  We define a class of multi--hop erasure networks that approximates a wireless
multi--hop network. The network carries unicast flows for multiple users, and
each information packet within a flow is required to be decoded at the flow
destination within a specified delay deadline. The allocation of coding rates
amongst flows/users is constrained by network capacity. We propose a
proportional fair transmission scheme that maximises the sum utility of flow
throughputs. This is achieved by {\em jointly optimising the packet coding
rates and the allocation of bits of coded packets across transmission slots.}
