The PSNs of different classifications are physically separated. The classified circuits are encrypted so they may share a common trunking infrastructure. All circuits to the maximum extent possible are routed over the IDNX multiplexor infrastructure. Line speeds for the IP router networks vary from 9.6 kbps to T-1.
Interfaces supported include all primarily serial and ethernet connections.
The Defense Message System is supported on the IPR router networks. All classified networks are appropriately protected with a combination of physical protection at the router and KG encryption for exposed circuits. In Fall of 1992, a study was conducted and it was determined that the DDN should be phased out and its requirements be satisfied by IPR router networks. As a result, DISA orchestrated an effort to phase out the four sub-networks of the DDN to be completed by October 1995. Often, they simply concentrated them and in some cases, rehoming them to alternate networks.