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Figure 5.20. ATM Forum-defined private ATM address
formats.
Each address format consists of two parts: the Initial Domain Part (IDP) and the
Domain-Specific Part (DSP). The IDP consists of an Authority and Format Identifier
(AFI) and an Initial Domain Identifier (IDI). The AFI indicates the type of ATM
address format being used. The IDI will be Data Country Code (DCC), International
Code Designator (IDC), or a public E.164 address. The remainder of the address is
DSP, which consists of two parts. The first is the network address, which is indicated
by the High-Order Domain Specific Address (HO-DSA). The HO-DSA, a multipart
address that permits a structured addressing scheme within the ATM network. The
second part is the node address, which consists of the End System Identifier (ESI)
which is an endpoint specific address and a Selector address (SEL).
Address registration between endpoints and switches is facilitated through the use
of the Interim Local Management Interface (ILMI). This protocol is used to exchange
the node information on the endpoint with the network information on the ATM
switch. This information exchange is performed between the switch and all its
connected endpoints. These endpoint addresses are then exchanged between
connected switches, so they can construct address databases, which are needed to
establish SVCs between endpoints attached on different switches within the ATM
network.