By definition, there is only one running config. This is the config currently active on a device. However, there is a feature in newer versions of IOS that lets you take periodic snapshots of this configuration, and save them to flash or to a network server. The purpose of this is to be able to quickly roll back to a known good configuration, rollback individual changes, or do config comparisions without additional tools such as CiscoWorks.
For more information on embedded IOS configuration archive and rollback see http://www.cisco.com/en/US/customer/products/ps6350/products_configuration_guide_chapter09186a00800ca73a.html . One particularly cool feature is the ability to do a timed config rollback. This lets you make a very risky configuration change (e.g. one that could lock you out of the device) then have it automatically rolled back if something goes wrong (no more using "reload at" then waiting for the device to reload).
My understanding is there can be only one running config/startup config but when we give copy run start we get the the (startup config- file) some thing like that....
An IOS device copies the startup config to memory at boot time. All changes are then written directly to the running config in memory. When you issue the write mem or copy running start commands, this config is saved to NVRAM as the startup config. You can also save multiple copies of the running config to flash or a network server. Certain versions of IOS also support the "boot config" command which allows you to boot from a config other than the one in NVRAM.
There can be a startup and a running config on IOS devices.
CatOS only have a running config.
You can store multiple configs on your devices thought provided there is room on the device.
Not true on newer versions of CatOS. You can have both startup and running configurations by setting the config mode to text. See http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_5/cmd_ref/ses_sete.htm#wp1153974 for more details.
We are using Siemens SGSN, Siemens GGSN XP140 with Cisco 7613(Medium Size Configuration) with CPG3300.
We have got two border gateways and two core routers connected to Cisco 7613 for internet traffic and WAP/MMS.
We are going to integrate another Cisco router CSG/DSCP solution betwwen our border gateways and Cisco 7613.
In case if there occurs some problem or the proposed solution doesn't work properly.What will be the easiest procedure to rollback/fall back Cisco7613 router(Medium Sized Configuration)?
In order to obtain rollback/fallback in Cisco 7613 using "Configuration replace and Configuration Rollback" procedure, at what level(which card level) i.e. SUP or Aggregator or MWAM etc. should we apply this particular rollback/fall back procedure to get successful complete rollback to previous VLAN connections,IP addresses,connections etc.??
Please suggest and advise...
Where you use the rollback will depend on what configuration you are going to be changing. It may also not be doable with your current hardware. Config archive and rollback was integrated into 12.3(7)T and 12.2(25)S. However, as of 12.2(18)SXF5, it is not available in the 7600 IOS. It does appear to be in 12.2(33)SRA, though. I am uncertain about the MWAM IOS.
We are going to change few new IP addresses,new VLAN and new physical LANs connected to the router.If someting doesn't work then we want to have a roll back option on Cisco7613?
As I said, config rollback is dependent on the version of IOS on your 7600. Unless you're running 12.2(33)SRA on this router, you do not have this capability.
A much older trick to allow for recoverability is to use the "reload at" command. You can schedule a reload to happen at some point in the future. Once the reload timer is running, make your config changes. If you lock yourself out of the router, the router will reload at the specified time, and eventually you will have connectivity restored. If the config changes work, use the "reload cancel" command to abort the scheduled reload. For example:
reload at 02:00
ip access-group 101 in
If that series of commands locks you out of the router, the router will reload at 2:00 am, without saving your changes. It will come up on the previous startup config. If, however, the commands do not lock you out, abort the pending reload:
Can we restore the changes performed in routing tables by reload?Cisco 7613 is a set of 13 routers with 2-SUP.Do you suggest reload or config rollback (if applicable) on SUP cards or aggregator router.
The idea behind both config replace and reload at is to restore the config on the IOS device in question to the last saved state (i.e. the last time write memory was performed). You should perform a config replace or reload at on the device (or instance of IOS) where you are making the config change (i.e. the device you telnet or SSH to just prior to making the configuration change).
Thanks, what I understand is that "reload at" can be used to UNDO all the changes performed "last good configuration".This command can be used just before typing any routing, configuration changes over the same command prompt.
What type of details are stored in Cisco 7613 router configuration file?Does it contain configuration of router itself such as router's personal IP address,start up details,boot sequence etc. or it contain details/database about routing tables,VLAN and IP addresses of VLANs connected with router?Is there any command to restore the router settings to a previously saved configuration file or previously saved database details like 20 days old backup?
You should connect to your 7613, and do a show run to get an idea of what you have configured there. Most of what you mention is typically contained in the running configuration. Of course, dynamically learned routes, and routing topology will not be there. There are other show commands that can get that information.
As for restoring an old config from 20 days ago, config archive offers this capability, but as I said, you must be running very new code on a 7600 to have this feature. Beyond that, external network management tools such as CiscoWorks RME offer configuration archive capabilities which can allow you to rollback to previous configs.
Just before doing reload at, is it advisible to do wr mem to write configuration,vlan information etc from memory to file?Thanks
Yes, you should write mem, then schedule the reload, then perform your questionable configuration changes.
I should also note that this kind of procedure should only be done as a last resort. The best way to test configuration changes is in a lab environment.
Any further suggestions, as we have a running/operational GPRS network using Cisco 7613, CPG3300. It have 13 routers and 2SUP.We need a rollback procedure before making any changes to VLAN and routing tables??
Current configuration : 7750 bytes
! Last configuration change at 11:58:03 GMT Wed May 10 2006 by siemens
service timestamps debug datetime localtime show-timezone
service timestamps log uptime
service gprs ggsn
Without knowing the _exact_ version of IOS, I cannot say if your device supports config archive and rollback. However, it does support "reload at" and you always have the option of using an external management system like CiscoWorks Resource Manager Essentials to do your configuration management.
I understand, is there any command through which we can simply see/check that when the last configuration was written from memory to file on disk?
Typically, a show run or show conf will give you this at the top of the config if the config was saved since the device was booted. For example:
! Last configuration change at 00:53:10 EST Sun Nov 12 2006
! NVRAM config last updated at 01:43:20 EST Sat Nov 11 2006
This indicates that the startup config was last modified on November 11 at 01:43:20. If the config has not been saved since the last reload, then you will not see a date in the show run/conf output, but you can use the show ver output to see when the device was last reloaded.
Problem with Cisco IOS structure is that it never saves different
of the configuration. Only 2 copies running and startup so if you
save configuration then reload at will help only doing rollback with
Automatically rolling back to different configuration versions was one of the problems config archive and rollback is supposed to solve. However, you can always choose to save multiple backups of a configuration and manually copy them back into the running-config. For example, to store an extra copy of the config to flash:
copy runn flash:config.bak
Then to restore that version:
copy flash:config.bak runn
This isn't a perfect rollback, but it will work for most commands.