A method and apparatus for a base station to trigger a random access procedure for carrier aggregation in a wireless communication system are disclosed. An apparatus, including a chassis having a first module bay with a first plate mounting bracket, a second module bay with a second plate mounting bracket and a repositionable plate that is removably connectable to the first plate mounting bracket and removably connectable to said second plate mounting bracket. The method further includes determining that the packet includes a tunnel header and an original header concealed by the tunnel header, selecting one link from among a set of parallel links of the link group based at least on one or more fields of the concealed original header, and forwarding the packet to the second network node via the selected link. In other embodiments, proximity relationships between animals may be detected based on detecting the co-location of computing devices associated with the animals.