WHITE PAPER Achieving Total Traffic Visibility in Enterprise and Carrier Grade Optical Networks www.ixiacom.com 915-6905-01 Rev. A, July 2014
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Table of Contents Data Access and Reliability In Modern Optical Networks... 4 Getting Network Traffic Access Right... 4 High Speed Networks Require More Sophisticated Solutions... 5 Flex Tap Solves Urgent Emerging Issues for Data Centers... 5 Use Case #1: Service Provider - Provide Monitoring Access Without Adding the Risk of Network Outages... 6 Implementation... 7 Conclusion... 7 3
Data Access and Reliability In Modern Optical Networks Network Service Providers (NSPs) and other service sectors own the daunting task of transporting ever-growing quantities of data to and from billions of customers with the highest data integrity possible. To be certain of that integrity, the providers must constantly monitor the traffic to ensure application performance, user satisfaction, and service level agreements. In performing this job, the data centers need tools that enable total traffic visibility to analyze the quality of the data and at the same time preserve the integrity of the network. It is critical to use the right tools and technology for providing total traffic visibility, because if access and monitoring solutions introduce problems, the cure can be worse than the disease. Today using the right solution is more important than ever because network speeds and traffic volumes are increasing. Today using the right solution is more important than ever because network speeds and traffic volumes are increasing, while many new applications and services are also being introduced. As a result, Service Providers (and Enterprises) must deploy many tools to monitor the performance of many aspects of their networks and services. To accomplish this, they must deploy very reliable, high-quality access Taps, or other high-quality access equipment that can handle modern network speeds with no impact on data integrity. The professionals that manage high-speed networks, complex applications and digital services face new challenges on a daily basis. New customers or applications both mean more traffic. More traffic translates to more monitoring, more management and more equipment. But, without the right technology and equipment, more access, can bring about more network errors, and a loss of data integrity. Getting Network Traffic Access Right There are many important considerations in implementing the best solutions for total network access and visibility. Equipment reliability, density, flexibility, insertion loss characteristics, and speed grades are all relevant factors. But, there is one factor that many solutions don t take into account, and many solution providers do not fully understand; this factor can create real problems in optical plants. The culprit is modal dispersion. Briefly, modal dispersion is a distortion mechanism that occurs in some fiber optic components. When modal dispersion takes place, the various modes (light components) in multimode optical signal become more spread out in time because the propagation velocity of each signal s light component is not the same through the distorting materials, resulting in a distortion of the composite signal. This has the effect of introducing noise, or error, to the signal as the receiver is tuned to receive the specific modes of the optical signal transmitted. If there is enough modal dispersion in the multimode signal, and the modes of light are sufficiently shifted (distorted), then the optical receiver will not be able to correctly recover the signal, thereby introducing errors. This problem of modal dispersion is of particular concern in higher speed networks. While the issue fundamentally exists in gigabit networks, the frequency precision needed to recover a signal is an order of magnitude lower than that needed in 10 Gigabit networks. Therefore, as network speeds increase, it is critical to minimize modal dispersion to avoid introducing errors in both the network and the sampled network traffic. 4
Modal dispersion can be introduced by the quality of optical fiber used, connectors, splitter technologies and design geometry, as well as by other factors. So, in providing access Taps, or other access equipment to modern networks, it is essential to make sure that the equipment used does not degrade the signal, and that the equipment employs the right combination of technologies to prevent this problem. High Speed Networks Require More Sophisticated Solutions At higher speeds, such as 10G, 40G and 100G, the Tapped signals of most multimode traffic, using common solutions, have become excessively noisy, resulting in unacceptable data error rates. In practice, this is observed to be an even bigger problem in 60/40 and higher split ratios. The source of the noise is attributed to inferior Tap designs that introduce modal interference on these high bandwidth networks (10G and above). The difference between signals that experience modal distortion and cleaner signals is very apparent and can be seen in the optical waveforms shown in Figure 1 below. This narrowing eye clearly illustrates the lower signal-to-noise ratio introduced by the distortion. Access solutions that worked well for multimode access in 1 Gigabit networks simply do not work acceptably in higher speed modern networks. More care must be taken in the construction of access Taps to provide suitable solutions that support total visibility while maintaining network reliability. Flex Tap Solves Urgent Emerging Issues for Data Centers The Flex Tap resolves system-wide signal loss issues for Service Providers and other organizations as network volumes increase and optical networks migrate to 10G, 40G and 100G. These signal loss issues arise from the fact that as optical network speeds increase, even the smallest imperfections in optical couplers, cable, or access Taps can introduce enough modal distortion that bit error rates quickly become unacceptable. By combining the highest quality fiber optics, connectors, and splitter technology with a leading edge design, the Flex Tap provides network operators the means to gain visibility to these highspeed networks without the risk of injecting errors. This breakthrough product supports deployment with any multimode transceiver, eliminating data errors from signal loss in high-speed networks. Access solutions that worked well for multimode access in 1 Gigabit networks simply do not work acceptably in higher speed modern networks. This Flex Tap solution uses the most enhanced fiber optic technology today, which enables us to provide the highest quality fiber Tap. This solution ensures that customer deployments reclaim high signal-to-noise ratios. The new version of Flex Tap has shown more than 100 percent improvement in signal noise reduction for the 60/40 and higher split ratios in 10G, 40G, and even 100G networks. The effectiveness of the Flex Tap is revealed in the diagrams below. In addition, the Flex Tap solution also passes a wider spectrum of light, accommodating the small imperfections in the transmitter (shown in Figure 2, below). This comparison (Figure 2) shows the difference between the transmit range of a typical SFP+ transceiver and the acceptance range of the different access Tap solutions. The graph makes it apparent that the acceptance range for the Flex Tap is wider than any 5
possible transmitted light the SFP+ can supply. Existing technologies have a narrower band of light that can be passed through. Figure 1: Optical Waveform Graphs In many cases inserting security tools into such an environment introduces risks that a data center cannot afford. Figure 2: Wavelength Transmit and Acceptance Graph Use Case #1: Service Provider - Provide Monitoring Access Without Adding the Risk of Network Outages For Service Providers today, customer service (network uptime) is the top requirement to retain existing business and continue to grow. In many cases inserting security tools into such an environment introduces risks that a data center cannot afford, even with today s tools, which have become more reliable. These networks now process more data than ever before, meaning that even the slightest risk of failure is unacceptable. Most service providers opt to use an out-of-band monitoring policy, with their security tools sitting off the network data, to balance their approach to security and service uptime. This approach ensures that all data flows without interruption and in the event of a security breach the network team can take actions downstream to rectify the issue. When looking to use out-of-band monitoring access devices these companies rely on the following checklist: Customers must not see any performance loss when the Tapping device is connected All security and monitoring tools must have all data passed to them to ensure proper processing of the network traffic The device must have the flexibility to deploy into any speed or fiber environment The device should have a small product footprint for use in large deployments without adding cost to allocate more rack space 6
To meet these requirements, the device must be passive, with low insertion loss and wide signal acceptance, all in a small enough footprint to support large deployments. Implementation Net Optics Flex Tap products are the ideal Tapping solutions to fulfill these requirements and are available today. The products provide up to 24 Taps in 1U, and the 10G/40G/100G multimode models use the newest fiber optics to ensure signal reliability. The following chart shows how the Flex Tap product meets the requirements we ve found in the use case above. Requirement Satisfied by Flex Tap Notes 1: Network performance unaffected 2: Pass all traffic to security/monitoring tool 3: Flexibility 4: Small footprint Flex Tap is a fully passive device that when connected will not impact the performance of the connection. Since monitoring is done out-of-band, the monitoring tool is also isolated from affecting the network data stream. Flex Tap is designed to pass all traffic, including all network errors. The security or monitoring tool, while out-of-band, will see all traffic as if it were inline. The Flex Taps come in all speeds, from 1G to 100G, and fiber variations, multimode or single mode, to meet the customer's variety of needs. Within a single 1U rack mount frame the customer can deploy any combination of Tap types, LC and MTP, at all speeds and ratios. The footprint of the Flex Tap is very small. Each rack mount can hold up to 24 Taps or up to 12 MTP Taps or any combination of the two. Total network visibility is critical for operators to monitor network, application and service performance. Conclusion Total network visibility is critical for operators to monitor network, application and service performance. However, with higher speed optical networks it is essential to use modern access equipment that can provide visibility without introducing even marginal errors in the traffic traversing the network. For the reasons discussed above, the latest additions to the Flex Tap family introduce the right combination of product design, components, geometry and packaging to optimize performance and eliminate the risk of error injection. Reinforced with these latest additions, the Flex Tap provides the high density, multiple speed grades, flexibility and quality needed to be the ideal access platform for optical networks. 7
WHITE PAPER Ixia Worldwide Headquarters 26601 Agoura Rd. Calabasas, CA 91302 (Toll Free North America) 1.877.367.4942 (Outside North America) +1.818.871.1800 (Fax) 818.871.1805 www.ixiacom.com Ixia European Headquarters Ixia Technologies Europe Ltd Clarion House, Norreys Drive Maidenhead SL6 4FL United Kingdom Sales +44 1628 408750 (Fax) +44 1628 639916 Ixia Asia Pacific Headquarters 21 Serangoon North Avenue 5 #04-01 Singapore 554864 Sales +65.6332.0125 Fax +65.6332.0127 915-6905-01 Rev. A, July 2014