EE connection network reachability awareness

When a dial failure or a connection failure occurs for a connection over an Enterprise Extender connection network, the partner node cannot be reached using the connection network path across the virtual routing node (VRN). This connection network path might have been chosen for this connection because it had a lower weight than any alternate path available at one of the following times:

The time of this failing dial
The time of the dial that set up the existing connection
The time of a path switch to this connection network path for an existing connection

If this path still has the lowest weight of any available path to the partner node, any attempt to redial the partner node will continue to try the path over this particular VRN, which is likely to result in failure until the underlying problem with the path is corrected.

EE connection network reachability awareness detects the dial failure or connection INOP for the connection over an Enterprise Extender connection network and prevents that specific path to the partner node from being used for a period of time. The path through the Enterprise Extender VRN to the unreachable partner is unidirectional and consists of three components:

The node on the origin side of the virtual node, which is the node that detects the problem
The virtual node defined by the Enterprise Extender connection network
The unreachable partner node on the destination side of the virtual node

It is possible for the path in one direction between two nodes and through the VRN to be usable for route selection, while the path in the other direction is not usable. This function can detect that distinction and when new sessions are established and HPR path switches occur, it allows routing in the direction that is usable, while preventing the path in the direction that is not usable from being selected.