Contents
What is GRE tunnel and why it required?
For example, GRE tunnels allow routing protocols such as RIP and OSPF to forward data packets from one switch to another switch across the Internet. In addition, GRE tunnels can encapsulate multicast data streams for transmission over the Internet.
How does GRE tunnel work?
A Generic Routing Encapsulation (GRE) tunnel connects two endpoints in a point-to-point, logical link. The packets travel through the GRE tunnel (over a transit network such as the internet) to the cloud service while on their way to the destination address.
What is GRE keepalive?
The GRE keepalive feature enables the keepalive interface command for tunnels, and allows you to configure keepalives for point-to-point GRE tunnels. GRE tunnels provide a method to encapsulate arbitrary packets inside a transport protocol.
What layer is GRE?
OSI layer 3
GRE is defined by RFC 2784 and as a tunneling protocol, carries OSI layer 3 protocols in the network. GRE creates a private point-to-point connection, just like that of a virtual private network. Therefore, it finds widespread usage in the creation of VPNs (with PPTP and IPsec).
Is GRE tunnel a VPN?
While many might think a GRE IPSec tunnel between two routers is similar to a site to site IPSec VPN (crypto), it is not. A major difference is that GRE tunnels allow multicast packets to traverse the tunnel whereas IPSec VPN does not support multicast packets.
Why to use a GRE tunnel?
You need to encrypt multicast traffic.
What does GRE stand for in tunnel?
Generic Routing Encapsulation ( GRE) is a tunneling protocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links or point-to-multipoint links over an Internet Protocol network.
How to configure GRE tunnel IP source and destination?
How to Configure GRE Tunnel IP Source and Destination VRF Membership SUMMARY STEPS 1. enable 2. configure{terminal| memory| network} 3. interface tunnel number 4. ip vrf forwarding vrf-name 5. ip addressip-address subnet-mask 6. tunnel source(ip-address| type number)
What is the point of a GRE tunnel?
GRE (Generic Routing Encapsulation), GRE Tunnel is the mechanism that encapsulate one protocol in another protocol and provides connection between the nodes. This is done basically IP over IP. A Service Provider Network or Internet is used for GRE (Generic Routing Encapsulation).