CDP and IPSEC Tunnels

[RICHARD MESSINGER]

Is there a trick to being able to have CDP be transported across an IPSEC tunnel between Cisco Routers? This would make discovering the network much easier without using multiple seed devices.

[Marvin Rhoads]

CDP is a layer 2 protocol. CDP neighbors need to be in a contiguous Layer 2 broadcast domain - most commonly a shared LAN segment or VLAN. It is possible to tunnel layer two protocols through an IPSec Layer 3 connection (one configuration guide example: http://www.cisco.com/en/US/partner/products/hw/routers/ps368/products_configuration_guide_chapter09186a008027893e.html).

Personally, I'd just use seed devices for the remote sites.