Generic routing encapsulation gre tunnels have been around for quite some time. Configuring gre tunnel by r p porwal configuring a gre tunnel. The ipv6 over ipv4 gre tunnel protection feature allows both ipv6 unicast and multicast traffic to pass through a protected generic routing encapsulation gre tunnel. To configure a gre tunnel implies the creation of a tunnel. Using generic routing encapsulation gre tunnels on cisco routers can come in handy with cisco router administration, and configuring gre tunnels is. Gre stands for generic routing encapsulation, and it is an extremely simple form of tunneling. Security for vpns with ipsec configuration guide, cisco. The tunnels behave as virtual pointtopoint links that have two endpoints identified by the tunnel source and tunnel destination addresses at each endpoint. The device at one end of a vpn tunnel takes an ip packet, encrypts it making it unreadable, and then sends the encrypted packet after encapsulating it in a new ip header. Tunneling protocols, including gre tunnel hanks et al. The following configuration example shows a static public ip address on the branch router with a static. The below example explain about how to create simple gre tunnels. This design guide is part of an ongoing series that addresses vpn solutions, using the latest vpn technologies from cisco, and based on practical design principles that have been tested to scale.
Gre, based on the example configuration shown in figure 192 on page 193. This is how to configure ip gre tunnel from linux foundation. With gre we can easily create a virtual link between routers and allow them to be directly connected, even if they physically arent. The gre tunnel does not authenticate or encrypt traffic. See conventions on page lxvii of preface in the front of this manual for details. Quality of service per p2p gre tunnel interface 12. Generic routing encapsulation gre semantic scholar. Configuring gre tunnel by r p porwal configuring a gre tunnel involves creating a tunnel interface, which is a logical. However, gre tunnels are not as secure as a tunnel established using ipsec.
However, many routing protocols rely on multicasts. Gre tunnel configuration in cisco packet tracer gre. Example configuration for multipoint gre encapsulation of ip over ip. Generic routing encapsulation gre is a communication protocol used to establish a direct, pointtopoint connection between network nodes. Configuration example page 4 generic routing encapsulation gre configurable tunnel destination ipv4 address configurable tunnel destination using hostname configurable checksum insertion and checking disabled by default configurable ttl value for insertion into the outer header configurable dscp value for insertion into the outer header copied from the inner. Configuringgretunnels genericroutingencapsulation gre isatunnelingprotocolthatprovidesasimplegenericapproachto. How to configure gre tunnel on cisco ios router tunneling is a concept where we put packets into packets so that they can be transported over certain networks. For example, if ten sites were fully meshed with gre over ipsec tunnels, it would take. Pdf generic routing encapsulation gre researchgate. Headends are p2p gre and crypto tunnel aggregation routers servicing multiple p2p gre over ipsec tunnels for a prescribed number of branch office locations. Gre stands for generic routing encapsulation, which is a very simple form of tunneling.
Generic routing encapsulation gre is one of the available tunneling mechanisms which uses ip as the transport protocol and can be used for carrying many different passenger protocols. You will also configure the ospf routing protocol inside the gre vpn tunnel. Routing configuration guide, cisco ios xe everest 16. Gre tunnel configuration in cisco packet tracer youtube. This lesson discusses the theory behind a generic routing encapsulation gre tunnel and describes how a gre tunnel can be combined with an ipsec tunnel. Pdf study of the impact of routing and the profoundness of gre. You are familiar with the fundamental operation of a virtual private network vpn, and the concept of tunneling by now.
Gre was first developed by cisco as a means to carry other routed. Convert vce to pdf exam formatter vce mobile tutorial terms of service privacy policy billing policy. Generic routing encapsulation gre is a tunneling protocol developed by cisco systems that encapsulates a wide variety of network layer protocols inside virtual pointtopoint links over an internet protocol internetwork. For example, the internet does not route multicast messages.
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