DELIVERY SERVER FOR INTEGRATING DIFFERENT VIDEO SURVEILLANCE NETWORK SYSTEMS Shi Fang Bachelor of Computer Engineering/Master of Biomedical Engineering University of New South Wales, Australia fang.sam@gmail.com ABSTRACT Nowadays, many countries are speeding up in their video surveillance system update process. Following numbers of individual video surveillance systems established in different regions and departments, it become essential to integrate the local video surveillance system as a unified platform. So that it allows the sharing of video resource. Maximize the capabilities of controlling and commanding from video surveillance system. However, video surveillance system was developed from many small groups at beginning. It is luck in unity of layout. Video encoders from different producers were adopted; at the same time, for transferring remote digital video signal, it must establish wide network. Due to the limitation in bandwidth of wide network digital transportation, it must adopt the combination of unicast and multicast in order to satisfy the need for large unified network through limited bandwidth [1]. However, the digital linking devices in wide network, for example the switcher and router are came from different producer as well, it s hard to perform multicast over different network. This article introduces a special designed video delivery server. Based on the vast number of established local video surveillance network, it sets up wide video surveillance network by using this delivery server which is capable of handling encoder and digital linking device from different producer. Keywords: Delivery, Server, Surveillance. 1 INTRODUCTION This Delivery Server is a general IP digital video stream server designed for different manufactories. The Delivery Server provides the ability that copy requested digital video stream to several identical video streams by following specified rules and then delivers them to many receptors/decodes (including hardware decoder and software decoder). At the same time, it can perform the transformation between unicast and multicast video stream in bi-direction. It can deliver the multicast video stream to remote terminal through LAN connection that multicast is even not supported. Later on, the video streams are regrouped to multicast stream. It has the ability to transform single video source to several unicast video stream plus single multicast video stream. In the area with isolator network interface build-in, the Delivery Server supports delivery of isolated video: deliver video to different network with IP address entirely isolated. It guarantees one-way video stream is transferred, no any other bi-directional data communication. Hence it acts as a video gateway or video network isolator [2]. Main functions are described below: deliver single unicast video stream to multiple unicast video stream deliver single unicast video stream to single multicast video stream deliver single unicast video stream to multiple unicast video stream + single multicast video stream deliver single multicast video stream to multiple unicast video stream support one way isolated deliver 2 MAIN WORKING PRINCIPLE After delivery server received the command from management system, it then receives the specified IP video data stream. Follow the command request, copy it into multiple IP video streams and deliver to different destination separately. The main working principle described as below figure: Volume 3 Number 3 Page22 www.ubicc.org
Main Power Supply: 90-250V /50-60Hz self-adaptive AC power source Delivery Ability: No less than 66M/s- 90M/s(based on single port input and output) Considering different needs, delivery server can be grouped into two versions: 4 U chassis & 1 U chassis. Figure 1: Deliver Server work flow From above figure, after IP video encoder delivered the original IP video stream to video server, video delivery server then follow the request from external management program (manage server/centralized management platform/main control system etc), copy the IP video stream into multiple identical set and deliver to different destination. Such destination includes hardware decoder/storage device/software decoder/video analysis system etc which need IP video stream. 3 PRODUCT HARDWARE DESCRIPTION This product consists with embeddable hardware. All software is programmed inside flash in order to enhance the stability and capability to protect system from invasion/virus. Based on the mature hardware system of Archer5400 main control board, it has passed long period of practical running test and provides better stability for hardware system [3]. 3.1 Mainly Hardware Parameter CPU: RISC 400MHz embedded CPU, internal hardware guide dog RAM: DDR200MHz 128M high speed dynamic Flash: 16M-32M flash Clock: high stability clock module Internal Power Supply: adopted multiple redundant power supply to enhance isolability and stability 3.2 Independent Delivery Servers (1 U) Figure 2: Independent Delivery Server Example 1U version adopts 1 U independent design, suitable in case that relatively small amount of delivery is needed. The main parameters of 1U independent delivery server are described below: Network port: 4 X 10/100M self-adaptive port, RJ-45 Female, self-adaptive MDI/MDIX network cable State indicator light: 10M/100M speed indicator light, data transfer indicator light Protocol: following related Ethernet and TCP/IP standards, support unicast, multicast, multiple unicast Local control port: RS232 serial port, 9 pins male, D type port Power supply: AC input voltage 100-240V, frequency 50-60HZ Physical dimension: standard 1U chassis, 430mm(L)X354mm(W)X44.5mm(H) Weight: 5.2Kg Rated power: 35W 3.3 Delivery Server Group (4 U) Volume 3 Number 3 Page23 www.ubicc.org
Figure 3: Delivery Server Group Example Physical dimension: 19 inch standard 4U chassis Fully equipped weight: approx 12.5Kg Power Supply (include power from equipment rack) < 135W Heat dissipation: <100W Single Archer5400 chassis can insert 5 pieces of delivery server card in maximum. There are 4 10M/100M network port on each card. Each delivery server card is described as below: Network port: 4 X 10/100M self-adaptive port, RJ-45 Female, self-adaptive MDI/MDIX network cable State indicator light: 10M/100M speed indicator light, data transfer indicator light Protocol: following related Ethernet and TCP/IP standards, support unicast, multicast, multiple unicast Local control port: RS232 serial port, 9 pins male, D type port After adopting delivery server group, we can perform flux balance on each server based on different requirement, set the threshold value on flux, so that to perform balance control automatically [4]. In fact delivery server group is acting as a stack in order to enhance the capability of expansion for delivery; hence to suit customer needs better in the way as these needs are always increasing and changing. The hardware in the system is packed with CPU and operates system in a way that it is relatively tight and special designed for independent device, not as interfered easily with other software and hardware as those un-embedded system (e.g. general computer system) does. Hence it has advantage on stability, so that it become easy for installation, maintenance, administration and performs the module design on system. As the result it increases the stability (include the stability for performance) and consistency on system dramatically. 4.2 System Constructions It is adopted the basic working principal of internal-core data process + hardware delivery for our delivery server. So that it supplies the best delivery efficiency. When IP video stream from source transferred into delivery server, base on the request received previously, the server then perform quick search on system internal delivery table and follow the related request to perform different instruction including copy/transform/delivery. This system construction can be concluded as three layers: User port layer ---- responsible for joining user administration port User application layer ---- responsible for performing analysis and execution on user command from high level Hardware internal core layer ---- responsible for performing analysis/transform/delivery on video stream Through different layers, it guarantees the data delivered in high efficiency and also perform management strategy in a highly flexible way. This system construction is showed on figure below: 4 PRODUCT FIRMWARE 4.1 Embedded System Platform Embedded Linux is adopted as internal firmware platform for our delivery server. Based on the advantage from embedded design: Volume 3 Number 3 Page24 www.ubicc.org
Management IP Command Source IP Video Stream System Architecture User Interface User Interface (optional) User/Application Layer Management Module Core Layer Delivery Socket Receiver Figure 4: System Architecture Socket Sender 5 SYSTEM APPLICATION MODE IP Video Stream Output IP Video Stream Output 5.1 Full time Delivery Mode Under this mode, delivery server only performs a single job: responsible for IP video data delivery. Although it can add some additional function with simple condition, such as feedback of data state (state of delivery table, enquiry etc), statistical value on data flow, it never need delivery server to participate the management work on control system. The delivery server can be simply considered as an execution parts for management control system. 5.2 Intelligent Delivery Mode Under this mode, beside from acting as basic delivery server, it also needs delivery server to participate works on condition-management control system. Precisely it can be grouped by functionality into different combinations as described below: 5.2.1 Function on Flux Monitory & Control Delivery server can monitor the data flux on delivery port in real time, and base on presetting threshold value to start different processing mode, for example, after threshold value reached to 60%, enable the function on flux balance, when threshold value reach 80%, trigger the alarm function, when threshold value reach 90%, it gives pause to new server or performs high priority control strategy etc [5], all the process plans can be handled by control system settings and download to delivery server for auto run. 5.2.2 Function on Auto-Cascading Delivery For a multi-level networking, there is always cascading delivery problem. To maximize the utility of the WAN or the bandwidth on the bottleneck of network, we want that when an IP video stream is arrived to local, once superior system requested the same IP video stream, it can copy and deliver the stream from local directly; this is where auto-cascading delivery needed [6]. Performing auto-cascading delivery simultaneously, it can greatly simplify the complications on external application system. Hence let the management system focus on management performance and optimization. 5.2.3 Function on Permission Control when there is insufficient bandwidth in WAN, at the same time new data request from superior management system is arrived, it rises an issue about how to deal with existing video digital stream on local and the high priority data request from superior system. this issue can be handled by delivery server after putting the permission control strategy on management system, so that it guarantees the permission control on real time, guarantees the accuracy on state (the state in delivery server is the most recent and accurate one), so that enhance the reliability of permission control, avoid the problem that superior management system can not get requested data on time. 5.2.4 Function on Advanced General Command The meaning of advanced general commands is that the management system will send unified control command and no longer differentiates the different video sources (encoder). It s like: please send the video picture from station No.1, camera No.32 without understanding what device camera No.32 is adopted. So that the commands which from different devices are differentiated by using different encoder driver through the delivery server. Hence it greatly simplifies the complications on management system. Different encoders can unitize the control by adding different drivers. 5.2.5 Function on auto flux balance When single delivery server can not fully support the great amount of delivery workload, auto flux balance is needed: gathering other delivery servers together to complete the delivery job for single IP video stream. The auto flux balance is kind of work to keep this in line, it manages servers together to form a unified delivery working group. 6 AREA OF APPLICATION 6.1 Local Delivery Server If poor network performance of some encoders is showed, or from management reason that requesting multi-deliver on video delivery server, it can be done by choosing local delivery server. Follow different requests, it can be classified into two cases: 6.11 Conditional Delivery Mode If there are a lot of local encoders, decoders, or different devices have different capabilities of network delivery, or from management reasons, it Volume 3 Number 3 Page25 www.ubicc.org
need use modes described below: 1. When first user established video link to this encoder, this video IP stream will be linked from encoder to decoder directly, delivery server is not participating for job. 2.When this video is requested by second user, in another words this video will be linked to second connection, the delivery server will be activated from management control server, switch video link from both user to the stream which established by delivery server at same time. So that both users receive video IP data stream from delivery server. 3. If any other new user tries to establish link to this video, it will receive video IP stream from the same delivery server. Conditional delivery mode is described on below figure: streams are delivered through delivery server. Speaking to management system, all the video data are came from delivery server. Logically the delivery server is to consider as a centralized video source. Unified delivery sever mode is shown on below picture: Figure 5: Condition Delivery Mode Under the conditional delivery mode, the development of management system is relatively complicate, management system need to know clearly the state of encoder in real time, when the delivery server is needed. Under this mode, it may be a stage of switching direct encoder/decoder link to delivery server stream. During this delivery switch stage, the current real time user can be effect considerably (there is not seamless switch [7]). There are also chances which leading to switch failing. As a consequence the video is watching by current user may be lost. (It is like failing on mobile phone switching, can not communicate). Once the failing appeared, it must need reconnection to be established manually for coverage. The biggest advantage of conditional delivery server is: fully utilize the network capability of encoder, decrease the number of delivery server. At the same time, reduce the latency of local picture. Figure 6: Unified Delivery Mode From above picture, we can see that: encoders are grouped as original data layer. Decoders are grouped as destination layer. Delivery server is the meeting point of two layers. The logic relationship between layers is very clear; the request to the management system is relatively simple. It dramatically reduced the difficulty of development of management system. There is not delivery switch stage at all; it can guarantee the real-time system running stably & smoothly. 6.2 Gateway Delivery Mode At some circumstances, we only allow singledirection delivery for video data to some individual or private networks. There is no permission for any data returning from the secured network to the video data network. For this special need, we can adopt the 1U dependent delivery server which has delivery capability for two network segment and working under the gateway delivery server mode. The gateway delivery mode is shown on below figure: 6.1.2 Unified Delivery Mode Compared with conditional delivery server, under the unified delivery sever mode all video Volume 3 Number 3 Page26 www.ubicc.org
Figure 7: Gateway Delivery Mode As above figure, it can show that for a complicated and isolate-needed network, after adopting the gateway delivery mode, it can guarantees the video network is not effect by external network mostly. This is because delivery server is acting as an isolation device between the two networks. 7 REFERENCE [1] Juniper Networks: Video Distribution in a Hybrid Multicast-Unicast world: Introduction to Automatic IP Multicast Without Explict Tunnels, Juniper Networks Inc, pp.5-8 (2005) [2] Adam H. Li, Dong-Seek Park, John D: Villasenor Video Stream Services Stage 1. 3GPP2, pp.10-15(2000) [3] Avtrace: Video Delivery Servers: evaluation report, Avtrace Inc, pp. 5-12(2006) [4] Yang Ding Yi, Lu Hong Ying: the design of the video monitor system for the railroad transport security based on IP net work technology, Micro Computer Information, pp.12-14(2004) [5] Li Zhong Nian, Xia Zhen Hua: Design of An IP Video Monitoring and Control System Based on Direct Show. Chang Jiang University, pp.20-34(2005) [6] AI Shu Hua, Xu Li Hong, Xu Sheng Lin: IP Multicast Technology Research Based on Embedded Video Monitoring System. Computer and Modernization, pp.34-40(2006) [7] Dong Qian, Xie Jian Yin: A Utility Maximizing Rate Control Algorithm, Journal Of system Simulation Dec, pp.23-30(2003) Volume 3 Number 3 Page27 www.ubicc.org