The intersection of image capture system solutions
In recent years, with the continuous development of economy, the number of city population and the rapid growth of motor vehicles, city road traffic pressure is more and more big, traffic accidents have occurred, a serious threat to people's lives and property safety, one of the important reasons is that the motor vehicle driver driving in the sight of the illegal traffic police the situation is very common. Relying solely on human management, waste of human resources, the effect is not obvious. So the image capture is slowly applied in various places, the electronic police is called.
The monitoring system has become an important part of non site enforcement means, for police departments to effectively prevent and reduce vehicle red light violation the behavior has played a positive role, and it has been widely used in the modern traffic law enforcement, has made great achievements in speeding up the city traffic. Information management system, intelligent process, to improve the capacity of urban road network in the existing scale of urban construction to ensure safe driving of vehicles, improve the execution and efficiency of traffic management system etc., the image capture system is very important.
2, System composition
At the crossroads of image capture system is divided into three parts: control center, terminal equipment network camera, network transmission equipment (Four-Faith 3G 4G Cellular Router F-R100). The monitoring center includes VPN server, web server, data server and PC, the main system communicates with the image grabbing system around the beat by monitoring platform, monitoring every intersection, real time check vehicle violation information, timing of the captured image, and can view the local video, statistics related data such as the number of vehicles and traffic.
Capture system terminal equipment using high-definition network camera, with memory function, can store local video and capture images can clearly show the state of the signal lamp, the license plate number, illegal vehicles the color of the vehicle, the vehicle type, illegal time, location, direction of travel. Network transmission equipment with Four-Faith router F-R100 by the 4G network transmission to the monitoring center, and to ensure that the monitoring center can view real-time capture image.
Terminal equipment and monitoring center communicate in two ways, one is use VPN tunnel, second is to use the operator special line.
3.1 VPN tunnel mode
With the F-R100 routers VPN client. F-R100 is a networking wireless communication router, to provide users with long distance wireless data transmission using network operators, network compatibility 4G/3.5G/3G/2.5G, support VPN client.
Due to the use of NAT mode to establish a remote connection for all users of the network, that is, all of the users in the network can access the service port and the communication connection is established. So at some point will cause data security. So here using remote VPN connection, the data in a common a LAN as safe transmission.
Could be used here in the PPTP VPN or L2TP VPN, F-R100 client, monitoring center server server, after the establishment of the VPN, between the client and the server establish a virtual VPN tunnel, the dashed part of the diagram, the server side IP tunnel for 22.214.171.124, at the junction of a F-R100 tunnel client address for 126.96.36.199. when the monitoring center server communicates with a terminal equipment, VPN server will through the VPN tunnel to sending data to a remote 188.8.131.52 VPN clients User side, can be seen as data only in this virtual tunnel transmission, to ensure the safety of data transmission. Terminal equipment through the VPN tunnel, and monitoring center platform software to achieve data interaction.
In the field to check image capture, laptop or PC can be through a VPN and VPN server connection is established, through the monitoring center software platform can view the image capture.
3.2 Operator Special line mode
VPDN, known as virtual private dialup network is a VPN service, is based on dial in user virtual private dialup network business. The dial-up access to the Internet, using IP network carrying function with the corresponding authentication and authorization mechanisms set up the security of virtual private network (VPN) is a technique in recent years with the development of Internet and the rapid development. The router F-R100 with the operator specific network card.
Operators designed card distribution with a fixed IP, dial in the network need to verify the information, the operators there will be given specific user name and password or APN No., put these fill in the relevant information of corresponding router settings as shown in the following picture.
After the establishment of VPDN, webcam web access port is port 80, the router F-R100 mapped by the port to port 80 turn into other ports such as 8000, such as intersection of 1 F-R100 router gets to address for 10.1.1.2, monitoring center access 10.1.1.2:8000, can access F-R100 below the webcam.
3.3 Advantages of 3G networks
WCDMA network and is currently the world's most widely used, the most mature technology, bandwidth is the highest, the most powerful business 3G standard, download the theoretical peak speed up to Mbps, upload speed up 5.75Mbps; network access time is less than 5S. And when it encountered emergencies or area the channel is busy, Chengdu can increase frequency, additional emergency communication vehicle etc. to optimize processing; to places with poor signal coverage, can also be through the planning Acer station to optimize the way.
Advantages of SDH/MSTP transmission network
MSTP (Based on SDH multi service transport platform) is refers to the platform based on SDH TDM, ATM, Ethernet business access, processing and transmission, provide flexible adjusting bandwidth and access Ethernet, access rate between the 2M-1000M data line industry provided for customers.
MSTP functional characteristics
Having access to TDM services, ATM services or Ethernet services;
With the TDM business, transparent transfer function transfer function of ATM or Ethernet including point-to-point;
A bandwidth statistical multiplexing function with ATM traffic or Ethernet services;
The ATM service or Ethernet Services map to the SDH virtual container with the finger matching function.
MSTP dedicated business is using MSTP MSTP technology, relying on SDH transport network to provide the data line business. Is MSTP is superimposed on the SDH based on data features and, in network transmission, is still the standard STM-N transfer mode, at the transmission level is independent of the logic channel, transmission to the router is a physical line, with the same level of SDH high security.
1, MSTP itself can be protected by the SDH mechanism (MSP, PP, SNCP, device level protection, etc.) on the VCtrunk channel for self-healing protection;
2, MSTP can through LPT (link state through) to realize the function of peer to peer port level protocol state information transmission, source end of the channel data or VCtrunk abnormal, the state information can be through LPT functions passed to the destination peer port level, by the sink data equipment control follow-up action.
3, in has a backup path and is a full static routing design of network and SDH network can realize the wrong port (bifurcation point and convergence) level business hot switching, MSTP network can realize, for customer network center aggregation router, CPOs encapsulation PPP protocol support to end to end detection. When a fault occurs in the transmission link, the PPP protocol detection timeout post down, static routing interface corresponding to the automatic failure, hot business will switch to the backup route points to the port. And Ethernet without this technique, when after termination of the branch point or VCtrunk transmission link port router is unable to perceive and Using static routes is still valid, the fault link corresponds to the local business interruption;
4, deployment of dynamic routing protocol can solve problem of MSTP network can not be switched, such as in the main link deployment OSPF, the priority weight is higher than static routing backup links, so that when the main VCtrunk transmission link failure, the routing protocols exchange message timeout after rapid convergence and static standby routing effectively, the business can smooth switching to an alternate path.
3.4 Network topology of practical application
Network topology structure of the electronic police system
1, As the backstage data receiving platform access 80M MSTP Ethernet line. Used to connect the background data receiving platform firewall (LNS) and MSTP network. In the front-end user access, use L2TP protocol with VPDN platform establish a secure tunnel connection, corresponding to each of the front-end a L2TP tunnel.
2, According to the need, the background data receiving platform can choose a VPDN authentication server for the front end of the access terminal of the two authentication, in order to protect access control and upload data security.
3, The front-end acquisition equipment configuration WCDMA VPDN exclusive SIM card, the chap authentication protocol, combined with the phone number, terminal IP, username, password (even including SIM card code, the base station cell) of the legality authentication of the user, through the authentication access GGSN, establish PPTP connection.
4, By the front-end acquisition device authentication and access GGSN, GGSN background data to the receiving platform to send the second authentication information, through the authentication system, by the background data receiving firewall platform (LNS) in the front-end collection of IP address allocation, establishment of front-end acquisition device and the backstage data receiving platform of virtual tunnel connection, data uploading, while achieving on the acquisition, the front-end equipment, remote control and management.
4.1, Stability: With industrial grade high-performance processors, can withstand long-term adverse environmental test, to ensure the smooth communication; reliable network connection, there are online to maintain the function, to ensure that the device is always online.
4.2, Two-way: With the monitoring platform can view the current situation of the camera in real time, but also with the control center to control the camera.
4.3, Flexibility and expansibility : Standard communication protocols, requiring easy installation and construction, commissioning, operation, maintenance; remote management can reduce the maintenance costs of personnel.
4.4, 4G network, to ensure the smooth communication.