Protocol Overview
Start in SP mode by sending REQUEST over unicast path
If enough resources, REQUEST proceeds like in PIM
If not at some node, switch to MP by sending NACK to parent
Parent “detour” REQUEST to all neighbors except from which REQUEST and NACK were received
Each REQUEST independently search its own subpath
NACK triggers multiple branches to grow “searching tree”
The routing fails if receiver receives NACK from all neighbors (state F)
The best branch is chosen, the others pruned off using BREAK
Can restrict the number of branching points (QMRP-m)