Netopia r6100 参考指南

The Netopia R6000 Series offers dial backup functionality in the event of a line failure on its primar y WAN link. 
The firmware suppor ts backup to an external modem connected to the Auxiliar y por t or an internal V.90 modem 
via a V.90 modem WAN module or an ISDN inter face via an ISDN WAN inter face module in the second WAN slot.

R6120 models have integrated V.90 backup built in. R6131 models have integrated ISDN backup built in.

This chapter covers the following topics:

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The purpose of dial backup is to provide a recover y mechanism in the event that the primar y connection fails. A 
failure can be either line loss, for example by central site switch failure or physical cable breakage, or in the 
case of Frame Relay (with LMI) or PPP, loss of end-to-end connectivity. Detection of one of these failures causes 
the router to switch from using the primar y WAN por t to using the Auxiliar y por t to which a modem has been 
attached or to an internal asynchronous modem or ISDN WAN module if one is installed. The por t used for 
backup is determined by whether or not a second WAN module is installed in the router. If there is only one 
WAN module installed then the Auxiliar y por t is the backup por t. If an asynchronous modem or ISDN WAN 
module is installed in the second slot, then that is the backup por t.

In the event of a loss of primar y connectivity you have the option of switching back to the primar y por t 
automatically once it has recovered its connection.

The suppor ted backup por ts are the Auxiliar y por t or an asynchronous V.90 modem or ISDN WAN module in 
Switched Asynchronous mode with PPP as the data link encapsulation.