[MEGACO] Mid call codec negotiation with unspecified Local descriptor
Manpreet Singh <[email protected]> Wed, 27 Aug 2014 21:47:30 +0530
| Newsgroups | gmane.ietf.megaco |
|---|---|
| Message-ID | <CAO_t5PaE7eQJyO+aQ3hk6WsuTH+Yq+4djdvYVOco6Q3nnJ-55w@mail.gmail.com> |
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Hi All,
Need you input in a MEGACO mid call codec negotiation scenario. In this
scenario Local descriptor was unspecified in mid call codec change and we
want to understand what will be correct behavior.
Call flow in summary
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
1. Firstly there is negotiation of audio codec and it is successful (first
modify request and its reply from MG is shown in message 1 & message 2).
2. Second Modify Request send by MGC with unspecified Local (Message 3)
3. MG reply Modify with =E2=80=9C515 Unsupported_Media_Type=E2=80=9D. (Mes=
sage 4)
As per the RFC
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
An unspecified Local or Remote Descriptor is considered to be a missing
mandatory parameter. It requires the MG to use whatever was last specified
for that descriptor. It is
possible that there was no previously specified value, in which case the
descriptor concerned is ignored in further processing of the command.
Behavior
=3D=3D=3D=3D=3D=3D=3D=3D
In this case local Descriptor was unspecified in modify (message 3) due
to this at media gateway previously specified value was PCMA.
As there is no matching codec in local and new remote Descriptor so MG
return error.
Question
=3D=3D=3D=3D=3D=3D=3D=3D=3D
Is MG behavior correct ?
Can anyone please confirm the right behavior of MG with second modify
request (Message 3) ?
Call follow
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
[Message 1:: First modify from MGC]
!/2 <nord2.interconnect.mgc.voip.telefonica.de>:2945
T=3D111526820{C=3D2913{mf=3Dds/stm1_2/e1_50/29{m{o{mo=3Dsr,TDMC/EC=3DOFF}},=
e,sg{}},mf=3Dtgwrtp/8456{m{o{mo=3Dsr},r{v=3D0
o=3Danonymous 140490962784 140490962786 IN IP4 213.20.251.120
s=3DSIP Call
c=3DIN IP4 213.20.251.120
t=3D0 0
m=3Daudio 13076 RTP/AVP 8 0 125 101
b=3DAS:82
a=3Drtpmap:8 PCMA/8000/1
a=3Drtpmap:0 PCMU/8000/1
a=3Drtpmap:125 CLEARMODE/8000/1
a=3Drtpmap:101 telephone-event/8000
a=3Dfmtp:101 0-15
a=3Dptime:20
a=3Dsendrecv
}},e,sg{}}}}
[message 2 :: REPLY message for selected remote and local codecs form MG]:
!/2 <tmgx-brln-de103-2>:2945 P =3D 111526820{ C =3D 2913
{mf=3Dds/stm1_2/e1_50/29 ,mf=3DTGWRTP/8456 { m { l {
v=3D0
o=3D- 392 1404909627 IN IP4 62.53.160.73
s=3D-
c=3DIN IP4 62.53.160.73
t=3D0 0
m=3Daudio 30356 RTP/AVP 8 101
a=3Dptime:20
a=3Drtpmap:8 PCMA/8000/1
a=3Drtpmap:101 telephone-event/8000/1
a=3Dfmtp:101 0-15
} ,r {
v=3D0
o=3Danonymous 140490962784 140490962786 IN IP4 213.20.251.120
s=3D-
c=3DIN IP4 213.20.251.120
t=3D0 0
m=3Daudio 13076 RTP/AVP 8 101
a=3Drtpmap:8 PCMA/8000/1
a=3Dptime:20
a=3Drtpmap:101 telephone-event/8000
a=3Dfmtp:101 0-15
} } } }}
[message 3 :: second Modify Request with unspecified Local with change in
codec]
!/2 <nord2.interconnect.mgc.voip.telefonica.de>:2945
T=3D111528469{C=3D2913{mf=3Dds/stm1_2/e1_50/29{m{ts{CTYP/CALLTYP=3D[FAX,TEX=
T,DATA]},o{mo=3Dsr,TDMC/EC=3DOFF}},e=3D1{CTYP/DTONE},sg{}},mf=3Dtgwrtp/8456=
{m{o{mo=3Dsr},r{v=3D0
o=3Danonymous 140490962784 140490962787 IN IP4 213.20.251.120
s=3DSIP Call
c=3DIN IP4 213.20.251.120
t=3D0 0
m=3Daudio 13076 RTP/AVP 0 101
b=3DAS:82
a=3Drtpmap:0 PCMU/8000/1
a=3Drtpmap:101 telephone-event/8000
a=3Dfmtp:101 0-15
a=3Dptime:20
a=3Dsendrecv
}},e=3D1{IPFAX/FAXCONNCHANGE},sg{}}}}
[message 4 :: Modify Reply]
!/2 <tmgx-brln-de103-2>:2945 P =3D 111528469{ C =3D 2913
{mf=3Dds/stm1_2/e1_50/29 ,mf=3DTGWRTP/8456 { er =3D 515 {
"Unsupported_Media_Type" } } }}
Any information will be appreciated!
Thanks &Regards,
Manpreet
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<div dir=3D"ltr">
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Hi All,</span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Need you input =
in a MEGACO mid
call codec negotiation scenario. In this scenario Local descriptor was
unspecified in mid call codec change and we want to understand what will be
correct behavior.</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Call flow in su=
mmary</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">1. Firstly ther=
e is negotiation
of audio codec and it is successful (first modify request and its reply fro=
m MG
is shown in message 1 & message 2).</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">2. Second Modif=
y Request send by
MGC with unspecified Local (Message 3)</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">3. MG reply Mod=
ify with =E2=80=9C515
Unsupported_Media_Type=E2=80=9D.=C2=A0 (Message 4)</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">As per the RFC =
</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0=C2=A0 An=
unspecified
Local or Remote Descriptor is considered to be a missing mandatory paramete=
r.
It requires the MG to use whatever was last specified for that descriptor. =
It is</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">possible that t=
here was no
previously specified value, in which case the descriptor concerned is ignor=
ed
in further processing of the command.</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Behavior</span>=
</p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=3D=3D=3D=3D=3D=
=3D=3D=3D</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0 In this =
case local
Descriptor was unspecified in modify (message 3) due to this at media gatew=
ay
previously specified value was PCMA.</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0 As there=
is no matching
codec in local and new remote Descriptor so MG return error.</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Question</span>=
</p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=3D=3D=3D=3D=3D=
=3D=3D=3D=3D</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0=C2=A0 Is=
MG behavior
correct ?</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0 Can anyo=
ne please confirm
the right behavior of MG with second modify request (Message 3) ?</span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Call follow</sp=
an></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">[Message 1:: Fi=
rst modify from
MGC]</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">!/2
<<a href=3D"http://nord2.interconnect.mgc.voip.telefonica.de">nord2.inte=
rconnect.mgc.voip.telefonica.de</a>>:2945
T=3D111526820{C=3D2913{mf=3Dds/stm1_2/e1_50/29{m{o{mo=3Dsr,TDMC/EC=3DOFF}},=
e,sg{}},mf=3Dtgwrtp/8456{m{o{mo=3Dsr},r{v=3D0</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">o=3Danonymous 1=
40490962784
140490962786 IN IP4 213.20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">s=3DSIP Call</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">c=3DIN IP4 213.=
20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">t=3D0 0</span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">m=3Daudio 13076=
RTP/AVP 8 0 125
101</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">b=3DAS:82</span=
></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:8 PC=
MA/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:0 PC=
MU/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:125 =
CLEARMODE/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:101
telephone-event/8000</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dfmtp:101 0-=
15</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dptime:20</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dsendrecv</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">}},e,sg{}}}}</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">[message 2 :: R=
EPLY message for
selected remote and local codecs form MG]:</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">!/2
<tmgx-brln-de103-2>:2945 P =3D 111526820{ C =3D 2913
{mf=3Dds/stm1_2/e1_50/29=C2=A0 ,mf=3DTGWRTP/8456=C2=A0 { m { l { </span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">v=3D0</span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">o=3D- 392 14049=
09627 IN IP4
62.53.160.73</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">s=3D-</span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">c=3DIN IP4 62.5=
3.160.73</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">t=3D0 0</span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">m=3Daudio 30356=
RTP/AVP 8 101</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dptime:20</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:8 PC=
MA/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:101
telephone-event/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dfmtp:101 0-=
15</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">} ,r { </span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">v=3D0</span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">o=3Danonymous 1=
40490962784
140490962786 IN IP4 213.20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">s=3D-</span></p=
>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">c=3DIN IP4 213.=
20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">t=3D0 0</span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">m=3Daudio 13076=
RTP/AVP 8 101</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:8 PC=
MA/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dptime:20</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:101
telephone-event/8000</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dfmtp:101 0-=
15</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">}=C2=A0 }=C2=A0=
} }}</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">[message 3 :: s=
econd Modify
Request with unspecified Local with change in codec]</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">!/2 <<a href=
=3D"http://nord2.interconnect.mgc.voip.telefonica.de">nord2.interconnect.mg=
c.voip.telefonica.de</a>>:2945
T=3D111528469{C=3D2913{mf=3Dds/stm1_2/e1_50/29{m{ts{CTYP/CALLTYP=3D[FAX,TEX=
T,DATA]},o{mo=3Dsr,TDMC/EC=3DOFF}},e=3D1{CTYP/DTONE},sg{}},mf=3Dtgwrtp/8456=
{m{o{mo=3Dsr},r{v=3D0</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">o=3Danonymous 1=
40490962784
140490962787 IN IP4 213.20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">s=3DSIP Call</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">c=3DIN IP4 213.=
20.251.120</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">t=3D0 0</span><=
/p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">m=3Daudio 13076=
RTP/AVP 0 101</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">b=3DAS:82</span=
></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:0 PC=
MU/8000/1</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Drtpmap:101
telephone-event/8000</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dfmtp:101 0-=
15</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dptime:20</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">a=3Dsendrecv</s=
pan></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">}},e=3D1{IPFAX/=
FAXCONNCHANGE},sg{}}}}</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">[message 4 :: M=
odify Reply]</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">!/2
<tmgx-brln-de103-2>:2945 P =3D 111528469{ C =3D 2913
{mf=3Dds/stm1_2/e1_50/29=C2=A0 ,mf=3DTGWRTP/8456=C2=A0 { er =3D 515 {
"Unsupported_Media_Type" }=C2=A0 } }}</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Any information=
will be
appreciated!</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Thanks &Reg=
ards,</span></p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">Manpreet</span>=
</p>
<p class=3D"MsoNormal"><span style=3D"color:rgb(31,73,125)">=C2=A0</span></=
p>
</div>
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