1
00:00:00,870 --> 00:00:06,070
It's good practice to back up your iOS images, especially as your network grows.

2
00:00:06,660 --> 00:00:12,840
You're going to want to have a central place to back up and store your iOS images and configuration

3
00:00:12,840 --> 00:00:13,370
files.

4
00:00:13,740 --> 00:00:20,620
So it's good practice to back up your iOS files to a central TFTP server or FTP server.

5
00:00:21,240 --> 00:00:22,200
This is useful, 

6
00:00:22,200 --> 00:00:29,430
for example, if an iOS image gets accidentally deleted or erased or becomes corrupted, you're going

7
00:00:29,430 --> 00:00:34,220
to want to be able to restore your iOS from a TFTP server.

8
00:00:34,590 --> 00:00:40,050
So good practice to copy from the Flash to a TFTP server and have that available.

9
00:00:40,410 --> 00:00:48,450
If you need to restore an image or perhaps when you upgrade a router, you encounter issues and may

10
00:00:48,450 --> 00:00:51,880
need to downgrade back to an older version of operating system.

11
00:00:52,330 --> 00:00:57,390
So good practice to have your iOS images backed up to a central location.

12
00:00:57,960 --> 00:01:04,489
Now, what about iOS images that have these cryptic names that may be difficult initially to understand?

13
00:01:04,950 --> 00:01:10,740
So when looking at an iOS image, the first part such as  C2900 is the platform.

14
00:01:11,130 --> 00:01:14,400
This is an image for a 2900 Cisco router.

15
00:01:15,000 --> 00:01:22,680
The universal canine option means that this image is universal, so it's a single image set that includes

16
00:01:22,680 --> 00:01:27,660
the IP base, security, unified communications, and data feature sets.

17
00:01:28,320 --> 00:01:31,600
Each router is activated for an IP based feature set.

18
00:01:31,890 --> 00:01:37,770
However, for other feature sets, you'll need to activate those features by loading a license onto

19
00:01:37,770 --> 00:01:40,620
the router and we'll discuss that in a separate video.

20
00:01:41,310 --> 00:01:47,060
So in this example, the platform is a Cisco 2900 series integrated services router.

21
00:01:47,670 --> 00:01:54,870
The third part, M Zed or M Z, indicates where the image runs and if the file is compressed. In this example, 

22
00:01:55,560 --> 00:01:58,140
In this example, the image is run in RAM.

23
00:01:58,530 --> 00:02:04,380
So M indicates runs in RAM and Z or Zed indicates a compressed image.

24
00:02:05,630 --> 00:02:13,340
Digitally signed Cisco iOS images identified by a three-character extension in the image name. S stands

25
00:02:13,340 --> 00:02:20,630
for digitally signed software POS stands for production or special development image.

26
00:02:21,170 --> 00:02:28,520
So P in the name indicates that it's a production image that is approved for general release.

27
00:02:29,090 --> 00:02:29,650
A

28
00:02:30,020 --> 00:02:37,700
S indicates a special image that is development software and should only be used in special circumstances.

29
00:02:38,270 --> 00:02:43,490
The A indicates the key version that is used to digitally sign the image.

30
00:02:43,970 --> 00:02:52,160
A key version is identified by an alphanumeric character such as A, B or C, the fifth part 152-

31
00:02:52,160 --> 00:03:00,340
4.M1 indicates the software version number and the final part bin is the file extension.

32
00:03:00,830 --> 00:03:04,530
This indicates that the file is a binary executable file.

33
00:03:05,090 --> 00:03:08,750
Just be aware that the Cisco iOS naming conventions do change.

34
00:03:09,200 --> 00:03:11,990
The best place to look for information is on the Cisco website.

35
00:03:13,710 --> 00:03:18,240
For example, on the Cisco software downloads, Help and FAQ page.

36
00:03:20,490 --> 00:03:22,230
You'll find a lot of information.

37
00:03:23,340 --> 00:03:27,630
For example, the Cisco iOS software release naming convention is explained.

38
00:03:28,680 --> 00:03:35,490
So in this example, we have a major release of 12.1 the maintenance release enterprise designator

39
00:03:35,490 --> 00:03:40,540
a sixth build of the release and first rebuild release date.

40
00:03:41,490 --> 00:03:48,000
Have a look at documents such as the following for instructions on how to download software and how

41
00:03:48,000 --> 00:03:55,080
to discover more information about the different options available with regards to the Cisco iOS.