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Tech Note #22: Asynchronous Transfer Mode (ATM)  Addresses
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1998 Bionic Buffalo Corporation; All Rights Reserved.
       14 September 1998
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calling node
network (switch or
exchange)
called node
call proceeding
setup
setup
call proceeding
connect
connect
connect
acknowledge
connect
acknowledge
Setup messages, either from an end-point to the network, or from the network to an end-point,
may suggest or require VCI/VPCI values. (VPCIs are used instead of VPIs because - as
explained above - VPIs are ambiguous in the context of cross-connects.) If a setup message
requires specific values which are not available, then the call may fail to complete. The values
eventually used, when the call is successfully completed, are returned in the connect message.
Address Formats for Call Establishment
The call setup message (as specified by Q.2931) allows six address types for the calling and
called nodes, and three standard address formats. The six address types are:
 
network-specific numbers use a format defined by the specific network, and are used for
administrative purposes (such as “operator” or “information”)
 
abbreviated numbers use a format defined by the specific network, and are intended for
short forms of other address types
 
subscriber numbers are local to a specific area, PSTN, or network, and normally use one of
the three standard formats (described below)
 
national numbers include a subscriber number, along with routing information to a specific
PSTN, region, network, trunk, or other subset of a country’s networks, and normally use
one of the three standard formats
 
international numbers include the country code, and normally use one of the three standard
formats