WHITE PAPER. The LLDP Advantage. Link Layer Discovery Protocol Enhances Overall Service Performance

Transcription

1 WHITE PAPER The LLDP Advantage Link Layer Discovery Protocol Enhances Overall Service Performance

2 INTRODUCTION The marriage of Ethernet/IP services with wavelength-based Optical Transport Networks has been a technical and economic boon to broadcasters, video transport providers, and regional carriers alike. In comparison with SONET, the previous generation of optical transport technology, these new high bandwidth, high capacity optical networks use Wavelength Division Multiplexing (WDM) over a single fiber strand to split the optical spectrum into as many as 160 different channels. Products in this category include Coarse or Dense WDM (CWDM, DWDM) multiplexers as well Reconfigurable Add/Drop Multiplexers (ROADM). The use of WDM over fiber yields many benefits, including far greater bandwidth, lower service costs, and simplified transport provisioning. Broadcasters can readily transport virtually any type of video over these networks, including 270 Mbps SDI, uncompressed HD-SDI at 1.485Gbps, and ultra-high definition 4K/UHD. New enhanced data services such as remote production and massive media content file transfers are also easily accommodated. Furthermore, this approach readily supports a wide range of connectivity options, including point-topoint, point-to-multipoint, and multipoint-to-multipoint. Service availability is another significant advantage gigabit Ethernet services over DWDM are expanding, readily offered in many areas. A representative configuration of an Ethernet/IP network spanning an Optical network is as shown below in Figure 1. Figure 1 Combined Ethernet/IP and WDM Optical Networks DRAWBACKS While delivering many significant advantages, the Ethernet/WDM approach is not without a few notable shortcomings. Diagnostic, monitoring tools, and health indicators to more quickly identify and correct network transport issues are not as prevalent in these lower cost, more ubiquitous newer technologies DATASHEET-MDX This results in greater complexity isolating and troubleshooting problems, potential throughput issues, and longer network outages. The task is further exacerbated by the fact that most service providers have diverse groups/staff members to manage the Ethernet/IP and optical portions of their network. 2

3 Seamlessly combining Layer 1 (optical transport) and Layer 2/3 (Ethernet/IP) networking technologies into a cohesively managed whole has never been without its challenges. Misconfiguration or occasional hardware faults may occur for a variety of reasons or in any of the following areas: Dirty or attenuated fiber connections Inexperienced or untrained network technicians Inaccurate or out-of-date equipment and circuit record keeping Unintended hardware or software loopbacks in the optical transport network Layer 2/3 Ethernet transport equipment such as gigabit Ethernet cards Near-end Ethernet concentrators and optical multiplexers Intermediate optical multiplexers, line repeaters, and fiber spanning multiple hops Far-end Ethernet and optical equipment Figure 2 DWDM Intermediate Path Impairments In most instances, there is often little or no integration between Ethernet/IP and Optical Network Management Systems (NMS), making event correlation and outage coordination more difficult and time consuming. Some refer to this as the swivel chair approach to network management, where one standalone NMS is dedicated to the optical network and another totally separate NMS is used for the Ethernet/IP transport network. Event correlation is the ability to determine the root cause of multiple events/problems that occur either within or across multiple networks. Another gap is the lack of proactive monitoring tools that can identify and correct degraded network performance issues before they result in an actual hard path or network outage. In most cases, when an outage occurs anywhere along the optical path, the personnel managing the Ethernet/IP WAN have no visibility and are unaware of the outage until their phone rings (reference Figure 2). And all too often, a technician and truck may have to be dispatched to identify and resolve the above issues, resulting in additional delay and expense. The bottom line: longer outages, higher operational costs, lower revenues, and most importantly, lower customer satisfaction. DATASHEET-MDX

4 SOLUTION Recognizing the need to provide improved monitoring and diagnostic tools when connecting 10Gigabit Ethernet trunk cards to a WDM transport network, Media Links has developed an enhanced software toolset based on the widelyused Link Level Discovery Protocol (LLDP). This technology gives Media Links MD8000 transport products as well as MDX2040 & MDX4090 switches visibility into disruptions affecting local, metropolitan, and long haul optical links, multiplexers, and repeaters. On the MD8000, the LLDP feature is a combination of firmware and FPGA code updates. On the MDX2040 & 4090, the feature is added as a software upgrade. Configuration and management visibility for this feature is delivered through an enhanced version of Media Links ProMD management software. LLDP is a significant step towards improved network integration and alarm/trap management. LLDP configuration and status information is stored locally on each MD8000 chassis in a Management Information Database (MIB). Figure 3 LLDP Exchange and MIB database When the protocol is first activated, it goes through a neighbor-discovery process to determine the identity of its adjacent neighbor, in this case utilizing the remote MD GbE Ethernet trunk card. After this neighbor-discovery process, LLDP then periodically transmits keep-alive messages or PDUs (protocol data units) to the 10GbE Ethernet trunk card in the far-end MD8000 chassis. The far-end 10GbE trunk card, in turn, transmits its own LLDP PDUs so that both chassis stay in constant contact. The role of these keepalive messages is to act as a heartbeat to monitor the end-to-end path of the entire circuit while adding very little additional bandwidth or overhead to the circuit. The transmit and receive time interval for these LLDP messages is configurable based on the geographic size of the network and the number of Layer 1/2 hops in the network. As part of the LLDP information exchange, each local chassis also receives the following information from its corresponding far-end device: System Type Either MD8000 or MDX2040 or MDX4090 Chassis ID number of the remote device Port description of the remote 10GbE trunk card System Name of the remote device Firmware version of the remote device In the event of a lost or missing LLDP packet, the MD8000, MDX2040 and MDX4090 are designed to transmit DATASHEET-MDX Trap messages to one or more NMS systems in the network, thereby alerting network operators of either degraded network conditions or circuit outages. The LLDP protocol also has a built-in loop detection feature. If the source 10GbE trunk card sees its own Tx LLDP packets coming back as Rx packets, then it flags the error as a loop and sends a trap. Each 10GbE trunk card also maintains a set of historical statistics for LLDP protocol exchanges with its remote counterpart. 4

5 During new or modified MD8000 installations, an added benefit of LLDP is that it provides the operator with system information (system type, chassis ID, port and system description) on the remote or far-end device, thus discovering and/or providing confirmation that the proper devices and Ethernet trunk cards are connected to each other. Without requiring any external test equipment, LLDP can also be used to verify full end-to-end WAN circuit connectivity for new installations during test and turn-up time periods. CONCLUSION The implementation of the LLDP feature on the MD8000 platform represents a significant industry first among contribution/distribution media equipment manufacturers. As faster and less expensive gigabit Ethernet networks further grow displacing older legacy SONET-based circuits, LLDP will assume an even greater role in assisting network operations personnel monitor and maintain network reliability, availability and integrity. LLDP traps can be directed to umbrella management systems such Media Links NetGazer NMS or multiple NMS systems separately managing both Layer 1 optical and Layer 2/3 Ethernet/IP networks, providing greater fault visibility, event correlation and root cause analysis. Simple to deploy and simple to use, LLDP functionality can improve both network availability, overall service performance, and customer satisfaction in any regional, national, or global media transport network. ABOUT MEDIA LINKS Since 1993, Media Links has been a global leader in the development and manufacturing of broadcast network transport and infrastructure solutions. Our mission is to offer broadcasters, network service providers and sporting event hosting companies superior, leading edge technology, enabling them to economically convert and move the complete suite of broadcast media signals whether video, audio or data onto their multi-service networks. As a pioneer in the broadcast television industry, Media Links is an active participant in numerous video, audio, and data over IP standards bodies, including the Society of Motion Picture and Television Engineers (SMPTE), the Video Services Forum (VSF), and the International Telecommunications Union (ITU). Media Links is a driving force behind the current standards work surrounding the transition of older SDI-based networks to full IP-based networks for the seamless transport of video, audio, and data. For more than 15 years, Media Links products have been used globally to add flexibility and reliability to major international sporting events such as the summer and winter Olympics, the soccer World Cup, the Super Bowl, the FIS Nordic World Ski Championships, the NFL Super Bowl, the Asian Games, and numerous other events. Media Global Links Kawasaki Tech Center 18F Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Japan Phone: query@medialinks.co.jp WHITE-PAPER-LLDP-ADVANTAGE Media Links, Inc. 431-C Hayden Station Road Windsor, CT USA Phone: Fax: info@medialinks.com Media Links Australia 2-12 Rokeby Street, Collingwood, VIC 3066, Australia Phone: Fax: info@medialinksaustralia.com.au Media Links EMEA Thremhall Park Start Hill, Bishop s Stortford, Herts CM22 7WE United Kingdom Phone: +44(0) emea_info@medialinks.com 2017 Media Global Links. All rights reserved. Specifications subject to change without notice. Media Links and Media Defined Networking are trademarks of Media Global Links. 5