CN100341296C - Mobile node switching control method for MIPv6 experiment - Google Patents

Abstract

The present invention provides a mobile node switching control method for MIPv6 experiments, which belongs to a network experiment and simulation technical field. The present invention establishes an MIPv6 experimental environment by using a network switch and a plurality of general computers, wherein the network switch supports an SNMP protocol and the grouping of a virtual local area network (Virtual-LAN, VLAN), the roam switching of a mobile node from a home link to an other place link and form an other place link to an other place link is realized by that a VLAN for an access port of the mobile node is reset on the network switch, and the setting of the VLAN is realized by a control end through an SNMP protocol. Compared with a method for realizing the switching of a mobile node by traditional manual plug-pull network cables or modifying SSID in MIPv6 experiments, the present invention make the switching of the mobile node need no manual operation, and therefore, the automaticity degree of the MIPv6 experiments can be enhanced.

Description

A Mobile Node Handover Control Method for MIPv6 Experiments

technical field

The present invention relates to network experiment and emulation technology, especially the experiment technology of Mobile IPv6 namely Mobile IPv6 or MIPv6, particularly a kind of mobile node switching control method for MIPv6 experiment.

Background technique

With the development of network technology, various mobile devices urgently need to access the network anytime and anywhere. Therefore, the Internet Engineering Task Force (IETF) has formulated the mobile IPv6 protocol standard, which can realize seamless roaming of hosts between different IPv6 networks.

Three important functional entities are defined in the MIPv6 protocol: Mobile Node (MN), Home Agent (Home Agent, HA) and Correspondent Node (CN). When the mobile node is on the home link, it works like a fixed host. After roaming to a foreign link, using the address configuration mechanism of the IPv6 protocol, the mobile node can obtain one or more care-of addresses; after that, the mobile node sends a "binding update" to the home agent to apply for registration, and establish the mobile node's The "binding" relationship between the home address and the care-of address, in this way, the home agent will intercept all IPv6 data packets whose destination address is the home address of the mobile node on the home link, and forward them to the care-of address of the mobile node through the tunnel; At the same time when the home agent is registered, the mobile node also sends a "binding update" to the corresponding end to inform the corresponding end of the current care-of address, so that the corresponding end can modify its own "binding cache", and then use the "second class Routing Header" to send packets directly to the mobile node to complete "optimized routing" and reduce network load.

In the research and development work related to MIPv6, in order to verify the validity and performance of various protocols, equipment or software, it is necessary to build an experimental environment for experiments and tests. An important task of the experiment is to control the mobile node to roam and switch between the home link and the foreign link, and measure and collect relevant data at the same time to verify the actual working conditions of these protocols, equipment or software. Due to the limitation of cost and complexity, these MIPv6 experimental systems are usually established in the local area network under the laboratory environment.

At present, in the existing MIPv6 experimental systems, computers are mostly used as home agents and access routers, and different network switches are used to form home links and foreign links, and the control of mobile nodes switching between home links and foreign links There are usually two methods: when the mobile node accesses the network in a wired manner, manually pull out the network cable from the access port, and then insert it into the access port of the network switch corresponding to the external link; WLAN) to access the network, manually modify the SSID (Service Set Identifier) of the mobile node to force it to access the wireless access point (Access Point, AP) corresponding to the foreign link. Since each mobile node switching needs to be manually operated, the experiment cannot be carried out automatically, and the precise control of the switching time is also difficult to achieve.

Contents of the invention

The purpose of the present invention is to provide a mobile node switching control method for MIPv6 experiments, the MIPv6 experimental method has strong controllability, automatic and flexible mobile node switching.

The technical scheme of the present invention is achieved in that a computer is set as the experimental control terminal, on which the MIPv6 experimental control program is run, and the experimental control terminal should be connected with at least one network switch. When carrying out the MIPv6 experiment, a The computer is used as the experimental control terminal, on which the MIPv6 experimental control program is run, and more than two virtual local area network VLANs are divided on the network switch through the simple network management protocol SNMP. One of the virtual local area network VLANs is used as the home link, and the remaining one or more are selected. A virtual local area network VLAN is used as a foreign link; when it is necessary to control the roaming switching of the mobile node between the home link and the foreign link or between the foreign link and the foreign link, the control terminal adopts the port-based virtual local area network VLAN division method, Through the simple network management protocol SNMP, the virtual local area network VLAN is re-divided on the network switch, the access port of the mobile node is deleted from the current virtual local area network VLAN, and it is added to the virtual local area network VLAN corresponding to the target link, thereby completing Switching process.

The experimental control terminal is connected to at least one network switch, and the MIPv6 experimental control program is run on the computer as the experimental control terminal, and the virtual local area network VLAN configuration parameters on the network switch are read and modified through the simple network management protocol SNMP, and the virtual local area network VLAN is sent to the network switch. Divide command.

The present invention only needs a layer-2 switch capable of dividing virtual local area network VLANs, adopts a port-based virtual local area network VLAN division method, and does not need to consider physical connections, and can simply and flexibly divide home links and foreign links on the switch ; The mobile switching control is flexible and simple, and can be completed conveniently and quickly only by dynamically changing the virtual local area network VLAN to which the mobile node MN belongs. The test results show that in the MIPv6 experimental system built by the present invention, the MIPv6 protocol can work well, and the packet loss and time delay in the MN switching process have also been improved.

Description of drawings

Figure 1 is the physical topology of the experimental system when the mobile node adopts wired access mode;

Figure 2 is the physical topology of the experimental system when the mobile node accesses through the wireless local area network;

Fig. 3 is a system structure diagram of the control terminal;

Figure 4 is the logical topology of the experimental system;

FIG. 5 is a schematic diagram of the handover process of the mobile node MN;

Fig. 6 is the output result of the packet sniffer tcpdump on the home agent HA before and after the handover of the mobile node;

The content of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in detail:

With reference to Fig. 1, shown in Fig. 2, the MIPv6 experiment system that builds based on the present invention comprises a control terminal, one or more than two network switches and more than two computers, if mobile node accesses the network by wireless local area network, then also One or more wireless access points AP are required. All mobile nodes MN, home agent HA, access router AR and control end are interconnected through network switches to form a local area network. The figure shows the physical topology of the minimum configuration MIPv6 experimental system. If the mobile node accesses the network through the wireless local area network, the physical topology of the experimental system is shown in Figure 2. The mobile node MN is connected to the network switch through the wireless access point AP instead of Ethernet. The switching mode of the mobile node MN Same situation as with wired access.

In the experimental system, the network switch must support the simple network management protocol SNMP protocol and virtual local area network (Virtual LAN, VLAN) division; it is installed on the computer used as home agent (Home Agent, HA) and access router (Access Router, AR) The Ethernet card is connected to the network switch, and the LINUX operating system, MIPL (Mobile IPv6 for Linux) software and RADVD software are installed on these computers at the same time; the Ethernet card or wireless network is installed on the computer used as a mobile node (Mobile Node, MN) The module runs an operating system that supports the IPv6 protocol. The MIPv6 experiment control program is installed on the computer used as the control terminal.

Figure 3 is a structural block diagram of the MIPv6 experiment control program. The control program has two functions: one is to manage and maintain resource conditions, mainly the use information of the network switch; the other is to complete the division of the virtual local area network VLAN on the network switch through the simple network management protocol SNMP.

The MIPv6 experiment control program is installed on the control terminal, and the functions of each module are as follows:

1) The input/output control module is an interface provided to the user. Input control includes basic input error detection, such as incorrect data type, data overflow, non-existent virtual local area network VLAN number and other illegal input; the main function of output control is to control the output format;

2) The hardware resource recording module of the experimental system records the detailed information of the hardware resources (including host computer and network switch) of the experimental system. Record the host's CPU, memory, IP address, network card type, and the port number that the host is connected to the network switch; record the use of the port of the network switch and the virtual local area network VLAN;

3) The network switch control module reads and modifies the current configuration of the network switch. The module constructs the SNMP protocol data unit by calling the SNMP interface, communicates with the SNMP agent (Agent) of the network switch, and requires the Agent to process the SNMP request message.

Fig. 4 is the MIPv6 logical topology configured in the experimental system shown in Fig. 1 . The handover control of the mobile node will be described below in combination with this topology.

The address of the home agent HA is fec0:106:2700::2/64, the address of the mobile node is fec0:106:2700::4/64, and the address of the remote access router AR is fec0:106:1100::1/ 64. The experiment process is as follows: at the initial moment, the mobile node is on the home link; at a later time, the mobile node will switch to the foreign link; in the whole experiment process, the mobile node MN continues to use the ping6 program to communicate with the home agent HA. Measure the time delay and packet loss during the switching process under this method and manual switching, and take the average value of multiple measurement results for analysis.

In order to enable the terminals in VLAN A and B of the virtual local area network to communicate with each other, do the following settings:

1) The home agent HA and the access router AR belong to the virtual local area network VLAN C at the same time;

2) The home agent HA and the network card on the access router AR are set to support forwarding;

3) Modify the routing table of the home agent HA and the access router AR, so that all data packets sent to the virtual local area network VLAN B in the virtual local area network VLANA are forwarded by the home agent HA, and all data packets sent to the virtual local area network VLAN A in the virtual local area network VLAN B The packet is forwarded by the access router AR.

FIG. 5 is a schematic diagram of a handover process for controlling mobile node handover based on virtual local area network (VLAN) division.

When the mobile node MN switches between the home link and the foreign link, MIPv6 can take effect. Initially, the mobile node MN is located in the home link and belongs to the virtual local area network VLAN A; when the mobile node switches to the foreign link, it can be realized by re-dividing the network switch VLAN. Its detailed process is, as shown in Figure 5, delete mobile node MN from virtual local area network VLANA first, then add it to virtual local area network VLAN B again; After mobile node MN switches to virtual local area network VLAN B, can receive access router For the route advertisement message sent by the AR, the mobile node MN reconfigures a new care-of address according to the local information in the route advertisement. Through the above process, it is equivalent to the handover of the mobile node MN from the home link to the foreign link. In the experiment, only the port number of the mobile node MN connected to the network switch and the VLAN number of the virtual local area network it wants to join need to be input at the control terminal, and the control terminal can re-divide the virtual local area network VLAN at the set time. The serial numbers 1, 2... in the figure are the port numbers of the network switch.

Figure 6 is the result of using the data packet sniffer tcpdump on the home agent HA after the mobile node switches to the foreign link.

Throughout the experiment, the mobile node MN uses the ping6 program to communicate with the home agent HA. Use the tcpdump tool to view the packets sent and received by the home agent HA, and you can clearly see the handover process: as shown in Figure 6, ① is the last ping6 message of the mobile node MN in the home virtual local area network VLAN; ② shows that the mobile node MN is switched Go to the foreign virtual local area network VLAN, obtain the care-of address fec0:106:1100:0:20d:88ff:fe48:1803, and successfully complete the registration at the home agent HA; ③ indicates that ping6 is restored, and the mobile node MN is working in the foreign virtual local area network VLAN normal.

To sum up, when the MN switches between the home virtual local area network VLAN and the foreign virtual local area network VLAN, the communication between the mobile node MN and the home agent HA returns to normal after the brief interruption caused by the handover, and the mobile node MN is in the home agent HA. The registration is successfully completed, and ping6 continues to work, indicating that MIPv6 can operate normally in this experimental system.

Table 1 compares the delay and packet loss of two mobile node handover schemes. The performance data of two mobile node switching control methods, manual plugging and unplugging network cables and virtual local area network (VLAN) division, are given. It can be seen from the data in the table that compared with the switching method of manually plugging and unplugging cables, the switching method based on virtual local area network VLAN has improved packet loss and delay in the switching process, but the switching method based on virtual local area network VLAN control has a lower The controllability is stronger, and the switching is more convenient and fast.

Table 1 Comparative test results Average switching packet loss (pieces) Average switching delay (ms) Based on VLAN division 7.33 445.03 Manual plugging and unplugging 7.60 519.99

The equipment configuration and parameters used in the above tests are as follows: a Ruijie Star-S1926F+ Layer 2 network switch, which is configured with 24 10/100Mbps network ports, and supports both "port VLAN" and "tag VLAN" work In the experiment, the working mode based on "port VLAN" is adopted; the home agent HA, the mobile node MN, and the access router AR adopt three PC compatible computers with the same configuration, and the configuration is P4 2.4G, 256MB RAM, 10/100M D -Link adaptive network card, operating system is Linux Red Hat 9.0 (kernel version Linux-2.4.26), MIPL (MobileIPv6 for Linux) version is mipv6-1.1-v2.4.26; both HA and AR have installed version radvd-0.8 The RADVD software can periodically send routing advertisement messages.

Claims (2)

1, a kind of mobile node switching control method that is used for the MIPv6 experiment, it is characterized in that, a computer at first is set as the experiment control end, operation MIPv6 experiment control program on it, and should should link to each other with at least one the network switch by the experiment control end, when carrying out the MIPv6 experiment, on the network switch, mark off plural virtual LAN VLAN by Simple Network Management Protocol SNMP, one of them virtual LAN VLAN is chosen all the other one or two above virtual LAN VLAN as foreign link as home link; When needs control mobile node is roamed switching between home link and foreign link or between foreign link and the foreign link, control end adopts the virtual LAN VLAN dividing mode based on port, on the network switch, repartition virtual LAN VLAN by the Simple Network Management Protocol snmp protocol, delete the virtual LAN VLAN of access interface under current with mobile node, simultaneously it is added among the target link corresponding virtual local area network (LAN) VLAN, thereby finish handoff procedure.

2, the mobile node switching control method that is used for the MIPv6 experiment according to claim 1, it is characterized in that, by a computer as the experiment control end, and link to each other with at least one the network switch, as operation MIPv6 experiment control program on the computer of experiment control end, read and revise virtual LAN VLAN configuration parameter on the network switch by Simple Network Management Protocol SNMP, send virtual LAN VLAN to the network switch and divide order.

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