Ein neues Modell zur Behebung von Netzwerkproblemen | NETSCOUT
Technischer Anwendungsbericht
| Technischer Anwendungsbericht |

A NEW PARADIGM FOR
NETWORK PROBLEM SOLVING

48 percent of all organizations average longer than half a day to close trouble tickets
Es ist paradox. Obwohl Netzwerke zuverlässiger denn je ausgelegt werden, verbringen Unternehmen nach wie vor signifikante Zeit mit der Problembehandlung und stehen unter dem Druck, den Zeitaufwand für das Lösen von Problemen zu verringern. This white paper discusses state-of-the-art network problem solving and how a new approach – based on the NETSCOUT OneTouch™ AT Network Assistant – can reduce troubleshooting time by one full week each month.

Are Problems a Thing of the Past?

Every year, networks become more reliable. New standards promise interoperability, new devices simplify configuration and advanced monitoring solutions offer to detect problems before users are impacted. IT departments are entering an era where problems will be a thing of the past.

Or are they? A recent research study of over 300 network professionals in large - and medium - sized organizations found that:
  • 48 percent of all organizations average longer than half a day to close trouble tickets
  • 46 percent of all organizations are under pressure to reduce the time it takes to close trouble tickets
  • Network professionals spend about 25 percent of their time solving problems
Why is this happening in light of so many IT advances designed to eliminate problems? One explanation is that for every reliability and simplicity advancement, there is an offsetting technology advancement that makes things more complex: unified communications, 802.11ac, cloud computing or IPv6. Unabhängig vom Grund der Probleme steht dennoch fest, dass durch Verbessern der Problemlösungsproduktivität noch viel gewonnen werden kann.

To increase productivity, troubleshooting tools not only need to keep up with technology changes, but must continue to improve processes used to solve problems.

How Troubleshooting is Done Today

The vast majority (72 percent) of organizations do not follow a standardized troubleshooting process. Not only does this process vary within an organization but the tools used to troubleshoot problems vary substantially. Survey respondents reported using eight different types of tools to solve problems. In 47 Prozent aller Fälle waren mindestens zwei Tools oder sogar mehr erforderlich. Bei derart unterschiedlichen Fehlerbehebungsverfahren und -tools überrascht es nicht, dass 63 Prozent der Fehlerbehebungssitzungen mehr als eine Stunde in Anspruch nehmen.

There is a part of problem solving that is worth considering separately. In vielen Fällen können Techniker ein Problem nicht alleine beheben. Sometimes they need additional help with especially difficult problems. In other instances, it’s because the problem lies outside their domain of responsibility, and they need to work with a separate group inside (server management or application developers) or outside (service providers or equipment vendors) the enterprise. Dies sind beileibe keine Einzelfälle: Unsere Untersuchungen zeigen, dass ein Anteil von 41 Prozent aller Probleme einen gewissen Grad an Zusammenarbeit erfordert. This can take too long for at least two reasons. Zunächst kann ein aufgetretenes Problem für die verantwortlichen Parteien nicht immer einfach transparent gemacht werden. Second, the technician may not have the ability to easily capture the trace files that are often required (19 percent of the time) for these problems.
To increase productivity, troubleshooting tools not only need to keep up with technology changes, but must continue to improve processes used to solve problems

Eine Studie zu Problemlösungstechniken

This white paper refers to a NETSCOUT research study of 315 network professionals in April 2012. The respondents came primarily from medium- to large-sized networks in a variety of industries. Most of them were top-level networking support staff.

Abbildung 1: Welche dieser Tools verwendeten Sie für die Fehlerbehebung des letzten bei Ihnen aufgetretenen Benutzerproblems?

Abbildung 2: Wie viele Problemmeldungen bearbeiten Sie in einem typischen Monat?

Abbildung 3: What is your group’s average time to close a trouble ticket? Beachten Sie, dass 48 Prozent aller Befragten mehr als vier Stunden angeben.

Abbildung 4: Was war die Hauptursache des letzten von Ihnen behobenen Benutzerproblems? (Mehrere Antworten sind zulässig.)

The survey asked respondents to identify the root cause of their most recent user-reported problem (respondents could select more than one root cause). The most common cause was network problems (wired or Wi-Fi), occurring in 27 percent of instances. However, end-user configuration or operation problems combined were at fault in 42 percent of cases.

The OneTouch AT identifies the most common network problems in about one minute1

Changing the Problem-solving Paradigm

At NETSCOUT, we looked to shorten the entire problem-solving process. The process, as described earlier, traditionally consists of two steps – solo troubleshooting and collaboration when necessary. To streamline troubleshooting, NETSCOUT developed a three-step process and designed a new tool based on it. The three steps are:

1. Automatisiertes Testen
2. Fehlersuche
3. Zusammenarbeit

The OneTouch™ AT Network Assistant, enhances each of the steps and greatly reduces the time to solve problems.

Schritt 1: Automatisiertes Testen

It may seem counterintuitive that adding a step reduces time. But if the additional step actually saves more time in subsequent steps, the total time is reduced. That’s the idea behind automated testing.

The OneTouch AT identifies the most common network problems in about one minute1. It performs a thorough network analysis from the end-user’s point-of-view. Such an analysis, performed manually, would take roughly one hour2. The OneTouch AT performs that same testing in about a minute (tests are configurable and can take anywhere from ten seconds to a few minutes, with most being less than a minute). Results are then compared against user-defined limits to provide a simple pass/fail result. This approach allows technicians to find the most common problems that result in end-user complaints.

There are several benefits to automated testing. First, it’s much faster than a typical trial-and-error test. Second, it’s more thorough than a manual approach, which means it can find problems that the technician may not have even considered. Third, it allows anyone, regardless of skill level, to run tests and identify problems.

Schritt 2: Fehlersuche

While the AutoTest uncovers a wide variety of problems on its own, not all problems can be found that way. The OneTouch AT provides a veritable arsenal of troubleshooting power to reduce the time spent in this phase.

AutoTest – even if the initial AutoTest does not identify the problem, all the measurement results are ready and available to help the technician understand what is happening. Further, the AutoTest can be modified in seconds and re-run to test a different server, application or wireless connection.

Wired Tests – a complete set of tests provide information on the cable, Power over Ethernet, the nearest switch and network services. The OneTouch AT features a web browser, Telnet and a SSH client to assist with configuration of network devices including switches and access points. It features a toner and can flash switch port lights to help locate unmarked cables in congested closets. A video probe can be connected to the OneTouch AT to inspect the endface of fiber optic connectors for contamination.

The OneTouch AT can pay for itself within 4 months with time savings while troubleshooting and validating networks
Wireless Tests – OneTouch AT provides more analysis of the Wi-Fi network than a library of wireless freeware and shareware tools, and provides answers in an easy to understand format. The OneTouch AT discovers all the networks, AP’s and clients in range and quickly identifies problems such as improper security, interference, bandwidth hogs, overloaded channels, unauthorized devices and more.

Schritt 3: Zusammenarbeit

Wie bereits erwähnt, müssen Netzwerktechniker regelmäßig zur Problemlösung mit weiteren Personen zusammenarbeiten. The process of getting the right information to the right people, however, can drag on for days. Even if the technician is able to work on other problems during this period, that’s little comfort to an end user who can’t get their job done or the IT manager missing targets for trouble ticket times.

The OneTouch AT includes features specifically designed to expedite collaborative troubleshooting with the Link-Live Cloud Service. With Link-Live Cloud Service, everything is always captured with zero-touch reporting, providing you with complete records of your work and results, at all times. In dieser umfassenden, durchsuchbaren Datenbank können Sie leicht Änderungen im Netzwerk identifizieren. Weder Raumbegrenzung noch Zeitbeschränkung existieren und es besteht kein Bedarf, die Daten von Testgeräten am Ende des Tages von Testgeräten abzurufen und zu übertragen. This cloud service is available to all Handheld Network Tools: LinkSprinter, LinkRunner AT, and the AirCheck G2, all automatically upload their test results at the moment they happen. If you don’t have connectivity at that drop, the testers can buffer results, which are pushed to the Link-Live Cloud Service when connectivity returns. Techniker brauchen nicht mehr als Hüter und Transporteure von Testdaten zu fungieren oder sogar sich daran erinnern, auf Speichern zu drücken. Stattdessen können sie ihre Produktivität verdoppeln und Jobs, die früher Wochen benötigten, in Tagen abschließen. In addition, managers can have access to the test results dashboards.

Reporting – a detailed report of everything that the OneTouch AT tested and observed will be recorded in the Link-Live Cloud Service. This allows the tech to show a colleague exactly what is happening when they are observing the problem. These results include results a less-experienced technician might not have looked at but are there for more knowledgeable team members to evaluate.

In-line Packet Capture – a trace file is indispensable for very difficult problems or as evidence to an outside group such as application developers, service providers or equipment suppliers. Collecting this information typically requires reconfiguration of the switch or a network tap. Dies kann 30 Minuten oder länger dauern. Worse, many techs may not have access to switch provisioning or a tap. Dies bedeutet weitere Verzögerungen, während das Problem an andere Personen delegiert wird.

The OneTouch AT can perform an inline packet capture in just a few screen touches without the need to access the switch or a tap. This means the tech can capture the problem packets immediately while the user demonstrates the problem.

Web Remote Interface – while it’s not always possible to get a colleague physically in the location of the problem, the OneTouch AT can be accessed and controlled through a remote device such as a PC, tablet or smartphone. Not only can the remote user see what the tech is seeing, but they can control the OneTouch AT and export trace files or reports to their device.

Camera – connect a webcam to the OneTouch AT USB port and the remote helper can see livevideo of the physical environment the tech is working in. This is useful if the tech is in a wiringcloset or a data center and the remote colleague needs to see the switch or patch panel, for example.

Savings

The first step in estimating savings from the OneTouch AT is to look at the time saved in each of the three parts of the test.

Automated Testing – Table 1 compares the amount of time it would take to perform the AutoTest functions with the actual time of the AutoTest. The time is dependent on the skill of the technician as well as how many applications would need to be tested.

Troubleshooting – it’s less straightforward to quantify these savings, as it is highly dependent on the actual problem and the skill of the technician. Users of other NETSCOUT Handheld Network Test Solutions generally report 30 percent to 40 percent faster troubleshooting, but we will set that aside and consider it a “bonus” savings in addition to what is demonstrated here.

Collaboration – to quantify the time savings in these scenarios, we compared time to set up a packet capture using port mirroring (roughly 20 minutes) versus the inline packet capture with the OneTouch AT (three minutes). In instances where the technician does not have access to reconfigure the switch, the time savings would be much greater.

Better collaboration offers a bigger benefit by reducing the overall time to close trouble tickets. Without the OneTouch AT, it’s often difficult to get all the relevant data in front of the appropriate people quickly. This is a significant cause of trouble tickets dragging on, sometimes for days. Armed with the OneTouch AT, the first responder easily generates a report or a trace file and shares these plus provides remote access for the rest of the team in real time. So while the total amount of time the staff spends on a problem may not be reduced, the time the end user spends waiting for a resolution is greatly reduced.

Again, such a benefit is hard to quantify – so we won’t – but for many organizations this may be more valuable than actual hours saved for the department staff.

Schlussfolgerung

An estimation of the savings expected from using the OneTouch AT is presented in Table 1. Even ignoring the time saved in solo troubleshooting and purchase of the top of the line model, one would expect payback in less than six months.

AutoTest Savings
Trouble tickets per month per tech 20 (median)
Minutes per ticket 90
Dauer des Autotests 1 minute
Time to manually perform autotest functions
(from Table 1)
60 minutes
Time saved per ticket 59 minutes
Hours saved per month 19,7 per tech
Collaboration Savings
Percentage requiring packet capture 19% (average)
Number requiring packet capture 3,8
Time for packet capture setup 20 minutes
Packet capture setup with OneTouch AT 3 minutes
Time saved per capture 17 minutes
Hours saved per month 1,1 per tech
Number of users 2 per OneTouch AT
Total time saved 41 hours per month
Dollar Savings
Hourly rate 60 USD
Total monthly savings 2.489 USD
OneTouch AT cost 10.000 USD
Payback 4,0 Monate

Tabelle 1: An estimation of time and cost savings provided by OneTouch AT.

Abbildung 5: Summarizes the concepts of this paper: the ways in which the OneTouch AT saves time throughout the entire problem-solving process as compared to traditional methods.

Appendix A – An Hour of Troubleshooting in One Minute

Getting to the root cause is critical but can involve extra steps. For example, when you go to the doctor’s office, regardless of your complaint, you’re first seen by a nurse who immediately measures your weight, temperature, blood pressure and often reviews your health history. This step not only saves the doctor’s time, but often catches issues that might otherwise be overlooked.

This concept also applies to testing a network. Since your team doesn’t usually include a nurse, the OneTouch AT automates a complete test of “network vital signs” into an AutoTest that compresses an hour of traditional testing into about a minute. The results are then compared against userdefined limits to provide a simple pass/fail result. This approach not only saves time, but allows technicians to solve more problems.

Testing Step OneTouch Network
Assistant (AutoTest)
Traditional Methods
Basic Connectivity (Wired or Wi-Fi) 1 minute Cable Tester, PC, Wi-Fi Utilities 5 minutes
Infrastructure Services PC, Utilities 5 minutes
Wireless Operation and Performance Two PC’s, iPerf 10 Minuten
Network Services and Application Performance Packet Capture, Protocol Analyzer 40 minutes
(three apps)

Tabelle 2: The OneTouch AutoTest performs nearly an hour of manual testing in one minute.

Basic Connectivity – OneTouch AT tests both wired and Wi-Fi connectivity. On the wired side, it checks the physical layer (including cabling and Power over Ethernet), identifies the switch port, speed and duplex settings and identifies the switch port and VLAN. For Wi-Fi, it verifies connectivity and security settings for the nearest AP and tests connection speeds.

Infrastructure Services – OneTouch AT tests availability and response time of DNS and DHCP across both the wired and wireless network.

Wireless Operation and Performance – the exclusive test measures the actual wireless performance by sending a stream of traffic out the wireless port, through the nearest AP, the wired infrastructure and back to its wired port. The test runs simultaneously in the reverse direction with programmable upstream and downstream rates. The test provides measurement results for throughput, loss, latency and jitter in both directions. These latter two measurements are vital for quality performance of real time application such as streaming video or voice over Wi-Fi.

Network Services and Application Performance – these tests provide a detailed breakdown of application performance by analyzing an actual interaction with the server/service under test. Seven different tests/applications are supported and can be customized for specific sites or applications whether hosted locally or through cloud-based providers.

The detailed breakdown provides the results shown in Figure 7 and shows the results for both the wired and Wi-Fi network side-by-side for easy comparison.

While the overall measurement can be used to quantify the performance of the application, the detail can be used to determine the cause of the slow performance, whether it’s the network, application server, or the DNS server. While an expert can provide this level of analysis in ten or twenty minutes with a protocol analyzer (once they have a trace file), the OneTouch AT provides it under a minute as part of a standard AutoTest.

Abbildung 6: The test measures performance of the wired and Wi-Fi network.

Abbildung 7: The application performance tests provide a detailed breakdown of the response time of servers and services.

Appendix B: List of problems that can be discovered by the OneTouch AT Network Assistant AutoTest

Fiber problems Wrong SFP/vendor mismatch, Dirty fiber endface*, Dead port/broken fiber, Low power
Twisted pair problems Open cable, Bad cable mapping, Shorted cables, Mislabeled/undocumented cables*, Too long cable, Dead port
PoE Not present or disabled, Switch unable to supply adequate power, Wrong pins, Low voltage, Non-Ethernet voltage, Low power under load, Class 4 negotiation mismatch
Verkabelungsstrecke Polarity mismatch, Low link level, Receive pair issues (MDIX), Speed mismatch, Duplex mismatch
Switch port Incorrect switch, Incorrect port, Incorrect data VLAN*, Incorrect voice VLAN*, Unstable switch uptime*, Switch congestion*, Switch errors*, FCS errors*, Frame size errors*, Other frame errors (7)*, Excessive broadcast traffic*, Excessive multicast traffic
Wi-Fi Security settings wrong, AP missing, AP misconfigured, AP not connected, WLAN controller problems*, Excessive noise*, AP congestion*, Channel over utilized*, Too many APs on channel*, AP overlap on channels*, Roaming problems*, Unauthorized APs*, Finding rogue APs*, Ad hoc networks*, Insufficient network coverage, Slow connection, Bandwidth hogs APs and client*, Bad client NIC*
Veri-Fi QoS settings wrong*, MTU problems*, Port problems*, Upstream bandwidth issues, Downstream bandwidth issues, IPv6 issues*, Excessive loss, Latency issues*, Jitter issues*, Sequencing issues*
DHCP Missing, Slow, Out of addresses, Incorrect lease time, Rogue DHCP server, Wired versus Wi-Fi configuration problems, Duplicate static IP address, IP address hijacked, Incorrect address delivery, Incorrect subnet delivery, Incorrect router address, Incorrect DNS address
DNS Missing, Slow, No secondary server*, Wired versus Wi-Fi configuration problems*
Gateway Missing / Failed, Not IPv6 capable*, Unstable gateway uptime*, Overloaded*, Bad traffic*, Incorrect routing protocols*
Discovery Wrong VLAN*, Wrong subnet*, Unexpected IPv4/IPv6 devices
Web (HTTP) DNS lookup failure, DNS lookup slow, Server unavailable, Slow connectivity, Server slow to start, Server slow to complete, Wired versus Wi-Fi transport problems, IPv4 versus IPv6 transport problems
Ping (ICMP) DNS lookup failure, DNS lookup slow, Server unavailable, Slow connectivity, MTU misconfigurations, Wired versus Wi-Fi transport problems, IPv4 versus IPv6 transport problems

Appendix B: (continued)

Connect (TCP) DNS lookup failure, DNS lookup slow, Server unavailable, Slow connectivity, Firewall misconfigured for ports, Wired versus Wi-Fi transport problems, IPv4 versus IPv6 transport problems
Multicast (IGMP) Server not multicasting, Switch IGMP snooping disabled, Incorrect port configuration, Server authentication
Datei (FTP) Slow WAN, DNS lookup failure, DNS lookup slow, Server unavailable, Slow connectivity, Server slow to start, Server slow to complete, Wired versus Wi-Fi transport problems, IPv4 versus IPv6 transport problems
Video (RTSP) Slow WAN, DNS lookup failure, DNS lookup slow, Server unavailable, Slow connectivity, Server slow to start, Server slow to complete, Wired versus Wi-Fi transport problems, IPv4 versus IPv6 transport problems

* May require a secondary test after the AutoTest.

1 See appendix A, “An Hour of Troubleshooting in One Minute”
2 See appendix B, “Problems That can be Discovered by the OneTouch AT Network Assistant AutoTest”

 
 
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