With the basic setup you install a collectd agent with every system that you want data from and send the data directly to the long term storage. This page describes further setup possibilities.
Integrating a proxy
You can setup proxies to collect the data of multiple machines and to forward them to other proxies or to the long term storage interface.
This could be meaningful to channel the traffic through some specific nodes only (often a benefit for firewall activations). In even more advanced setups you could use proxies to translate between IPv4 and IPv6 environments.
You can build up even more complicated setups and have proxies sending to proxies if you desire.
Data encryption
If you need the data to be encrypted you can set this up in an easy way. Please note that right now the communication to the longterm storage does not support encryption yet. To circumpass this you can use the proxy setup describes above to encrypt the communication between the agents and the proxy and forward the data plain from the proxy to the longterm storage (and place the proxy "near" the longterm storage).
Client setup (Encryption)
<Plugin "network">
<Server "172.16.0.42">
SecurityLevel "Encrypt"
Username "user0"
Password "foo"
</Server>
</Plugin>
Proxy setup (Encryption and plain forward)
<Plugin "network">
<Listen "172.16.0.42">
SecurityLevel "Sign"
AuthFile "/etc/collectd/auth_file"
</Listen>
<Server "192.168.0.42" />
</Plugin>
For the proxy you have to create a authentication file that contains the username and password. The format is as follows:
user0: foo user1: bar