Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery.
To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl".
1.) Install the utilities to make our bridge
sudo apt-get i........
The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs.
qemu-kvm command:
/usr/libexec/qemu-kvm -version
QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard
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