If applying the configuration changes fails on any of the
devices in the service path, a rollback mechanism can be
used to revert all the changes and return the network
devices to their initial status before the service
deployment was attempted. Configuration templates can
be used at this stage to easily and quickly provision new
devices.
As of this writing, an educational version of Cisco NSO
can be downloaded from Cisco DevNet at
https://developer.cisco.com/site/nso/. Installation steps
can also be found there. The following examples use
Cisco NSO version 5.1 running locally on macOS
Catalina.
Cisco NSO provides a network simulation tool called
ncs-netsim. This tool makes it very easy to test NSO
packages against simulated devices and to learn how to
use the platform without any hardware needed. The
same YANG models are used for both real and NetSim
simulated devices. Several options are available with ncs-
netsim, as shown in Example 15-3.
Example 15-3 ncs-netsim OptionsClick here to view code image
$ ncs-netsim --help
Usage ncs-netsim [--dir <NetsimDir>]
create-network <NcsPackage>
<NumDevices> <Prefix> |
create-device <NcsPackage>
<DeviceName> |
add-to-network <NcsPackage>
<NumDevices> <Prefix> |
add-device <NcsPackage>
<DeviceName> |
delete-network
|
[-a | --async] start
[devname] |
[-a | --async ] stop
[devname] |
[-a | --async ] reset
[devname] |