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Cisco Router and Security Device Manager Version 2.2 User’s Guide
OL-4015-08
Chapter11 DMVPN
Dynamic Multipoint VPN
SDM’s Configure Spoke feature enables you to create a text file that contains the
information that spoke administrators need about the hub’s configuration. This
feature is available from the Summary window of this wizard.
You also need to tell the spoke administrators which subnet mask to use, and
assign each spoke an IP address from the same subnet as the hub so that address
conflicts do not occur.
Type of Hub
DMVPN networks can be configured with a single hub, or with a primary and a
backup hub. Identify the type of hub you are configuring your router as.

Primary Hub

Check if the router is the primary hub in the DMVPN network.

Backup Hub

Check this button if the router is a backup hub in a full-mesh DMVPN network.
Configure Pre-Shared Key
DMVPN peers can use a pre-shared key or digital certificates to authenticate
connections from each other. If pre-shared keys are used, each hub router and
spoke router in the network must use the same pre-shared key.
Pre-shared keys should be exchanged with the administrator of the remote site
through some secure and convenient method, such as an encrypted e-mail
message. Question marks (?) and spaces must not be used in the pre-shared key.
The pre-shared key can contain a maximum of 128 characters.
Pre-Shared Key
Enter the pre-shared key used in the DMVPN network. Question marks (?) and
spaces must not be used in the pre-shared key. The pre-shared key can contain a
maximum of 128 characters.