1. A computer-implemented method for facilitating forwarding a packet, the method comprising: receiving, by a computer, a packet with a hierarchically structured variable-length identifier (HSVLI); performing a lookup at a forwarding engine based at least on the packet's HSVLI; wherein the forwarding engine is implemented using a hardware-based exact-match lookup engine, a hardware-based longest-prefix-match lookup engine, or both; and wherein performing the lookup comprises searching for matches against at least one of: a content store, a pending interest table, and a forwarding information base; making a forwarding decision based on the lookup; and in response to the packet containing an interest for a piece of content and the lookup resulting in a match in a pending interest table but not a match in a content store, updating the pending interest table to include the packet's input interface with the corresponding pending interest entry.