I found some interesting blogs about this topic:

Notes:

  • Router IOS should support voice. I’m using 12.4 Advanced Entreprise IOS version,
  • Vmware network adapter: set to “host only” mode. Remember that during the installation of CUCM on Vmware, we set the network adapter to “bridged”, so it can connect to Internet and contact an NTP server,
  • After adding the cloud component in GNS3, you may find that no adapter is seen under NIO Ethernet. GNS3 mentions that it needs “Administrator or root access”. Solution: close GNS3, right click and choose “run as administrator”. Then you’ll see the list of adapters under NIO Ethernet.