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From: JOHN@heap.cisco.com (John Wright)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: replace config
Message-ID: <12641311988012@heap.cisco.com>
Date: 27 Nov 90 18:40:43 GMT
References: <1990Nov19.205855.18509@arcturus.uucp>
Sender: usenet@csl.sri.com
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There are three configuration files that one could have:

The contents of non-volatile battery backup up memory.
The active running RAM configuration information.
The file on a local TFTP server.

The configuration information is at startup from the console or via
tftp.  Once a system is up any changes made are to the active running
system configuration file in RAM...this is done from the console or
from a tftp loaded file. Yes, both the console and tftp loaded
commands will do the same thing and modify the existing running
configuration file.  To make any changes you would need to turn off
any services/commands which you do not wish to keep, for example NO
DEFAULT-NETWORK A.B.C.D, most commands are removed from the
configuration by placing a NO in front of the command being parsed. It
may seem easier to make a large number of changes at once by erasing
memory and placing the modified configuration file on a local tftp
server and net booting the new configuration file during a reload.  I
do this alot when testing customer configurations in the CE lab. The
problem with a replace command would be having to erase the active
configuration and therefor halt the running of the system while we
parse the brand new configuration information, not something you
normally want to do on an active running production network. It is
more likely you would load a file containing commands with both
disabling some services with "NO ..."  commands, and then turning
services on with perhaps difference addresses or parameters later
in that file.  The contents of the active configuration file in RAM
are written to NVM with the write memory command.

John Wright
Customer Engineering
cisco Systems, Inc.