dsx1LineIndex 1.3.6.1.2.1.10.18.6.1.1

This object is the identifier of a DS1 Inter- face on a managed device. If there is an ifEn- try that is directly associated with this and only this DS1 interface, it should have the same value as ifIndex. Otherwise, the value exceeds ifNumber, and is a unique identifier following this rule: inside interfaces (e.g., equipment side) with even numbers and outside interfaces (e.g., network side) with odd numbers.