Configure your CentOS 6.x system to be able install RPM packages provided by the EPEL 6 project. The rohc RPM package uses software that is not provided by CentOS but by EPEL.
Please run as root:
# yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
Now, install the rohc RPM package and its dependencies. Please run as root:
# yum install https://rohc-lib.org/download/rohc-latest.x86_64.rpm
Once the ROHC library is installed, you may: