Data Link Layer Protocols; Determining A Backup Method - HP 7102dl - ProCurve Secure Router Configuration Manual

In addition to these three options, the ISDN BRI S/T backup supports:
Euro-ISDN—Also called Normes Européennes de Télécommunication 3
(NET3), Euro-ISDN was defined in the late 1980s by the European Com-
mission so that equipment manufactured in one country could be used
throughout Europe.
You must configure your router's BRI interface for the type of signaling your
service provider implements. Because switches can implement various types
of signaling depending on their software, the signaling type will not always be
that of the CO switch's manufacturer.

Data Link Layer Protocols

On the ProCurve Secure Router, backup ISDN connections always use PPP as
the Data Link Layer protocol, no matter what Data Link Layer protocol is used
for the primary connection. For example, if the ISDN line is used to back up
a Frame Relay connection between two offices, the ISDN uses PPP.

Determining a Backup Method

The ProCurve Secure Router initiates a backup connection in response to a
backup condition. Backup conditions include Layer 1, or Physical Layer,
failures such as:
T1 and E1 alarms
ADSL failure due to low signal-to noise ratio (SNR)
other line failures and WAN alarms
Backup conditions also include Layer 2, or Data Link Layer, failures such as:
signaling failure
loss of permanent virtual circuit (PVC)
You have two choices for configuring how the ProCurve Secure Router
responds to a backup condition:
You can configure demand routing, which is activated only if both of the
following conditions are met:
• A backup condition occurs, bringing the primary interface down.
• The router receives traffic that must be transmitted to the far-end
network.
Configuring Backup WAN Connections
Determining a Backup Method
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