One Way Audio with MGCP Gateway

[g-werner]

We got a problem with sporadic "one way audio" one mgcp connections to PSTN.

Call flow:

PSTN-->2811-->mgcp-->cucm-->CP7942-->CFWDall-->CP7942

or

PSTN-->2811-->mgcp-->cucm-->CP7942-->Pickup-->CP7942

or

PSTN-->2811-->mgcp-->cucm-->Huntpilot-->CP7942

If we got an direct call, everything works fine.

We got the Problems since we updated the Gateway to 15.1(4) M7.

Is there a bug? Has anyone an idea?

regards Guido

[Aaron Harrison]

Do you have the 'mgcp bind' commands in the config to tie the calls to the correct interface? This is typically your LAN interface...

Aaron

[g-werner]

Hi Aaron,

yes we have configured "mgcp bind".

mgcp
mgcp call-agent X.X.X.X 2427 service-type mgcp version 0.1
mgcp modem passthrough voip mode nse
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp package-capability pre-package
mgcp package-capability srtp-package
mgcp default-package mt-package
no mgcp timer receive-rtcp
mgcp sdp simple
mgcp validate call-agent source-ipaddr
mgcp fax t38 ecm
mgcp fax t38 inhibit
mgcp rtp payload-type g726r16 static
mgcp bind control source-interface GigabitEthernet0/1
mgcp bind media source-interface GigabitEthernet0/1

Guido

[saif musa]

Please try to attach router running configuration.

Regrads

[Dennis Mink]

although your problem started occuring after IOS upgrade (and is most likely not connectivity related) in general when expereriencing one way audio issues, it good to just test connectivity from the phone to the other  RTP end point, by simply pinging it. so in your case, from the phone's subnet to the IP address that MCGP binds to.

[g-werner]

Hi Dennis,

teh Phone and Gateway are in the same Subnet. We are using sRTP as audio stream.

Guido

[g-werner]

We found a BUG in IOS:

MGCP SRTP One Way Audio to Phone as GW not using correct key to encrypt

CSCtv21900

https://tools.cisco.com/bugsearch/bug/CSCtv21900/?referring_site=bugquickviewredir

[voicesupportsg]

Hi,

   I have exact same issue and I have been working with TAC for over a year to find a bug for this issue.Can you help me with SR number or bug details to confirm 15.1(4) M7 is affected.

CSCtv21900 was fixed in 15.1(4) M4 so I am very surprised it is still affecting 15.1(4) M7.

details would be highly appreciated on the solution for this issue,

my setup:

PSTN>>3925 MGCP Gateway >>8961 IP phone

CSCtv21900

CSCtv21900