Behavior of Unreachable Demand Dial Interfaces in RRAS (193834)

MORE INFORMATION

When a DOD interface in RRAS attempts to dial a number, the status field will have a value of "Connecting." The static route that is used to activate the DOD is viewable by using the KERNROUT PRINT command.

If the number that is dialed is not available, the DOD interface will be marked "Unreachable" only after it has failed all redial attempts. It will then stay unreachable for a default period of 10 minutes. The static route disappears from the routing table when the interface status is marked "Unreachable."

After the wait interval, the status of the DOD interface will change to "Disconnected," at which point the DOD interface is available for use. When the status changes to "Disconnected," the static route in KERNROUT will reappear.

If the DOD interface fails to connect again after this wait interval, it will then be marked "Unreachable" for a period of 20 minutes and, again, the static route will disappear from KERNROUT. Then, when the wait period is over, the status goes back to "Disconnected."

This cycle continues in 10 minute intervals until 6 hours has been reached. The default maximum wait time remains at 6 hours until one of the following occurs:

• A successful connection has been established [through either the wait interval described here or manual dialing].
  
  -or-
• The router has been stopped and restarted.

These default minimum and maximum times can be changed through the registry.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

The 10-minute wait time is a default value that can be changed by adding the registry entry shown below:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Router\Interfaces \<interface name>\MinUnreachabilityInterval
REG_DWORD with a value in seconds

NOTE: The above registry key is one path; it has been wrapped for readability.

The MinUnreachabilityInterval is the smallest amount of time that the interface will stay "Unreachable" AND also defines what the wait interval is incremented by in next attempts.

The maximum wait time is a default value that can be changed by adding the registry entry shown below:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Router\Interfaces \<interface name>\MaxUnreachabilityInterval
REG_DWORD with a value in seconds

NOTE: The above registry key is one path; it has been wrapped for readability.

The MaxUnreachabilityInterval is the highest wait time the DOD interface will stay "Unreachable" and RRAS will not increment above this wait time.