## 2 Literature Survey
### Limitations of Single Virtual Interface  
Two VI solutions are proposed by [PERSON] et al. [7], [PERSON] et al. [1] in the Network-based Mobility Extensions Working Group (NETEXT WG). The important idea is to mask the PI's status change to stop connectivity interruptions from IP address modification while a host node with many interfaces performs inter-technology transfer.  
The given two mechanisms are projected to conceal changes in the status of PIs. Link-layer technology can conceal these changes in the first approach. For example, IEEE 802.11 may toggle among IEEE 802.11 technology exclusive of the IP stack being responsive to the association. Here, the IEEE 802.11 MAC layer takes care of the mobility. It thus conceals the PI change at the upper layer. The VI is not a factual PI, and the sign is a logical one. The VI is proof in the network layer, and the IP layer only transfers the VI packets. The PI is tied to the VI. Inside a network unit, the VI has connections with the PI. The VI specifies the route among the PI and the VI based on the pre-configured policies of consumers or service providers. In PMIPv6, [PERSON] & Gundavelli [8] and [PERSON] et al. [7] identify the use of the VI-like multi-homing mechanism of inter-technology handover and identify considerations and flow versatility.  
Nonetheless, they rule out the LL-ID bond among PIs and Vis, which indicates the use-cases of LL-ID among PIs and VIs. The similar LL-ID is shared by the PI and VI. All interfaces have a common LL-ID like MAC address. The devices must agree to spoof of the source address or agree to modification of the LL-ID to set the same LL-ID, and the type of access mechanism LL-ID format must be identical. Nonetheless, this solution cannot be recommended, as it is neither endorsed nor permitted by the general wireless devices. In addition, most devices can use dissimilar types of access method LL-ID formats. Therefore, the PI and VI must differ.  
Figure 3 illustrates an example of the sharing of interface 1 (if 1) through LL-ID (ZZZ), and interface 2 (if 2) LL-ID (YYYY). This solution creates multiple issues. Because of using two different interfaces, the MN is unable to transfer the CN packets through AP2, since the AP2 only identifies 2's LL-ID (YYYY).  
When AP2 loses its connection or becomes inactive, the MN may send the packets through the CN. However, the CN is unable to transfer the packets through AP2 because of the property of the global IP address. Then, by sending a neighbor request (NS) to the MN, the MN obtains the global address for its concerned LL-ID. The VI sends the neighbor advertisement (NA) by means of the LL-ID (ZZZ), as the VI's neighbour supply has its personal IP address for the concerned LL-ID. The MN cannot receive transmit packets from the CN, because 1's LL-ID (ZZZ) is unknown to the router. Figure 3 illustrates the method that is enacted by the LL-ID swapping problem [1].  
These techniques, however, are not sufficient for the next generation networks (NGN's). The Auxiliary Advertisement for Neighbour Detection (AAND) technique is proposed to overcome these problems in the VI. The major contribution of the proposed work is to provide an efficient mobility management protocol for the modern mobility environment.