Principle of Mobile IPv6 technology in core network

Now that the Network Protocol version has been replaced, the use of IPv6 has been promoted by many Parties. Therefore, in terms of communication networks, we must also connect with the Internet to achieve v6 of communication networks. Now, we will conduct a research on the core network of mobile IPv6 technology. Next, let's take a look at the application of mobile IPv6 technology in the core network.

Application of Mobile IPv6 technology in 3G core network

Whether it is the UMTS of 3GPP or the CDMA 2000 System of PP2, their system architecture will evolve and develop towards a full IP address, the bearer of services, such as data and multimedia, is IP-based; the end-to-end service call model is IP-based; the core network switching and call control of RAN and CN are also IP-based. In the 3G/B3G system planning, according to the 3GPP and ipvpp2 specifications, IPv6 is the development direction of 3G/B3G network bearer and business applications. In the IMS phase of 3G/B3G, the network system (including the grouping domain and the circuit domain) will be fully based on or compatible with IPv6 ｡

The Mobile IP technology is a new routing policy introduced in the original IP technology. The IP address-based service on the upper layer will not be interrupted due to the movement of nodes, this kind of mobility is based on the third layer, so it can shield the heterogeneity of the underlying link. The introduction of Mobile IP technology in UMTS is to make up for the shortcomings of mobility management in the original mobile communication system ｡

In UMTS, the principle 2 of applying mobile IPv6 technology is shown. In the figure, the real line indicates the registration process from the UE to the region where it is located. The dotted line indicates the binding process between the UE and the communication node, this is the channel through which the UE sends data to the communication node, and the channel from the communication node to the UE after the UE is bound to the Communication Node; dashes indicate that the data packet sent from CN to UE is first routed to the local proxy ｡

Figure 2 working principle of applying mobile IPv6 technology in UMTS

When a mobile UE is started on, it first checks whether it is in its local network. If yes, it does not need operations related to the Mobile IP address (including Address Allocation and tunneling). However, you must check whether the firewall is deployed on the local network at intervals. The firewall placement varies with the security requirements, generally, it is placed in the connection between the GGSN and the external network. If the UE detects that the current network is not a local network, the GGSN of the current network or the DHCP (Dynamic Host Configuration Protocol) connected to the GGSN) the server allocates a temporary IP Address (Care of Address, CA) to UE through the Dynamic Address Allocation Scheme) send a binding request message to the leased line proxy of the Public Land Mobile Network (the leased line proxy in Figure 2 can be used by the GGSN or the edge router of the leased line network) of the Public Land Mobile Network, tell the local proxy to the current CA. After receiving the local proxy, send the binding response to the UE. This completes the binding process ｡

The local proxy directs all data packets sent to the UE to the local proxy, and then transmits the data packets to the current CA of the UE through a tunnel (actual location of the UE). When a mobile node sends data packets, using a CA as the source address and writing the local IP address to the local IP address option solves the entry filtering problem (because some routers have the source route filtering function) the Node (CN) that communicates with the UE copies the local IP address to the source IP address. In this way, the upper layer regards that the datagram is sent from the source IP address and does not feel the UE's movement, this ensures the transparency of the Movement to the upper layer. After the UE receives the data packet from the CN, it will directly send the Binding Request to the CN. After receiving the data packet from the CN, it will send the binding response to the UE, later data packets are directly sent to the CA, instead of being transferred through the local proxy. This is a feature of the Mobile IPv6 technology to optimize routing. All these are completed on the third layer, the upper-layer data communication does not feel this change. That is to say, IP-based applications will not be terminated because of UE movement ｡