This attribute identifies the cluster consisting of the Route Reflector
and its peer clients. When routeReflector of Bgp is true, value of
0.0.0.0 or 255.255.255.255 is invalid; the default value of this
attribute is same as bgpIdentifier. For redundancy, a cluster may
have more than one Route Reflector; in this case, the value of this
attribute of all the Route Reflectors in the same cluster should be
same. The value of this attribute is ignored when routeReflector of
Bgp is false