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Calling public IP address through MCU instead of IP@SC_IP

Publication Date:  2018-08-29 Views:  809 Downloads:  0

Issue Description


1.       The network topology in which is involved the calling scenario is: SMC, MCU, Internal SC and External SC

2.       Call flow described:

l  How do you actually performing the call? (from a terminal which is connected to SC, from the MCU directly? etc.)

   From terminal we have no problem making the call, only if it is a conference schedule by SMC.

l  What is the flow call path when you call just the public IP and from where you call it?

   Directly from the Endpoint: EPàSC IntàSC ExtàEP; From a scheduled conference (MCU) the flow is MCUàSC IntàSC ExtàEP

l  What is the flow call path when you call public IP@ (in which is the SC?) and from where you call it using the format IP destination@SC’s IP?

   In this case the correct flow is: MCUàSC IntàSC ExtàEP; This address must be put when create a participant on SMC to participate on a conference;

·         MCU IP:      

·         SC_Int IP:   

·         SC_Ext IP:  

MCU version:

Handling Process

I collected the one click to locate diagnostic from the MCU so we can better understand the topology near the MCU device.

I also captured the wireshark traces made from MCU, SC Int and SC Ext with both scenarios: with only the public IP address calling (FAIL) and workaround with public destination IP@SC_Int IP (SUCCESS).

I have checked the Call IP ARQ mode if was enabled or disabled on the MCU CLI, sicne that feature is allowing you to call the public IP addresses only directly through MCU, and found out that is disabled:

<HUAWEI VP9630>dis h323-config

    h225 ras port                  : 1729   

    h245 port{Tcp}                 : 11720-12744

    h225 listen port               : 1720   

    enable h245 tunneling          : disable

    enable brzail test modle       : disable

    enable calling party number    : disable

    display company name           : Huawei 

    enable tcp seq number init     : disable

    enable Call IP ARQ modle       : disable

Also after a deep investigation from the debug logs could observe the same thing:

Root Cause

Call IP ARQ mode was disabled.


Enable the CALL IP ARQ mode via CLI in MCU:

Save the settings: