In-depth research on mobile IPv6 Service Quality

We have discussed the basic concepts of Mobile IPv6 technology. Now let's take a look at the quality of service issues related to this technology. In mobile communication, the example here is the CDMA system. What is the quality of service for China Mobile IPv6 in this system network? Let's take a deeper look at this issue.

Mobile IPv6 Service Quality Problems

When a mobile node changes the network connection point, the intermediate network domain that the data packet passes through may change. Therefore, appropriate service quality support must be provided in these network domains, in this way, apps running on mobile nodes that are sensitive to service quality can maintain available service levels ｡

1. Mobile IPv6 Service Quality System Based on RSVP

The Mobile IPv6 Service Quality System Based on RSVP (Resource Reservation Protocol) proposes a set of Signaling Protocols in mobile networks. When a mobile host moves from one subnet to another, allows the mobile host to establish and maintain the reserved resources in the current path ｡

Mobile IPv6 supports QoS mainly in the flowlabel field, which is a pseudo-random number generated by bit, the source end cannot reuse the stream flag. The stream flag is 0, indicating that this package does not belong to any stream. The common mobile IPv6 technology works with RSVP to identify a stream in two ways: one is to identify the source or destination of the stream based on the home address of the mobile node; the other is to use the transfer address (COA) of the mobile node) to identify the source or destination of the stream. However, either method has some problems: if you use the home address of a mobile node to identify the stream, the package category mismatch may occur. The package category of the intermediate router in the reserved path may be based on the home address of the mobile node rather than the transfer address of the mobile node, therefore, this method is not feasible. If the stream is identified by the transfer address of the mobile node, when the mobile node moves to another subnet, the PATH Message and RESV message with the new forwarding address will trigger the vro on the reserved PATH to reserve new resources instead of reusing the original resource reservation, even if the new path is simply changed based on the old path, resource reservation must be made on the new path after the switchover regardless of whether the mobile node is used as the source or destination, stream transparency cannot be achieved ｡

In view of the shortcomings of the mobile IPv6QoS model, mobile IPv6 and RSVP are extended, there have been some improved mobile IPv6QoS models, including the "stream-transparent mobile IPv6QoS model" proposed by CharlesQi Shen of the National University of Singapore ", xiaoming Fu of Berlin University of Technology proposed the "Conditional QoS Switching Model for Mobile IPv6 ｡

CharlesQiShen method to achieve stream transparency, change the storage location of the package sent by the mobile node from the destination option header to the hop-by-hopoption header ), all intermediate routers on the path need to check the option header of each packet's relay point. When the path passes through a lot of routers, the cost is very high. Therefore, this mobile IPv6QoS model is not scalable ｡

XiaomingFu adopts a hierarchical QoS conditional switching mechanism to reduce the number of signaling signals during intra-Domain Switching. However, it only proposes a framework without a specific QoS processing mechanism, streaming transparency is not considered ｡

2. Mobile IPv6 Service Quality System Based on Differentiated Services

In a service-differentiated Mobile IPv6 service quality system, each management domain has at least one global server, called GQA, on the control plane; several subordinate nodes act as the subordinate service quality proxy (LQA) on the transmission plane. The communication between GQA and LQA adopts the COPS (commonopenpolicyservice). Because global information is retained on the central server, in addition, the control and data transmission are separated. Therefore, it is very flexible for mobile environments and is easy to add new services, this structure also takes into account other issues of integrating Mobile IPv6 and differentiated services, such as the provision of network resources in a mobile environment, the lack of dynamic configuration issues, the definition and selection of service level agreements, and the identification and billing of mobile data streams.:

◆ Differentiated Services are suitable for well-designed networks with reasonable bandwidth allocation. networks supporting mobile environments are complex due to the fact that nodes on the networks are moving at any time ｡

◆ In differentiated services, service level negotiation (SLA) in different QoS regions (such as networks provided by different ISPs) is often static, the high dynamic environment of the Mobile IP address conflicts with the static bandwidth allocation of differentiated services. Therefore, dynamic service level negotiation must be supported for the Dynamic Bandwidth Allocation of MN ｡

◆ At the entrance of different QoS regions, the edge router of the network should identify the grouped streams, traditional grouped streams can be identified by a quintuple on the group header. The source IP address (the Group sent by MN) or destination IP address (the group received by MN) of the group in Mobile IPv6) is the transfer address of MN, which dynamically changes with the movement of nodes ｡

In order to implement Differentiated Services on Mobile IP networks, the network providing mobile services should be precisely designed to Dynamically Predict the bandwidth requirements of mobile nodes and the number of MN for access, or adopt signaling mechanisms such as resource reservation, more accurately predict the bandwidth required to meet the QoS of mobile nodes ｡

3. Other issues affecting Mobile IPv6 Service Quality

The packet transmission latency and packet loss introduced by MN during over-the-zone switching are also urgent problems for Mobile IP addresses. If this problem is not solved, QoS Assurance for Mobile IP addresses is impossible ｡

At present, there are many proposals for fast switching of Mobile IP addresses. The basic ideas include grouping cache, multicast, and pre-Switching Based on Mobile triggering. In addition, resource Reservation for Mobile IP addresses, authentication during MN registration, and synchronization procedures for Mobile IPv6 Header Compression will introduce latency during MN switching, therefore, a more effective method is required for the cross-region switchover of Mobile IP addresses ｡