1 00:00:00,730 --> 00:00:08,170 In this example, I'm connected to the console of a router, when I type enable and then show version, 2 00:00:10,220 --> 00:00:17,840 we can see the version of Cisco iOS running on this router. So here's the show version command Cisco 3 00:00:17,840 --> 00:00:22,270 iOS software that we're running as an 1841 version of software. 4 00:00:22,790 --> 00:00:32,570 It's advanced enterprise software version 15.1(4)M8 release software FC2 what you'll notice 5 00:00:32,570 --> 00:00:40,430 is that a version of software is different to the software in ROM or read only memory. The system bootstrap 6 00:00:40,430 --> 00:00:40,910 a version 7 00:00:40,910 --> 00:00:46,180 here is 12.4 this router has been up for 5 hours and 40 minutes. 8 00:00:46,730 --> 00:00:50,500 This is the version of operating system that the writer booted. 9 00:00:50,930 --> 00:00:58,940 So the system image file is this file which is stored in Flash and that was loaded into memory. 10 00:01:00,900 --> 00:01:07,270 Spaceball shows me more information and I'll be able to see as an example, the amount of RAM in the 11 00:01:07,270 --> 00:01:09,760 router as well as the amount of NV 12 00:01:09,760 --> 00:01:15,100 RAM. Before I look at that, let's use the command show Flash notice 13 00:01:15,190 --> 00:01:20,260 there's the operating system that was loaded into RAM on the router. 14 00:01:20,770 --> 00:01:23,300 So Show Flash is similar to your hard drive. 15 00:01:23,710 --> 00:01:27,410 We have the operating system as well as another file stored in Flash. 16 00:01:27,940 --> 00:01:32,600 This is the size of flash in bytes and this is how much has been used. 17 00:01:33,100 --> 00:01:34,180 Here's another router. 18 00:01:37,670 --> 00:01:39,050 Show Flash here 19 00:01:40,440 --> 00:01:46,530 shows us that a different version of operating system is found in the Flash of this router and other 20 00:01:46,530 --> 00:01:49,340 files are also stored in the Flash of the router. 21 00:01:49,950 --> 00:01:54,870 So this is very similar to a hard drive where multiple files can be stored in flash. 22 00:01:55,640 --> 00:01:59,160 As an example, I could use a command show run pipe 23 00:02:02,620 --> 00:02:05,080 and then redirect the output to Flash 24 00:02:07,170 --> 00:02:11,850 and let's create a file called showruntest. 25 00:02:13,000 --> 00:02:13,990 cfg 26 00:02:16,260 --> 00:02:23,100 and now when I use the command show flash, notice that file is available in Flash, I've just copied 27 00:02:23,100 --> 00:02:28,950 the running-config from RAM onto the flash drive on this router. 28 00:02:29,490 --> 00:02:33,840 You can use the more command to view that file 29 00:02:35,460 --> 00:02:43,140 and what you'll notice is it shows us that this is the current config at a specific time, and that's 30 00:02:43,140 --> 00:02:46,650 because this is a copy of the running-config on the router. 31 00:02:47,220 --> 00:02:49,940 So the running-config of the router is stored in RAM. 32 00:02:50,640 --> 00:02:58,040 So the show running-config or show run command for short shows us the size of the current configuration. 33 00:02:58,410 --> 00:03:05,370 In other words, the live config that's used by the router, the show startup-config or show start 34 00:03:05,370 --> 00:03:12,090 config shows us the saved configuration stored in NVRAM notice the difference. 35 00:03:12,090 --> 00:03:20,910 Show startup shows us output using so many bytes out of so many bytes, whereas the show running-config 36 00:03:22,280 --> 00:03:28,340 shows current config being so many bytes. So just know the output when you use show run, you're going 37 00:03:28,340 --> 00:03:29,600 to see current config. 38 00:03:30,230 --> 00:03:33,920 When you use the command show startup-config or show start 39 00:03:34,920 --> 00:03:37,500 you're going to see so many bytes out of so many bytes. 40 00:03:40,950 --> 00:03:46,290 Now, we could use the command erase startup-config, I noticed we're told that we are going to erase the 41 00:03:46,290 --> 00:03:49,910 NVRAM file system. Do we want to continue? 42 00:03:49,960 --> 00:03:54,040 And I'm going to press enter to confirm that we want to erase the startup-config. 43 00:03:54,870 --> 00:04:01,920 So now when we use the command show startup-config, we are told that there is no startup-config present, 44 00:04:02,580 --> 00:04:08,220 no startup configuration is stored in NVRAM, but the running-config is still available on the 45 00:04:08,220 --> 00:04:08,670 router. 46 00:04:09,540 --> 00:04:15,570 To save the configuration, we would use the command copy running-config, startup-config, 47 00:04:16,990 --> 00:04:20,930 and that copies the configuration from RAM to NVRAM. 48 00:04:21,459 --> 00:04:24,130 So now when we type the command show startup-config, 49 00:04:25,510 --> 00:04:29,320 we see that a config is stored in NVRAM. 50 00:04:30,290 --> 00:04:37,520 That config is not live, so as an example, if I created a loopback interface on this router and 51 00:04:37,520 --> 00:04:40,760 gave it an IP address of something like the following. 52 00:04:43,930 --> 00:04:46,420 Show IP interface brief 53 00:04:49,090 --> 00:04:54,110 shows me that that IP address is available now on the loopback interface on the router. 54 00:04:54,610 --> 00:04:58,360 In other words, the change was immediate, show run 55 00:05:01,760 --> 00:05:08,240 shows us that loopback interface, in other words, it happened immediately and was added to the running 56 00:05:08,240 --> 00:05:08,870 config. 57 00:05:10,460 --> 00:05:17,840 Show startup-config, however, doesn't show us the loopback interface changes are only written to the 58 00:05:17,840 --> 00:05:24,870 startup-config when you use the copy run startup-config command or WR for short. 59 00:05:25,430 --> 00:05:28,100 So now when we look at the startup-config 60 00:05:31,150 --> 00:05:36,790 you'll notice that the loopback interface is configured as part of the startup-config. So the running 61 00:05:36,790 --> 00:05:40,420 config is stored in RAM startup-config is stored in NVRAM. 62 00:05:41,020 --> 00:05:49,660 You can copy the startup-config to NVRAM by using the command copy running-config startup-config. 63 00:05:50,740 --> 00:05:57,880 That would be an exam answer, but for the real world, you could simply use the command WR, you can 64 00:05:57,880 --> 00:06:00,140 also store files in Flash. 65 00:06:01,000 --> 00:06:07,150 So as I demonstrated, you could copy the running-config or startup-config to flash. 66 00:06:07,720 --> 00:06:11,620 Flash can store multiple files as seen on this router 67 00:06:12,010 --> 00:06:19,690 but the primary file that flash is used for is the storing of the operating system, which is loaded 68 00:06:19,690 --> 00:06:23,970 into RAM when the router boots up. Flash is nonvolatile 69 00:06:24,250 --> 00:06:30,250 in other words, when the router reboots, this file is not lost, but it will be removed from RAM when 70 00:06:30,250 --> 00:06:31,330 the router boots up 71 00:06:31,840 --> 00:06:36,720 the operating system is copied from Flash to RAM so that it can be used in real time. 72 00:06:37,480 --> 00:06:38,650 So let's look at the show version 73 00:06:38,650 --> 00:06:39,340 command again. 74 00:06:41,150 --> 00:06:46,550 This shows us information once again about the uptime of the router, the operating system used, how it 75 00:06:46,550 --> 00:06:47,300 was reloaded. 76 00:06:47,330 --> 00:06:48,710 So this was normal reload 77 00:06:50,000 --> 00:06:57,110 and scrolling down, we can see the amount of RAM available on the router now that's in kilobytes. 78 00:06:58,250 --> 00:07:05,150 To get the total RAM on the router you need to add those two together, so 239616 79 00:07:05,840 --> 00:07:08,990 + 22528. 80 00:07:09,800 --> 00:07:12,260 That gives us the amount of RAM on the router. 81 00:07:14,360 --> 00:07:21,770 So we need to divide by 1024, and that shows us the amount of RAM on this router, it's got 256 mega 82 00:07:21,770 --> 00:07:22,280 ram. 83 00:07:23,450 --> 00:07:30,290 This router, however, is using a different version of operating system, as we've seen and has a 84 00:07:30,290 --> 00:07:40,070 different amount of RAM, so 233472 plus 286 85 00:07:41,200 --> 00:07:45,400 72 gives us that divide by 1024 86 00:07:48,510 --> 00:07:57,150 also gives us 256 mega ram. So you need to add these values together to work out the amount of RAM in 87 00:07:57,150 --> 00:07:57,630 the router. 88 00:07:58,170 --> 00:08:05,700 You'll notice that the NVRAM value is a lot smaller than RAM, only 191 kilobytes of NV 89 00:08:05,700 --> 00:08:10,480 RAM is available, whereas we've got 256 megabytes of RAM available. 90 00:08:10,950 --> 00:08:15,990 This is the size of the compact flash on this router, which is the same on this router. 91 00:08:16,800 --> 00:08:23,100 Notice this router has two FastEthernet interfaces and two serial interfaces, whereas this router 92 00:08:23,100 --> 00:08:30,840 has two FastEthernet interfaces, one serial interface, and one VPN module. 93 00:08:31,440 --> 00:08:36,090 The interfaces on a router can vary, show IP interface brief 94 00:08:39,080 --> 00:08:46,730 on this router shows us the physical interfaces and once again show IP interface brief, on this router 95 00:08:46,730 --> 00:08:51,890 shows us the interfaces on it, which are different to router 1.