Optimizing Industrial Networks for HD IP Surveillance: An In-Depth Case Study

Transcription

1 Optimizing Industrial Networks for HD IP Surveillance: Ray Hsu Product Manager Mark Wu Writer

2 Executive Summary Recent market studies show an increasing number of IP surveillance deployments as analysts predict megapixel resolution to be the baseline requirement for future IP surveillance systems. As IP surveillance networks expand and security operators demand higher resolutions for HD surveillance applications, one fundamental concern will continue to plague network designers and system administrators: bandwidth. Only a well-balanced infrastructure design with ample bandwidth and sufficient data storage can sustain a high-performance surveillance system and enhance network scalability, availability, efficiency, and security. This paper will identify key considerations for building a robust HD IP surveillance network, as well as provide an in-depth analysis of an HD IP surveillance network for a high-speed train station. Overview Present trends in the video surveillance industry indicate an increasing number of analog CCTV systems migrating to HD IP surveillance networks. Analysts (IMS Research) also report that by 2015, more than 70% of all network cameras shipped will be capable of delivering megapixel resolutions. In recognition of this shift in the security industry, the U.S. Department of Homeland Security (USDHS) recently released a handbook documenting the guidelines for best practices in design, selection, and deployment of video surveillance systems (VSS), as well as identifying the minimum requirements for infrastructure devices and components. The USDHS also recommended that HD surveillance be used whenever possible, stating that the HD format offers high color fidelity and is the only megapixel subset with resolution and frame rate standardization. As video surveillance applications expand in size and require higher resolutions, it becomes imperative that video traffic management and network resource allocations are at optimal levels to avoid network congestion. Network scalability for future expansion requirements is also an important factor to consider when planning HD IP surveillance deployment. Released on August 1, 2013 All rights reserved. Moxa is a leading manufacturer of industrial networking, computing, and automation solutions. With over 25 years of industry experience, Moxa has connected more than 30 million devices worldwide and has a distribution and service network that reaches customers in more than 70 countries. Moxa delivers lasting business value by empowering industry with reliable networks and sincere service for automation systems. Information about Moxa s solutions is available at You may also contact Moxa by at info@moxa.com. How to contact Moxa Tel: Fax:

3 Identifying the type of video surveillance that is required can help to determine the amount of bandwidth and storage that will be needed for the surveillance network. The USDHS also cites three service classifications of video applications; real-time observation (live monitoring), forensic review (event recording), and recognition (intelligent video analysis). Each of these classifications will have different network resource demands that will directly impact bandwidth and storage requirements. It is possible for a video surveillance system to require more than one service classification type, which will require additional network resources. Bandwidth and Storage Calculation Whether upgrading an existing network or installing a new infrastructure for IP surveillance, key information regarding the needs of the video surveillance system such as the number of cameras, video resolution, FPS rate, scene complexity, and compression type must first be gathered before bandwidth and storage requirements can be determined. There are many tools available to calculate bandwidth requirements for IP surveillance. However these numbers are purely estimates and should only be used for reference. Bandwidth While a 100-Megabit network will generally be enough for a network of 10 to 15 cameras (each using roughly 3 Mbps of 720p resolution), a large scale surveillance network with more than 30 cameras will likely require a Gigabit backbone for video transmission. Figure 1 below shows a typical surveillance system with two remote sites. The viewing stations are continuously active in the control center and each HD IP camera in sites A and B is generating 3 Mbps of network traffic. The viewing station for site A is displaying 25 video streams from site A. Viewing stations for A/B site monitoring are displaying a total of 45 video streams, 25 from site A and 20 from site B. To ensure video quality at all viewing stations and enhance network scalability, a Gigabit network backbone should be implemented for this HD surveillance network. Figure 1 2

4 Storage Storage requirements can vary greatly depending on factors such as resolution, number of cameras, frame rate, compression type, and days of storage. Sample storage calculations for the two compression formats, H.264 and Motion JPEG, are provided below. Formula for MJPEG storage = Average Frame Size x Frame Rate x Duration Example: For a 8-hour archive of a 4CIF video stream with 100 percent quality and 15 frames per second, the requirement of storage is: 100 KB x 15 fps x 3600s = 5,400,000 KB / hour = 5.4 GB / hour x 8 hours = 43.2 GB Formula for H.264 storage = Bit Rate (kbps) x Duration Example: For a 8-hour video stream with target bit rate of 3M bps (375 KB), the requirement of storage is: 375 KB x 3600s = 1,350,000 KB / hour = 1.35 GB / hour x 8 hours = 10.8 GB Reducing Network Bandwidth Consumption and Storage Requirements For surveillance applications that do not require continuous visual monitoring, distributed video recording and IVA allow security operators to access video footage for review after an event has occurred, consuming network bandwidth only when necessary. Distributed Storage Storing video footage on local SD cards or network-attached storage devices (NAS), known as distributed storage, can drastically reduce bandwidth consumption across the video surveillance network when compared to the traditional centralized storage platform; video data is stored locally and does not have to be transmitted back to the central control room until requested by an user. Another advantage of using distributed storage is that local security personnel can still access video data even when the central network is unavailable. Video surveillance networks using a distributed storage platform can be quickly expanded without having a direct impact on the bandwidth requirements of the central network backbone. Intelligent video analytics IVA allows an event to trigger recognition-based video recording and security personnel notifications, such as when an intrusion or a predetermined variable is detected, to minimize the consumption of storage/bandwidth resources. IVA can also significantly reduce operating costs by reducing the number of security personnel required to visually monitor the video surveillance system. Video Compression Using an efficient compression format can significantly reduce bandwidth and storage requirements. The most efficient compression standard in use today is H.264, which uses an advanced intra prediction scheme to achieve average bit rate reductions of up to 50% (compared to MJPEG) and 80% (compared to MPEG-4). Multicast IP Multicasting protocols allow a camera to stream only one copy of every datagram to the specified address for a multicast group, where copies of every datagram are forwarded to each subscribed member of that multicast group. IGMP snooping are used by layer 2 switches to prevent network flooding from multicast traffic by monitoring IGMP 3

5 messages. Multicast and IGMP snooping can dramatically reduce bandwidth requirements on the IP surveillance network. The benefits of multicast filtering include: Minimized load on the source (for example, the camera); only one copy of the video data will need to be transmitted Efficient use of network bandwidth and is highly scalable as the number of multicast group members increases Network Without Multicast Filtering All hosts receive multicast traffic, even if they did not request data. Network With Multicast Filtering Hosts only receive data from other hosts belonging to the same group. 4

6 High Performance Network to Ensure Uninterrupted IP Surveillance Availability - Network availability directly affects the bottom line, and needs to be a primary requirement in any network design. For non-stop operation and minimize system downtime, we recommend using millisecond-level network redundancy for both wired and wireless Ethernet devices. Infrastructure - A layered edge-to-core architecture (edge, distribution, and core) will enhance network flexibility, scalability, and manageability, which allow operators to easily plan for storage, bandwidth, and redundancy requirements to quickly deploy future surveillance network expansions. Security - Cyber security is a concern for any network infrastructure. In addition to using secure routers to provide firewall/vpn to deny unauthorized access, 802.1x or port-based authentication can be applied to IP surveillance applications with high security requirements. Efficiency - To increase network efficiency, VLANs and QoS (quality of service) should be implemented on the IP surveillance network. VLANs provide a network segmentation system that is far more flexible than traditional networks and provides the following benefits: VLANs ease the relocation of devices on networks Hosts on a VLAN do not need to be on the same physical network and can even be located in different remote locations. VLANs allow network administrators to logically group network nodes based on functionality and/or service type. VLANs provide extra security Devices within a VLAN can only communicate with other devices on the same VLAN. If a device on VLAN A needs to communicate with devices on VLAN B, the data must pass through a routing device or a Layer 3 switch. VLANs help control network traffic With traditional networks, congestion can be caused by broadcast traffic that is directed to all network devices. VLANs increase the efficiency of the network because each VLAN can be set up to contain only those devices that need to communicate with each other. QoS priority allows data prioritization so that time-sensitive and system-critical packets can be processed and expedited across the network with minimal delay to ensure a particular level of performance. QoS can be applied based on port or packet type, depending on the complexity of the application/service and network architecture, to prevent latency and jitter. 5

7 A Design and Implementation Case Study: HD Surveillance Network for Train Station Monitoring A national railway company in Asia intended to deploy a data-intensive IP surveillance network with more than 200 IP cameras to monitor a newly-finished terminal station at the capital city. Engineers from Moxa s PiNS (Professional industrial Networking Service) were requested to provide assistance in designing a high-performance 720p (1280 x 720) HD surveillance system. Project Requirements With over 200 HD IP cameras at the three-story terminal station, the surveillance network will require high-speed video transmission to provide high-quality video for live viewing, recording, and playback, even when all cameras are running 720p video at 30 FPS in H.264 format back to the control center. In addition to multiple monitoring stations for local surveillance of lobbies, rest areas, and train platforms, a main control center will have access to all cameras within the surveillance network to conduct full-scale monitoring of the terminal station. Surveillance network scalability is necessary for future convergence and/or expansions to include additional terminal station services, such as passenger information systems (PIS) and digital audio broadcast (DAB). Initial Considerations The main challenge of this project is to deploy an optimized surveillance network to deliver uninterrupted live view and playback of HD video with maximum performance, reliability, and system uptime. High bandwidth is the basic required element throughout the network design. Rugged product durability with millisecond-level redundancy is the baseline standard in deploying this surveillance network. Easy operation and maintenance bring the best value for the project investment. Routing protocols, such as OSPF (Open Shortest Path First), will be used to construct a two-level hierarchical network composed of one backbone area and many edge stub areas. OSPF keeps redundant routing path information and exchange routing information between the backbone and stub areas to enhance network scalability and can quickly adapt to topology changes. Each HD IP camera connects to an access switch at 100 Mbps. Each edge switch delivers 720p (1280 x 720) upstream video to an aggregation switch, which gathers and forwards traffic to the backbone area. Turbo Ring topology is used to define a stub area for every five edge switches and one aggregation switch. Every aggregation switch uplinks all video data to core switches with layer 3 routing and switching connectivity between the stub area and the backbone area at Gigabit speeds. Each layer 3 core switch provides Gigabit and 10-Gigabit Ethernet bandwidth to connect all aggregation switches and management platforms including NVR (network video recorder) and industrial network management software were utilized to ensure 6

8 high-performance and reliable network connectivity and HD IP video viewing and recording. Risk of network congestion can be minimized by connecting viewing stations and NVRs directly to core switches to prevent video data from traversing the network when reviewing recorded video. Solution Deployment PoE HD IP cameras, compliant with IEEE 802.3af standards, were selected for a surveillance network rollout of this scale to quickly provide convenient power input and eliminate additional costs for power cable installation. With embedded software for IVA (intelligent video analytics), these box-type 720p HD IP cameras, upon detecting a breached perimeter or a triggered alarm, can transmit pop-up videos to security personnel to enable faster response times and enhance security operation efficiency. Bandwidth requirements must first be determined before a PoE switch can be selected for edge-layer connectivity. In addition to evaluating IP camera output, port density, backplane capacity, and uplink requirements, special network design considerations were given in regards to scalability, isolation, and cost efficiency. Each IP camera, with roughly 3.5 Mbps output, will connect to an 8-port switch. With 8 cameras attached to each edge switch, each 8-port switch in a 5-switch stub area will produce about 28 Mbps of video traffic, which means that each stub area will generate 40 channels of video feed and will require a total uplink bandwidth of at least 140 Mbps to the backbone area (core switch). 7

9 Managed PoE/PoE+ edge switches, each with 8 10/100 Mbps ports, 2 Gigabit uplink ports, and 5.6 Gbps available on the backplane, will provide ample bandwidth for uplink to the distribution switch. The Managed PoE/PoE+ switches incurs a higher initial cost than non-poe managed switches, but the benefits of convenient deployment, installation savings, and smart power management will sum up to a lower total cost of ownership. 24-port full Gigabit distribution switches will aggregate all 40 channels of IP video streams from each stub area to the backbone area (core switch) using OSPF routing protocol to determine the shortest network path. With high port-density and layer 3 capabilities, these rackmount switches can easily adapt to topology changes and have enough bandwidth reserved for future network expansions and services. VLAN network segmentation was also implemented to alleviate network congestion. The edge layer generates the most video traffic from the HD IP cameras and if traffic control is not properly administered, broadcast traffic between networked devices will cause serious network congestion. The OSPF network uses subnets and VLAN segments to set isolation between various IP camera groups, media servers, and viewing stations in order to control traffic broadcast, enhance performance, and reinforce security access. Network redundancy was a major concern for the train station operator. To ensure uninterrupted train station surveillance, the network uses OSPF protocol for layer 3 routing path redundancy, and Turbo Ring protocol for layer 2 switching path redundancy. The backup paths between IP cameras and recording servers must be well-calculated for fast failure recovery and load balancing. The switching and routing links between edge and aggregation switches, aggregation and core switches, and between core switches must have an alternate path for redundancy. Core switches with 24 Gigabit ports for distribution-switch uplinks, and 2 10-Gigabit ports for massive backbone data transport provide real-time video streaming to viewing stations. Turbo Ring redundancy was applied to core-layer switching links to guarantee sub-50 millisecond network recovery when a link failure occurs. The routing paths between source-destination pairs are reinforced with OSPF support to ensure fast connection failover. The high portdensity of the core switches also grants flexibility for future expansion. Network management is also an important component for a surveillance network of this size. Typical surveillance systems do not have network management software/tools. When cameras/images are inaccessible, security operators must send maintenance personnel to the remote location to troubleshoot. With intelligent network management software, security operators will have real-time access to the status of every SNMP-enabled device (including switches and IP cameras) on the surveillance network, capable of immediately identifying the location of the failure (link/node/device) to quickly restore service. 8

10 Guidelines for HD Surveillance Network Design and Deployment Installing a new network is typically recommended for mid-sized to large-scale HD IP surveillance systems, which can require extensive system planning, network design, and a substantial investment. However, a dedicated network for HD IP surveillance will offer the widest range of functionalities, improve systems interoperability, ensure network reliability, enhance scalability, and add up to a lower total cost of ownership. Every HD IP surveillance network will have different system requirements and design considerations. However, layering a surveillance network will ultimately enhance performance, improve scalability, and simplify management. Listed below are possible considerations for building an optimized HD IP surveillance network. Network Considerations for HD IP Surveillance Edge Layer Distribution Layer Performance 10-Gigabit backbone for transmitting heavy video traffic High-density Gigabit connections for massive HD video aggregation Gigabit uplinks for HD video streaming High Power PoE capability for powered devices (up to 36 W) n for wireless streaming (up to 300 Mbps) 3.5G HSPA for mobile streaming Availability Millisecond-level network redundancy 2.4/5 GHz dual-radio mode for zero wireless packet loss Isolated dual power inputs for redundant power system Hot swappable for uninterrupted service (modular devices) Efficiency Layer 3 routing and switching for efficient VLAN operation Intelligent layer 2 switching for efficient network management IGMP snooping for efficient multicast video distribution Smart PoE functionality for easy power management Easy network management and visualization Modular design ensures flexible options for network expansion Flexible port combination and density Security High performance VPN/firewall for cyber security (up to 500 Mbps) Secure router for firewall and NAT functions SNMPv3, IEEE 802.1X, HTTPS, or SSH to enhance network security Industrial-Grade Design Fanless design for maintenance-free operation Wide temperature tolerance for extreme conditions Redundant dual power inputs High MTBF, high EMI protection, and industry-proven standards Core Layer Additional considerations for edge devices (cameras and NVRs) ONVIF for interoperability IP66 for ingress protection SDK for IVA embedded applications H.264/MJPEG compression Imager viewing options for day/night, color, and black/white Wide focal length range for maximum magnification (zoom) HDTV conformance Internal memory recording (SD storage) To meet the growing needs of the security industry, Moxa is dedicated to optimizing industrial Ethernet solutions for HD surveillance applications. Moxa offers innovative technologies, 9

11 comprehensive high-bandwidth networking and high-definition video solutions, and efficient network management, all of which enable a highly-flexible edge-to-core network infrastructure for dynamic HD surveillance network deployments and upgrades. For more information on how to optimize your HD IP surveillance network, please visit: Disclaimer This document is provided for information purposes only, and the contents hereof are subject to change without notice. This document is not warranted to be error-free, nor subject to any other warranties or conditions, whether expressed orally or implied by law, including implied warranties and conditions of merchantability, or fitness for a particular purpose. We specifically disclaim any liability with respect to this document and no contractual obligations are formed either directly or indirectly by this document. 10