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Page 1468 of 1536 Appendix B — Basic and Network Alternate Route Selection (BARS/NARS)
An SL-1 Node equipped with NARS can accommodate 256 (0-255) route
lists; an SL-1 node equipped with BARS can accommodate 128 (0-127) route
lists. Associated with each entry in a route list is information relevant to:
— the route number (0-511) (depending on the release)
— the minimum FRL required for access
— the time-of-day the route can be accessed
— whether or not queuing (OHQ or CBQ) is allowed on the route
— whether or not the route is to receive ERWT treatment
— a digit manipulation table index number
— a Free Calling Area Screening (FCAS) table index number
— activation/deactivation of conversion from an on-net number to an
off-net number (NARS only)
Route eligibility
BARS or NARS translates the number dialed (1-11 digits) after an access
code into a route list, and searches sequentially the routes in the list for an
available route. Route eligibility for a given call is based on the caller's
NCOS, the NCOS-defined FRL, the current time of day, and SL-1 COS.
Because each entry in a route list has a minimum FRL required for access and
all network users are assigned an FRL through their NCOS, the network
communications manager can restrict the type of calls allowed to particular
users. For example, if the minimum FRL for all calls is 1, except for special
local services numbers which are assigned an FRL of 0, then a user assigned
to an NCOS group with an FRL of 0 would only be able to make calls to the
special numbers. In addition, the communications manager can restrict the
use of high-cost facilities by assigning a high FRL to the expensive routes in
a route list and a lower FRL to a user's NCOS.
553-3011-315 Standard 10.0 May 1999