HP 7102dl - ProCurve Secure Router Configuration Manual page 436

Network Monitoring
Overview
N o t e
9-8
Local network
Router
Routing Table
0.0.0.0 /0 ppp 1
10.1.0.0 /16 ppp 1 track remote
demand 1
Local network
Router
Routing Table
0.0.0.0 /0 ppp 1
10.1.0.0 /16 demand 1
Figure 9-2. Detecting a Failed Connection to a Remote Network
For more information on configuring these routes, see the Basic Management
and Configuration Guide, Chapter 11: IP Routing—Configuring Static
Routes. For more information on demand routing and ISDN, see the Basic
Management and Configuration Guide, Chapter 8: Configuring Demand
Routing for Primary ISDN Modules and the Advanced Management and
Configuration Guide, Chapter 3: Configuring Backup WAN Connections.
In addition to monitoring static routes, tracks can monitor default routes
received with a DHCP address or a negotiated IP address. For example, your
router might receive an IP address, default gateway, and other information
from your ISP. If connectivity to necessary resources fails, network monitor-
ing removes the information learned from the ISP. If you have configured an
alternate route to the remote network, that route can become active.
Even if no viable alternate route exists, network monitoring can serve a useful
function: removing the route from the table conserves valuable bandwidth by
preventing the router from forwarding traffic that will only be dropped.
ppp 1
Internet
Probe
ISDN
ppp 1
Internet
Probe
Remote network
Remote network
Failure