a method of routing packets across a packet switched network domain , comprising a multiplicity of nodes . each node comprises an ingress interface and an egress interface . for each destination node a default and a detour branching are defined , each specifying a route to the destination node . for each two - edge connected node the default and detour branchings do not share a common ingress interface . each node operates as an intermediate node receiving a packet at an ingress interface , identifying an egress interface based upon the ingress interface upon which the packet is received and the packet destination , forwarding the packet via that egress interface if the connected link is available and , if the connected link is not available , forwarding the packet via an alternative egress interface associated with said detour branching if the packet was received at an ingress interface associated with said default branching or dropping the packet if the packet was received at an ingress interface associated with said detour branching .