high order domain specific part (ATM address) (HO-DSP)

The High Order Domain Specific Part(HO- DSP) data field is a data field in ATM addresses.

Depending on the address format, the HO-DSP data field comprises ten bytes, and this is the case if the ATM addresses operate with Data Country Code( DCC) or with International Code Designator( ICD). If the address structure according to E.164 is used, the scope is reduced to four bytes.

The HO-DSP data field is part of the network part of the ATM addresses and combines the Routing Domain( RD) and the Area Identifier (AREA). The Routing Domain occupies the data fields of bytes 12 and 13, and the AREA function occupies those of bytes 10 and 11. The Domain Specific Part (DSP) contains the current routing information. The ATM Forum supports this flexible address hierarchy for the use of routing protocols.