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New Member

GRE in hub and spoke w/o configuring 20 different tunnels on hub?????

We have over 80 routers all pointing back to one hub router. We are using GRE tunnels. Do I have to configure a separate tunnel interface for each incoming GRE tunnel on the hub router? Is there a way to set up one tunnel that receives from multiple locations. Thanks in advance.

Jpoulos

  • Other Security Subjects
4 REPLIES
Bronze

Re: GRE in hub and spoke w/o configuring 20 different tunnels on

Hi there,

Consider using the new feature in 12.2(13)T called DMVPN.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t13/ftgreips.pdf

Hope that helps

Jazib

VIP Purple

Re: GRE in hub and spoke w/o configuring 20 different tunnels on

I'm pretty sure that you can define a multi-point GRE tunnel.

New Member

Re: GRE in hub and spoke w/o configuring 20 different tunnels on

The previous post is right, you can run a multipoint GRE tunnel using NHRP, and then layer encryption over the top using TED. You don't need to be using 12.2(13)t to do this so you won't necessarily have to upgrade flash/ram in all your boxes.

The advantage of 13t is that it uses crypto profiles on just the tunnel, rather than crypto maps on the physical and tunnel interface. It also supports spokes with dynamically assigned public addresses better and supports cef for multipoint GRE.

By using 13t, if you want to you can have the spoke routers play in the gre mesh and also terminate VPN RAS on their outside interfaces because of the clear separation in crypto maps. You could do this to a limited extent in earlier versions, but the routers got tripped up by XAUTH on the overlapping crypto maps, and features like RRI would instate a route for VPN clients out both the tunnel and the physical interface

New Member

Re: GRE in hub and spoke w/o configuring 20 different tunnels on

Can you use multipont GRE with just NHRP and no ipsec? Not running over the public Internet -- no security concern.

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