Fall-Back Routing
Fall-Back Routing defines how the Gateway (in this example, Gateway
500) will send data to another path when the primary route is unavailable.
The criteria used to determine which alternate path is selected
are defined through the menus. In this example:
| |
Priority |
Server |
| |
Primary
Secondary
Tertiary |
Server One
Server Two
Server Three |
Fallback Options
The available
options for fallback include:
|
TCP
Fallback |
Failover
between two Ethernet interfaces (on same subnet) |
| Fallback
from one Ethernet to another Ethernet (different subnet)
|
| Fallback
from one Ethernet connection to a PPP connection
|
| Fallback
from one PPP connection to another PPP connection |
| |
|
Serial
Fallback |
Failover
between two Serial ports (same protocol) |
| Failover
between two Serial ports (different protocol) |
The Gateway normally uses the heartbeat (IMCP ping) facility of
TCP/IP to determine if the other device is available. If the connections
were all serial, the Gateway uses the normal protocol level polling
responses to determine availability.
When the original connection resumes, the Gateway will reestablish
the primary route. Fall-Back routing is often combined with Connection
routing to seamlessly integrate load balancing and integrity for
the data.
| 
