Problems with Huawei 4G / LTE routers from 3 and others
SIP ALG must be turned on in the Huawei router and the port number used in your IP telephony equipment (5070 in Redspot's instructions) must be specified.
If you are using Cisco or Linksys equipment, on the "Line 1" tab, set "Nat Mapping Enable" to "Yes" and "Nat Keep Alive" to "Yes".
Note that it is not possible to use line 2 or more IP telephones via these routers. However, it depends on a test and they must use the same port number as specified under SIP ALG if it is to have a chance to work.
Help Topic HT040058. Published 26 August 2004. Updated 25 January 2021.