele.com>
> To: "jra" <j...@baylink.com>
> Cc: "North American Network Operators' Group" <nanog@nanog.org>
> Sent: Sunday, November 27, 2016 10:18:20 PM
> Subject: Re: Voice channels (FTTH, DOCSIS, VoLTE)

> With MGCP we're just using DSx Qos which is just services classification 
> within
> the packet cable standard. Still runs over the same docsis network as all 
> other
> traffic and not separated besides qos side of things.
> 
> We use a 64K reserved channel to set the call up, after that each call has its
> own service flow that is QOSed.
> 
> We also have reserved BW in the CMTS for 911 calls so that they always get
> through.
> 
> Where the modem resides in relation to 911 isn't really a factor as we go by
> services address for the account, a customer could moved the modem to another
> house across town and it will still work.
> 
> I know Time Warner has completely separate networks for voice and data, they
> didn't even reside on the same CMTS from what I understand. Don't know of
> anyone else doing it that way.

It's my jackleg appraisal -- I'm not an attorney much less an FCC specialist
attorney -- that that subjects your service to regulations and restrictions
that don't pertain to people who do it the other way; you are simply a VoN
carrier, competing with all the other VoN carriers like Vonage; if you *do*
give your own traffic priority, then you're violating... title II? Some 
net neutrality provision that they don't cause they're not *moving the calls*
"over the Internet".

Cheers,
-- jra
-- 
Jay R. Ashworth  Baylink   j...@baylink.com
Designer The Things I Think   RFC 2100
Ashworth & Associates   http://www.bcp38.info  2000 Land Rover DII
St Petersburg FL USA  BCP38: Ask For It By Name!   +1 727 647 1274

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Luke Guillory]

With MGCP we're just using DSx Qos which is just services classification within 
the packet cable standard. Still runs over the same docsis network as all other 
traffic and not separated besides qos side of things.



We use a 64K reserved channel to set the call up, after that each call has its 
own service flow that is QOSed.

We also have reserved BW in the CMTS for 911 calls so that they always get 
through.

Where the modem resides in relation to 911 isn't really a factor as we go by 
services address for the account, a customer could moved the modem to another 
house across town and it will still work.

I know Time Warner has completely separate networks for voice and data, they 
didn't even reside on the same CMTS from what I understand. Don't know of 
anyone else doing it that way.


Luke



Sent from my iPhone

On Nov 27, 2016, at 8:49 PM, Jay R. Ashworth 
<j...@baylink.com<mailto:j...@baylink.com>> wrote:




Luke Guillory
Network Operations Manager


[cid:image1f21cf.JPG@56d24e46.43b1142f] <http://www.rtconline.com>

Tel:985.536.1212
Fax:985.536.0300
Email:  lguill...@reservetele.com
Web:www.rtconline.com

Reserve Telecommunications
100 RTC Dr
Reserve, LA 70084





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- Original Message -
From: "Mikael Abrahamsson" <swm...@swm.pp.se<mailto:swm...@swm.pp.se>>
To: "Jean-Francois Mezei" 
<jfmezei_na...@vaxination.ca<mailto:jfmezei_na...@vaxination.ca>>
Cc: Nanog@nanog.org<mailto:Nanog@nanog.org>
Sent: Monday, November 21, 2016 2:53:41 AM
Subject: Re: Voice channels (FTTH, DOCSIS, VoLTE)

On Mon, 21 Nov 2016, Jean-Francois Mezei wrote:

I need to verify some claims made by incumbents in Canada that VoLTE
data travels on a totally separate channel between the phone and the
antenna.

Typically it travels on another "bearer" compared to Internet traffic.

http://blog.3g4g.co.uk/2013/08/volte-bearers.html

Think of bearers as "tunnels" between the mobile core network and the
device. They have a lot in common with ATM PVCs in that they can have
different QoS characteristics. So the VoLTE bearer can have scheduling
priorities that means it'll always be low-latency and highest priority,
meaning it might work well when the "Internet" bearer does not.

That is congruent with my understanding of how cableco voice is provisioned;
it has different rules WRT VoN -- specifically about 911 -- because the cable
company segregates it and handles it differently (your cablemodem is expected
to be tied to your service address -- or whatever terminal device does the
voice).

Cheers,
-- jra
--
Jay R. Ashworth  Baylink   
j...@baylink.com<mailto:j...@baylink.com>
Designer The Things I Think   RFC 2100
Ashworth & Associates   http://www.bcp38.info  2000 Land Rover DII
St Petersburg FL USA  BCP38: Ask For It By Name!   +1 727 647 1274

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Jay R. Ashworth]

- Original Message -
> From: "Mikael Abrahamsson" <swm...@swm.pp.se>
> To: "Jean-Francois Mezei" <jfmezei_na...@vaxination.ca>
> Cc: Nanog@nanog.org
> Sent: Monday, November 21, 2016 2:53:41 AM
> Subject: Re: Voice channels (FTTH, DOCSIS, VoLTE)

> On Mon, 21 Nov 2016, Jean-Francois Mezei wrote:
> 
>> I need to verify some claims made by incumbents in Canada that VoLTE
>> data travels on a totally separate channel between the phone and the
>> antenna.
> 
> Typically it travels on another "bearer" compared to Internet traffic.
> 
> http://blog.3g4g.co.uk/2013/08/volte-bearers.html
> 
> Think of bearers as "tunnels" between the mobile core network and the
> device. They have a lot in common with ATM PVCs in that they can have
> different QoS characteristics. So the VoLTE bearer can have scheduling
> priorities that means it'll always be low-latency and highest priority,
> meaning it might work well when the "Internet" bearer does not.

That is congruent with my understanding of how cableco voice is provisioned;
it has different rules WRT VoN -- specifically about 911 -- because the cable
company segregates it and handles it differently (your cablemodem is expected
to be tied to your service address -- or whatever terminal device does the
voice).

Cheers,
-- jra 
-- 
Jay R. Ashworth  Baylink   j...@baylink.com
Designer The Things I Think   RFC 2100
Ashworth & Associates   http://www.bcp38.info  2000 Land Rover DII
St Petersburg FL USA  BCP38: Ask For It By Name!   +1 727 647 1274

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Jean-Francois Mezei]

On 2016-11-21 21:56, joel jaeggli wrote:

> Not really the air interface uses OFDMA coding scheme, so it is both
> divided into sub-carriers from 1.4 to 20mhz wide which are then also
> scheduled accordingly.

I have read in a number of places that 1 * 20mhz yields much more
capacity than 2 * 10mhz for LTE. but...

On the other hand, just read something on
> https://www.nxp.com/files/wireless_comm/doc/white_paper/3GPPEVOLUTIONWP.pdf


and it states:
##
Unlike single carrier systems described above, OFDM communication
systems do not rely on increased symbol rates in order to achieve higher
data rates. This makes the task of managing ISI much simpler.
***OFDM systems break the available bandwidth into many narrower
sub-carriers and transmit the data in parallel streams.***
 Each subcarrier is modulated using varying levels of QAM modulation,
e.g. QPSK, QAM, 64QAM or possibly higher orders depending on signal
quality. Each OFDM symbol is therefore a linear combination of the
instantaneous signals on each of the sub-carriers in the channel.
Because data is transmitted in parallel rather than serially, OFDM
symbols are generally MUCH longer than symbols on single carrier systems
of equivalent data rate.
##


At page 8:
##
In OFDMA, users are allocated a specific number of subcarriers for a
predetermined amount of time. These are referred to as physical resource
blocks (PRBs) in the LTE specifications. PRBs thus have both a time and
frequency dimension.
##

At page 9, a table shows that a PRB is 180KHz, and that if you have
20mhz of spectrum, you have 100 PRBs.

And more importantly:
##
A PRB is the smallest element of resource allocation assigned by the
base station scheduler.
##


Intertingly, the data I have read in that document points to performance
that is linear with more spectrum, no mention that 1 block of 20mhz
yields more capacity than 2 blocks of 10mhz.


So, if I read this right, (and please confirm if I understand
correctly), an LTE system of 20mhz breaks itself into 100 180KHz chunks
(a PRB) and the base station then schedules which user gets to use which
PRB.

So instead of giving each use a time slot, OFDMA gives it one or more
PRB, a frequency slot  180KHz wide ?

I assume that this is how VoLTE gets priority, with VoLTE bandwidth
causing the base station to give the handset enough PRBs to handle the
VoLTE connection, at the expense of normal users who will see a reduced
number pf PRBs given to them for default data ?

Is that how it works ?

Would it be correct to assume there is some baseband signalling so the
base station tells each user which PRBs it should be listening to (and
sending on for the uplink) ?


(One piece of text which helped me understand was stating that LTE
doesn't transmit packets).

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[joel jaeggli]

On 11/21/16 3:12 PM, Jean-Francois Mezei wrote:
> On 2016-11-21 15:18, joel jaeggli wrote:
>
>
>> SRB and URB are the l2 presentation of the tunnels established for user
>> and signaling traffic.
> OK, so wth LTE, if carrier has 10mhz up and down, this represents a
> single chunk of spectrum providing one pipe ? (in fibre terms: a single
> light colour through one strand)
Not really the air interface uses OFDMA coding scheme, so it is both
divided into sub-carriers from 1.4 to 20mhz wide which are then also
scheduled accordingly.
> The "smoke and mirrors" is accomplished by having different tunnels
> inside that one pipe, with some tunnels granted QoS or other
> preferential treatment between the IMS/VoiP servers and the RAN ?
you kinda want you qos policy to apply end-to-end in the carrier
network, not just on the ran.
> When a handset sends a VolTE packet to the "IMS" APN, is there any
> preferential treatment given between the handset and the antenna ?
sure, hence the qos policy template on the radio bearer.
differing numbers of subcarriers and slots can be assigned to UE based
on the services they are using.

>  Or
> does preferential treatment begin at the RAN where the packet is
> recognized as going to "IMS" APN and going on the fast track to it ?
>
> or put another way. If everyone uploads a HD selfie movie at the same
> time, are handset uploads slowled with normal TCP flow control (drop a
> packet, no ack received, handset halves the TCP window size)?
Those flows going to have the best effort policy. but yes it is
reasonable to presume that in the event of congestion the best effort
queue will be preferentially dropped. likewise if you have voice and
data going at the same time they are not strictly speaking competing for
resources, because the volte radio bearer has a resource assigned to it
and the and the ip data bearer has a resource assigned to it.
> In other words, some router near antenna, to prioriotize packets to the
> IMS/VoLTE server, will flow control normal IP traffic to maintain
> sufficient upload capacity for VolTE traffic ?
>
> Or are the tunnels fixed in capacity such that unused capacity in one is
> never used by the other ?
>
>
>
> From a policy point of view, if I propose a net neutrality policy, I
> have to make sure it doesn't prevent normal VoLTE functioning, while
> preventing abuse of the ability for an incumbent to prioritize/zero-rate
> its own services.
> For instance:
>
>
> AT in USA zero rates voice but not video calls over VoLTE.
> Rogers in Canada zero rates both voice and video calls over VoLTE.
>
> So if VoLTE video travels to the same IMS as voice, and not through the
> normal IP APN, that means AT has to count the video traffic separately
> and add it. But if Video goes through the normal IP traffic APN, it gets
> counted fairly, like Skype packets, but Rogers then captures that
> netflow and later deducts it from the total usage.
>
> The issue here is that VoLTE is the new kid on the block with video
> capability and incumbents can use their power to displace competitors
> such as Skype/Facetime and that may constitute undue preference, unless
> the standards are such that they have no choice because that it how it
> has to work. (But AT shows that it can still count video and treat
> video calls fairly compared o skype video calls).
>
>




signature.asc
Description: OpenPGP digital signature

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Jean-Francois Mezei]

On 2016-11-21 15:18, joel jaeggli wrote:


> SRB and URB are the l2 presentation of the tunnels established for user
> and signaling traffic.

OK, so wth LTE, if carrier has 10mhz up and down, this represents a
single chunk of spectrum providing one pipe ? (in fibre terms: a single
light colour through one strand)

The "smoke and mirrors" is accomplished by having different tunnels
inside that one pipe, with some tunnels granted QoS or other
preferential treatment between the IMS/VoiP servers and the RAN ?

When a handset sends a VolTE packet to the "IMS" APN, is there any
preferential treatment given between the handset and the antenna ? Or
does preferential treatment begin at the RAN where the packet is
recognized as going to "IMS" APN and going on the fast track to it ?

or put another way. If everyone uploads a HD selfie movie at the same
time, are handset uploads slowled with normal TCP flow control (drop a
packet, no ack received, handset halves the TCP window size)?

In other words, some router near antenna, to prioriotize packets to the
IMS/VoLTE server, will flow control normal IP traffic to maintain
sufficient upload capacity for VolTE traffic ?

Or are the tunnels fixed in capacity such that unused capacity in one is
never used by the other ?



>From a policy point of view, if I propose a net neutrality policy, I
have to make sure it doesn't prevent normal VoLTE functioning, while
preventing abuse of the ability for an incumbent to prioritize/zero-rate
its own services.

For instance:


AT in USA zero rates voice but not video calls over VoLTE.
Rogers in Canada zero rates both voice and video calls over VoLTE.

So if VoLTE video travels to the same IMS as voice, and not through the
normal IP APN, that means AT has to count the video traffic separately
and add it. But if Video goes through the normal IP traffic APN, it gets
counted fairly, like Skype packets, but Rogers then captures that
netflow and later deducts it from the total usage.

The issue here is that VoLTE is the new kid on the block with video
capability and incumbents can use their power to displace competitors
such as Skype/Facetime and that may constitute undue preference, unless
the standards are such that they have no choice because that it how it
has to work. (But AT shows that it can still count video and treat
video calls fairly compared o skype video calls).

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[joel jaeggli]

On 11/21/16 11:13 AM, Jean-Francois Mezei wrote:
> On 2016-11-21 02:53, Mikael Abrahamsson wrote:
>
>> Typically it travels on another "bearer" compared to Internet traffic.
>>
>> http://blog.3g4g.co.uk/2013/08/volte-bearers.html
>>
>> Think of bearers as "tunnels" between the mobile core network and the 
>> device. 
> Many thanks for the pointer. The fact that VoLTE has its own dedicated
> APN explains things.
>
> I am however a bit confused on the "bearer" term.
>
> Say a carrier has spectrum in 700Mhz  bands A and B  each 5mhz in each
> direction, bonded together as a single 10mhz (each way) channel.
>
> The docunment states:
> "R.92 requires the use of a particular set of radio bearers"

the radio bearers described are are the signaling radio bearers. their
existence is independent of of the link/mac layer configuration. The mac
layer layer (e-utra) exists below the l2 bearers.

https://en.wikipedia.org/wiki/E-UTRA
> Does this mean that a bearer is given specific spectrum within a block
> (such as a dedicated colour on a fibre) or that it is just given
> dedicated capacity on the single data channel formed by LTE compressing
> all of the spectrum into one big channel ?
>
> I though I understood the concept when the name "tunnel" had been
> mentioned because I understand that a handset estabishes a "hopping"
> tunnel with local IP which changes as you move from tower to tower, but
> the tunnel itself maintains a permanent IP connection that remains
> unchanged as you move from tower to tower. In such a concept, I could
> understand each tunnel (one to the data APN, one to the IMS/VoLTE APN)
> having bandwidth allocations.
these are URBs they are terminated between the UE and the P-GW
> But when the text brought up "radio bearer", I got confused again sicne
> radio implies breaking the spectrum apart, which would reduce LTE
> compression efficiency.
SRB and URB are the l2 presentation of the tunnels established for user
and signaling traffic.
>
>
>




signature.asc
Description: OpenPGP digital signature

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Jean-Francois Mezei]

On 2016-11-21 02:53, Mikael Abrahamsson wrote:

> Typically it travels on another "bearer" compared to Internet traffic.
> 
> http://blog.3g4g.co.uk/2013/08/volte-bearers.html
> 
> Think of bearers as "tunnels" between the mobile core network and the 
> device. 

Many thanks for the pointer. The fact that VoLTE has its own dedicated
APN explains things.

I am however a bit confused on the "bearer" term.

Say a carrier has spectrum in 700Mhz  bands A and B  each 5mhz in each
direction, bonded together as a single 10mhz (each way) channel.

The docunment states:
"R.92 requires the use of a particular set of radio bearers"

Does this mean that a bearer is given specific spectrum within a block
(such as a dedicated colour on a fibre) or that it is just given
dedicated capacity on the single data channel formed by LTE compressing
all of the spectrum into one big channel ?

I though I understood the concept when the name "tunnel" had been
mentioned because I understand that a handset estabishes a "hopping"
tunnel with local IP which changes as you move from tower to tower, but
the tunnel itself maintains a permanent IP connection that remains
unchanged as you move from tower to tower. In such a concept, I could
understand each tunnel (one to the data APN, one to the IMS/VoLTE APN)
having bandwidth allocations.

But when the text brought up "radio bearer", I got confused again sicne
radio implies breaking the spectrum apart, which would reduce LTE
compression efficiency.

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Mikael Abrahamsson]

On Mon, 21 Nov 2016, Jean-Francois Mezei wrote:


I need to verify some claims made by incumbents in Canada that VoLTE
data travels on a totally separate channel between the phone and the
antenna.


Typically it travels on another "bearer" compared to Internet traffic.

http://blog.3g4g.co.uk/2013/08/volte-bearers.html

Think of bearers as "tunnels" between the mobile core network and the 
device. They have a lot in common with ATM PVCs in that they can have 
different QoS characteristics. So the VoLTE bearer can have scheduling 
priorities that means it'll always be low-latency and highest priority, 
meaning it might work well when the "Internet" bearer does not.


--
Mikael Abrahamssonemail: swm...@swm.pp.se

Re: Voice channels (FTTH, DOCSIS, VoLTE)

[Marcin Cieslak]

On Mon, 21 Nov 2016, Jean-Francois Mezei wrote:

> Would DOCSIS be the same as FTTH, with the cableco voice service riding
> isnide the same DOCSIS bandwidth but with pre-allocated bandwidth, or do
> they allocate separate NTSC channels with a totally separate data pipe ?

DOCSIS has a possibility to provision unidirectional data flows with
certain quality of service characteristics. A pair of these is usually
dedicated to a casual Internet connection, another one can be used for
layer 2 telephony service, etc. Allocating a whole TV channel frequency
would be a big waste. Not even sure it would be possible with standard
DOCSIS.

Marcin Cieślak

Voice channels (FTTH, DOCSIS, VoLTE)

[Jean-Francois Mezei]

I need to verify some claims made by incumbents in Canada that VoLTE
data travels on a totally separate channel between the phone and the
antenna.

Does anyone have links to relevant VoLTE documentation that would
provide how VoLTE is provisioned ? I was under the impression that it
was more of an "app" on the phone that used the same IP address given
for access to Internet. Does the phone get a separate IP and possibly
separate VLAN with dedicated bandwidth to ensure voice call quality?

Or are all the performance tricks done on land beyond the antenna once
the packets are identified as VoLTE, but the phone itself just treats
them as a normal app ?

I know that for FTTH, there is a separate "channel" where the "POTS"
emulation can be provided with its own dedicated IP and bandwidth.

Would DOCSIS be the same as FTTH, with the cableco voice service riding
isnide the same DOCSIS bandwidth but with pre-allocated bandwidth, or do
they allocate separate NTSC channels with a totally separate data pipe ?

(in which case, in systems with only 42mhz of uplink frequencies, the
voice would have its own NTSC channel on uplink?