Solving the SIP Connectivity Problem between Cisco Gateways and VoIP Providers

At one time I ran into a problem - we decided to use an account on sipnet.ru to make MN / MG calls, however the calls were fought off by sipnet.ru, although the money was on the account and the test calls from the soft client passed.



Long struggled with their technical support, as a result on the forum (not in the STF :), they suggested that their softswitch does not like Delayed media, which triskovy gateways use by default in case of IP-IP calls.
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Digging in the documentation showed that at that very moment software 12.4 (20) T1 was released in which they added such a feature - Forced Early Media on IP-IP calls.

I downloaded the fresh software, brought the config to something like this:

 
 voice service voip
 redirect ip2ip
  sip
  early-offer forced

and everything ran. :)

Why in the topic is written by "providers": later I ran into exactly the same problem when docked with Huawei SoftX3000.
Also, there is a suspicion that a similar situation with Measure.