Question about "sim0" in dce-quagga-ospfd.cc

[watalou]

• ns3 version : 3.34
• DCE version: 1.11
• Operating system/version (lsb_release -a): Ubuntu 16.04.7 LTS
• Libc version (ldd -v): ldd (Ubuntu GLIBC 2.23-0ubuntu11.3) 2.23
• compiler version : 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12)

Description of the problem

In the examle script "../dce/source/ns-3-dce/myscripts/ns-3-dce-quagga/example/dce-quagga-ospfd.cc", there is a line of code:

AddAddress (nodes.Get (0), Seconds (0.1), "sim0", "10.0.0.1/24");

which means to run command "ip -f inet addr add 10.0.0.2/24 dev sim0", right?
My question is: where is the dev "sim0" defined?

Thanks in advance!