H.248 Mode property vs. signals/events
Mark Overton <[email protected]> Tue, 5 Mar 2013 11:00:35 +0000
| Newsgroups | gmane.ietf.megaco |
|---|---|
| Message-ID | <[email protected]> |
--===============6078998049717860766==
Content-Language: en-US
Content-Type: multipart/alternative;
boundary="_000_526E686CB8CF4B40B84CFE0938D75DE76319A612ENFIRHMBX1datco_"
--_000_526E686CB8CF4B40B84CFE0938D75DE76319A612ENFIRHMBX1datco_
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Hi,
Can someone please help me understand the interaction between the H.248 Mod=
e property and Signals/Events? We're testing MGC-MG interop, and aren't qui=
te agreeing over a Modify request for a termination with a single stream th=
at
* sets the Mode to RecvOnly
* plays an external tone.
The key bits of H.248.1 text up for discussion seem to be:
* from 7.1.7:
The allowed values for the Mode Property are "SendOnly", "RecvOnly", "SendR=
ecv", "Inactive"
and "LoopBack". "SendOnly", "RecvOnly" and "LoopBack" are with respect to t=
he exterior of the
context, so that, for example, a stream set to mode =3D "SendOnly" does not=
pass received media into
the context. When a stream is set to "LoopBack" on a termination, media rec=
eived (Local
Descriptor) on the termination will be looped back to the sending side (Rem=
ote Descriptor) of the
termination and no media is passed between that termination and other termi=
nations in the context.
The looped back media shall be sent according to the Remote Descriptor. The=
default value for the
Mode Property is "Inactive". Signals and events are not affected by the Mod=
e Property. The
LocalControl Mode Property takes precedence over any mode specified in the =
Local and Remote
Descriptors.
* From 6.1.1:
* The Topology Descriptor (who hears/sees whom).
The topology of a context describes the flow of media between the terminati=
ons within a
context. In contrast, the Mode Property of a termination ("SendOnly"/"RecvO=
nly"/...)
describes the flow of the media at the egress/ingress of the media gateway.
So I think we've both interpreted the Mode property differently:
* One view treats the Mode property as absolute: that is, RecvOnly =
means absolutely no media is sent out to this termination, SendOnly means a=
ny and all received media is absolutely ignored. Setting the mode doesn't a=
ffect the Signals and Events that are programmed on a given termination, ne=
ither does it affect any subsequent programming - but it can and does affec=
t the result of the programming. So in this case a Mode of RecvOnly combine=
d with an external tone means the tone gets played in the DSP but absolutel=
y no media is sent out to that termination.
Another way to explain our implementation is in this picture:
[MG egress/ingress]<--- flow affected by Mode property --->[termination inc=
luding DSP for signals/events]<--- flow affected by Topology descriptor ---=
>[context media mixpoint]
* The other (that expects to see the tone played to the termination=
) effectively says that the Mode property affects the flow of media between=
the termination and the context media mixpoint:
[MG egress/ingress]<------>[termination including DSP for signals/events]<-=
-- flow affected by Mode and Topology --->[context media mixpoint]
What's the right answer here? The first view seems to go against the text f=
rom 7.1.7, and the second view seems to go against that from 6.1.1.
Please don't hesitate to get back to me if any of this is unclear. Many tha=
nks in advance,
Mark
----
Mark Overton
Project Manager, Carrier Systems Division
Metaswitch Networks
[email protected]<mailto:[email protected]>
+44 20 8366 1177
www.metaswitch.com<http://www.metaswitch.com/>
--_000_526E686CB8CF4B40B84CFE0938D75DE76319A612ENFIRHMBX1datco_
Content-Type: text/html; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
<html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-micr=
osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:=
//www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"=
>
<meta name=3D"Generator" content=3D"Microsoft Word 12 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:1171484482;
mso-list-type:hybrid;
mso-list-template-ids:46813614 134807553 134807555 134807557 134807553 134=
807555 134807557 134807553 134807555 134807557;}
@list l0:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Symbol;}
@list l1
{mso-list-id:1319113527;
mso-list-type:hybrid;
mso-list-template-ids:-808305774 134807553 134807555 134807557 134807553 1=
34807555 134807557 134807553 134807555 134807557;}
@list l1:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Symbol;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext=3D"edit">
<o:idmap v:ext=3D"edit" data=3D"1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=3D"EN-GB" link=3D"blue" vlink=3D"purple">
<div class=3D"WordSection1">
<p class=3D"MsoNormal">Hi,<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Can someone please help me understand the interactio=
n between the H.248 Mode property and Signals/Events? We’re testing M=
GC-MG interop, and aren’t quite agreeing over a Modify request for a =
termination with a single stream that<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l0 leve=
l1 lfo1"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>sets the Mode to RecvOnly<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l0 leve=
l1 lfo1"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>plays an external tone.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">The key bits of H.248.1 text up for discussion seem =
to be:<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l1 leve=
l1 lfo2"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>from 7.1.7:<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">The allowed values for =
the Mode Property are "SendOnly", "RecvOnly", "Sen=
dRecv", "Inactive"<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">and "LoopBack"=
;. "SendOnly", "RecvOnly" and "LoopBack" are =
with respect to the exterior of the<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">context, so that, <b><u=
><span style=3D"background:yellow;mso-highlight:yellow">for example, a stre=
am set to mode =3D "SendOnly" does not pass received media into<o=
:p></o:p></span></u></b></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt"><b><u><span style=3D"ba=
ckground:yellow;mso-highlight:yellow">the context</span></u></b>. When a st=
ream is set to "LoopBack" on a termination, media received (Local=
<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">Descriptor) on the term=
ination will be looped back to the sending side (Remote Descriptor) of the<=
o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">termination and no medi=
a is passed between that termination and other terminations in the context.=
<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">The looped back media s=
hall be sent according to the Remote Descriptor. The default value for the<=
o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">Mode Property is "=
Inactive". <b><u><span style=3D"background:yellow;mso-highlight:yellow=
">Signals and events are not affected by the Mode Property</span></u></b>. =
The<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">LocalControl Mode Prope=
rty takes precedence over any mode specified in the Local and Remote<o:p></=
o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">Descriptors.<o:p></o:p>=
</p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l1 leve=
l1 lfo2"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>From 6.1.1:<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">• The Topology De=
scriptor (who hears/sees whom).<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">The topology of a conte=
xt describes the flow of media between the terminations within a<o:p></o:p>=
</p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">context. In contrast, <=
b><u><span style=3D"background:yellow;mso-highlight:yellow">the Mode Proper=
ty of a termination ("SendOnly"/"RecvOnly"/…)<o:p=
></o:p></span></u></b></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt"><b><u><span style=3D"ba=
ckground:yellow;mso-highlight:yellow">describes the flow of the media at th=
e egress/ingress of the media gateway</span></u></b>.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">So I think we've both interpreted the Mode property =
differently:<o:p></o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l1 leve=
l1 lfo2"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>One view treats the Mode property as absolut=
e: that is, RecvOnly means absolutely no media is sent out to this terminat=
ion, SendOnly means any and all received media is absolutely ignored. Setti=
ng the mode doesn't affect the Signals
and Events that are <i>programmed</i> on a given termination, neither does=
it affect any subsequent programming - but it can and does affect the
<i>result</i> of the programming. So in this case a Mode of RecvOnly combin=
ed with an external tone means the tone gets played in the DSP but absolute=
ly no media is sent out to that termination.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt">Another way to explain =
our implementation is in this picture:<o:p></o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt"><b>[MG egress/ingress]&=
lt;--- flow affected by Mode property --->[termination including DSP for=
signals/events]<--- flow affected by Topology descriptor --->[contex=
t media mixpoint]<o:p></o:p></b></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoListParagraph" style=3D"text-indent:-18.0pt;mso-list:l1 leve=
l1 lfo2"><![if !supportLists]><span style=3D"font-family:Symbol"><span styl=
e=3D"mso-list:Ignore">·<span style=3D"font:7.0pt "Times New Rom=
an"">
</span></span></span><![endif]>The other (that expects to see the tone play=
ed to the termination) effectively says that the Mode property affects the =
flow of media between the termination and the context media mixpoint:<o:p><=
/o:p></p>
<p class=3D"MsoNormal" style=3D"margin-left:36.0pt"><b>[MG egress/ingress]&=
lt;------>[termination including DSP for signals/events]<--- flow aff=
ected by Mode and Topology --->[context media mixpoint]<o:p></o:p></b></=
p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">What’s the right answer here? The first view s=
eems to go against the text from 7.1.7, and the second view seems to go aga=
inst that from 6.1.1.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Please don’t hesitate to get back to me if any=
of this is unclear. Many thanks in advance,<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Mark<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">----<o:p></o:p></p>
<p class=3D"MsoNormal">Mark Overton<o:p></o:p></p>
<p class=3D"MsoNormal"><i>Project Manager, Carrier Systems Division<o:p></o=
:p></i></p>
<p class=3D"MsoNormal"><b><span style=3D"color:#17365D">Metaswitch Networks=
<o:p></o:p></span></b></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><span style=3D"color:gray"><a href=3D"mailto:mark.ov=
[email protected]"><span style=3D"color:gray">[email protected]=
m</span></a><o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"color:gray">+44 20 8366 1177<o:p>=
</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"color:gray"><a href=3D"http://www.met=
aswitch.com/"><span style=3D"color:gray">www.metaswitch.com</span></a><o:p>=
</o:p></span></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>
--_000_526E686CB8CF4B40B84CFE0938D75DE76319A612ENFIRHMBX1datco_--
--===============6078998049717860766==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
_______________________________________________
Megaco mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/megaco
--===============6078998049717860766==--