Chapter 2: About the HSIM-W6

ISDN Back-up

The ISDN back-up feature provides a back-up link for a remote site or branch office when one or more primary WAN interfaces for a frame relay circuit or a nailed-up PPP connection fails. The WPIM-S/T serves as the backup medium for this primary connection. The WPIM-S/T uses the ISDN interfaces to back-up any primary interfaces which have been configured for ISDN back-up.

Time to Connect, Time to Disconnect, Connect Retries, Back-up Override, Input Idle Time-out and Output Idle Time-out, are the six back-up parameters used to manage the ISDN Back-up feature on the HSIM-W6, and are described as follows:

Time to Connect — Time to Connect allows you to configure the amount of seconds the primary interface can be in a failed state, before attempting to switch over to the back-up interface.

Time to Disconnect — Time to Disconnect allows you to configure the amount of seconds the restored primary interface must remain connected, before attempting to switch over from the back-up interface.

Connect Retries — Connect Retries allows you to configure the number of tries to restore the back-up interface, before giving up.

Backup Override — Backup Override forces the back-up interface to remain connected, and does not allow the back-up interface to switch back to the primary interface, even if the primary interface is restored.

Input Idle Time-outInput Idle Time-out allows you to determine the amount of time necessary for data packets to be received, before the interface is automatically disconnected.

Output Idle Time-outOutput Idle Time-out allows you to determine the amount of time necessary for data packets to be transmitted, before the interface is automatically disconnected.

HSIM-W6 User’s Guide 15

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Cabletron Systems HSIM-W6 manual Isdn Back-up