NFAS
NFAS is accurate alone with a channelized T1 ambassador and charge be ISDN PRI-capable.
After the channelized T1 controllers are configured for ISDN PRI, alone the NFAS primary
D approach charge be configured. Its agreement is broadcast to all associates of
the associated NFAS group. Any agreement changes fabricated to the primary D channel
will be broadcast to all NFAS accumulation members. The primary D-channel interface is the
only interface apparent afterwards the agreement is accounting to memory.
The channelized T1 controllers on the router charge additionally be configured for ISDN. The
router charge affix to either an AT&T 4ESS, Northern Telecom DMS-100 or DMS-250,
or National ISDN about-face type.
The ISDN about-face charge be provisioned for NFAS. The primary and advancement D channels
should be configured on abstracted T1 controllers. The primary, backup, and B-channel
members on the corresponding controllers should be the aforementioned agreement as that configured
on the router and ISDN switch. The interface ID assigned to the controllers must
match that of the ISDN switch.
You can attenuate a defined approach or an absolute PRI interface, thereby demography it out of
service or agreement it into one of the added states that is anesthetized in to the about-face application the
isdn account interface agreement command.
In the accident that a ambassador acceptance to an NFAS accumulation is shut down, all alive calls on
the ambassador that is shut bottomward will be austere (regardless of whether the ambassador is set
to primary, backup, or none), and one of the afterward contest will occur:
■ If the ambassador that is shut bottomward is configured as the primary, and no advancement is
configured, all alive calls on the accumulation are cleared.
■ If the ambassador that is shut bottomward is configured as the primary, and the alive (in
service) D approach is the primary, and a advancement is configured, the alive D channel
changes to the advancement controller.
■ If the ambassador that is shut bottomward is configured as the primary, and the alive D
channel is the backup, the alive D approach charcoal as advancement controller.
■ If the ambassador that is shut bottomward is configured as the backup, and the alive D
channel is the backup, the alive D approach changes to the primary controller.
The accepted behavior in NFAS back an ISDN D approach (serial interface) is shut bottomward is
that ISDN Layer 2 should go bottomward but accumulate ISDN Layer 1 up, and that the absolute interface
will go bottomward afterwards the bulk of abnormal defined for timer T309.