# OPMSS: Optimal Producer Mobility Support Solution for Named Data Networking
## 2 Related Works
### Anchor-Based and Tracing-Based Methods  
The AB and TB methods are typical examples of IBMA solutions. In the AB method, the immobile anchor router or resolution server (RS) is placed in the network when the mobile producer moves to a new location and obtains a new prefix name. The new prefix is then sent to the anchor router or the RS. Next, the consumer sends a pending interest packet to the known location of the anchor router, and the anchor router tunnels it to the new location of the mobile producer. Unlike in the TB method, the anchor router or RS utilizes the traces of the mobile producer stored in pending interest tables (PITs) or FIB tables. When the interest packet arrives, the anchor router or RS forwards the interest along the traces without tunneling. [PERSON] et al. [25] proposed a TB solution called Kite that utilizes the PITs and FIBs to store mobility traces and reach the new location of the mobile producer through routable anchors [13]. This scheme is also called an AB approach [27] or a PIT-based approach [39], where a mobile producer sends traced interest or trace interest [25] packets to the immobile anchor or the RS and establishes a trace route in the PITs of the intermediate routers, and sends the new location of the mobile producer to the anchor router or RS. The traced or trace interest packets, as presented in a report about the Kite mobility solution, can be sent to the immobile server or the data report. The corresponding node, consumer, immobile server, or data report requesting content sends tracing interest packets as in [13] or traced data as in [25] back to the anchor router or RS. In the latest Kite report, the RS announces a routing prefix and the mobile producer issues a trace interest packet with a special tag to the RS. The RS verifies this and responds with trace data to update the intermediate routers as trace setup processes [25]. The consumer sends an interest packet to the RS and then forwards the trace to the mobile producer. These processes are similar to those in a previous Kite solution, except for the change of tracing and traced interest packets that are replaced with trace interest (_TI_) packets and trace data (_TD_) in addition to the consumer's interest packet. However, the Kite solution results in high signaling to keep the traces active, along with the intermediate router in PITs, by sending _TI_ packets and _TD_ in a timely fashion. Moreover, the solution results in path stretching, where the optimal routing path is not guaranteed because the consumer's interest packets pass through the RS or anchor point. An attempt was made by [PERSON] and [PERSON] [27] and [PERSON] [39] to improve the Kite solution by providing an optimal routing path and reducing the signaling overhead cost. [PERSON] and [PERSON] [39] proposed a scheme for a large-scale NDN to solve the path stretching and routing problem of the Kite solution and to reduce the signaling overhead cost. The author [39] introduced a fast handoff mechanism that directs the subsequent interest packets to the new location of the mobile producer and creates an optimal data path. A special mobility management packet is used to make the update before the handoff occurs. The scheme uses a forwarding plane of NDN to establish an optimal data delivery path and predict producer movements. However, the solution is not guaranteed for large deployment, as claimed by the author. In addition, due to the processes of fast handoff, the signaling overhead cost becomes higher, and the addition of a binding cache and neighbor information tables increases the look-up time. [PERSON] and [PERSON] [27] proposed an on-demand anchor-based solution to producer mobility that uses a mechanism called adaptive interest packets forwarding. When the producer moves to a new location, the FIB entries become invalid, and the interest packets looking for the content from the mobile producer are redirected towards the anchor node from the previously known location of the producer, instead of being dropped.