Codec Negotiation

AllStarLink
1

Hi List,

Ok, so I have a portable node and it works great at home but on the road using my iPhone hotspot with Verizon it’s quite jittery and doesn’t sound very good, even when I have 2 or 3 bars. I can connect to the same node using echolink and it works fine even with 1 to 2 bars.

I’m using the hamvoip image without any codec changes and I notice it connects to our local repeater hamvoip node with g726aal2 which makes sense because
g726aal2 is first in [general] which I believe controls outbound connections.

So I wanted to see what I sounded like so I connected to 40894 so I could hear my own voice. It connected using ulaw for some reason. The only way I could get it to change was to comment out the codecs I didn’t want to use in [general]. Apparently it doesn’t negotiate how I think it does.

On ulaw and
g726aal2 it sounded pretty terrible. gsm was better but it was still broken up. I wanted to try ilbc but codec negotiation failed which I’m sure means that 40894 doesn’t allow ilbc.

I then connected successfully to our local repeater node with ilbc and it sounded just fine, even with one bar, but I need to test more…

Is this anyone else’s experience with using hotspots?

I’ve modified the codec under [genera] to the below, which the way I understand is for outgoing connections. And the codec order is the order of attempted negotiation. I ordered them on my portable node in order of least bandwidth to greatest.

So with that said, when I connect to my local node, which allows ilbc, why does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest bandwidth codec that the other side allows?

allow=ilbc

allow=gsm

allow=g726aal2

allow=ulaw

73,

Will, KE4IAJ

2

Will et al:

Read this message please.

Given the bandwidth availability of LTE and even remaining 3G, from
cellular providers, going from 88kpbs to 18kpbs is NOT going to make a
difference. While many seem to think this is true, it is simply not the
case. Even with poor signal, but able to maintain a cellular data
connection, the bandwidth is still going to be hundreds of kbits. Just
not [UDP] reliable.

Cellular data providers don't really care about UDP, their main concern
is TCP reliability. Many streaming services are now TCP, hence lagging
and slow to buffer video and voice streams, but little to zero
"noticeable" drop-outs.

I have several friends that use cellular hotspots, with their radio
hotspots and be it DMR, allstar, echostink, it's very unreliable. The
bigger the city the more unreliable it seems. My experience with
cellular data is the same.

What I am seeing now, and have a theory is this:
Verzion and ATT now use IPv6 for their cellular data subscribers. No
cellphone in their US networks get IPv4 any more. In the middle of last
year, Verizon started issuing ONLY IPv6 addresses to their subscribers.

This means that any IPv4 address must be routed through their limited
placement, subscriber internet access gateway (overloaded) and then
through another IPv6 to IPv4 gateway. These IPv6 <-> IPv4 gateways are
getting overloaded, causes the data unreliability issues.

How to solve this? Use the open repeaters in the area you are in!!!

radio hotspots are nice, but if everyone is using a hotspot, then why
should repeaters exist? Then, that one time, when some natural disaster
takes out cellular, your cellular data connected radio hotspot is NOT
going to work, but I am pretty sure the amateur radio repeaters in the
area will - even if the internet at the repeater site doesn't work. If
there are any repeaters left when that happens.

What does not get used, does not get maintained.

~Benjamin, KB9LFZ

···

On Thu, 2018-02-08 at 20:38 -0500, Will Bashlor wrote:

Hi List,

Ok, so I have a portable node and it works great at home but on the
road using my iPhone hotspot with Verizon it's quite jittery and
doesn't sound very good, even when I have 2 or 3 bars. I can connect
to the same node using echolink and it works fine even with 1 to 2
bars.

I'm using the hamvoip image without any codec changes and I notice it
connects to our local repeater hamvoip node with g726aal2 which makes
sense because g726aal2 is first in [general] which I believe
controls outbound connections.

So I wanted to see what I sounded like so I connected to 40894 so I
could hear my own voice. It connected using ulaw for some reason. The
only way I could get it to change was to comment out the codecs I
didn't want to use in [general]. Apparently it doesn't negotiate how
I think it does.

On ulaw and g726aal2 it sounded pretty terrible. gsm was better but
it was still broken up. I wanted to try ilbc but codec negotiation
failed which I'm sure means that 40894 doesn't allow ilbc.

I then connected successfully to our local repeater node with ilbc
and it sounded just fine, even with one bar, but I need to test
more...

Is this anyone else's experience with using hotspots?

I've modified the codec under [genera] to the below, which the way I
understand is for outgoing connections. And the codec order is the
order of attempted negotiation. I ordered them on my portable node in
order of least bandwidth to greatest.

So with that said, when I connect to my local node, which allows
ilbc, why does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest
bandwidth codec that the other side allows?

allow=ilbc
allow=gsm
allow=g726aal2
allow=ulaw

73,

Will, KE4IAJ
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3

Hi Benjamin,

I agree 100% about the small bandwidth savings not making a difference when you have great signal, however; that doesn’t mean that one codec won’t perform better than another given certain network conditions. I will do some more testing, but my first initial tests were that ilbc sounded much better than the others when I had 1 bar of LTE. When there’s heavy network degradation throughput suffers and in certain situations you will see better results with a lower bandwidth codec.

Think about it, cellular is now VOIP over LTE. And although it doesn’t go through double NAT and has QoS and all that jazz, there’s no reason I shouldn’t be able to use AllStar without issues when I have good LTE signal (i.e. 2 bars or more). Skype, Google Voice, FaceTime Audio, Facebook Audio, and even Echolink doesn’t seem to have this problem on my same commute with the same network conditions, and neither should AllStar. I mean, I can sit here at home and stream HD video with no issues on my iPhone. One thing I will test is connecting via AllStar via Echolink. I’m not sure what codec is used with AllStar connecting via Echolink.

Verizon is using IPv6 and they are also giving out IPv4 via CGN, which is what I’m seeing on my phone/hotspot. This is a double NAT, yes, but that’s no excuse either. I could also setup a VPN but then there’s even more complexity and in some cases can make performance worse.

Come to think of it, I hear Grady talking a good bit on his AllStar micro node through his cellular hotspot while driving and his sounds great. I’ll like to know what cellular service he has and what codec his micro node is using.

Pretty much off topic, but I do use our local repeaters via RF. When I get out of range is mainly when I use my hotspot. But I use it to connect back to our local repeater, when if I didn’t have a hotspot I wouldn’t be able to use it. So the way I see it, I get to use the repeater more than if I didn’t have the node, because now all I need is Internet access anywhere in the world. So I guess I look at it completely different. And as you already know, it also allows me to connect to Columbus and join in on the AllStar Tech Net. If I didn’t have my node and hotspot while mobile, then that’s less use those repeaters would see.

But for what it’s worth I appreciate the time you spent to think about it and white up your reply.

73 for now.

Will, KE4IAJ

···

On Thu, Feb 8, 2018 at 11:47 PM, Benjamin Naber Benjamin@project23d.com wrote:

Will et al:

Read this message please.

Given the bandwidth availability of LTE and even remaining 3G, from

cellular providers, going from 88kpbs to 18kpbs is NOT going to make a

difference. While many seem to think this is true, it is simply not the

case. Even with poor signal, but able to maintain a cellular data

connection, the bandwidth is still going to be hundreds of kbits. Just

not [UDP] reliable.

Cellular data providers don’t really care about UDP, their main concern

is TCP reliability. Many streaming services are now TCP, hence lagging

and slow to buffer video and voice streams, but little to zero

“noticeable” drop-outs.

I have several friends that use cellular hotspots, with their radio

hotspots and be it DMR, allstar, echostink, it’s very unreliable. The

bigger the city the more unreliable it seems. My experience with

cellular data is the same.

What I am seeing now, and have a theory is this:

Verzion and ATT now use IPv6 for their cellular data subscribers. No

cellphone in their US networks get IPv4 any more. In the middle of last

year, Verizon started issuing ONLY IPv6 addresses to their subscribers.

This means that any IPv4 address must be routed through their limited

placement, subscriber internet access gateway (overloaded) and then

through another IPv6 to IPv4 gateway. These IPv6 ↔ IPv4 gateways are

getting overloaded, causes the data unreliability issues.

How to solve this? Use the open repeaters in the area you are in!!!

radio hotspots are nice, but if everyone is using a hotspot, then why

should repeaters exist? Then, that one time, when some natural disaster

takes out cellular, your cellular data connected radio hotspot is NOT

going to work, but I am pretty sure the amateur radio repeaters in the

area will - even if the internet at the repeater site doesn’t work. If

there are any repeaters left when that happens.

What does not get used, does not get maintained.

~Benjamin, KB9LFZ

On Thu, 2018-02-08 at 20:38 -0500, Will Bashlor wrote:

Hi List,

Ok, so I have a portable node and it works great at home but on the

road using my iPhone hotspot with Verizon it’s quite jittery and

doesn’t sound very good, even when I have 2 or 3 bars. I can connect

to the same node using echolink and it works fine even with 1 to 2

bars.

I’m using the hamvoip image without any codec changes and I notice it

connects to our local repeater hamvoip node with g726aal2 which makes

sense because g726aal2 is first in [general] which I believe

controls outbound connections.

So I wanted to see what I sounded like so I connected to 40894 so I

could hear my own voice. It connected using ulaw for some reason. The

only way I could get it to change was to comment out the codecs I

didn’t want to use in [general]. Apparently it doesn’t negotiate how

I think it does.

On ulaw and g726aal2 it sounded pretty terrible. gsm was better but

it was still broken up. I wanted to try ilbc but codec negotiation

failed which I’m sure means that 40894 doesn’t allow ilbc.

I then connected successfully to our local repeater node with ilbc

and it sounded just fine, even with one bar, but I need to test

more…

Is this anyone else’s experience with using hotspots?

I’ve modified the codec under [genera] to the below, which the way I

understand is for outgoing connections. And the codec order is the

order of attempted negotiation. I ordered them on my portable node in

order of least bandwidth to greatest.

So with that said, when I connect to my local node, which allows

ilbc, why does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest

bandwidth codec that the other side allows?

allow=ilbc

allow=gsm

allow=g726aal2

allow=ulaw

73,

Will, KE4IAJ

App_rpt-users mailing list

App_rpt-users@lists.allstarlink.org

http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://lists.allstarlink.o

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bottom of the page. Enter your email address and press the

“Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email

confirmation. If you have trouble unsubscribing, please send a

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To unsubscribe from this list please visit http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

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4

Will,

iLBC and g729 probably sound best over highly "jittery" mobile networks.

Note that the hamvoip iLBC implementation is patched to use 20msec frames,
NOT 30msec frames, which are the default in Asterisk. You *MUST* use
20msec frames with AllStar!

My patches for Asterisk to add iLBC and use 20msec frames were published
years ago. If interested, here is the link:
https://hamvoip.org/downloads/patch-kit-with-ilbc.tgz

And, here are example iax.conf stanzas, which only allow a specific CODEC:

[radio-ulaw]
type=user
disallow=all
allow=ulaw
codecpriority=host
context=radio-secure
transfer=no

[radio-g726]
type=user
disallow=all
allow=g726aal2
codecpriority=host
context=radio-secure
transfer=no

[radio-g729]
type=user
disallow=all
allow=g729
codecpriority=host
context=radio-secure
transfer=no

[radio-ilbc]
type=user
disallow=all
allow=ilbc
codecpriority=host
context=radio-secure
transfer=no

....For your setups, take a look at the CODEC definitions in the [radio]
stanza. Also, you can have multiple stanzas (like above), and force
various nodes to connect with a specific CODEC, etc. I run this style
setup on all my systems.

73, David KB4FXC

···

On Thu, 8 Feb 2018, Will Bashlor wrote:

Hi List,

Ok, so I have a portable node and it works great at home but on the road
using my iPhone hotspot with Verizon it's quite jittery and doesn't sound
very good, even when I have 2 or 3 bars. I can connect to the same node
using echolink and it works fine even with 1 to 2 bars.

I'm using the hamvoip image without any codec changes and I notice it
connects to our local repeater hamvoip node with g726aal2 which makes sense
because g726aal2 is first in [general] which I believe controls outbound
connections.

So I wanted to see what I sounded like so I connected to 40894 so I could
hear my own voice. It connected using ulaw for some reason. The only way I
could get it to change was to comment out the codecs I didn't want to use
in [general]. Apparently it doesn't negotiate how I think it does.

On ulaw and g726aal2 it sounded pretty terrible. gsm was better but it was
still broken up. I wanted to try ilbc but codec negotiation failed which
I'm sure means that 40894 doesn't allow ilbc.

I then connected successfully to our local repeater node with ilbc and it
sounded just fine, even with one bar, but I need to test more...

Is this anyone else's experience with using hotspots?

I've modified the codec under [genera] to the below, which the way I
understand is for outgoing connections. And the codec order is the order of
attempted negotiation. I ordered them on my portable node in order of least
bandwidth to greatest.

So with that said, when I connect to my local node, which allows ilbc, why
does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest
bandwidth codec that the other side allows?

allow=ilbc
allow=gsm
allow=g726aal2
allow=ulaw

73,

Will, KE4IAJ

5

Fantastic, thanks David. A couple questions...

How do I specify to use a particular stanza while connecting to a certain node?

I thought the [radio] stanza was for incoming connections, no? Since I can't receive incoming connections using my cellular hotspot I didn't think I needed to modify [radio]. At work and home where I have ports forwarded I have a high speed connection, I don't really need to change the codecs as it works great using ulaw.

Will
KE4IAJ

···

-----Original Message-----
From: App_rpt-users [mailto:app_rpt-users-bounces@lists.allstarlink.org] On Behalf Of David McGough
Sent: Friday, February 9, 2018 9:39 AM
To: Users of Asterisk app_rpt <app_rpt-users@lists.allstarlink.org>
Subject: Re: [App_rpt-users] Codec Negotiation

Will,

iLBC and g729 probably sound best over highly "jittery" mobile networks.

Note that the hamvoip iLBC implementation is patched to use 20msec frames, NOT 30msec frames, which are the default in Asterisk. You *MUST* use 20msec frames with AllStar!

My patches for Asterisk to add iLBC and use 20msec frames were published years ago. If interested, here is the link:
https://hamvoip.org/downloads/patch-kit-with-ilbc.tgz

And, here are example iax.conf stanzas, which only allow a specific CODEC:

[radio-ulaw]
type=user
disallow=all
allow=ulaw
codecpriority=host
context=radio-secure
transfer=no

[radio-g726]
type=user
disallow=all
allow=g726aal2
codecpriority=host
context=radio-secure
transfer=no

[radio-g729]
type=user
disallow=all
allow=g729
codecpriority=host
context=radio-secure
transfer=no

[radio-ilbc]
type=user
disallow=all
allow=ilbc
codecpriority=host
context=radio-secure
transfer=no

....For your setups, take a look at the CODEC definitions in the [radio]
stanza. Also, you can have multiple stanzas (like above), and force
various nodes to connect with a specific CODEC, etc. I run this style
setup on all my systems.

73, David KB4FXC

On Thu, 8 Feb 2018, Will Bashlor wrote:

Hi List,

Ok, so I have a portable node and it works great at home but on the road
using my iPhone hotspot with Verizon it's quite jittery and doesn't sound
very good, even when I have 2 or 3 bars. I can connect to the same node
using echolink and it works fine even with 1 to 2 bars.

I'm using the hamvoip image without any codec changes and I notice it
connects to our local repeater hamvoip node with g726aal2 which makes sense
because g726aal2 is first in [general] which I believe controls outbound
connections.

So I wanted to see what I sounded like so I connected to 40894 so I could
hear my own voice. It connected using ulaw for some reason. The only way I
could get it to change was to comment out the codecs I didn't want to use
in [general]. Apparently it doesn't negotiate how I think it does.

On ulaw and g726aal2 it sounded pretty terrible. gsm was better but it was
still broken up. I wanted to try ilbc but codec negotiation failed which
I'm sure means that 40894 doesn't allow ilbc.

I then connected successfully to our local repeater node with ilbc and it
sounded just fine, even with one bar, but I need to test more...

Is this anyone else's experience with using hotspots?

I've modified the codec under [genera] to the below, which the way I
understand is for outgoing connections. And the codec order is the order of
attempted negotiation. I ordered them on my portable node in order of least
bandwidth to greatest.

So with that said, when I connect to my local node, which allows ilbc, why
does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest
bandwidth codec that the other side allows?

allow=ilbc
allow=gsm
allow=g726aal2
allow=ulaw

73,

Will, KE4IAJ

_______________________________________________
App_rpt-users mailing list
App_rpt-users@lists.allstarlink.org
http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the "Unsubscribe or edit options button"
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6

Will,

You are correct that the [radio*] stanzas are for incoming connections, at
least as they are used by AllStar.

I haven't looked the iax2 driver code over, but, empirically speaking, the
CODECs listed in in the "allow=" don't seem to be used in any guaranteed
order, even though the iax2 documentation says otherwise. I've tried
combinations of "bandwidth=" and "codecpriority=" settings, etc...So, I
assume this is a bug---unless I'm overlooking something obvious (anyone
got any other ideas?).

The only 2 ways (so far!) I've found to guarantee that a certain CODEC is
used are:

Method 1: ---Only specify a single allowed CODEC for outbound connections.

;;; On the portable node, allow only one CODEC you want:
[general]
disallow=all
allow=ilbc

;;---------------------------------------------------------------

Method 2: ---Allow multiple CODECs for outbound, but connect to a
destination stanza that only allows a single CODEC.

;;; On the portable node, your CODEC list:
[general]
disallow=all
allow=ilbc
allow=g729
allow=ulaw

;;; On the portable node, your defined nodes:
[nodes]
abcd = radio-g729@my-abcd-hub.com/abcd,NONE ; Hub stanza --- only g729
wxyz = radio-ulaw@my-wxyz-hub.com/wxyz,NONE ; Hub stanza --- only ulaw

;;; On the abcd HUB:
[radio-g729]
type=user
disallow=all
allow=g729
context=radio-secure
transfer=no

;;; On the wxyz HUB:
[radio-ulaw]
type=user
disallow=all
allow=ulaw
context=radio-secure
transfer=no

;;;-------------------------------------------------------

73, David KB4FXC

Fantastic, thanks David. A couple questions...

How do I specify to use a particular stanza while connecting to a certain
node?

I thought the [radio] stanza was for incoming connections, no? Since I
can't receive incoming connections using my cellular hotspot I didn't
think I needed to modify [radio]. At work and home where I have ports
forwarded I have a high speed connection, I don't really need to change
the codecs as it works great using ulaw.

Will
KE4IAJ

···

On Fri, 9 Feb 2018, Will Bashlor wrote:

-----Original Message-----
From: App_rpt-users [mailto:app_rpt-users-bounces@lists.allstarlink.org] On Behalf Of David McGough
Sent: Friday, February 9, 2018 9:39 AM
To: Users of Asterisk app_rpt <app_rpt-users@lists.allstarlink.org>
Subject: Re: [App_rpt-users] Codec Negotiation

Will,

iLBC and g729 probably sound best over highly "jittery" mobile networks.

Note that the hamvoip iLBC implementation is patched to use 20msec frames, NOT 30msec frames, which are the default in Asterisk. You *MUST* use 20msec frames with AllStar!

My patches for Asterisk to add iLBC and use 20msec frames were published years ago. If interested, here is the link:
https://hamvoip.org/downloads/patch-kit-with-ilbc.tgz

And, here are example iax.conf stanzas, which only allow a specific CODEC:

[radio-ulaw]
type=user
disallow=all
allow=ulaw
codecpriority=host
context=radio-secure
transfer=no

[radio-g726]
type=user
disallow=all
allow=g726aal2
codecpriority=host
context=radio-secure
transfer=no

[radio-g729]
type=user
disallow=all
allow=g729
codecpriority=host
context=radio-secure
transfer=no

[radio-ilbc]
type=user
disallow=all
allow=ilbc
codecpriority=host
context=radio-secure
transfer=no

....For your setups, take a look at the CODEC definitions in the [radio]
stanza. Also, you can have multiple stanzas (like above), and force
various nodes to connect with a specific CODEC, etc. I run this style
setup on all my systems.

73, David KB4FXC

On Thu, 8 Feb 2018, Will Bashlor wrote:

Hi List,

Ok, so I have a portable node and it works great at home but on the road
using my iPhone hotspot with Verizon it's quite jittery and doesn't sound
very good, even when I have 2 or 3 bars. I can connect to the same node
using echolink and it works fine even with 1 to 2 bars.

I'm using the hamvoip image without any codec changes and I notice it
connects to our local repeater hamvoip node with g726aal2 which makes sense
because g726aal2 is first in [general] which I believe controls outbound
connections.

So I wanted to see what I sounded like so I connected to 40894 so I could
hear my own voice. It connected using ulaw for some reason. The only way I
could get it to change was to comment out the codecs I didn't want to use
in [general]. Apparently it doesn't negotiate how I think it does.

On ulaw and g726aal2 it sounded pretty terrible. gsm was better but it was
still broken up. I wanted to try ilbc but codec negotiation failed which
I'm sure means that 40894 doesn't allow ilbc.

I then connected successfully to our local repeater node with ilbc and it
sounded just fine, even with one bar, but I need to test more...

Is this anyone else's experience with using hotspots?

I've modified the codec under [genera] to the below, which the way I
understand is for outgoing connections. And the codec order is the order of
attempted negotiation. I ordered them on my portable node in order of least
bandwidth to greatest.

So with that said, when I connect to my local node, which allows ilbc, why
does it negotiate to g726aal2?

And how can I setup iax.conf so it always connects using the lowest
bandwidth codec that the other side allows?

allow=ilbc
allow=gsm
allow=g726aal2
allow=ulaw

73,

Will, KE4IAJ

_______________________________________________
App_rpt-users mailing list
App_rpt-users@lists.allstarlink.org
http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the "Unsubscribe or edit options button"
You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

_______________________________________________
App_rpt-users mailing list
App_rpt-users@lists.allstarlink.org
http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://lists.allstarlink.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the "Unsubscribe or edit options button"
You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.