QoS and Performance of a VPN

[AlexS]

Hello everybody...

I'd like to know which parameters should be considered in order to establish a qualification of a deployed VPN (site to site, and remote access), related to its Quality of Service and its Performance...

That is, how can I, in a empiric way, determine if a VPN is "good" or not, or "how much better" is a solution than any other?

Thanks in advance,

Alex Sanchez