In the RNAP-C architecture, the aggregation and de-aggregation entity are NRNs. Once again, we consider the aggregation of Reserve messages. At an aggregating NRN `a', the aggregate Reserve message will be formed and sent domain by domain towards the destination domain NRN `b'. In addition, the destination domain NRN is located through DNS SRV, and the aggregating NRN encapsulates the per flow Reserve messages in UDP packet headers and tunnels them directly to the destination domain NRN `b'.
The destination domain NRN sends a Commit messages ``hop by hop'' (each hop is one domain) upstream towards `a' in response to an aggregate Reserve message. It will also receive the encapsulated per flow Reserve messages from `a', process them to perform per-flow reservation in the destination domain, and determine from the Aggregate Flow Id field that per-flow response messages are to be encapsulated and tunneled back to `a'. There is a similar message flow for RNAP Quotation messages in the upstream direction. The mapping of pricing and charging information from aggregate session to per flow message is similar to that in RNAP_D. Multiple level aggregation is also supported in RNAP_C.