Handling frequent switch failures during work

Handling frequent switch failures during work. instance causes IOS version problems)
Upgrade switch IOS to solve frequent failures
The CISCO 2950 switch has frequent suspension failures, and the switch that has been suspended does not have any alarm information. After the switch is restarted, it returns to normal. After the switch IOS version is upgraded from 12.11EA1 to 12.12 (EA2), the fault will disappear. To facilitate other users to handle such faults, the following describes how to upgrade the CISCO 2950 switch to IOS:
I. Prerequisites

A vswitch is similar to a computer in terms of memory, Operating System, configuration, and user interface. In a Cisco switch, an Operating System is called an Internet Operating System or IOS. The following describes the memory of a vswitch.
ROM read-only memory): contains a copy of the IOS in use by the router;
RAM Random Access Memory): IOS divides random access memory into shared and primary storage, which is mainly used to store switch configurations in operation;

FLASH (FLASH): used to store IOS software image files. FLASH memory can erase the memory, which can be overwritten with the new version of IOS.

NVRAM non-volatile random access memory): used to store system configuration files.
The IOS upgrade of the switch is mainly to replace the IOS image file in flash memory.
Ii. Preparations
1. One Cisco2950 switch for IOS upgrade;
2. A desktop or notebook can be used on a computer. ○ 1 is used to configure a switch. ○ 2 is used as a TFTP server;
3. A direct connection network cable is used to transmit IOS files to the switch;
4. One vswitch configuration line;
5. A set of TFTP Server software. This time, we use the "Cisco TFTP Server ";
6. Copy the IOS Update file.
3. Start upgrading
1. Use the Console port of the configuration line to connect the vswitch to the COM port or USB port of the computer, depending on the configuration line). The network cable connects the F0/1 port of the vswitch to the Ethernet port of the computer. The IP address of the computer is 192.168.0.1.
2. Use the computer as the TFTP server, open the software on the TFTP server, and set its root directory to the directory where the IOS file is located.
3. To enable the switch to communicate with the TFTP server, we need to set an IP address for the switch. Use the super terminal software that comes with Windows to set the address of switch F0/1 to the same network segment as the IP address of the computer. The procedure is as follows ):

Switch <config> # interface vlan 99 // create and enter vlan99; Switch <config-subif> # ip address 192.168.0.2 255.255.255.0 // Add an IP address for vlan99; Switch <config-subif> # no shutdown // enable vlan99; Switch <config-subif> # exit // return to the global configuration mode; Switch <config> # interface fasethernet 0/1 // enter port F0/1; Switch <config-if> # switch access vlan 99 // route port F0/1 to vlan99; Switch <config-if> # exit // return to the global configuration mode;

At this time, if you can Ping 192.168.0.1 on the Super Terminal interface, it indicates that the switch and the TFTP server computer are connected normally.
4, in privileged mode input "show flash" can view the current switch flash IOS file name such as c2950-c3h2s-mz.120-5.3.WC.1.bin) and related information, we first need to back up this IOS file, just in case.

Switch # copy flash tftp // copy the file from flash to tftp; Source filename []? C2950-c3h2s-mz.120-5.3.WC.1.bin Address or name of remote host []? 192.168.0.1 Destination filename [c2950-c3h2s-mz.120-5.3.WC.1.bin]? Press ENTER)

Wait a moment and the file will be backed up. After the backup is complete, we will copy the new IOS file to flash.
The "show flash" command shows that the remaining storage space in flash is less than the IOS file to be upgraded. In order to enable the new IOS file to be merged into the flash file of the switch, you must delete the original IOS file first.

Switch # delete flash: c2950-c3h2s-mz.120-5.3.WC.1.bin // Delete the original IOS file; Delete file [c2950-c3h2s-mz.120-5.3.WC.1.bin]? Press ENTER) Delete flash: c2950-c3h2s-mz.120-5.3.WC.1.bin? [Confirm] Press ENTER)

The IOS file in flash has been deleted. Make sure that the switch will not be restarted before the new IOS file is merged into the switch. Otherwise, the switch will not start properly.

Switch # copy tftp flash: // copy the file from tftp to flash; Address or name of remote host []? 192.168.0.1 Source filename []? C2950-i6k2l2q4-mz.121-22.EA ** in press Enter) Destination filename [c2950-i6k2l2q4-mz.121-22.EA ** in]? Press ENTER)

After an exclamation point, the new IOS file is successfully copied to flash.

5. After all the copies are completed, enter "reload" to restart the switch. If the switch can be restarted normally, check that the IOS file in flash has become "c2950-i6k2l2q4-mz.121-22.EA ** in", then the upgrade of IOS is now complete. Finally, do not forget to delete the temporary Vlan99.
4. unfortunate failure
There are many causes of IOS upgrade failure, such as network cable looseness during the upgrade, mismatch between the IOS file and switch, and sudden power failure. There is only one result in the above situation, that is, the switch cannot be started ". If the switch cannot be started properly, you cannot use the method just now to perform a new IOS upgrade. Even normal use has become a problem. However, there are still some solutions to the "no path to perfection" problem. Our basic idea is to try to import the correct and complete IOS file into the flash of the switch, the switch can be started normally. Next, I will introduce the restoration method after the IOS upgrade failure. In fact, this is also a method for IOS upgrade, but it is more complicated than the previous one, so it is not very commonly used.
1. Use the configuration line to connect the console port of the switch to the COM port of the computer. Super Terminal connection settings: Speed 9600, no verification, no flow control, stop bit 1. Or click the default settings.
2. After the connection, press enter to display the switch without ios interface. The general prompt is: switch:
3. Unplug the power cord of the vswitch.
4. Press the mode key on the left side of the switch panel. Generally, the switch has a key.) insert the power plug behind the switch to power the switch. Wait until you see that the Ethernet indicator lights that are not wired on the switch panel are on and several system indicators of the switch are on.
5. Input flash_init on the Super Terminal.
The following prompt is displayed:

Initializing Flash... flashfs[0]: 1 files, 1 directories flashfs[0]: 0 orphaned files, 0 orphaned directories flashfs[0]: Total bytes: 3612672 flashfs[0]: Bytes used: 1536 flashfs[0]: Bytes available: 3611136 flashfs[0]: flashfs fsck took 3 seconds. ...done Initializing Flash. Boot Sector Filesystem (bs installed, fsid: 3 Parameter Block Filesystem (pb installed, fsid: 4

6. Continue input: No prompt is displayed after load_helper is input)
7. input the Copy command:
Switch: copy xmodem: c2950-i6k2l2q4-mz.121-22.EA ** in
The following prompt is displayed:
Begin the Xmodem or Xmodem-1K transfer now...
8. The system prompts that the letter "C" appears and you can start to upload files.
9. Click the Super Terminal menu: Send --- → send file, select Xmodem or Xmodem-1K protocol in protocol options, then select IOS file, start transfer.
10. Because the speed cannot be changed, the transmission speed is very slow. It takes about 60 minutes for me to transfer the data. Please wait.
11. After the file transfer is complete, enter: boot to enable the new IOS system)
12. After dozens of seconds, the switch enters the normal state. In this case, check the flash and there should be a new IOS file. Now the IOS recovery is complete.
Note that, due to different production times, not all CISCO2950 switches can run the same version of IOS software, some older CISCO2950 switches will not be recognized by the Ethernet service Board after upgrade. Therefore, be sure to back up the original IOS files before upgrade to prevent unexpected losses.