Network elements configuration supporting VoIP services must interconnect redundant uplinks following physically diverse paths to physically diverse network elements in the layer above with support for the full bandwidth handled by the network element using routing protocols facilitating failover.

Policy sets the minimum requirements for the availability and reliability of VoIP systems and the supporting LAN with emphasis on C2 communications. The high availability and reliability required for Special-C2 and C2 users is achieved in part by interconnecting LAN network elements with redundant uplinks via geographically diverse paths. The core layer connects to the distribution layer below it, which then connects to the access layer below it.

Voice services in support of high-priority military command and control precedence must meet minimum requirements for reliability and survivability of the supporting infrastructure. Design requirements for networks supporting DoD VVoIP implementations are in the Unified Capabilities Requirements (UCR), specifying assured services supporting DoD IP-based voice services. Network survivability refers to the capability of the network to maintain service continuity in the presence of faults within the network. This can be accomplished by recovering quickly from network failures quickly and maintaining the required QoS for existing services.