Hello. We currently have a Cisco 2620 router used for our Internet access. It is very old. A friend of mine recently gave me a brand new Cisco 1721 router that he did not need. I was thinking of dumping the configuration from the 2620 to the 1721 and use the 1721 as a backup router. If the 2620 ever died on me I could swap it out with the 1721 and be up and running instantly. Can I simply dump the configuration from the 2620 to the 1721? Thanks for the help.
The 2620 is a more capable router from the same era as the 1721, although I suppose the 2620 was EOL'd before the 1721 will be in March.
You don't state what interface cards you are using, or any other config info. If this is a straightup config with the most basic, like a WIC-1DSU-T1 card or some such, then copying the config over would be pretty basic, and essentially the same.
But, do make sure you have the same interface cards, and the level of IOS you have loaded support your interface card set.
Configuration needs to be copied from one router to another.
Microsoft Hyperterminal Terminal Emulation Software.
Install a text file configuration into a router by performing these steps.
If the configuration is already uploaded, go directly to Step 8.
Step 1: If the configuration needs to be copied from another router, connect to that router through the console or Telnet.
At the Router > prompt, issue the enable command and provide the required password. The prompt changes to Router#, indicating that the router is now in privileged mode.
Step 2: To force the router to return the entire response at once, rather than a screen at a time, issue the terminal length 0 command.
This allows you to capture the configuration without extraneous
--more-- prompts generated when the router responds a screen at a time.
Step 3: On the HyperTerminal menu, select Transfer > Capture Text. The Capture Text window appears.
Step 4: Name this file config.txt.
Step 5: To dismiss the Capture Text window and begin the capture, click Start.
Step 6: Issue the show running-config command and allow time for the router to complete its response.
Step 7: To end the screen capture, select Transfer > Capture Text >
Stop on the HyperTerminal menu.
Step 8: Open the config.txt file you created in any text editor, such as Notepad or Wordpad.
Step 9: Search for and remove any line that starts with AAA.
Note: This step removes any security commands that could lock you out of the router.
Step 10: For each interface that is followed by shutdown, leave it as it is.
Step 11: For all other interfaces, issue the no shutdown command, as shown in this example:
! interface Serial0/0 no ip address no ip directed-broadcast no shutdown !
Step 12: Save the file.
Step 13: Connect to the router that needs the configuration.
Step 14: Open the config.txt file.
Step 15: Highlight the entire contents of the config.txt file.
To accomplish this, drag the cursor from before the first character to after the last character in the file while holding down the left mouse button. If you are using Notepad, select Edit > Select All from the menu.
Step 16: Copy the selected text to the Windows clipboard.
To copy, you can either select Edit > Copy from the text editor's menu, or hold down the CTRL key and simultaneously press the C key.
Step 17: Switch to the HyperTerminal window and issue the configure terminal command at the Router# prompt and select Enter.
Step 18: Paste the configuration file into the router by selecting Edit
Step 19: After the configuration has finished pasting, and the router brings you back to the configuration prompt, issue the copy running-config startup-config command. This writes the configuration into memory.
Step 20: To return to the Router# prompt, issue the exit command.
Hope this helps.
Brad Reese BradReese.Com - Cisco Repair
Hendersonville Road, Suite 17 Asheville, North Carolina USA 28803 USA & Canada: 877-549-2680 International: 828-277-7272 Fax: 775-254-3558 AIM: R2MGrant BradReese.Com - Cisco Power Supply Headquarters
In a general sense the configs will be compatible unless the source router is using features that are not present in destination router due to either the Feature Set being more restrictive or the version being older and not supporting some particular feature. For simple stuff like routing, access-lists, there are unlikely to be any problems even if one of the routers has very old software. It seems to me that cisco take great care to maintain configuration compatibility across versions and router models.
One think that you will almost certainly have to take care of is that the interface names may be different.
i.e. Serial 0 vs Serial 0/0 FastEthernet 0 vs Ethernet 0/0
show ip interface brief ! displays one line per interface
Finally to re-iterate Brad's warning - You will have to add no shutdown to any interfaces that you want to use. Strange but true:-)
You can just edit the text file that Brad's method will produce with notepad and paste it in to the command line.
Thanks Doug, Brad, and Bod43. My 2620 router has a very basic configuration and both routers have the same T1 WIC card in them so this should be a piece of cake. One last question, the 2620 has 32 MB of memory installed and the
1720 has 64 MB of memory. Would one router be faster than the other or would no real difference be seen? Just curious. Thanks again. Corbin.
Ammount of memory in a router affects nothing performance wise. Its not like there's virtual memory or swap like on a workstation.
The main purpose of memory is for the router to uncompress IOS into to run off the flash storage device, and to setup static I/O buffers to move packets in and out. The buffers don't change, they are static.
So, once you are up and booted, there is no additional memory used or freed.
(more dynamic operations, like dynamic routing does allocated some memory on the fly, but you just have to make sure what you are trying to do has enough memory to hold it all, again, more memory doesn't equate any performance gain or loss).
One more thing. We have a simple setup on the WAN side I have the 2620 Internet Router, a PIX 515, and VPN 3005 Concentrator connected to a switch. If I swap out the 2620 router with the 1721 I know from experience that the PIX and the VPN box will not be able to talk to the 1721 until they are rebooted. I know this is related to the ARP cache. Isn't there a IOS command to clear the ARP cache on the PIX 515 and VPN 3005? In the past I have always just rebooted the devices and that of course automatically clears the ARP cache but I would like to swap out the router and clean the ARP caches without rebooting. Thanks.