What's the difference between GRE and IPSEC? Where we use them?

GRE is a tunneling protocol which is used to transport multicast, broadcast and non-IP packets like IPX etc.(Encapsulation method)

 IPSec is an encryption protocol(Security)

IPSec can only transport unicast packets not multicast & broadcast.

GRE allows you to creat point-to-point tunnel, it's unsecure, IPsec is a protocol represents to Internet Protocol securre, and you can use it in your traffic while using GRE tunnel.

So, you can encrypt and secure your date the send through GRE tunnel using IPsec

•  IPsec stands for Internet Protocol Security while GRE stands for Generic Routing Encapsulation.
• IPsec is the primary protocol of the Internet while GRE is not.
• GRE can carry other routed protocols as well as IP packets in an IP network while Ipsec cannot.
• IPsec offers more security than GRE does because of its authentication feature.

1) In IPsec the traffic gets encrypted while in GRE the traffic does not get encrypted.

2) we cannot run Dynamic Routing Protocols in Ipsec. In GRE we can use Dynamic Routing Protocols.

3) No need to create separate Tunnel interface in IPSEC. In GRE separate tunnel interface needs to be created.