1041 Alternate Routing

When all the circuits in an ESP's circuit switched trunk serving arrangement 
with alternate routing capability are busy due to traffic volume the network 
will attempt to complete subsequent calls to an alternate route served
by that switch as previously specified by the ESP.

Generic Name of ONA Service
 	Product Name			BSE or CNS
==========================================================
Alternate Routing
 	AM - Alternate Routing		BSA *
	BA - Alternate Traffic Routing 	BSE
	NX - Alternate Routing		BSE
	PB - Alternate Traffic Routing	BSA *
	SWB - Alternate Traffic Routing	BSE
	USW - Alternate Traffic Routing	BSE

* For Ameritech and Pacific Bell, this is a Circuit Switched BSA Trunk Type 
feature.

FEATURE OPERATION:
Alternate routing allows different routes to overflow in different ways, even
though they share the same physical trunk or circuit set.  Alternate routing
should always be specifiable without reference to calling line or called trunk,
circuit, or line set.

TECHNOLOGICAL AND FEATURE INTERACTION CONSIDERATIONS:
1. This feature is available in the following central office switches:

Switch Type			1A ESS(TM)	5ESS(rg)	DMS-100 (rg)
Earliest Generic Release	1AE8A		5E2(2)		BCS17

ESS is a trademark and 5ESS is a registered trademark of AT&T.
DMS is a registered trademark of Northern Telecom.

2. The routing and charging function consists of interpreting the dialed digits,
   directing the connection to a trunk or circuit, directing the transmission of
   call setup data to the distant end, and determining what charge treatment to
   use.  This process uses information associated with the calling line, dialed
   digit information, and route availability data.  Existing stored program
   controlled systems translate the dialed digit combination into classes of 
   dialed digit combinations.  These classes, along with the calling line 
   associated indicator, are translated into a charge index and a primary 
   route index.  The primary route index defines the call setup data to be 
   transmitted, a set of trunks, circuits, and an alternate route index to be 
   used if the initial set of trunks or circuits are unavailable.

3. The 1A ESS machine provides for the ability to have 16 Route Indexes on
   Route Transfer Keys (16 keys).  Through the operation of these keys it is
   possible to transfer outgoing traffic from one trunk group to another trunk
   group.  It is also possible to split a particular trunk group in order to
   control the traffic offered to a specific quantity of trunks instead of
   offering all traffic to all of the trunks.  The actual transfer key may be 
   either located in the 1A ESS office or located on the ESP's premises.

4. In the 5ESS, one primary route and up to four alternate routes may be
   specified.  These routes are assigned at the establishment of initial
   service.  The alternate routes are fixed and cannot be enabled via a
   key operation.

5. The DMS-100 has several methods to provide alternate routing.  The software
   methods used are similar to the 5ESS, in that the alternate routes are
   fixed and do not have the potential to be controlled manually as in the
   1A ESS.  The type of alternate routing method to use depends on the type 
   of trunks used for this feature.  Standard trunking can have up to eight
   alternate routes.

6. In some regional companies, this service may be limited to Feature Groups B 
   and D, or Feature Group D only.

7. References:
 o LSSGR (TR-TSY-000064), Section 5.3.5.2, Issue 2, July 1987, 
   Module TR-TSY-000505.

This service, if offered as a BSE, is associated with the Circuit Switched 
Trunk basic serving arrangement.
