[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:01.55,0:00:03.26,Default,,0000,0000,0000,,when you're troubleshooting complex Dialogue: 0,0:00:03.26,0:00:05.33,Default,,0000,0000,0000,,network problems you may find that the Dialogue: 0,0:00:05.33,0:00:07.46,Default,,0000,0000,0000,,resolution is not as obvious as you Dialogue: 0,0:00:07.46,0:00:09.44,Default,,0000,0000,0000,,might hope in this video we're gonna Dialogue: 0,0:00:09.44,0:00:11.75,Default,,0000,0000,0000,,step through a methodology that should Dialogue: 0,0:00:11.75,0:00:13.61,Default,,0000,0000,0000,,help you troubleshoot any problem you Dialogue: 0,0:00:13.61,0:00:16.61,Default,,0000,0000,0000,,run into this is the flow chart of that Dialogue: 0,0:00:16.61,0:00:18.65,Default,,0000,0000,0000,,network troubleshooting methodology and Dialogue: 0,0:00:18.65,0:00:20.66,Default,,0000,0000,0000,,we're going to step through each section Dialogue: 0,0:00:20.66,0:00:23.12,Default,,0000,0000,0000,,of this flow and describe how it can Dialogue: 0,0:00:23.12,0:00:24.98,Default,,0000,0000,0000,,help you solve those really difficult Dialogue: 0,0:00:24.98,0:00:27.62,Default,,0000,0000,0000,,problems the first thing you want to do Dialogue: 0,0:00:27.62,0:00:29.93,Default,,0000,0000,0000,,is identify the problem this may not be Dialogue: 0,0:00:29.93,0:00:32.27,Default,,0000,0000,0000,,as straightforward as you might think we Dialogue: 0,0:00:32.27,0:00:33.89,Default,,0000,0000,0000,,first need to collect as much Dialogue: 0,0:00:33.89,0:00:36.17,Default,,0000,0000,0000,,information as possible about the issue Dialogue: 0,0:00:36.17,0:00:38.27,Default,,0000,0000,0000,,that's occurring in the best possible Dialogue: 0,0:00:38.27,0:00:39.92,Default,,0000,0000,0000,,scenario you'll be able to duplicate Dialogue: 0,0:00:39.92,0:00:42.26,Default,,0000,0000,0000,,this problem on demand this will help Dialogue: 0,0:00:42.26,0:00:43.76,Default,,0000,0000,0000,,later as we go through a number of Dialogue: 0,0:00:43.76,0:00:45.95,Default,,0000,0000,0000,,testing phases to make sure that we're Dialogue: 0,0:00:45.95,0:00:48.29,Default,,0000,0000,0000,,able to resolve this issue when a Dialogue: 0,0:00:48.29,0:00:50.15,Default,,0000,0000,0000,,problem happens on the network it Dialogue: 0,0:00:50.15,0:00:52.61,Default,,0000,0000,0000,,usually affects more than one device and Dialogue: 0,0:00:52.61,0:00:55.13,Default,,0000,0000,0000,,sometimes it affects those devices in Dialogue: 0,0:00:55.13,0:00:57.02,Default,,0000,0000,0000,,different ways you want to be sure to Dialogue: 0,0:00:57.02,0:00:59.15,Default,,0000,0000,0000,,document all of the symptoms that may be Dialogue: 0,0:00:59.15,0:01:01.22,Default,,0000,0000,0000,,occurring even if they are very Dialogue: 0,0:01:01.22,0:01:03.44,Default,,0000,0000,0000,,different between different devices you Dialogue: 0,0:01:03.44,0:01:05.18,Default,,0000,0000,0000,,may find that a single problem is Dialogue: 0,0:01:05.18,0:01:07.01,Default,,0000,0000,0000,,causing all of these different systems Dialogue: 0,0:01:07.01,0:01:09.80,Default,,0000,0000,0000,,across these different devices many Dialogue: 0,0:01:09.80,0:01:11.72,Default,,0000,0000,0000,,times these issues will be identified by Dialogue: 0,0:01:11.72,0:01:13.61,Default,,0000,0000,0000,,the end users so they may be able to Dialogue: 0,0:01:13.61,0:01:15.98,Default,,0000,0000,0000,,provide you with a lot more detail of Dialogue: 0,0:01:15.98,0:01:17.54,Default,,0000,0000,0000,,what's really happening you should Dialogue: 0,0:01:17.54,0:01:19.31,Default,,0000,0000,0000,,question your users to find out what Dialogue: 0,0:01:19.31,0:01:21.05,Default,,0000,0000,0000,,they're seeing and if any error messages Dialogue: 0,0:01:21.05,0:01:23.24,Default,,0000,0000,0000,,are appearing in this course we've Dialogue: 0,0:01:23.24,0:01:24.98,Default,,0000,0000,0000,,already discussed the importance of the Dialogue: 0,0:01:24.98,0:01:27.02,Default,,0000,0000,0000,,change control process and knowing Dialogue: 0,0:01:27.02,0:01:28.67,Default,,0000,0000,0000,,exactly what is changing in your Dialogue: 0,0:01:28.67,0:01:31.28,Default,,0000,0000,0000,,environment without some type of formal Dialogue: 0,0:01:31.28,0:01:33.26,Default,,0000,0000,0000,,change control process someone may be Dialogue: 0,0:01:33.26,0:01:35.45,Default,,0000,0000,0000,,able to make an unscheduled change that Dialogue: 0,0:01:35.45,0:01:37.31,Default,,0000,0000,0000,,would affect many different people so Dialogue: 0,0:01:37.31,0:01:39.29,Default,,0000,0000,0000,,when an error or network problem occurs Dialogue: 0,0:01:39.29,0:01:41.54,Default,,0000,0000,0000,,you may want to find out what was the Dialogue: 0,0:01:41.54,0:01:43.61,Default,,0000,0000,0000,,last thing that changed on this network Dialogue: 0,0:01:43.61,0:01:45.23,Default,,0000,0000,0000,,that could have affected all of these Dialogue: 0,0:01:45.23,0:01:47.66,Default,,0000,0000,0000,,users there's also going to be times Dialogue: 0,0:01:47.66,0:01:49.73,Default,,0000,0000,0000,,when you're examining a number of Dialogue: 0,0:01:49.73,0:01:52.04,Default,,0000,0000,0000,,different problems that may not actually Dialogue: 0,0:01:52.04,0:01:54.44,Default,,0000,0000,0000,,be related to each other it's always Dialogue: 0,0:01:54.44,0:01:56.15,Default,,0000,0000,0000,,best to separate all of these different Dialogue: 0,0:01:56.15,0:01:58.40,Default,,0000,0000,0000,,issues out so that you can approach and Dialogue: 0,0:01:58.40,0:02:01.18,Default,,0000,0000,0000,,try to resolve each issue individually Dialogue: 0,0:02:01.18,0:02:03.41,Default,,0000,0000,0000,,now that you've collected as much Dialogue: 0,0:02:03.41,0:02:04.94,Default,,0000,0000,0000,,information as possible Dialogue: 0,0:02:04.94,0:02:07.31,Default,,0000,0000,0000,,you can examine all of these details to Dialogue: 0,0:02:07.31,0:02:09.68,Default,,0000,0000,0000,,begin establishing a theory of what you Dialogue: 0,0:02:09.68,0:02:11.81,Default,,0000,0000,0000,,think might be going wrong since the Dialogue: 0,0:02:11.81,0:02:14.03,Default,,0000,0000,0000,,simpler explanation is often the most Dialogue: 0,0:02:14.03,0:02:15.11,Default,,0000,0000,0000,,likely reason Dialogue: 0,0:02:15.11,0:02:17.54,Default,,0000,0000,0000,,for the issue that may be a good place Dialogue: 0,0:02:17.54,0:02:19.58,Default,,0000,0000,0000,,to start but of course you'll want to Dialogue: 0,0:02:19.58,0:02:21.89,Default,,0000,0000,0000,,consider every possible thing that might Dialogue: 0,0:02:21.89,0:02:24.08,Default,,0000,0000,0000,,be causing this issue maybe start with Dialogue: 0,0:02:24.08,0:02:26.00,Default,,0000,0000,0000,,things that aren't completely obvious Dialogue: 0,0:02:26.00,0:02:28.40,Default,,0000,0000,0000,,you could start from the top of the OSI Dialogue: 0,0:02:28.40,0:02:30.35,Default,,0000,0000,0000,,model with the way the application is Dialogue: 0,0:02:30.35,0:02:32.39,Default,,0000,0000,0000,,working and work your way to the bottom Dialogue: 0,0:02:32.39,0:02:34.28,Default,,0000,0000,0000,,or you may want to start with the bottom Dialogue: 0,0:02:34.28,0:02:36.26,Default,,0000,0000,0000,,with the cabling and wiring in your Dialogue: 0,0:02:36.26,0:02:38.33,Default,,0000,0000,0000,,infrastructure and work your way up from Dialogue: 0,0:02:38.33,0:02:40.60,Default,,0000,0000,0000,,there you'll want to list out every Dialogue: 0,0:02:40.60,0:02:43.49,Default,,0000,0000,0000,,possible cause for this problem your Dialogue: 0,0:02:43.49,0:02:45.17,Default,,0000,0000,0000,,list might start with the easy theories Dialogue: 0,0:02:45.17,0:02:47.24,Default,,0000,0000,0000,,at the top but of course include all of Dialogue: 0,0:02:47.24,0:02:49.16,Default,,0000,0000,0000,,the more complex theories in this list Dialogue: 0,0:02:49.16,0:02:51.80,Default,,0000,0000,0000,,as well now that we have a list of Dialogue: 0,0:02:51.80,0:02:54.11,Default,,0000,0000,0000,,theories on how to resolve this issue we Dialogue: 0,0:02:54.11,0:02:56.21,Default,,0000,0000,0000,,can now test those theories we may want Dialogue: 0,0:02:56.21,0:02:58.49,Default,,0000,0000,0000,,to go into a lab and if we are able to Dialogue: 0,0:02:58.49,0:03:00.92,Default,,0000,0000,0000,,recreate this problem in the lab then we Dialogue: 0,0:03:00.92,0:03:03.80,Default,,0000,0000,0000,,can apply each theory until we find the Dialogue: 0,0:03:03.80,0:03:05.84,Default,,0000,0000,0000,,one that happens to resolve the issue if Dialogue: 0,0:03:05.84,0:03:08.15,Default,,0000,0000,0000,,you tried the first theory you may want Dialogue: 0,0:03:08.15,0:03:10.07,Default,,0000,0000,0000,,to reset everything and try the second Dialogue: 0,0:03:10.07,0:03:12.05,Default,,0000,0000,0000,,theory or the third and if you run out Dialogue: 0,0:03:12.05,0:03:13.79,Default,,0000,0000,0000,,of theories you may want to go back and Dialogue: 0,0:03:13.79,0:03:15.50,Default,,0000,0000,0000,,think of other things that might be Dialogue: 0,0:03:15.50,0:03:17.54,Default,,0000,0000,0000,,causing this problem this might be a Dialogue: 0,0:03:17.54,0:03:19.34,Default,,0000,0000,0000,,good time to bring in an expert who Dialogue: 0,0:03:19.34,0:03:20.84,Default,,0000,0000,0000,,knows about the application or the Dialogue: 0,0:03:20.84,0:03:22.70,Default,,0000,0000,0000,,infrastructure and they can give some Dialogue: 0,0:03:22.70,0:03:24.89,Default,,0000,0000,0000,,theories and possible resolutions to Dialogue: 0,0:03:24.89,0:03:27.59,Default,,0000,0000,0000,,test in the lab once you've tested a Dialogue: 0,0:03:27.59,0:03:29.30,Default,,0000,0000,0000,,theory and found that the theory is Dialogue: 0,0:03:29.30,0:03:31.49,Default,,0000,0000,0000,,going to resolve this issue you can then Dialogue: 0,0:03:31.49,0:03:33.38,Default,,0000,0000,0000,,begin putting together a plan of action Dialogue: 0,0:03:33.38,0:03:35.60,Default,,0000,0000,0000,,this is how you would implement this fix Dialogue: 0,0:03:35.60,0:03:38.06,Default,,0000,0000,0000,,into a production network you want to be Dialogue: 0,0:03:38.06,0:03:39.92,Default,,0000,0000,0000,,sure that you're able to do this with a Dialogue: 0,0:03:39.92,0:03:41.78,Default,,0000,0000,0000,,minimum amount of impact to the Dialogue: 0,0:03:41.78,0:03:43.88,Default,,0000,0000,0000,,production network and sometimes you Dialogue: 0,0:03:43.88,0:03:45.86,Default,,0000,0000,0000,,have to do this after-hours when nobody Dialogue: 0,0:03:45.86,0:03:48.26,Default,,0000,0000,0000,,else is working on the network you want Dialogue: 0,0:03:48.26,0:03:49.64,Default,,0000,0000,0000,,to be able to implement this with a Dialogue: 0,0:03:49.64,0:03:52.25,Default,,0000,0000,0000,,minimum amount of impact to production Dialogue: 0,0:03:52.25,0:03:54.38,Default,,0000,0000,0000,,traffic so often you'll have to do this Dialogue: 0,0:03:54.38,0:03:57.41,Default,,0000,0000,0000,,after hours my best practice is to Dialogue: 0,0:03:57.41,0:03:59.51,Default,,0000,0000,0000,,document the exact steps that will be Dialogue: 0,0:03:59.51,0:04:00.83,Default,,0000,0000,0000,,required to solve this particular Dialogue: 0,0:04:00.83,0:04:03.56,Default,,0000,0000,0000,,problem if it's replacing a cable then Dialogue: 0,0:04:03.56,0:04:04.97,Default,,0000,0000,0000,,the process will be relatively Dialogue: 0,0:04:04.97,0:04:06.68,Default,,0000,0000,0000,,straightforward but if you're upgrading Dialogue: 0,0:04:06.68,0:04:08.99,Default,,0000,0000,0000,,software in a switch a router or a Dialogue: 0,0:04:08.99,0:04:11.75,Default,,0000,0000,0000,,firewall there may be additional tasks Dialogue: 0,0:04:11.75,0:04:13.58,Default,,0000,0000,0000,,involved in performing this plan of Dialogue: 0,0:04:13.58,0:04:15.50,Default,,0000,0000,0000,,action you'll also want some Dialogue: 0,0:04:15.50,0:04:17.54,Default,,0000,0000,0000,,alternatives if your plan doesn't go as Dialogue: 0,0:04:17.54,0:04:19.70,Default,,0000,0000,0000,,designed for example you may run into Dialogue: 0,0:04:19.70,0:04:21.59,Default,,0000,0000,0000,,problems when upgrading the software in Dialogue: 0,0:04:21.59,0:04:23.60,Default,,0000,0000,0000,,a firewall so you may need an additional Dialogue: 0,0:04:23.60,0:04:26.15,Default,,0000,0000,0000,,firewall or a way to roll back to the Dialogue: 0,0:04:26.15,0:04:27.25,Default,,0000,0000,0000,,previous version Dialogue: 0,0:04:27.25,0:04:28.58,Default,,0000,0000,0000,,now that you Dialogue: 0,0:04:28.58,0:04:30.23,Default,,0000,0000,0000,,documented your plan of action you can Dialogue: 0,0:04:30.23,0:04:31.73,Default,,0000,0000,0000,,take that to your change control team Dialogue: 0,0:04:31.73,0:04:33.77,Default,,0000,0000,0000,,and they can give you a window when you Dialogue: 0,0:04:33.77,0:04:35.90,Default,,0000,0000,0000,,can implement that change the actual Dialogue: 0,0:04:35.90,0:04:38.24,Default,,0000,0000,0000,,fixing of the issue is probably going to Dialogue: 0,0:04:38.24,0:04:39.98,Default,,0000,0000,0000,,be during off-hours during non Dialogue: 0,0:04:39.98,0:04:41.99,Default,,0000,0000,0000,,production times and you may need to Dialogue: 0,0:04:41.99,0:04:43.73,Default,,0000,0000,0000,,bring in other people to assist Dialogue: 0,0:04:43.73,0:04:46.54,Default,,0000,0000,0000,,especially if your window is very small Dialogue: 0,0:04:46.54,0:04:48.86,Default,,0000,0000,0000,,once you have executed on your plan of Dialogue: 0,0:04:48.86,0:04:50.72,Default,,0000,0000,0000,,action your job isn't done yet Dialogue: 0,0:04:50.72,0:04:52.52,Default,,0000,0000,0000,,we need to make sure that all of these Dialogue: 0,0:04:52.52,0:04:55.46,Default,,0000,0000,0000,,changes actually resolve the problem so Dialogue: 0,0:04:55.46,0:04:56.75,Default,,0000,0000,0000,,now that the changes have been Dialogue: 0,0:04:56.75,0:04:59.00,Default,,0000,0000,0000,,implemented we now need to perform some Dialogue: 0,0:04:59.00,0:05:01.19,Default,,0000,0000,0000,,tests we may want to bring in the end Dialogue: 0,0:05:01.19,0:05:03.14,Default,,0000,0000,0000,,users who first experienced this problem Dialogue: 0,0:05:03.14,0:05:05.72,Default,,0000,0000,0000,,so that they can run through exactly the Dialogue: 0,0:05:05.72,0:05:07.79,Default,,0000,0000,0000,,same scenario to tell you if the problem Dialogue: 0,0:05:07.79,0:05:09.62,Default,,0000,0000,0000,,is resolved or if the problem still Dialogue: 0,0:05:09.62,0:05:12.38,Default,,0000,0000,0000,,exists this might also be a good time to Dialogue: 0,0:05:12.38,0:05:14.24,Default,,0000,0000,0000,,implement some preventive measures that Dialogue: 0,0:05:14.24,0:05:16.46,Default,,0000,0000,0000,,way we can either be informed that the Dialogue: 0,0:05:16.46,0:05:18.43,Default,,0000,0000,0000,,problem is occurring or we can provide Dialogue: 0,0:05:18.43,0:05:20.57,Default,,0000,0000,0000,,alternatives that we can implement if Dialogue: 0,0:05:20.57,0:05:23.72,Default,,0000,0000,0000,,that problem happens again after the Dialogue: 0,0:05:23.72,0:05:25.43,Default,,0000,0000,0000,,problem has been resolved this is a Dialogue: 0,0:05:25.43,0:05:27.44,Default,,0000,0000,0000,,perfect time to document the entire Dialogue: 0,0:05:27.44,0:05:29.75,Default,,0000,0000,0000,,process from the very beginning to the Dialogue: 0,0:05:29.75,0:05:31.64,Default,,0000,0000,0000,,very end you'll of course want to Dialogue: 0,0:05:31.64,0:05:33.38,Default,,0000,0000,0000,,provide as much information as possible Dialogue: 0,0:05:33.38,0:05:35.78,Default,,0000,0000,0000,,so if somebody runs into this issue Dialogue: 0,0:05:35.78,0:05:37.94,Default,,0000,0000,0000,,again they can simply search your Dialogue: 0,0:05:37.94,0:05:40.16,Default,,0000,0000,0000,,knowledgebase find that particular error Dialogue: 0,0:05:40.16,0:05:42.05,Default,,0000,0000,0000,,that popped up and know exactly the Dialogue: 0,0:05:42.05,0:05:44.53,Default,,0000,0000,0000,,process you use to solve this last time Dialogue: 0,0:05:44.53,0:05:47.54,Default,,0000,0000,0000,,many organizations have a help desk with Dialogue: 0,0:05:47.54,0:05:49.25,Default,,0000,0000,0000,,case notes that they can reference or Dialogue: 0,0:05:49.25,0:05:50.93,Default,,0000,0000,0000,,you might have a separate knowledgebase Dialogue: 0,0:05:50.93,0:05:53.00,Default,,0000,0000,0000,,or wiki that you create where you're Dialogue: 0,0:05:53.00,0:05:54.44,Default,,0000,0000,0000,,storing all of this important Dialogue: 0,0:05:54.44,0:05:57.35,Default,,0000,0000,0000,,information for the future a document Dialogue: 0,0:05:57.35,0:05:58.97,Default,,0000,0000,0000,,that was created a number of years ago Dialogue: 0,0:05:58.97,0:06:00.92,Default,,0000,0000,0000,,but still shows the importance of Dialogue: 0,0:06:00.92,0:06:02.90,Default,,0000,0000,0000,,keeping this documentation over time is Dialogue: 0,0:06:02.90,0:06:04.43,Default,,0000,0000,0000,,from Google research where they Dialogue: 0,0:06:04.43,0:06:06.83,Default,,0000,0000,0000,,documented the failure trends in a large Dialogue: 0,0:06:06.83,0:06:09.23,Default,,0000,0000,0000,,disk drive population and because they Dialogue: 0,0:06:09.23,0:06:11.45,Default,,0000,0000,0000,,were keeping extensive data over a long Dialogue: 0,0:06:11.45,0:06:13.79,Default,,0000,0000,0000,,period of time they were able to tell Dialogue: 0,0:06:13.79,0:06:16.25,Default,,0000,0000,0000,,when a drive was starting to fail based Dialogue: 0,0:06:16.25,0:06:17.99,Default,,0000,0000,0000,,on the types of errors that they were Dialogue: 0,0:06:17.99,0:06:20.36,Default,,0000,0000,0000,,receiving being able to store all of Dialogue: 0,0:06:20.36,0:06:22.04,Default,,0000,0000,0000,,this important information and being Dialogue: 0,0:06:22.04,0:06:23.99,Default,,0000,0000,0000,,able to go back in time to see what Dialogue: 0,0:06:23.99,0:06:26.27,Default,,0000,0000,0000,,happened becomes a very important part Dialogue: 0,0:06:26.27,0:06:28.63,Default,,0000,0000,0000,,of maintaining a network for the future Dialogue: 0,0:06:28.63,0:06:31.16,Default,,0000,0000,0000,,let's summarize this troubleshooting Dialogue: 0,0:06:31.16,0:06:33.05,Default,,0000,0000,0000,,methodology we start with gathering as Dialogue: 0,0:06:33.05,0:06:35.45,Default,,0000,0000,0000,,much information as possible asking Dialogue: 0,0:06:35.45,0:06:37.19,Default,,0000,0000,0000,,users about what they're seeing and Dialogue: 0,0:06:37.19,0:06:39.50,Default,,0000,0000,0000,,documenting any specific error messages Dialogue: 0,0:06:39.50,0:06:41.33,Default,,0000,0000,0000,,then we want to be able to create a Dialogue: 0,0:06:41.33,0:06:42.05,Default,,0000,0000,0000,,number of Dialogue: 0,0:06:42.05,0:06:43.79,Default,,0000,0000,0000,,series that might solve this particular Dialogue: 0,0:06:43.79,0:06:46.76,Default,,0000,0000,0000,,problem and once we have this list we Dialogue: 0,0:06:46.76,0:06:48.38,Default,,0000,0000,0000,,want to be able to put it in the lab and Dialogue: 0,0:06:48.38,0:06:50.39,Default,,0000,0000,0000,,try testing each one of these theories Dialogue: 0,0:06:50.39,0:06:52.34,Default,,0000,0000,0000,,until we find the one that actually Dialogue: 0,0:06:52.34,0:06:55.01,Default,,0000,0000,0000,,resolves the issue from there we can Dialogue: 0,0:06:55.01,0:06:57.17,Default,,0000,0000,0000,,create a plan of action and document any Dialogue: 0,0:06:57.17,0:06:59.60,Default,,0000,0000,0000,,possible problems that might occur we Dialogue: 0,0:06:59.60,0:07:01.28,Default,,0000,0000,0000,,can then get a time to implement the Dialogue: 0,0:07:01.28,0:07:03.53,Default,,0000,0000,0000,,issue and put it into our production Dialogue: 0,0:07:03.53,0:07:05.66,Default,,0000,0000,0000,,environment and then we can verify and Dialogue: 0,0:07:05.66,0:07:07.79,Default,,0000,0000,0000,,test and make sure that the entire Dialogue: 0,0:07:07.79,0:07:10.73,Default,,0000,0000,0000,,system is now working as expected and of Dialogue: 0,0:07:10.73,0:07:12.20,Default,,0000,0000,0000,,course finally we want to document Dialogue: 0,0:07:12.20,0:07:14.78,Default,,0000,0000,0000,,everything that we did from the very Dialogue: 0,0:07:14.78,0:07:16.73,Default,,0000,0000,0000,,beginning of our troubleshooting process Dialogue: 0,0:07:16.73,0:07:20.89,Default,,0000,0000,0000,,all the way through to the end Dialogue: 0,0:07:26.67,0:07:28.73,Default,,0000,0000,0000,,you