What is the difference between MPLS, MPLS VPN and IPsec VPN tunnel?
I know that MPLS is a type of WAN. and IPsec VPN tunnel is an encrypted connection (private) over the internet.
But what is MPLS VPN?
I also read that some use VPN over WAN connections like MPLS, why? isn't WAN connections impossible to be eavesdropped due to the amount of multiplexing and different traffic running through it?
Multi Protocol Label Switching is a switching technology used mostly by service providers. It allows them to build private WANs that are agnostic to the network protocol and type of addressing used. So for example, multiple customers can use the same private IPv4 address space without interfering with each other. Other customers can have a layer 2 WAN, all on the same provider network.
When a carrier provisions a private WAN for a customer, it's called a MPLS VPN. You can consider it a type of tunneling protocol, because it tunnels the customer traffic over the carrier network.
IPSec VPN is another tunneling protocol for IP only, and only point to point. IPsec offers encryption and authentication, while MPLS VPN doesn't.
isn't WAN connections impossible to be eavesdropped due to the amount of multiplexing and different traffic running through it?
It's not difficult for the carrier (how else would they route your traffic to the right place?). And it's not that difficult for governments to "ask" carriers to do it.
From the customer point of view, MPLS is a private site-to-site connection across a provider/carrier network. The connection can be layer 2/switched (most commonly) or layer 3/routed (MPLS VPN might indicate layer 3).
IPsec is a tunneling technique that you run on top of standard WAN/Internet connections (static IP addresses are usually required) or over just about anything else. It is mostly used for layer-3 VPN but can be used for layer-2 tunneling as well. With IPv6, tunneling can be used but encryption-only connects with transparent (global unicast) addressing are also possible.
Very often, MPLS comes with an SLA regarding availability and performance (end-to-end latency and minimum bandwidth), while IPsec VPN runs on top of your WAN/Internet connection where you have a maximum bandwidth and a certain availability at best, while performance is just best effort.
Brutally said, MPLS is more oriented towards network traffic priority, while VPN is more about encryption than MPLS.That's why you don't have encryption with MPLS unless you, for example, build an IPsec VPN tunnel over MPLS, as said above.
