Quality of service in an IP crypto partitioned network

It is planned that military grade IP crypto devices (ICD) will be increasingly deployed in defence networks. The ICDs are used to partition the network into clear text higher classification areas ("Red") and enciphered lower classification areas ("Black"), where the Black area may be implemented as an IP network of arbitrary complexity. We refer to this architecture as an IP crypto partitioned network (ICPN). When there is a need to prioritise critical or real-time traffic flows over other flows in an IP network, IP quality of service (QoS) may be required. Provision of end-to-end QoS across an ICPN is a balance between, on the one hand, the deliberate information hiding used to ensure data confidentiality, and, on the other hand, the need to signal QoS information across the Red/Black partition boundaries. The paper introduces IP QoS models and discusses their applicability to an ICPN. The relevant differences between ICDs and link level crypto devices are summarised. Aspects of an ICPN affecting end-to-end QoS are highlighted. Deployment experience with ICPN in the US Navy is described, as is the QoS architecture planned for the interoperable networks for secure communications project. Suggestions are given for design decisions and open issues are recorded. It is concluded that whilst end-to-end QoS is possible, a number of open issues remain.