[CentOS] Monitoring bandwidth, latency, packet drop.

Hi all.

I am currently thinking about monitoring a network link (bandwidth,
latency, packet drop). I have a centos server which is connected to
providers network through a switch. How to test the link? Should I:
- use ICMP to ping gateway and collect staistics of time/packet loss/etc.
- use software like here:
http://www.cyberciti.biz/faq/linux-unix-windows-monitor-outgoing-bandwidth-latency/
 (client/server)
?
Is there an option to monitor bandwidth, latency, packet drop without
installing additional software on gateway or external host?

Best regards,
Rafał.